Mechanisms and Pathophysiology of Obesity: Upgrading a Complex Scenario

Long-Term High-Fat Diet Inhibits the Recovery of Myocardial Mitochondrial Function After Chronic Hypoxia Reoxygenation in Rats

Yan, Jun, Kang Song, Sisi Zhou, and Ri-Li Ge. Long-term high-fat diet inhibits the recovery of myocardial mitochondrial function after chronic hypoxia reoxygenation in rats. High Alt Med Biol. 16:000-000, 2021. Aims: A high-fat diet (HFD) is associated with cardiovascular diseases and mitochondrial dysfunction. Obesity incidence is low at high altitudes, but the impact of HFD, which is closely associated with obesity at high altitudes, and the effects of reoxygenation on the heart are unclear. In this study, we investigated the effects of long-term HFD consumption on mitochondrial function in the myocardium after chronic hypoxia reoxygenation. Main Methods: Sprague-Dawley rats were randomized into the following six groups: normoxia groups, including a control group and HFD group; chronic hypoxia groups, including a normal chow diet (CH-CD) group and an HFD (CH-HFD) group; and hypoxic-reoxygenated (HR) groups, including a hypoxia-reoxygenation normal chow diet (HR-CD) group and a hypoxia-reoxygenation HFD (HR-HFD) group. All rats were euthanized in this study. Results: We found that chronic hypoxia aggravated myocardial mitochondrial dysfunction. The Flameng score (in which the higher the score, the more severe the mitochondrial damage) was used to assess the extent of mitochondrial structural damage. Compared with the control group and HFD group, the Flameng scores of the CH-CD and CH-HFD groups were significantly increased, respectively [1.260 ± 0.063 vs. 0.68 ± 0.05 (p < 0.05); 2.03 ± 0.07 vs. 1.48 ± 0.05 (p < 0.05)]. Moreover, progressive reoxygenation facilitated the recovery of myocardial mitochondrial function; this process was inhibited by long-term HFD. After reoxygenation, the Flameng scores in the HR-CD group became comparable to those in the CH-CD group [0.86 ± 0.05 vs. 1.26 ± 0.06 (p < 0.05)]. However, no significant changes were observed in the Flameng score between the HR-HFD and CH-HFD groups. Significance: Long-term HFD consumption inhibits myocardial mitochondrial function after reoxygenation. This finding may be helpful for the prevention and control of risk factors related to cardiovascular diseases in plateau residents.

Protective Association of Single Nucleotide Polymorphisms rs1861868-FTO and rs7975232-VDR and Obesity in Saudi Females

Background

Obesity is a major health threat worldwide. It predisposes individuals to diabetes, cardiovascular complications, and cancer. Genetic and environmental factors are responsible for the increasing incidence of obesity. In this study, we investigated the genetic factors associated with obesity in young Saudi women.

Subjects and Methods

In this cross-sectional study, 131 young Saudi female students were recruited. Body mass index (BMI), waist–hip ratio, blood glucose, triglyceride, cholesterol, HDL, LDL, and vitamin D3 levels of the subjects were determined. Twelve SNPs of different genes that showed a correlation with obesity in different population were tested, namely GNPDA2 (rs10938397), TCF7L2 (rs10885409), FTO (rs1477196), ADIPOQ (rs1501299), MC4R (rs17782313), ABCA1 (rs1800977), FTO (rs1861868), VDR (rs2228570), VDR (rs731236), VDR (rs7975232), ADIPOQ (rs266729), and PFPK (rs6602024). Student’s t-test was conducted for all parameters. Pearson correlation was performed to identify the correlated variables. The frequencies of different risk alleles were determined by direct counting of the test allele divided by the total number of alleles and compared.

Results

Only two SNPs, rs1861868 of FTO and rs7975232 of VDR, of the twelve tested SNPs showed significant protective associations with the BMI with odds ratio 0.3886 (0.1761–0.8572); p 0.0192 and odds ratio 0.4563 (0.2343–0.8888); p 0.0211, respectively.

Conclusion

The current study showed that minor alleles, “T” of FTO and “A” of VDR, might be protective factors against increased BMI in young Saudi female subjects. To elucidate this association, further studies with larger sample size involving both sexes are required.