RESUMO
Bone loss is a potential adverse consequence of rapid and sustained weight loss after bariatric surgery. The aim of the present study was to evaluate the bone mass, body fat distribution, and metabolic parameters in women submitted to Roux-en-Y gastric bypass (RYGB). The study included the following three groups: one group of lean women (control [C] group) and two groups of obese women, one evaluated one year (B1) and the other five years (B5) after RYGB. Dual-energy X-ray absorptiometry and magnetic resonance imaging were used to determine bone mineral density (BMD; lumbar spine, total hip, and femoral neck) and abdominal fat content (subcutaneous [SAT] and visceral [VAT] adipose tissues, and intrahepatic lipids [IHL]). The BMD/body mass index ratio was lower in the B5 compared with the C group at all sites. Serum C-terminal telopeptide of type I collagen (CTX) levels were higher in the B1 and B5 groups compared with the C group. Individuals submitted to RYGB showed greater SAT but similar VAT and IHL values compared with those in the C group. However, the B5 group had higher mean parathyroid hormone levels compared with the other two groups. Individuals submitted to RYGB presented increased levels of CTX and low BMD for body weight than those in the C group, suggesting that bone catabolism is a persistent alteration associated with RYGB. In conclusion, the long-lasting metabolic benefits obtained with RYGB in obesity are counterbalanced by a persistent catabolic effect of the procedure on bone and mineral metabolism.
Assuntos
Doenças Ósseas Metabólicas , Derivação Gástrica , Obesidade Mórbida , Absorciometria de Fóton , Densidade Óssea , Osso e Ossos , Feminino , Derivação Gástrica/efeitos adversos , Humanos , Obesidade Mórbida/cirurgiaRESUMO
Bone loss is a potential adverse consequence of rapid and sustained weight loss after bariatric surgery. The aim of the present study was to evaluate the bone mass, body fat distribution, and metabolic parameters in women submitted to Roux-en-Y gastric bypass (RYGB). The study included the following three groups: one group of lean women (control [C] group) and two groups of obese women, one evaluated one year (B1) and the other five years (B5) after RYGB. Dual-energy X-ray absorptiometry and magnetic resonance imaging were used to determine bone mineral density (BMD; lumbar spine, total hip, and femoral neck) and abdominal fat content (subcutaneous [SAT] and visceral [VAT] adipose tissues, and intrahepatic lipids [IHL]). The BMD/body mass index ratio was lower in the B5 compared with the C group at all sites. Serum C-terminal telopeptide of type I collagen (CTX) levels were higher in the B1 and B5 groups compared with the C group. Individuals submitted to RYGB showed greater SAT but similar VAT and IHL values compared with those in the C group. However, the B5 group had higher mean parathyroid hormone levels compared with the other two groups. Individuals submitted to RYGB presented increased levels of CTX and low BMD for body weight than those in the C group, suggesting that bone catabolism is a persistent alteration associated with RYGB. In conclusion, the long-lasting metabolic benefits obtained with RYGB in obesity are counterbalanced by a persistent catabolic effect of the procedure on bone and mineral metabolism.
RESUMO
The present study suggests that insulin resistance has no association with bone quantity, but quality. INTRODUCTION: The literature has contradictory results concerning the influence of insulin resistance on bone. The present study sought to evaluate the association of insulin resistance and adipose tissue with either bone mineral density or the trabecular bone score. METHODS: The study included 56 individuals (36 women and 20 men): age = 46.6 ± 14.2 years, weight = 67.8 ± 10.9 kg, height = 1.65 ± 0.10 m and BMI = 24.8 ± 3.9 kg/m2. The investigational protocol included biochemical determinations and bone assessment by dual X-ray absorptiometry for evaluation of bone mineral density and trabecular bone score. Magnetic resonance was employed to estimate visceral, subcutaneous and bone marrow adipose tissues, as well as intrahepatic lipids. RESULTS: The bone mineral density of the lumbar spine, femoral neck and total hip were not associated with insulin resistance-related parameters [visceral adipose tissue, intrahepatic lipids and homeostatic model assessment of insulin resistance (HOMA-IR)]. In contrast, there was a negative relationship between the trabecular bone score and all these components. The association between the trabecular bone score and HOMA-IR was reinforced after adjustment for age and BMI. Marrow adipose tissue was negatively associated with both bone mineral density and trabecular bone score. CONCLUSIONS: The present study shows that the trabecular bone score is negatively associated with marrow adipose tissue, insulin resistance, visceral adipose tissue and intrahepatic lipid measurements. Additionally, there was a negative relationship between saturated lipids in marrow adipose tissue and the trabecular bone score. These results encourage further studies to investigate the role of the trabecular bone score exam in the clinical evaluation of osteoporosis in conditions of insulin resistance.
Assuntos
Tecido Adiposo/diagnóstico por imagem , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Resistência à Insulina , Absorciometria de Fóton , Adulto , Medula Óssea , Feminino , Humanos , Gordura Intra-Abdominal , Lipídeos/análise , Fígado/química , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-IdadeRESUMO
Metalloproteinases (MPs) are Zn(+)-dependent endoproteolytic enzymes, abundant in crotalid and viperid snake venoms. Most snake venom metalloproteinases (svMPs) are active on extracellular matrix components and this effect is thought to result in bleeding as a consequence of the basement membrane disruption in capillaries. Jararhagin and ACLH are hemorrhagic svMPs from Bothrops jararaca and Agkistrodon contortrix laticinctus venom, respectively. Both enzymes demonstrate proteolytic activity on fibrinogen and fibronectin and jararhagin inhibits collagen-induced platelet aggregation in vitro. This work describes the expression, purification and successful refolding of the recombinant ACLH zymogen (rPRO-ACLH) as well as the catalytic domain of jararhagin (rCDJARA). The heterologous proteins were produced in E. coli, an in vivo expression system that does not make post-translational modifications. The recombinant refolded proteins did not show any hemorrhagic activity in mice skin, as well as the native deglycosylated jararhagin and ACLH. However, they preserved their proteolytic activity on fibrinogen and fibronectin. It seems that the hemorrhagic properties of these hemorrhagins are dependent on post-translational modifications, whereas their proteolytic activity is not dependent on such modifications.