Monthly Archives: September 2019

Cycle Training promotes bone growth following Spinal Cord Injury
Jayachandra Kura
Junior, Applied Physiology and Kinesiology
University of Florida
2019 UGSRF Fellow

My Research Project

Figure 1. Transverse view of long bone with red ROI

This past summer, I worked in Dr. Joshua F. Yarrow’s research lab at the Malcom Randall Department of Veteran Affairs Medical Center. Dr. Yarrow’s lab explores the effectiveness of pharmacologic and exercise treatments following spinal cord injury (SCI). For the specific SCI we studied, the posterior end of the 9th thoracic vertebrae was surgically removed, exposing the spinal cord underneath. A machine delivered an impact causing hindlimb paralysis. My research  used Sprague-Dawley rats that were given either a 1) SCI, 2) surgical control (SHAM), 3) SCI + Bodyweight Supported Treadmill Training, or 4) SCI + Passive Bicycle Training. We scanned the distal femurs at baseline, two weeks and four weeks after SCI using a micro tomography (microCT) scanner.

In order to observe the effect of each treatment on the spongy cancellous bone, a technician would individually draw a region of interest (ROI) in the transverse view of the femur (Fig. 1) to include the internal trabeculae while excluding both the growth plate and solid cortical bone. However, repeating this on more than 100 slices for every sample at every time point is very time intensive. Instead, I worked to adapt a registration procedure for the spinal cord injury model. The registration was created by using two scans at different time points are aligning them in 3D. An ROI was created at baseline and then applied to the two-week and four-week scans, reducing the amount of labor required. I then compared the data from registered images to data from nonregistered images. I also helped to develop a script that allowed the computer to automatically draw the ROI with minimal manual correction, which further improved efficiency.

Realities of Research

Figure 2. Spinal Cord Injury Model. However, instead of a contusion by weight drop, there is a machine performing the impact.

My introduction into research has definitely been equal parts trying and gratifying—trying in the sense that every solution I created seemed to raise a host of other questions that needed to be addressed. I remember when I finally figured out how to register two different time point images, but I then needed to decide what size volume of interest (VOI) to use so the computer knew which landmarks to use to align the two different bones. Intuitively, using a large VOI should provide more datapoints for the computer to use. Doing so caused the solid cortical borders to be well-aligned, but the internal structures weren’t. Repeating this with multiple samples yielded the same results, which suggested that, in bone remodeling, an individual bony landmark’s relative position to the cortical border changes with time. However, using a small VOI caused poor alignment of the two images. This seemed counterintuitive, so when I looked over previous scans of SCI samples, I observed a trend of severe bone loss occurring below the injury site. The registration procedures outlined in the literature couldn’t directly translate to a SCI model as those outlined procedures required clear internal bony landmarks. Without these data points, the automatic registration software couldn’t produce an accurate alignment.

In this seemingly never-ending cycle of forming new ideas only to eliminate them later on, I didn’t come any closer to developing a script, but I did develop a lot of patience and perseverance. I found research to be inherently challenging, but the setbacks I encountered only made me grow as a person and researcher, and ultimately, made the end result of creating a “mostly” functioning protocol all that more rewarding. I’ve also come to realize that there is never a true “end” in research as there arealways things that can be improved or new questions that can be asked. This opportunity for continual growth was really exciting and intrinsically motivating.

Life as a Scientist

Compared to my past work experiences, research has by far been the most enjoyable. Never did I have a bout of the “Sunday scaries,” where I was enveloped with the existential dread of going to work the following day. In contrast, my work environment was low-stress and was dictated entirely by my own drive and will to work. The lab was filled with diverse, interesting individuals and I enjoyed the conversations I had and the relationships I formed with my labmates. Although there was always monotonous data entry, most of the work I did within the lab was challenging and fun. I always felt the work I was doing was meaningful.

I recall a conversation I had with my labmate who’d recently graduated: I had jokingly asked what it was like not having class. He laughed and said, “I spent the last four years—every fall, spring and summer semester—taking classes and working here at the hospital. If you think about it, when you’re an undergraduate, you’re basically working 70+ hours a week with all the stuff you do, so you really never have to think about anything except for school. Now that I’ve graduated and work 40 hours a week here in the lab, my work ends when I leave. But I remember going home and sitting on my couch not knowing what to do with myself, thinking, ‘Man, time to find some hobbies.’” Being out of school, if only briefly, allowed me to finally begin to appreciate this. Now sitting on my own couch trying to find things to do, I’ve found this freedom to be exciting and paralyzing.  I definitely feel that the physician/scientist career path is like a pipeline and there’s constant pressure to continue moving towards the end. To be honest, I haven’t put much thought into the adult I want to be outside of my career or really explored the things I find fulfilling. I’m just thankful for the opportunity to have had these experiences, both in and out of the lab, and believe that this summer was largely beneficial for my growth not only as a researcher, but also as a person.

References:

L Arsuaga, J & Villaverde, Valentín & Quam, Rolf & Martínez, I & M Carretero, J & Lorenzo, Carlos & Gracia, Ana. (2013). Arsuaga et al. 2007.

“Establishment of a Rat Model of Spinal Cord Injury (SCI).” Neural Regeneration Research, www.nrronline.org/viewimage.asp?img=NeuralRegenRes_2016_11_12_2004_197145_f1.jpg.

Jayachandra Kura is a junior majoring in applied physiology and kinesiology and minoring in Japanese at the University of Florida in Gainesville. He is a 2019 American Physiology Society Undergraduate Summer Research Fellow (USGSRF) working in Dr. Joshua F. Yarrow’s lab at the North Florida/South Georgia Medical Center in Gainesville, Fla. Jayachandra’s fellowship is funded by the American Physiological Society and the Department of Veterans Affairs. After graduation, Jayachandra plans to pursue a career as a physician scientist.

An Internship to Cure Obesity
Caleb Smith
Senior, Applied Health Science
Messiah College
2019 UGSRF Fellow

My Research Project

Trayagli & Anselmi (2016). Vagal Control of Gastric Functions

When exposed to a high-fat diet (HFD), both human and rat models show inflammation in the brainstem. The specific area of concern is called the dorsal vagal complex (DVC) which is responsible for maintaining homeostasis, or the balance, of energy and gut function. Specific neuronal cells in the brain, called astroglia, along with inflammation, help to control the DVC.

Previous studies have shown models that experienced a short period of energy regulation after a 24-hour period of excessive eating when exposed to a HFD. Therefore, the purpose of this study was to determine how that energy balance is restored during exposure to a HFD through the activation of the astroglial cells. As part of this study,  control and HFD chow were fed to a rat model for one, three, five and 14 days. The brainstems were removed and cut into thin slices and the astroglial cells were tagged with proteins that illuminated under specific lighting. This process, known as immunohistochemistry, allowed for the density of astrocytes and physical characteristics—like size and shape—to be analyzed. To process the role of the astrocytes in this energy metabolism regulation, small tubes called cannulae were surgically inserted into the DVC in order to directly administer fluoroacetate, a drug that inhibits the function of astrocytes. Once the rats recovered from surgery, a five-day control and HFD exposure were fed to the rats while food intake and body weight were measured twice daily.

While data was still being collected, preliminary data confirmed the role of astrocytes in metabolic regulation during HFD exposure. That meant astrocyte activation was necessary in controlling metabolic balance when exposed to HFD. Ultimately, painting the picture of how energy balance is controlled will be essential to producing a therapeutic drug that can help treat obesity.

Realities of Research

Working in a lab was similar to what I expected while still being very different. In many ways, research in a lab is exactly what you would expect: you make solutions, follow very strict procedures and analyze data for results. The techniques that I learned in high school and college labs were carried over with regards to safety, proper procedure, how to handle materials and how to pipette. I would come in and begin my day the same way by weighing and giving rats shots. In other ways, the lab was not what I expected it to be.

There were long periods of time, whether a few hours or days, where researchers were writing manuscripts to submit to journals, editing their own or other colleagues’ manuscripts, writing grant proposals or reading research happening in someone else’s lab to stay up to date on the current information. Not every minute was spent performing an experiment and analyzing data. The rest of my day involved one or two various procedures, so every day was different. Usually, I would have one or two main goals or techniques for the day. Some days it was immunohistochemistry or analyzing material under a confocal microscope. Other days I performed surgeries on rats or loaded brain tissue onto microscope slides. I was surprised by how similar this lab was to high school or college labs.

In some instances, we had to develop our own techniques. For example, we performed surgery on rats using the procedures and equipment we developed. Other procedures followed strict protocol that had been around for many years, like immunohistochemistry. The lab mentors had a strong understanding of their expectations for the outcome of an experiment, so we were able to successfully perform the experiments and get conclusive results that either supported or refuted the hypothesis. The results were what we had expected. We had a solid background understanding that allowed us to make a very scientifically guided hypothesis. However, that didn’t mean we didn’t have to start over in some cases. There were surgeries that did not go as planned, which resulted in having to start over and try again. Not everything in a lab runs perfectly or goes according to plan. Accidents happen, mistakes are made, and fresh starts were common. Luckily for me, no changes in the overall plan had to be made. Preliminary data suggested that we were going to receive conclusive results.

Life as a Scientist

Brain-Gut Laboratory Members at Milton S. Hershey Penn State University College of Medicine

Over the summer, I was able to dive into the life of a scientist and see what the day-to-day job was like. I was highly surprised by how much time was spent doing activities other than hands-on, standard research much like one would expect from high school or college labs. I couldn’t believe how much time each scientist spent doing work on a computer. In fact, my summer lab seemed to spend about half of the time performing procedures and the other half is spent on the computer doing activities like writing grant proposals, writing articles to be published in a journal, reviewing journal articles, ordering supplies and reading recent research. I just never realized how much time would be spent on these things, but the best part, was performing surgeries on rats. I was able to independently perform hands-on science in a way that, quite frankly, made me feel pretty cool. Who wouldn’t think it sounds impressive saying they’ve given a rat surgery before? I liked being involved in physical work instead of taking care of business on the computer. The surgeries were challenging enough that they required critical thinking, simple enough that I could feel confident in what I was doing and unique enough that every rat’s surgery was a little different. Plus, it was neat to see the success of the surgeries I performed. On the flip side, the worst part of the job was immunohistochemistry. The process was very tedious and with the large number of samples I had to do, it became quite exhaustive and—dare I say—boring. I would spend days at a time washing samples, mixing them in different solutions, transferring them between containers and very carefully plating them on microscope slides.

The fact is that research does not always involve exciting and intriguing work. The other interesting aspect of working as a scientist was working as part of a lab team. Each person had independent projects that they were working on, but every project related back to the overall theme of the lab and contributed to the overall goal of the study. It was neat to be able to hear from other people about their findings and being able to learn as a collective. It was nice to be able to ask anyone in the lab for their input on a matter because person had an understanding of the science behind almost every project, even if it wasn’t their own. It allowed me to feel independent and like I was contributing my own work while having a support system in place in times of uncertainty or confusion. Ultimately, my summer research fellowship was a wonderful experience that allowed me to engage in hands-on research and experience the daily life of a scientist.

References:

Buckman,L.B. et al. Evidence for a novel functional role of astrocytes in the acute homeostatic response to high-fat diet intake in mice. Mol. Metab 4, 58-63 (2015).

Camilleri,M. Peripheral mechanisms in appetite regulation. Gastroenterology 148, 1219-1233 (2015).

Clyburn,C., Travagli,R.A., & Browning,K.N. Acute High Fat diet Upregulates Glutamatergic Signaling in the Dorsal Motor Nucleus of the Vagus. J. Amer. Physiol. Gastro. Liver Physiol. 314, 623-624 (2018).

Daly,D.M., Park,S.J., Valinsky,W.C., & Beyak,M.J. Impaired intestinal afferent nerve satiety signalling and vagal afferent excitability in diet induced obesity in the mouse. J. Physiol 589, 2857-2870 (2011).

de Lartigue,G., de La Serre,C.B., & Raybould,H.E. Vagal afferent neurons in high fat diet-induced obesity; intestinal microflora, gut inflammation and cholecystokinin. Physiol Behav. 105, 100-105 (2011).

Kentish,S. et al. Diet-induced adaptation of vagal afferent function. J Physiol 590, 209-221 (2012).

Janssen,P. et al. Review article: the role of gastric motility in the control of food intake. Aliment. Pharmacol. Ther. 33, 880-894 (2011).

Troy,A.E. & Browning,K.N. High fat diet decreases glucose-dependent modulation of 5-HT responses in gastrointestinal vagal afferent neurons. J Physiol 594, 99-114 (2016).

 

Caleb Smith is a senior majoring in applied health science with a pre-professional concentration at Messiah College in Mechanicsburg, Pennsylvania. He is a 2019 Undergraduate Summer Research Fellow (UGSRF) in the lab of Dr. Kirsteen Browning at the Penn State Hershey Medical Center’s College of Medicine in Hershey, Pennsylvania. Caleb’s fellowship is funded by the American Physiological Society. Upon graduating, Caleb hopes to continue into the medical field by becoming a physician assistant. 

A Summer Study: Respiratory Rehabilitation After Spinal Cord Injury
Amari Thomas
Senior, Biology
University of Florida
2019 STRIDE Fellow

My Research Project

The human body central nervous system.

Because the central nervous system is in control of every process taking place within the body, an injury to this system can be detrimental and sometimes fatal. Injuries to the cervical region of our spinal cord can be extremely difficult because they often lead to breathing impairment. The phrenic motor nucleus in this region innervates our diaphragm, which controls inhalation by creating a negative pressure ventilation system.

It has been shown that acute intermittent levels of low oxygen help to address the concern for the functional recovery of breathing after injury. This occurs because the phrenic motor nucleus elicits neuroplasticity. A key protein, phosphorylated-ERK (p-ERK), is involved mechanistically in the phrenic motor nuclei response to varying levels of low oxygen.

P-ERK’s expression can be analyzed through epifluorescent microscopy. The cervical spinal cord tissues were harvested from rodents and stained using inmunoflouresence, – a procedure that stains the tissues in a way that allows them to emit certain colors when viewed on a microscope. We injected cholera toxin B between the pleural cavity in the outer layers of the rodents’ lungs before injury, which allowed for selective localization of phrenic neurons. We imaged this tissue to assess different expression patterns of p-ERK after spinal injury and varying levels of intermittent hypoxia.

Once we analyzed the expression of p-ERK in phrenic motor neurons after spinal injury and intermittent hypoxia we were able to develop a better understanding of intermittent hypoxia and its elicited plasticity after spinal injury. This research will guide therapeutic strategies for improving breathing in people with spinal injury.

Life as a Scientist

Using rat models as a method for testing before human clinical trials.

My experience as a scientist this summer opened my eyes to the realities that occur behind the scenes of groundbreaking research. For example, I always believed clinical trials to be amazing advancements in research, but never truly understood all of the experiments that take place before humans are even brought into the picture. The work done in our lab on rats propose a model for human experimentation. This opportunity has also made me realize that things may not always go exactly as planned the first time around and that is perfectly okay. Often, these trials and errors allow us to learn more about the research we are doing in order to propose different hypotheses or use alternate methods. There is no right or wrong when it comes to research because it is a learning and growing experience.

Acknowledgements

Elisa Gonzalez-Rothi, DPT, PhD, Research Assistant Professor, University of Florida Department of Physical Therapy

Gordon S. Mitchell, PhD, Professor of Physical Therapy, University of Florida Department of Physical Therapy

Latoya Allen, PhD, University of Florida Department of Neuroscience

Marissa Ciesla, PhD, University of Florida Department of Neuroscience

Amari Thomas is a first-generation college student majoring in biology at the University of Florida in Gainesville. She was born and raised in Miami Gardens, Florida, where access to research labs and quality educational resources are minimal. Due to her academic success in grade-school and extracurricular involvement, Amari was accepted into one of the top universities in the country for her undergraduate education. She has continued to thrive in her undergraduate career by gaining dean’s list awards for academics, mentorship positions and an outstanding fellowship from the American Physiological Society. By working in a research lab, Amari has expanded her career options and strengthened her knowledge of the human body and its many processes. She hopes to obtain a medical license after graduating and plans to apply the knowledge learned in the research lab. Amari is a 2019 Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) Fellow in the lab of Dr. Elisa Gonzalez-Rothi at the University of Florida in Gainesville. Amari’s fellowship is funded by the National Heart, Lung and Blood Institute (NHLBI; R25 HL115473-01).