oringham's blog

The role of systems modeling in public health provides decision makers from all sectors of the health sciences with a dynamic, broad outlook at a complex system in order to make a fully informed decision based on the question at hand. The most relevant feature of systems modeling is the ability to analyze the immense number of interconnections between parts, that cannot necessarily be seen with basic models and deep thinking. This dynamic complexity of models allows for long delays between cause and effect to be seen more easily, discerning roots of problems that may have never been considered otherwise. Additionally, this feature also allows for future policies to modeled before implementation, showing all potential intended and unintended effects. These qualities allow officials and policy makers to learn exactly why past initiatives have failed when not obvious, and demonstrate an informed, calculated estimate of the of the aspects that are helpful and harmful in potential policies. This information if very useful to “troubleshoot” elements of policies, and alter certain variables of the policy in order to try and create the most effective and positive version. Factors that are considered in these dynamic models include environmental factors, risk and health factors, resource availability, economic status, and access to social and health services. Overall, the goal of systems modeling in public health is to analyze and create a rational, systematic decision under conditions leading to uncertainty. Providing a logical and transparent structure for decision making allows policy-makers and health care officials to make a sound and informed decision in the most complex of situations.

IMCL content within skeletal muscle is known to be a source of energy in numerous daily tasks. The purpose of this study was to examine the effects of age and sex on IMCL contents. These lipids were analyzed using electron microscopy (EM) images of the vastus lateralis. Based on our analysis we found that there is a significant age by sex difference in lipid area in which older women had a smaller IMCL lipid area than younger women.

    According to our analysis there is also a significant sex difference in respect to lipid circularity. Specifically, men appear to have lipids which are more circular than those found in women. We suspect that such a difference can affect the efficiency of lipid metabolism within muscle fibers which can in turn affect overall muscle function.By examining such relationships we hope this data will be helpful for creating clinical interventions to improve lipid metabolic efficiency which is beneficial for overall muscle function.

    When examining the effect of sex, age, and age by sex of adults on solidity of IMCL, it is apparent that there is a significant difference across all three variables (p= 0.027, p=0.00, p=0.00, respectively). Figure 4 demonstrates that there is a large difference  between the solidity of IMCL in younger women, with an average of around 8.895, as compared to young men, and old men and women who have much higher average solidities.

When examining the effects of age, sex, and age by sex variables on circularity of IMCL droplets, it is apparent that there is a significant difference between circularity with respect to sex (p=0.01). It appears that men have a circularity much closer to 1 (a perfect circle) than women do, with younger men accounting for most of this difference with an average circularity of about 0.805. Older men appear to also have a much higher average circularity than both young and old women (Figure 3). Both age differences and age by sex differences were found to be insignificant (p=0.14, p=0.061 respectively).

When comparing the differences in IMCL area across age, sex and age by sex, it is apparent that there is a significant difference in both age differences and age by sex differences (p=0.014 and 0.01, respectively). When examining figure 1, the graph demonstrates that the age and age by sex differences are mostly resulting from the large difference in lipid size from older women. Older women seem to have a significantly smaller IMCL area when compared to young women, and older and younger men. However, there was no significant difference between sex and IMCL area (p=0.251).

    Yesterday, February 1st, 2018, I indulged in many different foods throughout the day. It started off like any other Thursday, I grabbed a coffee from the small cafe in the Morrill Science Center and sipped on it throughout my Developmental Biology class. Lunch time was enjoyed at Franklin Dining Common, where I filled my plate with yaki udon noodles, a taco, and some green beans, accompanied by a glass of sparkling water.  Dinner, however, did not go as planned. Upon my arrival at the Newman Center cafe, in great anticipation for my long awaited grilled chicken wrap with garlic parmesan sauce, I was regretfully informed that the kitchen was fresh out of both burgers, and all styles of chicken. Disappointed, I returned home and made pasta with garlic and herb sauce. Late at night, my roommate and I decided to get Insomnia Cookies, and I ordered a peanut butter cookie with vanilla ice cream on top, and a red velvet cookie on the side.

In this study, twenty-four young and older men and women participated. All subjects were matched for physical activity. Biopsies from the vastus lateralis were taken from each subject and imaged using electron microscopy. These images were provided by collaborators at the University of Vermont. Images were then analyzed using a protocol to identify intramyocellular lipid droplets within the muscle fiber. Lipid droplets were identified using the criteria as follows; a gray/white interior, somewhat circular in shape, contains a gray outline, doesn’t have multiple membranes on the outside or have debris inside, and usually adjacent to mitochondria. A protocol was then developed in order to create a thresholded image containing only lipid droplets. These thresholded images were then analyzed for circularity, area ratio, roundness, solidity, and % area. using ImageJ. This data was collected and cross-checked between multiple (2) undergraduate researchers.

    Intramyocellular lipid content is not only used as a source of energy in adipose tissue, but also in skeletal muscle. It has been shown that during prolonged exercise, IMCL content decreases as the lipid content is transformed into energy. Similarly, prior to routine exercise, trained athletes exhibit elevated amounts of IMCL content within skeletal  muscle in order to compensate for the amount of energy that is regularly used and lost during exercise.  

    Previous studies have found that older men tend to have larger IMCL droplets and fewer droplets when compared with other groups (Crane et al. 2010). Based on these studies, it is expected that such variation in IMCL content is responsible for the differences in mitochondrial function and lipid metabolism between the young and older populations.

It is understood that within human muscle fibers there exist lipid droplets which are known as intramyoceullar lipids (IMCL). There have been numerous studies which have investigated the difference in intraymocellular content, but none have been matched for physical activity as our data has been matched for physical activity.  It is thought that older men have larger IMCL droplets than young adults. Additionally it was previously determined that older adults have a lower percentage of IMCL in contact with mitochondria as compared to young adults (Crane et al. 2010). Furthermore, trained athletes have a high IMCL content which is countered by having a greater concentration of mitochondria.

The purpose of this study was to examine the effect of age and sex on IMCL content within skeletal muscle. Identifying such relationships between IMCL content and other variables such as age and sex while being matched for physical activity can reveal relevant information regarding why IMCL storage in skeletal muscle is important for physical performance. From a clinical standpoint, examining factors that influence lipid size in respect to aging and sex differences can be beneficial in designing interventions to improve lipid metabolic efficiency.This in turn would increase the availability of energy to skeletal muscles, allowing for increased physical function.

    Intramyocellular lipid content is a source of energy used within skeletal muscle. In this study, EM images of the vastus lateralis were taken for twenty four subjects who were matched for physical exercise. These EM Images were analyzed for IMCL content using GIMP and ImageJ programs. Based on the analysis we found that there was a age by sex difference in IMCL lipid area older women were found to have a much lower IMCL lipid area than in younger women.

Overall, systems modeling provides a mathematical and holistic view on the dynamic range of effects that various actions may result in. This integrative modeling is an interictal component of achieving the SDGs, due to their highly integrative nature. The development of a modeling system specifically designed to aid in the completion of the SDGs would allow all sectors that impact public health and well-being, both large and small, to be examined and analyzed, providing a comprehensive outlook on a policy’s full impact on the earth and society. Systems modeling provides a heightened level of confidence to policy makers and citizens alike when implementing new systemic changes and allows for the effects of these changes to be explored more deeply before enacting new policies. By testing various policies individually and in combination, policy enactors are able to which policies to put forth in conjunction with others in order to attain the best result, and which aspects to omit.