Combined metformin and insulin treatment reverses metabolically impaired omental adipogenesis and accumulation of 4-hydroxynonenal in obese diabetic patients.
Obesity-associated impaired fat accumulation in the visceral adipose tissue can lead to ectopic fat deposition and increased risk of insulin resistance and type 2 diabetes mellitus (T2DM). This study investigated whether impaired adipogenesis of omental (OM) adipose tissues and elevated 4-hydroxynonenal (4-HNE) accumulation contribute to this process, and if combined metformin and insulin treatment in T2DM patients could rescue this phenotype.



OM adipose tissues were obtained from forty clinically well characterized obese individuals during weight reduction surgery. Levels of 4-HNE protein adducts, adipocyte size and number of macrophages were determined within these tissues by immunohistochemistry. Adipogenic capacity and gene expression profiles were assessed in preadipocytes derived from these tissues in relation to insulin resistance and in response to 4-HNE, metformin or combined metformin and insulin treatment.



Preadipocytes isolated from insulin resistant (IR) and T2DM individuals exhibited lower adipogenesis, marked by upregulation of anti-adipogenic genes, compared to preadipocytes derived from insulin sensitive (IS) individuals. Impaired adipogenesis was also associated with increased 4-HNE levels, smaller adipocytes and greater macrophage presence in the adipose tissues. Within the T2DM group, preadipocytes from combined metformin and insulin treated subset showed better in vitro adipogenesis compared to metformin alone, which was associated with less presence of macrophages and 4-HNE in the adipose tissues. Treatment of preadipocytes in vitro with 4-HNE reduced their adipogenesis and increased proliferation, even in the presence of metformin, which was partially rescued by the presence of insulin.



This study reveals involvement of 4-HNE in the impaired OM adipogenesis-associated with insulin resistance and T2DM and provides a proof of concept that this impairment can be reversed by the synergistic action of insulin and metformin. Further studies are needed to evaluate involvement of 4-HNE in metabolically impaired abdominal adipogenesis and to confirm benefits of combined metformin-insulin therapy in T2DM patients.
Anti-Doping Lab Qatar, Sports City, Doha, Qatar.
Morana
M
Jaganjac
Anti-Doping Lab Qatar, Sports City, Doha, Qatar; School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom.
Shamma
S
Almuraikhy
Anti-Doping Lab Qatar, Sports City, Doha, Qatar.
Fatima
F
Al-Khelaifi
Anti-Doping Lab Qatar, Sports City, Doha, Qatar.
Mashael
M
Al-Jaber
Bariatric and Metabolic Surgery, Hamad Medical Corporation, Doha, Qatar.
Moataz
M
Bashah
Microbiology and Immunology, Weill Cornell Medicine-Qatar, Doha, Qatar.
Nayef A
NA
Mazloum
Department of Pathology, Medical Faculty University of Zagreb, Clinical Hospital Centre Zagreb, Zagreb, Croatia.
Kamelija
K
Zarkovic
Laboratory for Oxidative Stress, Rudjer Boskovic Institute, Zagreb, Croatia.
Neven
N
Zarkovic
Karl Franzen's University of Graz, Institute of Molecular Biosciences, Austria.
Georg
G
Waeg
School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom. Electronic address: W.Z.Kafienah@bristol.ac.uk.
Wael
W
Kafienah
Anti-Doping Lab Qatar, Sports City, Doha, Qatar. Electronic address: melrayess@adlqatar.qa.
Mohamed A
MA
Elrayess
D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects*; D000328:Adult; D000447:Aldehydes / Q000378:metabolism*; D050110:Bariatric Surgery; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000601:surgery; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008687:Metformin / Q000494:pharmacology*; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism* / Q000601:surgery
D000447:Aldehydes; D007328:Insulin; D008687:Metformin; C027576:4-hydroxy-2-nonenal
4-hydroxynonenal; Adipogenesis; Insulin; Insulin resistance; Metformin; Obesity; Omental fat; T2DM