Research Projects

The goal of the Veterinary Scholars Summer Research Program is to increase the number of veterinarians involved in biomedical and clinical research. Take a look at past projects to see the impact the program is having.

I liked getting to meet students from other vet schools and learning about their research.”

Veterinary Scholar Participant

2024

Ongoing and Past Research Projects

Investigating the association between preterm birth and the development of vocal folds in lamb larynges

Researcher: Gaibrielle Bressler, Purdue
Mentor: Abigail Cox

The development of laryngeal vocal folds (VFs) plays a crucial role in voice production.
Voice abnormalities in humans often stem from premature birth, yet few studies have
explored how prematurity affects laryngeal health and voice outcomes. This study aims
to characterize the preterm lamb larynx for future translational studies, specifically
pertaining to preterm infants and school-age children speech pathology. Microscopic
examination focused on 3 lamb larynges: term, preterm, and extreme preterm.
Hematoxylin and eosin (H&E) stains evaluated VF lamina propria (LP) and epithelia
width, while alcian blue (AB) stains assessed glycosaminoglycan and matrix protein
levels. All developmental stages exhibited typical connective tissue components in the
LP. In preterm and extreme preterm VFs, fibroblasts, collagen, elastin, and vessels were
evenly distributed throughout the LP, contrasting with term VFs showing greater spatial
differences, with higher fibroblast and vessel densities in superficial versus deeper LP
layers. AB staining revealed that the deeper LP layers in term VFs had more
alcianophilic glycosaminoglycans than superficial layers, whereas preterm and extreme
preterm VFs showed more uniform glycosaminoglycan distribution. These findings
indicate significant LP reorganization in fetal lamb VFs during later gestational stages.
Future studies should further investigate these developmental changes to understand
their implications for human premature birth and associated voice pathology.

Investigating serum growth differentiation factor-8 concentrations in cats with early chronic kidney disease

Researcher: Kerrigan Fleming, Purdue
Mentor: William Whitehouse

Growth differentiation factor-8 (GDF-8), also known as myostatin, is a negative regulator of muscle growth. In people, GDF-8 is increased with chronic kidney disease (CKD). The objective of this study is to evaluate if the concentrations of circulating GDF-8 in cats with early CKD are increased compared to healthy cats. Associations of GDF-8 concentrations with age, sex, body weight, body condition score (BCS), muscle condition score (MCS), creatinine, blood urea nitrogen (BUN), symmetric dimethylarginine (SDMA), phosphorus, and urine specific gravity (USG) were also examined. Serum concentrations of GDF-8 in healthy (n=10), International Renal Interest Society (IRIS) stage 1 CKD (n=5), and IRIS stage 2 CKD (n=10) cats were quantified using a commercially available multispecies sandwich Enzyme-Linked Immunosorbent Assay (GDF-8/Myostatin; DGDF80; R&D Systems, Inc., Minneapolis, MN). GDF-8 was not different amongst healthy cats (2137 ±740 pg/mL) and cats with IRIS stage 1 (1785 ±530 pg/mL) and IRIS stage 2 (1961 ±638 pg/mL; P = 0.608) CKD. GDF-8 was negatively correlated to MCS (r = -0.517, P = 0.049), but no association was found between GDF-8 and the other selected renal parameters. However, age was significantly higher in IRIS stage 2 CKD cats compared to the healthy cats (P = 0.036), and GDF-8 was negatively correlated with age (r = -0.429, P = 0.032).  In conclusion, GDF-8 could be a marker for muscle mass. Further evaluation of the functional role of GDF-8 with age and CKD in cats is warranted.


Characterization of Biomechanical Properties of Canine Sclera and Lamina Cribrosa Tissue Using Atomic Force Microscopy

Researcher: Lisa Hoard, Purdue
Mentor: Shin Ae Park

Glaucoma is a group of progressive optic neuropathies characterized by progressive degeneration of retinal ganglion cells (RGC) with no known cure. The initial insult responsible for the characteristic axonopathy is thought to occur within the lamina cribrosa (LC) region of the optic nerve head. As intraocular pressures rise, the LC is stretched and displaced, along with the other components of the corneoscleral shell, leading to narrowing of perforations containing RGC axons. While the LC is subject to variations in mechanical stimuli, it is a responsive and reactive structure. This project aims to characterize and analyze the biomechanical properties of the sclera and LC in canine eyes using atomic force microscopy (AFM). AFM uses a cantilever to scan across the surface of the sample and obtain various biomechanical measurements, such as force-displacement curves, by analyzing the deflection of the cantilever when the tip comes in contact with the sample. It is hypothesized that in advanced stages of glaucoma the sclera and LC will exhibit a significantly larger elastic modulus compared to normal control eyes. Thus, characterizing the biomechanical properties of normal canine eyes will serve as a control for future comparison with glaucomatous eyes. Overall analysis of biomechanical properties of tissues at the nanoscale from animals affected with naturally occurring glaucoma in life provides more insight into the adaptability of this fibrous shell in response to disease. This helps researchers identify new targets of intervention to manage or prevent advanced stages of glaucoma. By doing so there is potential for long-term preservation of vision in animals predisposed to glaucoma or diagnosed with early glaucoma. The aim of this study optimizes AFM methods to establish normal AFM data for the canine sclera and LC. Thus, this study establishes control data for future studies utilizing AFM to characterize and analyze biomechanical properties in canine eyes with varying types and stages of glaucoma.


MicroRNA differential expression analysis in placental tissue from cases of miscarriage in Brazil

Researcher: Kyra Holt, Purdue
Mentor: Andrea Pires dos Santos

Ureaplasma parvum is a commensal bacterium of the genitourinary tract that when in disbalance, it has been identified as a possible cause of miscarriage in women. MicroRNAs are known for regulating gene expression and their dysregulation have been associated with miscarriage as well. We hypothesized that miRNAs are differentially expressed in the placenta from women with normal delivery versus subjects who suffered an abortion, despite the presence of Ureaplasma. Placental samples from normal delivery and miscarriage cases in Northeastern Brazil previously placed into subgroups based on Ureaplasma parvum infection were submitted to DNA and RNA extraction and qPCR for microRNA differential expression analysis of miR-23a, miR-494-3p, and miR-146a-5p. This is a continuation of a project that had performed microRNA analysis of different markers. miR-23a was overexpressed in patients with normal delivery, despite the presence of Ureaplasma, when compared to patients that had a miscarriage in addition to Ureaplasma infection. MicroRNA expression differences between these groups could be used as prognostic markers for pregnancy in women.  Testing in larger cohorts and serum samples are necessary and can contribute to a better understanding of the miscarriage process.


Comparison of debridement of the canine antebrachiocarpal joint by arthrotomy and arthroscopy

Researcher: Madelynn Luebcke, Purdue
Mentor: Sarah Malek

Pancarpal arthrodesis in dogs involves surgical removal of all articular cartilage to the level of subchondral bone. Arthrotomy is the surgical approach used for cartilage debridement that can increase postoperative complication rates due to damage to adjacent soft tissues and blood supply. The objective of this study was to evaluate the feasibility and efficiency of a minimally invasive approach to antebrachiocarpal (AC) joint debridement compared to arthrotomy. Nine pairs of cadaveric canine forelimbs were randomly assigned to one of three groups of six limbs to undergo antebrachiocarpal joint debridement via arthrotomy or arthroscopy using either a rigid arthroscope or a flexible needle arthroscope. Next, the joints were opened and photographed pre- and post-staining with India ink. Percentage of debrided surface area (%DSA) on pre-stained images and completeness of debridement (%C) on post-stained images were measured. Measurements were made for the articular surfaces of the bones contributing to the AC joint (i.e., radius (R), ulna (U), radiocarpal (RC) and ulnarcarpal (UC) bones). Analysis using a linear mixed model for repeated measures found that neither %DSA nor %C significantly differed between groups (P=0.0622 and P=0.5737, respectively). However, both %DSA and %C did significantly differ amongst bone surfaces (P<0.0001). While the %DSA did not significantly differ between the R and RC, the U and UC differed from both R, RC and from each other (P<0.0001). The %C of U was significantly lower than the other three bones (P<0.001). These findings demonstrate that arthroscopic debridement of the AC joint is feasible with similar efficacy to the traditional arthrotomy technique in achieving cartilage debridement. 


Antifungal activity of antimicrobial peptide LL-37 on multidrug-resistant fungal pathogen Candida auris

Researcher: Casey Scarnati, Purdue
Mentor: Shankar Thangamani

Candida auris is a relatively recent emerging fungal pathogen.  This pathogen is notable in its multidrug resistance to common antifungal cleaners and medication including fluconazole, amphotericin B, and echinocandins as well as its ability to grow biofilm on surfaces and equipment within medical facilities.  The peptide LL-37 is a human peptide with antimicrobial activity against Gram-positive and Gram-negative bacteria.  The goal of our research was to test the antifungal properties of LL-37 on the growth of colonies of both the wild-type yeast form (0387) and filamentous form (Δalm1) of Candida auris.  Colonies of wild-type and mutated filamentous Candida auris were inoculated in YPD broth overnight.  They were then cleaned and diluted with 1x PBS until an acceptable absorbance (0.32-0.35 for 0387 and 1.6-2 for Δalm1) was found on a spectrometer reading at a wavelength of 600 nm.   The resulting final solution was combined with LL-37 at various concentrations, diluted further by a factor of ten seven times and grown via spot plating assay onto YPD agar plates.  These plates incubated for 24 hours afterward.  The colony growth following incubation of the wild-type samples was reduced with increasing concentrations of LL-37 while the filamentous Candida auris samples are expected to be unaffected.  Concentrations tested (10-200 µg/mL) showed varying levels of growth restriction with the minimum inhibitory concentration found to be near 25-50 µg/mL.  In conclusion, the antimicrobial peptide LL-37 has antifungal properties against certain forms of Candida auris.  These results show the viability of LL-37 as a potential tool for the removal of Candida auris growth within patients and on medical surfaces.


Does tunnel handling hinder identification of clinical conditions in mice?

Researcher: Jordan Toney, Purdue
Mentor: Amanda Darbyshire

Refined handling techniques such as tunnel handling and cupping, are becoming increasingly popular as they improve the animal welfare of laboratory mice. Tunnel handling has been shown to reduce anxiety in behavioral tests, increase an animal’s willingness to interact with handlers even after brief periods of restraint, and improve physiological parameters like glucose tolerance, blood glucose, and corticosterone levels. It has also been shown to reduce data variability which has the potential to reduce the number of animals needed for a particular study, aiding in the replication of experiments. There is limited research regarding how tunnel handling affects the ability of technicians to identify clinical conditions of mice during routine cage changes. The purpose of this study is to assess how different types of tunnels affect skin lesion identification during cage changes of mice. 50 C57BL6/N female mice housed 5 per cage will have an artificial skin lesion. These lesions will be created under anesthesia using hair removal (hair plucking and shaving) and sharpie markers at various locations (dorsal neck, ventral neck, front limb, inguinal region, base of tail, or none). Six technicians will be instructed to change all 10 cages using the tunnel that is provided (clear, red, or opaque) or tail handling (control). During the cage change, the technician observes each mouse in the tunnel and documents any lesions noticed. The number of correct skin lesions identified for each type of tunnel and traditional tail handling will be compared. Our hypothesis is that the clear tunnels will allow for similar lesion identification as tail handling, which will aid in implementation of refined handling techniques.


Investigating viral associations in ruminant sinonasal tumors

Researcher: Caitlin Wager, Purdue
Mentor: Viju Pillai

Enzootic nasal adenocarcinoma of sheep is a contagious neoplasm of the ethmoid turbinate mucosa caused by the betaretrovirus Enzootic Nasal Tumor Virus-1 (ENTV-1). Clinically, affected sheep present with respiratory distress, anorexia, weight loss, and unilateral mucopurulent nasal discharge secondary to the tumor in the nasal cavity. This disease poses considerable economic and animal health challenges globally, as it impacts sheep productivity and welfare. Diagnosis primarily relies on histopathological identification of the adenocarcinoma, with molecular confirmation seldom utilized. Recently, the jaagsiekte sheep retrovirus (JSRV), another betaretrovirus known to cause lung tumors in sheep, was identified in a nasal adenocarcinoma case that tested negative for ENTV-1. Given the infrequent use of molecular confirmation in enzootic nasal adenocarcinoma diagnosis and the detection of JSRV in an ENTV-1 negative case, this retrospective study aims to assess the presence of ENTV-1 or JSRV in histologically diagnosed nasal adenocarcinoma cases. DNA was extracted from archived formalin-fixed paraffin-embedded (FFPE) specimens of histologically confirmed nasal adenocarcinomas. A polymerase chain reaction (PCR) was performed using primer pairs specific to ENTV-1 or JSRV to determine the viral presence. Understanding viral etiology is crucial for accurate diagnosis, effective management, and control of the disease. This study seeks to elucidate the viral associations in nasal adenocarcinomas and enhance diagnostic protocols by incorporating molecular techniques.

Analysis of Fluid Dynamics of the Equine Upper Airway Using 3D Printed Models

Researcher: Audrey Wood, Purdue
Mentor: Michelle Tucker

This project investigates the fluid mechanics of the equine upper airway via the creation of 3D printed anatomical replicas of the trachea, larynx, and nasal passages. These models allow us to assess the performance of these structures in a state of health and provide insight into the dynamic airflow patterns within the equine airway.

The objective of this study is to create separate 3D printed models of each portion of the airway (trachea, larynx, and nasal passages) using 3D Slicer v. 5.6.2. These models will be created in such a fashion that they can be analyzed separately or fit together seamlessly to form the entirety of the airway for more specific applications. The fluid dynamics of air flowing through these structures will be evaluated using computational fluid dynamics (CFD) simulations under physiological conditions.

Results from this study may be used to inform treatment protocols for diseases of the upper airway; this is especially applicable to performance horses affected by both symptomatic and subclinical cases of laryngeal neuropathy. This study offers an approach to improving therapeutic procedures in equine respiratory health.


Can injectable antibodies give failure of passive transfer dairy calves a new lease on life?

Researcher: Emma Zaicow, Purdue
Mentor: Andrew Hubner

Bovine placentation prevents the mixing of maternal and fetal blood, leaving neonatal calves completely dependent on colostrum for immune transfer. Failure of passive transfer (FPT) is defined as a serum protein concentration of <5.5g/dL and can predispose a calf to premature morbidity, decreased production, and increased susceptibility to disease. Several management practices exist to prevent FPT in dairy calves, but our laboratory seeks to determine if an injectable antibody solution (Bovi-Sera, Colorado Serum Company; Denver, CO) can improve outcomes for calves with FPT. In an ongoing study across three locations, 408 FPT Holstein calves were randomly assigned to receive 60mL of Bovi-Sera administered subcutaneously at enrollment, which occurred within 7 days of life, or to remain as untreated controls. Prior to treatment and 1-week post-enrollment, serum samples were collected then plated on IgG radial immunodiffusion plates. The diameter of immunodiffusion was measured after 24 hours of incubation at room temperature and converted to mg/dL of IgG. compared between treated and untreated FPT calves. For calves with enrollment IgG concentrations less than 1200 mg/dL, treatment tended to increase circulating IgG one week after enrollment (Control: 841 mg/dL, Treatment: 922 mg/dL; P = 0.09) and significantly decreased farm-diagnosed cases of diarrhea (Control: 32.0%, Treatment: 8.7%; P = 0.04). However, for calves with IgG less than 1200 mg/dL, treatment did not affect average daily gain through 21 days of life (Control: 0.29 kg/day, Treatment: 0.31 kg/day; P = 0.65). Though not labeled specifically for the treatment of FPT, these findings suggest that Bovi-Sera may prevent neonatal diarrhea in Holstein calves.

bTBI-on-a-Chip: Synaptic Loss Following Blast Induced Traumatic Brain Injury or Biochemical Injury in Vitro

Researcher: Maddison Claybrooke, Franklin College
Mentor: Riyi Shi

Annually, up to 74 million people worldwide suffer traumatic brain injuries (TBIs), many of which go untreated. In particular, TBIs sustained as the result of a pressure wave due to an explosive, called blast TBIs (bTBI), are less likely to be adequately treated due to the initial injury often being mild and difficult to diagnose. TBI is classified into primary and secondary injury. Primary injury is the initial injury resulting from tissue damage and is irreversible, while secondary injury is damage due to the immediately ensuing biochemical cascades that spread from the primary injury. These biochemical cascades include inflammation and enhanced presence of reactive species, such as acrolein, which, if left untreated, can persist for years after the TBI is sustained and damage uninjured cells. These spreading biochemical injuries to the brain can result in an increased chance in developing conditions like epilepsy, neurodegeneration, and psychological disorders. One possible factor linking TBI and long-term pathologies is synaptic loss due to damaged neurons and axons. Synapse loss has already been linked to neurodegeneration, but the mechanisms relating synaptic loss, TBI, and secondary injury pathology remain unclear. While animal models have been helpful in understanding the pathological effects of both primary and secondary injury, the cellular and subcellular mechanism underlying the findings in animal studies remain unclear due to the high number of cofounding variables in animal models. To fill this gap in current knowledge, we developed a platform to deliver clinically relevant blast injuries to primary murine cortical networks in vitro, called bTBI-on-a-Chip, which allows direct study of the cellular and subcellular changes that arise from injury. Using this system, we delivered two types of injury to cultures and studied the resulting changes in synapse density. First, primary blast injuries were delivered to neuronal networks. Second, given that acrolein is a key component of secondary injury, we added a clinically relevant concentration of acrolein to uninjured cultures in order to determine if acrolein alone could cause similar synaptic loss as primary and secondary injury. After each type of treatment, we measured the change in number of synaptic terminals 24 hours post treatment using fluorescent imaging. There were significantly fewer pre and post synaptic terminals on each neuron after both bTBI and acrolein treatment. Together, these findings demonstrate that acrolein alone can cause synapse loss and could therefore be crucial in synaptic changes in secondary injury. Furthermore, our results confirm that even mild blast injury disrupts synaptic numbers in single cells. These findings may help elucidate the relationship between injury, synapse loss, neuron rewiring, and brain pathologies.


Identification of a Novel Candidate Variant in CLPX for Spinocerebellar Ataxia in a Mixed Breed Dog

Researcher: Justin Kim, Vanderbilt
Mentor: Kari Ekenstedt

Spinocerebellar ataxia (SCA) is a progressive neurodegenerative disorder primarily affecting the cerebellum, resulting in the loss of motor control and voluntary muscle coordination. While prevalent in Jack and Parson Russell Terriers due to autosomal recessive mutations in electrolyte channel coding genes such as CAPN1, KCNJ10, SCN8A, SLC12A6, and SPTBN2, an atypical case of SCA was recently documented in a mixed breed dog. Health records and necropsy findings identified paraparesis, SCA, anemia, and retinal degeneration in this individual. Because SCA is an inherited condition, whole-genome sequence (WGS) was generated for the affected dog.  The known canine mutations above were not present in the mixed-breed dog’s genome. Principal Component Analysis of genomic data was utilized to confirm the breed identity. The dog’s WGS was then screened for private variants compared to >700 unaffected dogs.  This revealed a homozygous 4-base-pair frameshift mutation in CLPX, a gene that encodes for caseinolytic mitochondrial matrix peptidase chaperone subunit X involved in mitochondrial protein degradation, as a novel candidate gene for SCA in any species. In-silico tools predict a frameshift and a premature stop codon within 591 amino acids, truncating 6.64% of the protein. Our study is the first to explore the association of a CLPX mutation with SCA. This connection is potentially significant for human health due to the high evolutionary conservation of CLPX across species.

 

 


Investigating suspected mosquitos for the presence of Cache Valley Virus in Indiana

Researcher: Rubyleane Linton, Prairie View A & M
Mentor: Rebecca Wilkes

Cache Valley Virus (CVV) is a rare but dangerous orthobunyavirus that causes abortions and
congenital disabilities in small ruminants, such as goats and sheep. The virus is zoonotic, having
implications for human health as well. Mosquitoes are considered the primary vector of CVV. It
is an emerging pathogen in the U.S and recent serologic testing of aborted small ruminants
suggests this virus is present in Indiana.
This study aimed to identify CVV in Indiana by testing mammal-biting mosquito species
collected from different parts of the state. A previously published real-time reverse transcriptase
PCR was verified for use in the lab and utilized to detect target sequences of CVV within nucleic
acids extracted from mosquito pools collected in 2023-2024. The mosquito species that were
analyzed include Aedes albopictus, Aedes canadensis, Aedes j.japonicus, Aedes vexans,
Anopheles punctipennis, Anopheles quadrimaculatus, Coquillettidia perturbans, and Culex
pipiens (mixed).
While the study is ongoing, no CVV was detected in the 165/648 pools of mosquitoes tested so
far. Detection of positive pools would confirm the presence of CVV in the state. Additionally,
testing various species of mosquitoes from different parts of the state would provide information
regarding the location of the virus and the species of mosquitoes responsible. Traps that collect
these mosquitoes mimic preferred hosts and environments to attract particular species. Infected
mosquito species knowledge is essential in determining which traps will be the most effective in
Indiana to increase the possibility of detecting this virus in the mosquito vector.

Microglia replacement therapy in Alzheimer’s mouse models using microglia CRISPR modified to produce lecanemab

Researcher: Connor Meek, Purdue
Mentor: Ranjie Xu

Alzheimer's disease (AD) is the most common cause of dementia, affecting 55 million individuals globally, with limited treatments. Microglia replacement therapy (MRT) is an emerging option for treating neurological disorders by replacing diseased microglia with healthy ones. Another avenue of Alzheimer’s research is exploring the use of newly FDA-approved antibody-based immunotherapies such as lecanemab. These antibody-based immunotherapies target amyloid beta, a major pathological hallmark of AD, and show slowing in cognitive decline. The major issues with this method are limited efficacy, low BBB permeability, and side effects like amyloid-related imaging abnormalities (edema and brain hemorrhages, called ARIA). This study aims to combine these two techniques by using CRISPR to modify human microglia to produce the lecanemab antibody and deliver these engineered microglia to replace the AD microglia. We hypothesize that this could help the healthy replacement microglia to more effectively clear amyloid beta plaques and could stop the more dangerous side effects, such as ARIA. The first aim of the experiment is to determine if CRISPR-edited human induced pluripotent stem cells (hiPSC), and hiPSC-derived microglia express the lecanemab-producing gene. The second aim is to determine if the microglia were successfully transplanted and are effectively able to remove amyloid beta plaques. This experiment is a novel use of genetically modified microglia to combat Alzheimer's pathologies such as with newly FDA-approved antibodies. This could be a possible option for the delivery of other antibodies into the brain as well and should be studied further.

 


Identification of mast cells within the tumor immune microenvironment of canine urothelial carcinoma

Researcher: Ally Schimpf, Purdue
Mentor: Meaghan Broman

There are over 80,000 reported cases of human urothelial carcinoma (UC) each year within the United States which contributes to about 17,000 deaths. Human UC research has shown that the tumor immune microenvironment can contain a variable number of mast cells whose presence may be a prognostic indicator for the response to treatment. Certain breeds of dogs such as Scottish and West Highland White terriers have a high incidence of UC which share many histological, morphological and treatment response similarities with human UC. However, little is known about the number and role of mast cells in canine UC. The goal of this project is to classify mast cell involvement within the tumor immune microenvironment of canine UC while determining mast cell association with prognosis for possible subsequent immunotherapy studies. Canine UC samples obtained from patients of the Purdue University Veterinary Hospital were evaluated by histology and immunohistochemistry. Visiopharm AI assisted technology was utilized for mast cell count, location, and structural distances. The recruitment of mast cells into the tumor microenvironment is governed in part by chemokines secreted by tumor cells. Five different canine UC cell lines were propagated in vitro and evaluated by PCR for chemokine expression. This project will establish foundational data validating the use of canine cancer patients as an invaluable model for human cancer immunological research leading to future immunotherapy studies benefiting both people and veterinary patients. 

 

Characterization of Maternal Care in Dogs in a Small-Scale Breeding Facility

Researcher: Kyle Barron, Purdue University
Mentor: Candace Croney

Kyle Barron1, Aynsley Romaniuk2, Shanis Barnard3, Candace Croney4

1 Purdue University College of Veterinary Medicine; 2 Departments of Comparative Pathobiology and Animal Science, Purdue University; 3 Center for Animal Welfare Science, Purdue University 

The postnatal period of mammals is essential for the emergence of social behaviors and responses to stress. Maternal care (e.g., contact with offspring, nursing styles) during this period plays a crucial role in the behavioral development of offspring later in life. Studies conducted on rodents, for example, demonstrated that maternal care has lasting effects on the physiology of their offspring throughout life as it can modulate the activation of the hypothalamic-pituitary-adrenal axis, which is involved in the stress responses of animals. Maternal care in dogs remains understudied with current literature showing conflicting results. A study conducted in a working dog population indicated that high levels of maternal care (e.g., increased contact with offspring, increased time spent in the whelping box, and nursing) are associated with lower levels of stress and anxiety in offspring as adults. Conversely, a study conducted in a guide dog population showed a positive association between high levels of maternal care and stress and anxiety in offspring later in life. This discrepancy could be due to the differences in populations as a result of factors such as genetic selection. It is crucial to better understand maternal care in different dog populations. In this study, we conducted behavioral observations of 2 dams and their litters from a small-scale commercial dog breeding facility during the first 3 weeks post-parturition. Characterization of maternal care in dams in diverse breeding populations will inform future investigations of the relationship between maternal care and stress in puppies, which in turn, may help support best management practices and standards of care for improved welfare. 

Research Grant: Dr Candace Croney Discretionary Funds

Student support: Purdue University College of Veterinary Medicine

 


 


Immunocontraception: Zona Pellucida Antigens with AS03-like Adjuvant Decreased Fertility in Mice

Researcher: Lea Gamez Jimenez, Purdue University
Mentor: Harm HogenEsch

Lea Gamez Jimeneza, Ahmed AbdelKhaleka, Harm HogenEscha, b

a Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN

b Purdue Institute of Inflammation, Immunology, and Infectious Diseases, Purdue University, West Lafayette, IN 

Wildlife overpopulation has detrimental consequences for the sustainability of ecosystems.  Contraceptive vaccination using native porcine zona pellucida (nPZP) proteins isolated from ovaries is among the most humane, safe, and least disruptive options to mitigate this. However, improvements in the longevity, safety, and preparation efficiency of current vaccines are needed. This study compared the humoral response and fertility outcomes in female mice immunized with different vaccine formulations. Antigens included nPZP, recombinant PZP2 and PZP3 and recombinant equine IZUMO1 derived from Chinese hamster ovary (CHO) cells, and PZP3 derived from GnTI deleted HEK293 cells. Antigens were formulated with an AS03-like emulsion adjuvant, AddaS03, or with a combination adjuvant comprised of a plant-derived nanoparticle, Nano-11, and a stimulator of interferon genes (STING) agonist, ADU-S100. Serum antibody responses to nPZP and IZUMO1 were determined by ELISA. The IgG, IgG1 and IgG2b levels were significantly increased after the third dose with the highest titer seen in mice immunized with nPZP with AddaS03. Although least abundant, IgG2a levels were highest in Nano-11/ADU-S100 groups, indicating a more balanced Th1/Th2 response. Fertility was assessed by fetal count, and only the nPZP with AddaS03 group had a significant decrease in fertility. To conclude, the nPZP with AddaS03 formulation appears to be a promising alternative contraceptive vaccine, although trials with wildlife species are necessary for further formulation refinement.

Research Grant: The Humane Society of the United States

Student support: Purdue University College of Veterinary Medicine and Boehringer Ingelheim Animal Health

Field of Research: Immunology


Optical Coherence Tomography of Optic Nerve Head in Dogs with Open Angle Glaucoma: Correlation with Axon Counts

Researcher: Lisa Hoard, Purdue University
Mentor: Shinae Park

Lisa Hoard1, Shin Ae Park1, Christine D. Harman2, Kelly A. Leary2, Vanessa A Raphtis2, Kate Jongnarangsin2, András M. Komáromy2

1Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA

2Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA

The gold standard for determining disease progression of glaucoma in research settings involves optic nerve axon counting, which is performed ex vivo. With the advancement of noninvasive imaging techniques, it is possible to image details of the retina and optic nerve head (ONH) in vivo. This study sought to determine the relationship between the number of axons at the ONH and various parameters using optical coherence tomography (OCT) and confocal scanning laser ophthalmoscopy (cSLO) in dogs with various stages of primary open angle glaucoma. Beagles (n=6 eyes) with open angle glaucoma and age matched non-glaucoma dogs (n=2 eyes) were included in the study. OCT and cSLO images were taken of each eye, capturing the ONH, and a built-in software was used to measure neuroretinal rim area, ONH area and diameter, and optic cup diameter. Total retinal thickness, ganglion cell complex (GCC), and outer retinal thickness were also measured. Slides with the ONH samples were scanned and axons were manually counted using Image J software. A strong positive correlation existed when comparing the following parameters to the number of axons: neuroretinal rim area (r=0.91, p<0.01), ONH area (r=0.73, p<0.04), total retinal thickness (r=0.75, p=0.02), and GCC (r=0.82, p<0.01).There was a strong negative correlation (r=-0.75, p=0.03) between the number of axons and optic cup area and a moderate negative correlation (r=-0.70, p=0.12) between number of axons and age. The strong positive and negative correlations between the number of optic nerve axons and the various parameters measured support the utility of OCT and cSLO as useful noninvasive imaging techniques to assess the progression of glaucoma in vivo in dogs with open angle glaucoma.  

Research Grant: ACVO Vision for Animals Foundation Resident Research Fund, NIH R01-EY025752, and NIH K08EY030950

Student Support: Purdue University College of Veterinary Medicine and Boehringer Ingelheim Animal Health

 


Does Host Stress Influence Virulence of Clostridioides Difficile?

Researcher: Sarah Kelley, Purdue University
Mentor: Deepti Pillai

Sarah Kelley1, M. Carlson2 , A. Hassan2, D Pillai2,3

1 College of Veterinary Medicine, Purdue University, West Lafayette IN, 47907, USA

2Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, 47907, USA

3Animal Disease Diagnostic Laboratory, Purdue University, West Lafayette IN, 47907, USA

Clostridioides difficile, a Gram-positive, spore-forming, anaerobic bacterium, is an opportunistic pathogen that causes severe colitis and death in humans and animals. Antibiotic treatment-induced disturbances in the gut microbiota frequently exacerbate infections caused by this bacterium. There is substantial evidence in the literature demonstrating that host stress can lead to changes in the gut microbiota. The gut is the epicenter of hormonal exuberance during stress. Stress modifies the gut physiology while modulating the gut microbiome. Previous studies have shown that norepinephrine, an abundant hormone in the gut experiencing stress, significantly affects the growth and virulence of many Gram positive and Gram negative bacteria. This research project aims to investigate the extent to which norepinephrine influences the virulence of C. difficile. The RNA seq and RT-PCR were performed to study the changes in expression and abundance on virulence genes of C. difficile. The effect of increasing concentrations of norepinephrine on the growth and virulence of C. difficile was evaluated. Our findings provide valuable insights that can inform treatment modalities and guide patient management decision-making processes. Results from this study could help us develop a treatment strategy that could include adrenergic blockers in treating C. difficile colitis.

Research Grant- PVM funds

Student support- Purdue University College of Veterinary Medicine and Boehringer Ingelheim Animal Health


Using Filters in the Sump for Monitoring Health of Laboratory Zebrafish

Researcher: Frank Leitgeb, Purdue University
Mentor: Amanda Darbyshire

Frank Leitgeb, Aidan Horvath, Mollie Madigan, Iris Bolton, Amanda Darbyshire

Purdue University Laboratory Animal Program, West Lafayette, IN

Early detection of pathogens is imperative for the health of laboratory zebrafish and to ensure reproducible scientific results. While most pathogens are present as subclinical or chronic infections, their presence can be a confounding factor in data collection, and some infections can affect zebrafish health and reproduction. Current methods to test for pathogens sample a myriad of sources, including cage swabs, detritus, water collection or filtration, and whole sentinel fish PCR or histopathology. Sentinel mice have been used in the past for mouse health monitoring, but there has been a recent shift to replace sentinel animals with filters in rack exhausts. We wished to see if such methods could be translated from mouse racks to zebrafish systems. We placed filters in the sumps of zebrafish racks to be collected and tested for pathogens at monthly intervals using PCR, and results will be compared to those detected on filters in which water was actively vacuum pumped through, swabs of sump biofilm, and whole fish PCR. We hypothesize that the filters present in the sumps will detect more pathogens than the other methods and may detect more pathogens over time. Should the evidence support the hypothesis, the use of filters could eventually replace the need for sentinel fish for health monitoring purposes of laboratory zebrafish.

Student Support: Purdue University College of Veterinary Medicine and Boehringer Ingelheim Animal Health


Analyzing Mouse Preferences in Environmental Enrichment using Behavioral and Physiological Parameters

Researcher: Mollie Madigan, Purdue University
Mentor: Debra Hickman

It is well-known that animals in laboratory facilities require environmental enrichment to allow them to display their natural behaviors. Examples of environmental enrichment include, but are not limited to, toys, nesting materials, gnawing materials, food and treats, and additional shelters. However, when given enrichment, it is unknown whether mice actually benefit from a specific enrichment, or if they have a preference as to the specific type of enrichment they receive. To see whether mice do indeed have a preference in their enrichment, several types of commercially available enrichment were placed in cages with singly housed C57BL/6 mice. After a few days of acclimation, acute behavioral trials and physiological analyses were conducted to see how the mice reacted to their enrichment. Later, chronic behavioral trials and physiological analyses were conducted to measure long-term effects of whether the provided environmental enrichment benefited the mice. Using the results from the behavioral trials and blood samples, we will observe the behavioral markers of evident stress along with analyzing the white blood cell counts for evidence of stress. This will allow visualization of any benefits from certain types of enrichment, allowing researchers to purchase that enrichment over others in the future.

 


Antigenic Evaluation and Proteomic Profiling of Excretory-Secretory Proteins of Sarcocystis Neurona

Researcher: Sharon Meoli, Purdue University
Mentor: Sriveny Dangoudoubiyam

Sharon Meoli, Annapoorani Jegatheesan, Vishnu Manikantan, Uma Aryal, Sriveny Dangoudoubiyam

Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN (Meoli, Jegatheesan, Manikantan, Dangoudoubiyam); Purdue Proteomics Facility, Purdue University, West Lafayette, IN (Aryal)

Equine protozoal myeloencephalitis (EPM) is a rare, but economically devastating, degenerative neurological disease caused by Sarcocystis neurona, an intracellular protozoan. Despite high seroprevalence of S. neurona, very few horses develop EPM or present with broad neurological signs of weakness, ataxia, and neurogenic muscle atrophy. Akin to sister genera, S. neurona relies on discharge of excretory-secretory proteins (ESPs) from its apical organelles to invade the host cell and survive intracellularly. Investigation into S. neurona ESPs may reveal important virulence factors associated with EPM progression. Therefore, the aim of this study was to evaluate the antigenicity and generate a proteomic profile of S. neurona ESPs for future studies and development of additional diagnostic tests. Cell-culture derived live S. neurona underwent induced secretion and the ESPs were collected for analysis. Sera and cerebrospinal fluid from five horses of known EPM status were tested for antibodies to S. neurona ESPs by Western blot. Reactivity at two distinct molecular weight ranges was observed and amino acid sequencing is needed to establish the identity of these unknown proteins. Bottom-up proteomics of in-gel digested ESPs was performed via Mass Spectrometry and 92 S. neurona proteins were identified. 21 proteins were found to be from secretory organelles, 22 from other cellular locations, and the remaining are unstudied with unknown localization. Further optimization of sample preparation and data analysis is required for deeper characterization. Overall, this study has provided a glimpse into S. neurona ESPs and establishes a foundation for their use in future research aimed at developing new diagnostic tools for EPM.

Research Grant: Departmental Start-up Grant, Purdue University

Student Support: Purdue University College of Veterinary Medicine, Boehringer Ingelheim Animal Health

 


Method Development to Cast the Vasculature of the Rat Larynx

Researcher: Tara Paarlberg, Purdue University
Mentor: Abigail Cox

Tara Paarlberg and Abigail Cox
Purdue University College of Veterinary Medicine
NIH/NIDCD R01 DC020179

Understanding the vascular anatomy of commonly used laboratory animals is necessary to improve research outcomes of studies focusing on image analysis (e.g. magnetic resonance angiography) and surgical approaches of comparative models. The rat is a popular model to use in experimental studies. However, due to the small size of the rat it can be difficult to visualize some of the anatomical details we wish to study. Attempts to perfuse the vascular system of the rat often omit the smallest of vessels. This method development study aims to determine the best procedure to generate casting of the rat laryngeal vascular system. Various combinations of saline, latex, and formalin were used for casting of the vascular system. Perfusion was attempted with both a perfusion pump and the rat heart pumping. Freeze thaw specimens fixed with formalin and latex produced the best cast, with the superior thyroid artery visible. Rats that were formalin fixed and then casted with latex produced the best perfusion results. In the future, a dehydration study is planned that will study how dehydration changes the effect of estrogen on ultrasonic vocalizations, blood vessel geometry, and the vocal fold tissue of the rat larynx. These casting method results will be used as a model for that dehydration study.

Non-Invasive Measurement of Skin Sympathetic Nerve Activity in Dogs with Naturally Acquired Arrhythmias

Researcher: Charlotte Peterkin, Purdue University
Mentor: LuÍ Dos Santos

It has been shown that changes in sympathetic innervation to the heart is correlated
with arrhythmogenesis, as it can lead to heterogeneous changes in cardiac electrophysiology.
The cervicothoracic (stellate) ganglia are one of the final common pathways for extrinsic cardiac
sympathetic fibers, and thus changes in its activity have been linked with arrhythmia
development. Traditionally, stellate ganglia nerve activity (SGNA) has been measured invasively
by surgically implanting electrodes directly into the ganglia or the subcutaneous space above
them. More recently, studies have shown that sympathetic nerve activity can be measured on
the skin’s surface, and that this method is accurate in estimating SGNA. Currently, the canine
research models have relied on artificially induced arrhythmia. However, this method does not
capture the change in nerve activity that occurs during progressive heart disease. The present
study examined skin sympathetic nerve activity in dogs with naturally occurring arrhythmias via
a non-invasive recording technique. We did so by placing conventional ECG electrodes over the
approximate area of the stellate ganglion, on either side of the body. Simultaneously, we
recorded traditional ECG activity using standard clips and procedures. Ganglion activity in dogs
with good cardiac health was also obtained to evaluate sympathetic tone in diseased versus
healthy patients. Examining sympathetic activity in dogs with naturally occurring cardiac diseasecan provide more clinically applicable insight. By understanding how the sympathetic nervous system affects cardiac electrophysiology, there may be opportunities to design more efficacioustreatment for malignant arrhythmias in the future.

Student Support: Purdue College of Veterinary Medicine, Boehringer Ingelheim

The Effect of Femur Angle During Computed Tomography Scan on Three-Dimensional Model Compliance

Researcher: Zachary Sayre, Purdue University
Mentor: Sun Young Kim

Three-dimensional (3D) modeling using computed tomography (CT) scans is becoming increasingly popular in veterinary medicine. CT scans create a series of images that can be used to generate 3D models. Error during 3D modeling has been reported. In human medicine, femurs are positioned perpendicular to the CT scan, but anatomical differences in veterinary medicine do not allow for this positioning. Standard procedures for CT scans used in the generation of 3D models have not yet been developed in veterinary medicine. The goal of this research is to examine the effect of femur angle during CT scan on 3D modeling. Soft tissue was dissected from three pairs of femurs from beagles. All six femurs were placed on a custom jig in a CT scanner and one scan was obtained at each 0, 20, 40, 60, and 80 degrees relative to the table. From these scans, 3D models were generated using open-source 3D modeling software. This yielded five models of each femur, one at each listed angle. Surface area and volume of each segmentation were calculated. The five models of each femur were overlayed and an iterative process was used to minimize error. Hausdorff distances were calculated and heat maps generated comparing models from each angle to the model from the 0 degree angle scan. Repeated measures ANOVA will be run to analyze the effect of femur angle during CT on surface area, volume, and maximum and mean Hausdorff distances. We expect a decrease in surface area and volume and an increase in maximum and mean Hausdorff distances as femur angle increases. We expect errors in the model to be localized to the proximal and distal ends of the femur where bone geometry is more complex.

Research Support: Purdue University, College of Veterinary Medicine

Student Support: Purdue University, College of Veterinary Medicine and Boehringer Ingelheim Animal Health

 


Growth Characteristics of a DDX5 Knockout Liver Cancer Cell Line

Researcher: Dawn Burch, Purdue University
Mentor: Ourania Andrisani

Dawn Burch, Zhili Li, and Ourania Andrisani

Department of Basic Medical Sciences, Purdue Institue for Cancer Research, Purdue University, West Lafayette, IN

The enzyme DDX5 regulates every aspect of RNA metabolism and is part of a protein family known as DEAD-box RNA helicase. RNA helicases hydrolyze ATP and use the energy from ATP hydrolysis to bind and remodel RNA. In earlier studies, the Andrisani lab discovered that the expression level of DDX5 correlates with the prognosis of liver cancer patients as patients with lower levels of DDX5 had a poorer prognosis. However, it is not yet understood why low expression of DDX5 contributes to a poor prognosis, leading to the question, “What happens to the liver cell/hepatocyte if DDX5 is no longer expressed?” A gene editing technique (CRISPR/CAS9) was used to eliminate the two genes coding for DDX5, ultimately knocking out the expression of DDX5 from the liver cell. In this study, the goal was to assess the effect of knockout DDX5 (DDX5KO) on the growth characteristics of a human liver cancer cell line (Huh7) compared to wild-type (WT) Huh7 cells. We hypothesized that since DDX5 regulates the mRNA metabolism elimination DDX5 will change the growth characteristic of the WT Huh7 cell line. This study was conducted by comparing the growth of the WT and DDX5KO Huh7 cells in 12-well plates over a four-day period. The results demonstrate that WT Huh7 cells grew faster than the DDX5KO Huh7 cells at higher densities. Further research is needed to better understand the role of DDX5 in liver cancer.

Research Grant: This research was supported by NIH grant DK044533

Student Support: The College of Veterinary Medicine

Canine Necropsy Cases with Unexplained Hemorrhaging: Investigation of Von Willebrand Disease Type 1 Variant

Researcher: Rebecca Chenoweth, Adrian College
Mentor: Kari Ekenstedt

R Chenoweth, G Burcham, S Hooser, K Ekenstedt

Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA (Chenoweth, Ekenstedt), Animal Disease Diagnostic Laboratory, Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA (Burcham, Hooser)

Canine necropsy cases with unexplained hemorrhage typically trigger anticoagulant toxicity testing in diagnostic laboratories. However, when these toxicity tests are negative, the bleeding etiology is not usually further pursued. DNA was previously extracted from banked tissues of canine necropsy cases with unexplained bleeding and negative anticoagulant tests (n = 62) or positive anticoagulant tests (auxiliary controls, n = 5). These dogs were genotyped for a Factor VII variant known to cause variable bleeding phenotypes in many breeds of dogs; all results were negative. As a next step, the present study investigated the known von Willebrand disease type I (vWDI) variant (c.7437G>A) in the same population. The mode of inheritance for vWDI is autosomal with incomplete penetrance, although the expressivity on different breed backgrounds is variable. To identify the vWDI variant, the DNA extractions were run through PCR and then submitted for Sanger sequencing. Four heterozygous (vWDWvWDI) dogs were identified in the sample population. Each of the identified carriers is from a breed known to possess the vWDI variant in its gene pool (German Shepherd, American Staffordshire Terrier, and Miniature Australian Shepherd) except for the Newfoundland. Our results provide a likely explanation for the bleeding phenotype observed in these four cases, however, the lack of von Willebrand’s factor plasma quantification means this conclusion has some uncertainty. Incorporation of routine vWDI genotyping for such cases in the future may be reasonable depending on the dog’s breed, although the likelihood of successful diagnostic resolution is moderate, given the rarity observed in our sample population.

Research Grant: None

Student Support: Purdue University College of Veterinary Medicine Veterinary Scholars Summer Research Program

Diagnosis of Plant Poisonings Using PCR

Researcher: Paola Diaz, St. Olaf College
Mentor: Steve Hooser

Paola G. Diaz1, Rebecca P. Wilkes2,3, Keith Woeste4, Angela Chan2, Hilary Richards2, Farren Osborn2,Stephen Hooser2,3 

1St. Olaf College, Northfield, MN, 2Indiana Animal Disease Diagnostic Laboratory, W. Lafayette, IN, 3Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, W. Lafayette, IN, 4Forestry and Natural Resources, Hardwood Tree Improvement and Regeneration Center, Purdue University, W. Lafayette, IN

Many plants can cause poisoning or death of animals following ingestion. Currently identification of the plant is performed by visually identifying plant material in stomach/rumen contents. In instances where poisonous plant parts cannot be identified, another method is needed to identify the causative plant. The goal of this study was to develop a polymerase chain reaction (PCR) based test to identify Taxus (yew) DNA in stomach/rumen contents. Taxus and non-Taxus samples were collected around the Purdue campus. DNA from each plant was extracted utilizing Qiagen’s DNeasy Plant Pro Kit. PCR primers were designed to amplify DNA from Taxus. Sensitivity was determined by extracting decreasing concentrations of Taxus, or by decreasing the amount of Taxus extracted from spiked stomach/rumen contents. Specificity was evaluated using non-Taxus plant species, non-spiked stomach/rumen contents, or nuclease free water. Cycle threshold (Ct) values were positive for samples containing Taxus DNA. However, samples from other trees were also positive. DNA from poison hemlock, an herbaceous plant, and nuclease-free water were negative. Conventional PCR and sequencing of amplicons from each plant correctly identified that plant, including those from Taxus in rumen/stomach contents. This study indicates that PCR with sequencing can be utilized as a specific and sensitive test to identify Taxus and potentially other poisonous plants in stomach/rumen contents.

Research Grant - Purdue University research account funded by the Total Wagers Tax.

Student Support - Purdue University College of Veterinary Medicine

 


Evaluation of the Anti-proliferative Effects of Indenoisoquinoline Dual MYC and Topoisomerase I Inhibitors in Canine Osteosarcoma Cell Lines Three

Researcher: Camila Gutierrez, University of Virginia
Mentor: Deborah Knapp

Three cytotoxic topoisomerase 1 (TOP1)-inhibiting indenoisoquinolines, I400 (indotecan), I776 (indimitecan), and I744, have demonstrated anticancer activity in preclinical and clinical trials. These drugs have recently been found to strongly bind to the MYC promoter G-quadruplex and potently downregulate the expression of MYC. MYC is a crucial oncogene overexpressed in most cancers; the G-quadruplex secondary structures in the promoter region acts as a transcriptional silencer. Osteosarcoma (OS) is a rare, aggressive primary bone cancer with a low survival rate of approximately 60% due to cancer metastasis. Though no new effective therapies for this cancer have emerged over 40 years, the overexpression of MYC is common in OS and may be a therapeutic target in this cancer. Naturally-occurring OS in pet dogs is a relevant animal model for the human disease, and is also characterized by MYC overexpression. We hypothesized that MYC-inhibitory indenoisoquinoline analogs would have antiproliferative effects on canine osteosarcoma cell lines. This study aimed to provide proof-of-concept for the efficacy of indenoisoquinoline drugs in canine OS. Two osteosarcoma cell lines, D-17 and OSCA-8, were treated with three indenoisoquinolines to calculate the percent growth inhibition. Cell-based cytotoxicity screening with sulforhodamine B colorimetric assays was used as a measurement of cellular protein content to identify the IC50 of each drug in the concentration range of 2 to 2000 nM. The results are expected to contribute to the design of follow-up studies in canine comparative oncology models with the goal of supporting further research on MYC-targeting agents in both canine and human OS.

Domestic Canine Vector-Borne Pathogens and their Presence in Remote Populations

Researcher: Matthew Johnson, Purdue University
Mentor: Rebecca Wilkes

Vector-borne pathogens (VBPs) transmit from one host to another via a vector intermediate, many of which are zoonotic. Common zoonotic VBPs include Borrelia burgdorferi and Rickettsia rickettsii. However, across different countries, the known circulating zoonotic VBPs are limited, especially within secluded regions of the world or remote populations of people. The purpose of this study was to identify whether certain VBPs found within domestic dogs were also found within their human companions. Fifty-eight human samples (nucleic acid extracted from whole-blood) obtained from remote South American populations were tested with targeted NGS using the Ion GeneStudio S5 System to detect vector-borne pathogens found in dogs. The resulting sequences from samples were mapped to a reference file using SPAdes in the Torrent Suite Software. Aligned BAM files were opened in Geneious software to evaluate the specific pathogens from the raw sequencing data. Sequences with ≥ 100 nucleotides were subjected to BLAST search in National Institute of Health's BLAST program to confirm the sequence similarity to the target pathogens. One of the 58 human samples tested positive for  Leishmania sp., which had previously been detected in these dog populations. Infected dogs are considered to be the primary reservoir for zoonotic visceral leishmaniasis and the most significant risk factor for predisposing humans to infection. This parasite tends to be sequestered in the spleen, bone marrow, or lymph nodes, which complicates use of whole blood for detection of the organism. Splenic or bone marrow aspirates are commonly used to diagnose visceral leishmaniasis. Thus, it is likely there are more positive individuals in these populations than we detected. This necessitates continued surveillance and potential use of additional sample types or the addition of serologic testing for detection of vector-borne pathogens in these populations.


Antifungal activity of Human B-Defensin-2 Against Candida Auris

Researcher: Brooke Tharp, Purdue University
Mentor: Shankar Thangamani

Candida auris is an emerging multi-drug resistant fungal pathogen that can give rise to life-threatening, invasive infections in humans. To date, C. auris remains resistant to the majority of FDA approved antifungal medications-many of which have the potential to cause cytotoxic effects to the patient. As such, there is a tremendous need for a safe, novel therapeutic treatment option against this devastating fungus. Unlike the majority of other Candida species, C. auris predominantly colonizes the skin and causes systemic bloodstream infections. Therefore, developing a stronger understanding of the factors regulating C. auris colonization in the skin is crucial to gain insights into this species’ pathogenesis. In this research effort, human b-defensin-2 (hbD-2), a common antimicrobial peptide expressed in human skin, was tested against C. auris in physiologically accurate conditions to assess for antifungal activity. Our results indicate that hbD-2 exhibits potent antifungal activity in vitro. Future studies will focus more in depth on the antifungal activity of hbD-2 using mice models of C. auris infection.