Monthly Archives: February 2019

Hypertension Prevention: does it also improve motor cognitive function?

Research Project

This summer, I’m studying the effects of inspiratory muscle strength training on motor and cognitive function in middle-aged to older adults. Motor function is the ability to move the muscles in your body, and cognitive function is your brain’s ability to perform tasks. Inspiratory muscle strength training, or IMST, is a relatively understudied technique of exercising the muscles you use to breathe in. By breathing in, or inspiring, against a resistance with a small device that looks similar to an inhaler, you can make these muscles stronger and hopefully improve many bodily and cellular functions, including motor-cognitive function. What is currently known about IMST is that it can significantly improve blood pressure in healthy adults (DeLucia, De Asis and Bailey, 2018), but its effects on adults with high blood pressure have not been tested yet. The IMST study on the large scale is focusing on the possible blood pressure and cardiovascular benefits of IMST in adults with high blood pressure, and I’m focusing my research and data analysis specifically on the motor cognitive functions that we also test.

Because a decline in motor-cognitive (shortened to motor-cog) function is highly correlated to mortality (death) risk, there is a large scientific effort to evaluate the effectiveness of various forms of intervention to improve these variables. Motor-cognitive decline is characterized by dementia and immobility, which are not only independent predictors of mortality risk, but large influential factors on perceived quality of life for older adults. It is well established that a consistent aerobic exercise routine will effectively prevent motor-cognitive decline in older adults, but because of its heavy burden, it is not frequently adhered to. Finding other effective practices of improving motor and cognitive function that are more adherable will greatly improve the quality of life for aging individuals and lower their mortality risk.

Realities of Research

Figure 1: Formaldehyde used for preserving endothelial cells

So far, I have found that doing clinical research in a lab is full of excitement and surprises! Beginning at the start of the fellowship, clinical interactions and the IMST study became only two of my many responsibilities. I have been trained on wet lab procedures such as cell collection and isolation, as well as blood processing to assess certain chemicals in the blood. These tasks can be tedious, and are very time and method sensitive. I can spend two hours doing the cell collection and isolation for them to later not give any helpful results when I analyze them. Experiencing frustrating aspects like this is helping me develop the very important skill of patience. I have to use patience in many aspects of my work; wet lab mishaps are not the only issues one can encounter during a typical day of research. I am working in one of the most dynamic physiology labs in the country, with some of the brightest in the field, but despite this we all run into our fair share of hiccups. For example, our huge datasheet for our study got deleted and we spent several days trying to find it. Also, our freezer logging software crashed and left us without decades of logged biological sample information!

Figure 2: Freezing plasma in liquid nitrogen for later analysis

 

 

On the other side of my work, I have to use patience with the clinical subjects. When working with more stubborn older subjects, I find it’s essential to remain patient to maintain professionalism, and to represent our lab in the most positive way possible. I’ve had difficult interpersonal interactions with some of the subjects, but remaining patient and working through issues and questions with them upholds the highest standards of human research we have as an institution. Anyways, our IMST study has (despite some problems) been very on-track and is moving along at a quick pace. We just received more funding from the NIH through a grant that will support us through the next two years of research. Woohoo!

Life of a Scientist

Living as a scientist this summer has been a truly rewarding and educational experience. Going from a very part-time volunteer in the lab doing data entry, to a full-time member of the lab team with much more responsibilities has been an eye-opening transition. I am a much more integral part of the team, and I have to be much more accountable than I was before. I went from only having one task to focus on at a time, to having three-four or more, including clinical visits, grant reviewing, abstract writing, journal club presentations, and reading physiology literature. Balancing and prioritizing my lab tasks is difficult and stressful, and has shown me the less-glamorous side of basic research that you don’t realize until you experience it for yourself. On the other hand, I have been supported in so many ways I never expected, and I love working in a team-based environment. As a non-traditional community college student, I always felt like an outsider and thought I would never be fully accepted into the scientific/academic world. I was proven wrong. Our lab has endless support and an open-door policy when it comes to questions and concerns, which encourages communication. Every member of my lab team has been so helpful in educating me in physiology and research topics I’m unfamiliar with, and has given me all the opportunities I could ask for to be successful at this early stage of my research career. In fact, I should have at least two publications by the end of next year, and probably three by the time I finish my undergraduate studies. This amazing experience has strongly encouraged me to further pursue my career in physiological research.

 

Sources:

DeLucia, C., De Asis, R. and Bailey, E. (2018). Daily inspiratory muscle training lowers blood pressure and vascular resistance in healthy men and women. Experimental Physiology, 103(2), pp.201-211.

Makinzie Hamilton is an undergraduate junior studying Integrative Physiology and Philosophy at the University of Colorado, Boulder. She is working at UCB under Dr. Douglas Seals at the Integrative Physiology of Aging Laboratory, which focuses on improving cardiovascular aging. She is funded through grants from the STRIDE fellowship from the APS and The National Heart and Lung Association (Grant #1 R25 HL115473-01). After graduating in 2020, she hopes to pursue a dual MD/PhD degree and do clinical research regarding infectious disease and tropical medicine. In her free time, she enjoys studying true crime, cooking, painting, and fishing.
Targeting NHE3 in the Hfe mouse model of hemochromatosis

Research Project

Over the summer I have been working in Dr. Bryan Mackenzie’s lab at the University of Cincinnati College of Medicine in the Pharmacology and Systems Physiology department. My focus has been on finding novel therapeutic targets in the treatment and/or prevention of iron overload disorders. Hemochromatosis is just one of several common hereditary disorders that result in iron overload and subsequent liver disease, heart damage, and a slew of other health disorders across several body systems. Since there is no regulated mechanism for iron excretion, iron homeostasis of the body is regulated by iron absorption. The main mechanism by which non-heme iron (the majority of iron humans consume from their diets) is absorbed from the small intestine is the divalent metal ion transporter-1 (DMT1) (3). DMT1 is already a validated therapeutic target in hereditary hemochromatosis. More recently, the Mackenzie lab identified a role for the Na+/H+ exchanger-3 (NHE3) in intestinal absorption of non-heme iron by DMT1.

 

Intestinal iron uptake (redrawn from reference 1)

The Mackenzie lab demonstrated that NHE3 generates the driving force for iron absorption via DMT1 by transporting protons into the small intestine (2). My project this summer has built upon this prior knowledge using an Hfe knockout mouse model. Rendering this single gene inoperative in mice results in a very good model of iron overload. We are then able to test the hypothesis that iron overload in the Hfe KO mouse can be corrected by ablation of NHE3. The idea is that without NHE3, the driving force for DMT1-mediated iron uptake is reduced, thereby reducing iron absorption. If the data supports this hypothesis, we can conclude that ablating NHE3 prevents iron loading in the Hfe mouse model of hereditary hemochromatosis. Even further, we can reveal intestinal NHE3 as a potential therapeutic target in the treatment of iron overload.

Realities of Research

Throughout the summer I have learned countless basic research techniques and have mastered various skills that are good to possess in the Mackenzie Lab. I have learned how to ween and care for our colonies of mice. I now know how to genotype them using tail clippings and polymerase chain reaction (PCR). This step is especially important because it determines which mice are our experimentals, or the mice we collect blood and tissue samples from on experiment days. I was placed in charge of the mouse experiments, learning how to effectively set-up and delegate responsibilities. Being my first full-time experience in a research lab, I appreciated this opportunity to take charge and have ownership over such a large task. I also had the task of running serum iron assays and non-heme iron assays on freezers full of samples that have been collected. This task proved to be challenging and slightly stressful at times, as I found errors in our established assay protocols and analytical procedures. For example, some mice had very little blood collected on experiment days, meaning I had very little serum to run the assays. When the protocols had detrimental errors, I felt I had wasted irreplaceable serum at times. Luckily, I have corrected our protocols and have finally organized/assayed most of our samples. I have also not only learned how to operate a software program called SigmaPlota to analyze my data, but have learned how to edit our labs established transformations within this software. This summer full of learning techniques, troubleshooting, and analyzing my data has been an invaluable experience. I have transformed into a proficient, independent, and productive lab member in just a few months’ time.

Life of a Scientist

I have enjoyed my day-to-day life in the lab this summer. I was pleased to learn that a 9-to-5 workday is certainly possible, with proper planning. I also understood that some late nights/early mornings are unavoidable, especially when things didn’t go as planned and required a little extra time. I discovered that the environment in the lab was much more relaxed than I anticipated. I was able to control my day to day activities with little intervention, unless I needed assistance or extra guidance. This assistance from other lab members is something I really appreciated. Although everyone has their own projects and own experiments to run, a helping hand was always there when I needed it. I liked this collaborative, team-based environment and believe it greatly increased all I was able to learn in the lab this summer. The only con in the life of a scientist that I can think of is the down time that sometimes occurs, as I’m the type of person that likes to stay busy. Luckily, I was able to fill my time by reviewing relevant literature in the field or discussing my progress with other lab members. Overall, I really enjoyed getting to experience the life of a scientist for a summer and look forward to finishing up my project/exploring new directions in the lab.

 

References

  1. Mackenzie B, Garrick MD. Iron Imports. II. Iron uptake at the apical membrane in the intestine. American Journal of Physiology-Gastrointestinal and Liver Physiology289, 2005.
  1. Shawki A, Anthony SR, Nose Y, Engevik MA, Niespodzany EJ, Barrientos T, Öhrvik H, Worrell RT, Thiele DJ, Mackenzie B. Intestinal DMT1 is critical for iron absorption in the mouse but is not required for the absorption of copper or manganese. American Journal of Physiology-Gastrointestinal and Liver Physiology309, 2015.
  1. Shawki A, Engevik MA, Kim RS, Knight PB, Baik RA, Anthony SR, Worrell RT, Shull GE, Mackenzie B. Intestinal brush-border Na /H exchanger-3 drives H -coupled iron absorption in the mouse. American Journal of Physiology-Gastrointestinal and Liver Physiology311, 2016.
Sydney Stone is a junior majoring in Medical Sciences at the University of Cincinnati in Cincinnati, OH. She is a 2018 Short-Term Research Education Program to Increase Diversity in Health-Related Research Fellow (STRIDE) working in Dr. Bryan Mackenzie’s lab at the University of Cincinnati College of Medicine. Her summer of research was supported by APS and a grant from the National Heart, Lung, and Blood Institute (Grant #1 R25 HL115473-01). Upon graduation, Sydney plans to pursue an MD/PhD or MD/MS in order to become a physician scientist. She hopes to combine proficiency in physiology with invaluable access to patients in order to follow her passion for preventing and curing human disease.
Life Behind the Lab Coat: Part 2

Are you curious about the world of science? Do you crave to find new and exciting things about physiology? Well, I do!  Last summer, I had the opportunity to work in a research lab at the University of South Florida Morsani College of Medicine. Furthermore, I was able to renew my APS STRIDE fellowship and continue to work in Drs. Jessica Dominguez Rieg and Timo Rieg’s lab.

Research Project

During my time at the lab, my research project expanded on my work from last summer involving a transporter called the sodium/hydrogen exchanger (NHE). NHE is used to exchange sodium for hydrogen across a cell’s membrane.  There are several different isoforms of NHE; however, my project focused on the isoform NHE3. When NHE3 is genetically deleted from a mouse, called a whole animal knockout, they absorb or reabsorb sodium from the intestine or kidney. Consequently, the NHE3 knockout mice have severe diarrhea, low blood volume, and low blood pressure1. Furthermore, since NHE3 transports hydrogen, it also plays an important role in acid-base regulation. Moreover, NHE3 is also significant for balancing fluid and the regulation of blood pressure.  Last year, my studies concluded that the inducible deletion of NHE3 only in the intestine causes fluid accumulation in the intestine and metabolic acidosis.

This year, my research project remained focused on the role of intestinal versus renal NHE3 and its effects on phosphate homeostasis and blood pressure regulation. Moreover, my research is significant as nothing like this has been done before!  Additionally, there are currently drugs on the market that block NHE3, one example is Tenapanor, which helps to lower blood pressure or high blood phosphate levels; however, the mechanisms of how they work are unclear. As of last year, I saw significant changes in acid-base regulation. Hopefully, this year I will be able to determine how NHE3 affects phosphate homeostasis. Furthermore, I hope I am able to produce more data in order to help answer these ongoing questions about NHE3 and its effects on phosphate homeostasis and blood pressure regulation. Thus far, I have been conducting physiological experiments to determine changes in fluid and food intake, collecting blood and urine for further analysis.  My project is still being conducted but I am excited to see the results!

Life of a Scientist

I love being part of a research lab! Working with people who share the same passion and love discovering new things is amazing! Although I love doing research, the hours can be long. Having to work 8 plus hours a day during the week can be tiring and then having to come in again on the weekends, but I’ll tell you it’s all worth it! One thing I learned is experiments are a process and take time. Last year I thought working in a lab would be similar to being in the labs at the university that were required for your major, but they’re not. Even though they are very different, I still loved every moment I came into work! I am so thankful for this opportunity that APS and my mentors allowed me to expand my knowledge and skills. I am forever grateful for this experience.

 

Citations:

  1. McDonough AA. Mechanisms of proximal tubule sodium transport regulation that link extracellular fluid volume and blood pressure. Am J Physiol Regul Integr Comp Physiol 298: R851–R861, 2010. doi:10.1152/ajpregu.00002.2010.
Alexandria Valdez is a Senior majoring in Biomedical Science and minoring in Psychology at the University of South Florida in Tampa, FL. Alexandria is a 2018 second year Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) Fellow working in Dr. Jessica Dominguez Rieg and Dr. Timo Rieg’s lab at the University of South Florida Morsani College of Medicine in Tampa, FL. Alexandria’s fellowship is funded by the APS and a grant from the National Heart, Lung and Blood Institute (Grant #1 R25 HL115473-01). Upon graduation, Alexandria wishes to pursue a career in biomedical science as a research scientist.
Take My Breath Away- A Summer of Asthma Research

Research Project

Pathology of asthma.

This summer I had the pleasure of working with Dr. Silveyra and her research team at the Penn State College of Medicine investigating the mechanisms behind adult asthmatic females being more susceptible to air pollution than males. Research has shown that upon exposure to an air pollutant like ozone, females that already have a respiratory disease, such as asthma, are much more likely to develop worsening asthma as well as other respiratory problems. I believe this study is very important in today’s world, where the majority of ozone can be found in cities and industrialized areas that have very high populations. Therefor a female with asthma living in a populated city risks the possibility of her asthma worsening or developing other complications.  When people think of asthma, they usually think of shortness, of breath, trouble breathing, and wheezing. These symptoms are all due to a person’s airways becoming inflamed and an air pollutant like ozone could trigger this. The body expresses proteins called cytokines and when certain types of these cytokines are expressed, they can lead to inflammation like we see in asthma. In recent years a special type of RNA called microRNA (miRNA) has been found to play a key role in regulating the expression of these inflammatory cytokines. My research team and I were particularly interested in miR-712, which is a miRNA known to play a role in regulating inflammatory cytokines. Our idea was that if this miRNA is expressed differently between males and females, this could explain why asthmatic females are more susceptible to air pollutants than males.  This study could lead to the development of treatments specific for males and females.

Realities of Research

This was the first real research project I had ever participated in, so it was pretty intimidating in the beginning. However, as time went on I learned new techniques and began to understand the project and why it was important and that got me really excited to be doing research. The part that surprised me the most is how things that are so small like miRNA can play such a huge part in disease and keeping us healthy. Along the way I had to learn new techniques like how to extract the miRNA’s and how to determine how much was being expressed. In the end the results were a little surprising. Yes, we saw higher levels of miR-712 expressed in asthmatic females that had been exposed to ozone, but we also saw even higher levels of it in asthmatic males that had been exposed to ozone. This may have been due to the fact that male mice typically react quicker to the asthma model we used and that it may take females longer to actually “develop” asthma. I think in the future this model may need to be changed a little bit, but that is all a part of doing research.

Life of a Scientist

I found day-to-day life in the lab to be very exciting. There was always something to be doing and it was nice to know that everything you were doing in a day was for a purpose. One thing that surprised me was how long some procedures can actually take. Procedures I would read about in textbooks always seemed like they were quick and then you have your results, but there is actually a lot of hours that go into some procedures. The worst part was exposing the mice to ozone, because it was a three-hour long exposure and it would get pretty boring. The absolute best part was getting to work with my research team. Every single one of them was so helpful and knowledgeable and I am so grateful for them.

 

Citations

  1. Fuentes, N., Roy, A., Mishra, V., Cabello, N. and Silveyra, P. (2018). Sex-specific microRNA expression networks in an acute mouse model of ozone-induced lung inflammation. Biology of Sex Differences, 9(18).
Ashley Weaver is a rising senior at Penn State University in State College, Pennsylvania majoring in immunology and infectious disease. She is a 2018 Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) fellow working in Dr. Patricia Silveyra’s lab at the Penn State College of Medicine in Hershey, Pennsylvania. Her fellowship is funded by APS and a grant from the National Heart, Lung, and Blood Institute (Grant #1 R25 HL115473-01). 
After graduating, Ashley plans to pursue a career in clinical lab work for government organizations and then to pursue her masters in immunology.