Single-cell analysis of insulin-regulated fatty acid uptake in adipocytes

Oleg Varlamov, Romel Somwar, Anda Cornea, Paul Kievit, Kevin Grove, Charles Roberts

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Increased body fat correlates with the enlargement of average fat cell size and reduced adipose tissue insulin sensitivity. It is currently unclear whether adipocytes, as they accumulate more triglycerides and grow in size, gradually become less insulin sensitive or whether obesity-related factors independently cause both the enlargement of adipocyte size and reduced adipose tissue insulin sensitivity. In the first instance, large and small adipocytes in the same tissue would exhibit differences in insulin sensitivity, whereas, in the second instance, adipocyte size per se would not necessarily correlate with insulin response. To analyze the effect of adipocyte size on insulin sensitivity, we employed a new single-cell imaging assay that resolves fatty acid uptake and insulin response in single adipocytes in subcutaneous adipose tissue explants. Here, we report that subcutaneous adipocytes are heterogeneous in size and intrinsic insulin sensitivity. Whereas smaller adipocytes respond to insulin by increasing lipid uptake, adipocytes with cell diameters larger than 80-100 μm are insulin resistant. We propose that, when cell size approaches a critical boundary, adipocytes lose insulin-dependent fatty acid transport. This negative feedback mechanism may protect adipocytes from lipid overload and restrict further expansion of adipose tissue, which leads to obesity and metabolic complications.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume299
Issue number3
DOIs
StatePublished - Sep 2010

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Single-Cell Analysis
Adipocytes
Fatty Acids
Insulin
Insulin Resistance
Adipose Tissue
Cell Size
Obesity
Lipids
Subcutaneous Fat

Keywords

  • Cell size
  • Insulin resistance
  • Obesity

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Endocrinology, Diabetes and Metabolism
  • Medicine(all)

Cite this

Single-cell analysis of insulin-regulated fatty acid uptake in adipocytes. / Varlamov, Oleg; Somwar, Romel; Cornea, Anda; Kievit, Paul; Grove, Kevin; Roberts, Charles.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 299, No. 3, 09.2010.

Research output: Contribution to journalArticle

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AU - Roberts, Charles

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