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Fortuin-de Smidt MC, Mendham AE, Hauksson J, Alhamud A, Stefanovski D, Hakim O, Swart J, Goff LM, Kahn SE, Olsson T, Goedecke JH.
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Endocr Connect. 2021 May 19;10(5):550-560. doi: 10.1530/EC-21-0153.
Abstract
The role of ectopic fat, insulin secretion and clearance in the preservation
ofβ-cell function in black African women with obesity who typically present with
hyperinsulinaemia is not clear. We aim to examine the associations between
disposition index (DI, an estimate of β-cell function), insulin secretion and
clearance and ectopic fat deposition. This is a cross-sectional study of 43 black
South African women (age 20-35 years) with obesity (BMI 30-40 kg/m2) and without
type 2 diabetes that measured the following: DI, insulin sensitivity (SI), acute
insulin response (AIRg), insulin secretion rate (ISR), hepatic insulin extraction
and peripheral insulin clearance (frequently sampled i.v. glucose tolerance test);
pancreatic and hepatic fat, visceral adipose tissue (VAT) and abdominal s.c. adipose
tissue (aSAT) volume (MRI), intra-myocellular (IMCL) and extra-myocellular fat
content (EMCL) (magnetic resonance spectroscopy). DI correlated positively with
peripheral insulin clearance (β 55.80, P = 0.002). Higher DI was associated with
lower VAT, pancreatic fat and soleus fat, but VAT explained most of the variance in
DI (32%). Additionally, higher first phase ISR (P = 0.033) and lower hepatic insulin
extraction (P = 0.022) were associated with lower VAT, independent from SI, rather
than with ectopic fat. In conclusion, peripheral insulin clearance emerged as an
important correlate of DI. However, VAT was the main determinant of a lower DI above
ectopic fat depots. Importantly, VAT, but not ectopic fat, is associated with both
lower insulin secretion and higher hepatic insulin extraction. Prevention of VAT
accumulation in young black African women should, therefore, be an important target
for beta cell preservation.
Keywords: .
Link/DOI: 10.1530/EC-21-0153