Change in abdominal, but not femoral subcutaneous fat CT-radiodensity is associated with improved metabolic profile after bariatric surgery

Abstract

Background and aims: Computed tomography (CT)-derived adipose tissue radiodensity represents a potential noninvasive surrogate marker for lipid deposition and obesity-related metabolic disease risk. We studied the effects of bariatric surgery on CT-derived adipose radiodensities in abdominal and femoral areas and their relationships to circulating metabolites in morbidly obese patients. Methods and results: We examined 23 morbidly obese women who underwent CT imaging before and 6 months after bariatric surgery. Fifteen healthy non-obese women served as controls. Radiodensities of the abdominal subcutaneous (SAT) and visceral adipose tissue (VAT), and the femoral SAT, adipose tissue masses were measured in all participants. Circulating metabolites were measured by NMR. At baseline, radiodensities of abdominal fat depots were lower in the obese patients as compared to the controls. Surprisingly, radiodensity of femoral SAT was higher in the obese as compared to the controls. In the abdominal SAT depot, radiodensity strongly correlated with SAT mass (r Z -0.72, p < 0.001). After surgery, the radiodensities of abdominal fat increased significantly (both p < 0.01), while femoral SAT radiodensity remained unchanged. Circulating ApoB/ApoA-I, leucine, valine, and GlycA decreased, while glycine levels significantly increased as compared to pre-surgical values (all p < 0.05). The increase in abdominal fat radiodensity correlated negatively with the decreased levels of ApoB/ApoA-I ratio, leucine and GlycA (all p < 0.05). The increase in abdominal SAT density was significantly correlated with the decrease in the fat depot mass (r Z -0.66, p Z 0.002). Conclusion: Higher lipid content in abdominal fat depots, and lower content in femoral subcutaneous fat, constitute prominent pathophysiological features in morbid obesity. Further studies are needed to clarify the role of non-abdominal subcutaneous fat in the pathogenesis of obesity. Clinical trial registration number: NCT01373892.

Serum Metabolite Profile Associated with Sex-Dependent Visceral Adiposity Index and Low Bone Mineral Density in a Mexican Population

“…In the present study, low glycine, arginine, and citrulline levels were associated with high VAI. Several studies have associated the non-essential amino acids (glycine and arginine), and citrulline, a metabolite of arginine, with an improved glycemic control [ 45 , 46 , 47 ], lower adiposity, and decreased risk factors for developing metabolic syndrome [ 48 ]. Interestingly, we found enrichment in glycine, serine, and threonine metabolism in our metabolic pathway analysis.…”

Metabolomic signatures after bariatric surgery – a systematic review

“…The upregulation of BCAAs catabolism is supported by the consistent postoperative decline of specific subproducts of BCAAs' mitochondrial oxidation, namely short chain acylcarnitine's C3 and C5 [17,18,28,30,43]. Although BCAAs decrease after both restrictive and malabsorptive surgeries [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][35][36][37], parallel arm studies reported a greater effect of RYGB in BCAAs levels [27,31]. Since the differences found in BCAA levels when comparing RYGB and the restrictive procedures seem to be independent of the weight loss, these were hypothesized to be related to impaired AAs absorption induced by the RYGB intestinal rearrangement [27,31].…”

“…Numerous studies demonstrated that circulating levels of valine [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34], isoleucine [17-24, 26, 27, 29-36], leucine [17-24, 26, 27, 29-33, 35-37], phenylalanine [17,18,20,21,23,24,[26][27][28][29]37], tyrosine [17-21, 23, 24, 27, 29, 30, 37], tryptophan [17,21,24,29,37,38], alanine [17-21, 23, 28, 30, 33, 39], proline [17-19, 21, 28, 39], methionine [18,23,30], aspartate [21], threonine [19,21,32], lysine [19] and ornithine [18,...…”

Ectopic fat in liver and skeletal muscle is associated with shorter overall survival in patients with colorectal liver metastases

“… 11 In visceral and subcutaneous adipose tissue, a low radiation attenuation probably is an indicator of high adipose tissue lipid content as it is associated with increased adipocyte size, high adipose tissue mass, and increased serum lipoprotein levels in obese individuals. 12 , 13 While adipose tissue fat content has been poorly studied in cancer, myosteatosis has been associated with decreased overall survival in several cancer types. 14 , 15 , 16 However, the aetiology of myosteatosis is not fully understood.…”