The Role of the Human Gut Microbiome and Inflammation in Heat Related Illness Among Migrant Farmworkers Open Access

Carr, Christopher Patrick (2017)

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Prolonged exposure to hot environments can lead to a continuum of conditions known as heat related illness (HRI). It has been well documented that the driving force behind the severity of HRI is septicemia. To examine the relationship between the gut microbiome and the body's inflammatory response caused by septicemia, farmworkers exposed to at least two weeks of working in a hot environment were enrolled in a cross-sectional study. Levels of lipopolysaccharide-binding protein (LBP), C-reactive protein, proinflammatory cytokines IL-1-beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-alpha, and IFN-gamma in both the serum and stool of subjects were measured along with gut microbiome alpha and beta diversity. It was hypothesized that individuals with higher levels of LBP would be better adapted to experiencing heat stress and would be protected against HRI. It was also hypothesized that the makeup of the gut microbiome would explain differences between the cases and controls. The results of the analysis found that stool CRP, stool IL-1-Beta, and stool IL-8 levels were significantly higher among cases. There were no significant differences between cases and controls among gut microbiome alpha or beta diversity. These results indicate cases had an increased inflammatory response to heat exposure meaning those with lower levels of CRP, IL-1-Beta, and IL-8 in their stool were less likely to experience HRI. There was also a significant difference between gender for serum LBP, serum IL-8, serum and IL-13. The results of this study highlight the need for further investigate the differences between those that experience HRI and those that do not.

Table of Contents

Table of Contents

1. Background/Literature Review

A. Introduction the Heat Related Illness 1

B. Population Affected by Heat Related Illness 1 - 2

C. Epidemiology of Heat Related Illness 2 - 3

D. Underlying Biological Processes of Heat Related Illness 3

E. Introduction to the Gut Microbiome 4

F. The Gut Microbiome, Immune System, Inflammation, and Sepsis 5 - 6

G. Study Aims 6

2. Methods

A. Overall Study Design 7

B. Sample Collection and Processing 7 - 8

C. Data Processing Procedures 9 - 10

D. Data Analysis Procedures 10 -11

3. Results

A. Descriptive Statistics of Cohort 12

B. Bivariate Analysis and Microbiome Analysis 13 - 14

C. Correlation Analysis and Linear Regression 14

4. Discussion 15 - 18

5. References 19 - 22

6. Tables 23 - 30

7. Figures 31 - 36

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