Depot-specific differences in visceral and subcutaneous adipose tissue from patients with obesity

Figure 1.. Depot differences in adipocyte size: A) Study overview: 22 patients with obesity (n = 4 men and n = 18 women) were undergoing elective Roux-en-Y gastric bypass surgery. Fat biopsies were obtained from omental-visceral white adipose tissue (VAT), and abdominal-subcutaneous white adipose tissue (SAT), used for downstream analyses in tissue (mRNA-sequencing, coulter counter) and isolated, mature adipocytes (glucose uptake, glycerol release and western blotting). (blood sample analyses and demographic information are presented in Table 1). B) Cell size distribution curves in visceral (VAT in red) and subcutaneous (SAT in blue) adipose tissue. n = 19. C) Peak of large cell fraction in µm in VAT and SAT samples. Statistical analysis of mean differences using a paired t-test. n = 19. D) Number of small cells in percentage in VAT and SAT. Statistical analysis of mean differences using a paired t-test. n = 19. E) Linear regression analysis showing the relationship between the peak diameter of large adipocytes (µm) and HOMA-IR (Homoeostatic model assessment of insulin resistance). n = 18 for VAT, n = 18 for SAT.

Figure 2.. Depot differences in adipose tissue gene expression: A) PCA plot of the bulk mRNA sequencing data on paired VAT and SAT intact adipose tissue samples for the top 5000 genes. n = 18. B) Venn diagram showing the distribution of differentially expressed genes (DEGs) between adipose tissue depots. C) Volcano plot of differentially expressed genes comparing VAT and SAT. D) Top 20 upregulated KEGG pathways in VAT and SAT.

Figure 3.. Depot differences in adipocyte glucose uptake and lipolysis: A) Basal and isoprenaline-stimulated glycerol release per cell in collagenase-isolated adipocytes of VAT and SAT samples (VAT in red, SAT in blue). Statistical analysis was performed using two-way repeated measures ANOVA and post-hoc multiple comparisons with the Bonferroni correction. n = 18. B) Isoprenaline response was calculated as the fold response of isoprenaline over basal glycerol release in collagenase-isolated adipocytes. Statistical analysis of geometric mean differences was performed using a ratio paired t-test. n = 21. C) Linear regression analysis showing the relationship between the peak diameter of large adipocytes (µm) and basal glycerol release per cell. n = 18. D) Heatmap of lipolysis-related gene targets highlighting depot differences in paired analysis of SAT and VAT samples. n = 18. E) Basal and insulin-stimulated glucose uptake per cell in isolated adipocytes of VAT and SAT samples. Statistical analysis was performed using two-way repeated measures ANOVA and post-hoc multiple comparisons with the Bonferroni correction. n = 17. Glucose uptake data was log-transformed prior analysis. F) Insulin…

Figure 4.. Depot differences in extracellular matrix composition, caveolin content and the link to systemic insulin sensitivity: A) Heatmap of extracellular matrix-related gene targets highlighting depot differences in paired analysis of SAT and VAT adipose tissue samples. n = 18. B) COL1A1 gene expression (bulk mRNA sequencing) in VAT and SAT adipose tissue samples. n = 18. C) COL3A1 gene expression (bulk mRNA sequencing) in VAT and SAT adipose tissue samples. n = 18. D) Ratio of COL1A1/COL3A1 gene expression in VAT and SAT adipose tissue samples. Statistical analysis of geometric mean differences was performed using a ratio paired t-test. n = 18. E) linear regression analysis showing the relationship between the peak diameter of large adipocytes (µm) and the COL1A1/COL3A1 ratio. n = 18. F) Heatmap of caveolae-related gene targets highlighting depot differences in paired analysis of SAT and VAT adipose tissue samples. n = 18. G) CAV1 gene expression (bulk mRNA sequencing) in VAT and SAT adipose tissue samples. n = 18. H) Quantification and representative western blot for the analysis of Caveolin 1 protein levels in collagenase-isolated adipocyte lysates. Statistical analysis of geometric…