👤 Maryam Moazzam-Jazi

Insulin resistance (IR), commonly associated with obesity, is linked to a range of metabolic and immune-related disorders in the contemporary human population. Nevertheless, it is evolutionary well-conserved, suggesting its potential survival advantages to our ancestors. This review aims to explore the intricate interplay between IR and the immune system as well as its implications for the development of immune-metabolic and allergic diseases in the modern era. From an evolutionary medicine perspective, the longevity of ancient humans relied on energy storage to endure food shortages and effectively activate the immune system against various diseases. Under normal conditions, insulin induces glycogen and triglyceride synthesis in the liver and adipose tissues. However, IR directs more glucose to insulin-independent tissues, such as the immune system, which are critical for survival in adverse conditions. The persistent IR in our current lifestyle promotes low-grade inflammation, accompanied by various metabolic and allergic disorders. Critically, this evolutionary mismatch not only explains disease susceptibility but also informs therapeutic design to target immune-metabolic crosstalk. Moreover, our evolutionary analysis demonstrates that the genomic regions near the PTEN, IL27, and NUPR1 genes could play an important role in this interaction across diverse populations. Show less

This population-based longitudinal study is the first investigation that assesses the association of common MC4R SNPs with the obesity-related parameters over time and determines the effect of risk alleles during the three adulthood life periods (early, middle, and late) in a large Iranian cohort, a population with a unique genetic make-up that has been understudied and relatively unexplored. We obtained the genotype of 5370 unrelated adults who participated in the ongoing Tehran Cardiometabolic Genetic Study (TCGS) cohort project for the common MC4R SNPs. Linear regression and linear mixed model analyses were performed to examine the effect of MC4R polymorphisms on maximum BMI and other obesity-related factors over time. We recognized that several SNPs associated with the maximum BMI and the increased BMI, waist circumference, and waist-hip ratio across Iranian adults over a lifetime. Interestingly, we found that rs9954571-A has a yet unreported protective role against obesity-related factors, including BMI, waist circumference, waist-hip ratio, and triglyceride level. Additionally, a survey of the impact of the MC4R risk score throughout the adulthood life periods indicated that the MC4R risk score is influenced both the elevated BMI and waist circumference only during the early adulthood period. Our findings can expand our knowledge about the MC4R genetic variant's contributions to adulthood obesity and highlight the importance of evaluating the genetic components affecting obesity over a lifetime, which could be considered for obesity clinical screening and treatment. Show less