Bariatric Roux-En-Y Gastric Bypass Surgery: Adipocyte Proteins Involved in Increased Bone Remodeling in Humans.

PURPOSE: Bariatric surgery has been associated with bone remodeling changes. The action of adipokines on the expression of receptor activator of nuclear factor kappa ß ligand (RANKL) and osteoprotegerin (OPG) and on an increase in sclerostin could be related to these changes. MATERIALS AND METHODS: This study aimed to assess the repercussions of weight loss, fat mass (FM), and fat-free mass (FFM) loss and biochemical and hormonal changes on bone remodeling markers after Roux-en-Y gastric bypass (RYGB). Anthropometric data, parathyroid hormone (PTH), bone-specific alkaline phosphatase (BSAP), collagen type 1 C-telopeptide (CTX), 25-hydroxy vitamin D (25-OH-VitD), leptin, adiponectin, RANKL, OPG, and sclerostin of 30 menstruating women were measured preoperatively (Pre), and 3, 12, and 24 months (m) after RYGB. RESULTS: Leptin (34.4 (14.7; 51.9) vs. 22.5 (1.9; 52.7) ng/mL) and OPG (3.6 (1.1; 11.5) vs. 3.4 (1.5; 6) pmol/L) decreased, and adiponectin (7.4 (1.7; 18.4) vs. 13.8 (3.0; 34.6) µg/mL), CTX (0.2 (0.1; 2.2) vs. 0.6 (0.4; 6.0) ng/mL), RANKL (0.1 (0.0; 0.5) vs. 0.3 (0.0; 2.0) pmol/L), and sclerostin (21.7 (3.2; 75.1) vs. 34.8 (6.4; 80.5) pmol/L) increased after 3 m. BSAP increased after 12 m (10.1 (5.4; 18.9) vs. 13.9 (6.9; 30.2) µg/mL) (p < 0.005). CTX correlated positively with adiponectin at 24 m and inversely with leptin Pre; OPG at 3 m; weight, FM, FFM, and leptin at 24 m. RANKL correlated directly with weight at 3 m. Sclerostin correlated inversely with weight Pre and FM at 3 m. BSAP correlated negatively with 25-OH-VitD at 12 m, and positively with PTH at 24 m. CONCLUSIONS: RYGB induced weight loss, and biochemical, hormonal, and body composition changes are associated with higher bone remodeling.

Weight-reducing gastroplasty with Roux-en-Y gastric bypass: impact on vitamin D status and bone remodeling markers.

BACKGROUND: Despite the weight loss benefits of bariatric surgery, studies have shown considerably compromised nutritional conditions, particularly in relation to bone metabolism, in patients who have undergone this procedure. The goal of this study was evaluate bone metabolism alterations after gastroplasty through the concentrations of carboxy-terminal cross-linking telopeptides of type-I collagen (CTX) and bone-specific alkaline phosphatase (BSAP) and vitamin D status. METHODS: This study, conducted at the Botucatu School of Medicine University Hospital, UNESP, analyzed 22 women with body mass index (BMI) values higher than 35 kg/m(2) who had undergone Roux-en-Y gastric bypass (RYGB) surgery, prior to and 3 and 6 months after the procedure. RESULTS: The patients were evaluated in relation to their anthropometric profile. Obese patients showed a vitamin D status that was compatible with moderate depletion, thus correlating negatively with parathyroid hormone (PTH) and positively with CTX. After surgery, 25-hydroxyvitamin D [25(OH)D] and CTX concentrations increased significantly. Other tests (calcium, phosphorus, magnesium, total AP and BSAP, and PTH) did not differ between the times of analysis and remained stable within the range of normality. Body fat correlated only with 25(OH)D concentrations and was inversely proportional to their increase. There was a positive correlation between PTH and CTX prior to surgery. CONCLUSIONS: Hypovitaminosis D is prevalent in obese individuals, and RYGB is related to CTX increase without BSAP alteration in the first follow-up semester.