Original Biochemical Framework for Understanding Obesogenic Dietary Patterns and Adipose Tissue Dysfunction in Nigerian Urban Adults

Adipose tissue dysfunction, encompassing adipocyte hypertrophy, impaired adipokine secretion, ectopic lipid deposition, and chronic low-grade inflammation, is the biochemical bridge between obesogenic dietary patterns and cardiometabolic disease, and characterising this axis in Nigerian urban adults experiencing rapid nutritional transition is an original contribution to African metabolic disease biochemistry. This dissertation develops an original biochemical framework for understanding obesogenic dietary patterns and adipose tissue dysfunction in Nigerian urban adults, integrating dietary assessment, adipose tissue biopsy biochemistry, and circulating biomarker profiling. A mixed-methods cohort study enrolled three hundred obese Nigerian urban adults from Lagos, Abuja, and Port Harcourt and one hundred lean controls. Detailed dietary assessment combined three-day weighed food records with dietary pattern analysis by principal component analysis, identifying three major dietary patterns including a traditional Nigerian pattern, a Westernised urban pattern, and a mixed urban pattern. Subcutaneous adipose tissue biopsies were obtained from a sub-cohort of forty obese participants. Adipose tissue was subjected to transcriptomic analysis, adipokine gene expression profiling, fatty acid composition analysis by GC-MS, lipid droplet morphometry, mitochondrial density by citrate synthase assay, and macrophage infiltration by CD68 immunohistochemistry. Circulating biomarkers measured included leptin, adiponectin, resistin, chemerin, vaspin, TNF-alpha, IL-6, free fatty acids, and ceramide species by LC-MS/MS. The Westernised dietary pattern was most strongly associated with adipose tissue macrophage infiltration, ceramide accumulation, and adiponectin suppression. An original mechanistic model was constructed linking dietary saturated fat load to ceramide-mediated adiponectin processing impairment as a key pathogenic step in Nigerian obesity-associated metabolic disease. Keywords: adipose tissue dysfunction, obesogenic diet, adipokines, ceramide, Nigeria.