GH and the insulin like growth factor type I (IGF-I) have synergistic functions on protein synthesis and muscle mass. In adipose tissue, GH stimulates lipolysis and lipid oxidation, while IGF-I stimulates the differentiation of pre adipocytes to adipocytes. In glucose metabolism , GH and IGF-I have antagonist opposite actions, been GH antagonist and IGF-I synergetic to insulin sensitivity (IS). Heterozygous adults individuals for the mutation c.104 = 1G> A in the GH releasing hormone receptor gene (MUT/N), present a mild reduction of GH and normal IGF-I levels accompanied by a significant reduction in lean body mass (Kg), with a tendancy of reduction in fat mass (kg), compared to homozygous normal adults individuals (N/N). IS and the beta cell function are unknown in individuals MUT/ N. To evaluate them, it was performed the oral glucose tolerance test with administration of 75g of glucose and serum glucose and insulin were measured at 0, 30, 60, 90, 120 and 180 minutes in 25 individual MUT/ N (12 M / 13 F, 40.08 ± 10.87 years) and 25 N/N (14 M / F 11; 39.96 ± 12.49 years). There was no difference in height, nevertheless weight, BMI, waist and hip circunferences were lower in individuals MUT/N. IS was assessed by HOMAir, where lower values indicate a greater IS and the QUICKI, OGIS 2 and OGIS 3, where higher values indicate higher SI. The beta cell function was assessed by HOMA-beta, insulinogenic index and area under the curve of insulin / glucose ratio (ASC I/G). ANOVA showed no difference between glucose and insulin responses between the groups. The areas under the curve of glucose and insulin were also similar between the number of patients with pre diabetes and diabetes. No changes were observed in the HOMAir, QUICKI, OGIS 2 and OGIS 3, HOMA beta, insulinogenic index and ASC I/G between the two groups. In conclusion, insulin sensitivity and beta cell function in MUT/N individuals are similar to MUT/N individuals. / GH e o fator de crescimento semelhante à insulina tipo I (IGF-I) apresentam funções sinérgicas sobre a síntese protéica e massa muscular. No tecido adiposo, o GH estimula a lipólise e oxidação lípidica, enquanto o IGF-I estimula a diferenciação dos pré adipócitos em adipócitos. No metabolismo glicídico, GH e IGF-I têm ações opostas, sendo o GH antagônico e o IGF-I sinérgico à sensibilidade insulínica (SI). Indivíduos heterozigóticos adultos para a mutação c.104=1G>A gene do receptor do hormônio liberador do GH (MUT/N) no, apresentam discreta redução do GH e níveis normais de IGF-I acompanhada de redução significativa da massa magra (Kg), com tendência à redução da massa gorda (Kg), em relação aos indivíduos homozigóticos normais (N/N). A SI e a função das células beta são desconhecidas nos indivíduos MUT/N. Para avaliá-las, foi realizado o teste de tolerância oral à glicose com administração de 75g de glicose e dosagens de glicose e insulina nos tempos 0, 30, 60, 90, 120 e 180 minutos em 25 indivíduos MUT/N (12 M/ 13 F; 40,08 ± 10,87 anos) e 25 N/N (14 M/ 11 F; 39,96 ± 12,49 anos). Não houve diferença na altura, contudo o peso, o IMC, a cintura e o quadril foram menores nos indivíduos MUT/N. A sensibilidade à insulina (SI) foi avaliada pelo HOMAir, onde menores valores, indicam maior SI e pelos QUICKI, OGIS 2 e OGIS 3, onde maiores valores, indicam maior SI. A função da célula beta foi avaliada pelo HOMA-beta, índice insulinogênico e área sob a curva da razão insulina/ glicose (ASC I/G). ANOVA indicou que não houve diferença entre as respostas glicêmica e insulinêmica entre os grupos. As áreas sob a curva de glicose e insulina foram semelhantes como também entre o número de pacientes com pré diabetes e diabetes. Não foram verificadas variações no HOMAir, QUICK, OGIS 2 e OGIS 3, HOMA beta, índice insulinogênico e ASC I/G entre os dois grupos. Em conclusão, a sensibilidade insulínica e a função de célula beta nos indivíduos MUT/N são semelhantes a dos indivíduos N/N.

The aim of this study was to assess the dissociation between the presence of cardiovascular risk factors, and the lack of premature atherosclerosis and left venticular hipertrophy (LVH) in isolated GH deficiency (IGHD) due to a mutation in the GH releasing hormone receptor gene. A two step protocol was performed. In the first experiment, serum adiponectin and leptin, and urinary albumin excretion (UAE) were studied in 20 IGHD individuals (7 M/ 13 F; 50,8 ± 14,6 years) and 22 control subjects (C) (8 M/ 14 F; 49,9 ± 11.5 years). IGHD subjects in comparison to C presents high adiponectin levels (p= 0,041) whereas leptin and UAE were similar. In the second experiment, oral glucose tolerance test (1,75 g/Kg in IGHD and 75 g in C) with glucose and insulin mesuarements at 0, 30, 60, 90, 120 e 180 minutes was performed in 24 IGHD subjects (12 M/ 12 F; 39,25 ± 11,73 years) and 25 C subjects (14 M/ 11 F; 39,96 ± 12,49 years). Insulin sensitivity (IS) was assessed by HOMAir, lower values, higher IS; QUICKI, OGIS 2 and OGIS, higher values, higher IS (for the three parameters). Beta cell function was assayed by HOMA-beta, insulinogenic index and area under the curve of the relation between insulin and glucose (AUC I/G). ANOVA indicated glucose response was higher (p<0,0001) and insulin response presented a trend of reduction (p=0,08) in the IGHD gruop. The number of pacients with glucose intolerance was higher (p= 0,001) in the IGHD group. HOMAir was lower (p= 0,041), QUICKI and OGIS 2 showed a trend of elevation (p= 0,066 and p= 0,09, respectively) in the IGHD subjects, whereas OGIS 3 showed no difference between both groups. IGDH presented reduction in HOMA-beta (p= 0,015), insulinogenic index (p<0,0001) and AUC I/G (p=0,02). These different adipokine profile with high adiponectin and normal leptin levels, linked to normal insulin sentitivity may delay vascular damage, LVH and lesions of the renal endothelium (normal UAE). Normal IS and reduced beta cell function featured this IGDH model. / O objetivo deste trabalho foi aprofundar a avaliação da dissociação entre a presença de marcadores de risco cardiovascular (CV) e a ausência de doença CV (DCV) na deficiência isolada do GH (DIGH) por mutação no gene do receptor do hormônio liberador do GH. Foi realizado um protocolo com duas etapas. No primeiro experimento, foram avaliados os níveis séricos de adiponectina e leptina e a excreção urinária de albumina (EUA) em 20 indivíduos com DIGH (7 M/ 13 F; 50,8 ± 14,6 anos) e 22 controles (C) (8 M/ 14 F; 49,9 ± 11.5 anos). Os indivíduos com DIGH em comparação a C apresentaram adiponectina mais elevada (p= 0,041) sem alteração nos níveis de leptina e EUA. No segundo experimento, foi realizado teste de tolerância à glicose oral de glicose (1,75 g/kg no DIGH e 75 g no C) com dosagens de glicose e insulina nos tempos 0, 30, 60, 90, 120 e 180 minutos em 24 indivíduos DIGH (12 M/ 12 F; 39,25 ± 11,73 anos) e 25 C (14 M/ 11 F; 39,96 ± 12,49 anos). A sensibilidade à insulina (SI) foi avaliada pelo HOMAir, onde menores valores, indicam maior SI; e pelos QUICKI, OGIS 2 e OGIS 3, onde maiores valores, indicam maior SI. A função da célula beta foi avaliada pelo HOMA-beta, índice insulinogênico e área sobre a curva da razão insulina/ glicose (ASC I/G). ANOVA indicou que a resposta glicêmica (p< 0,0001) foi maior e a insulinêmica apresentou uma tendência de redução (p= 0,08) no grupo DIGH. O número de pacientes com intolerância à glicose foi maior (p= 0,001) no grupo DIGH. HOMAir foi mais baixo (p= 0,031), e QUICK e OGIS 2 apresentaram uma tendência de elevação (p= 0,066 e p= 0,09, respectivamente) no grupo DIGH, enquanto o OGIS 3 foi semelhante nos dois grupos. DIGH apresentou HOMA-beta (p= 0,015), índice insulinogênico (p< 0,0001) e ASC I/G (p= 0,02) menores. O perfil de adipocinas caracterizado por adiponectina elevada e leptina normal, associado à SI normal pode retardar DCV e disfunção endotelial (EUA normal). SI normal e menor função da célula beta caracterizam este modelo de DIGH.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Doutor em Genética e Bioquímica / CHAPTER II: Purpose: We performed a meta-analysis of randomized trials to assess the effect of metformin on inflammatory markers and metabolic parameters in subjects with diabetes. Methods: We performed comprehensive searches on NCBI, Cochrane, Science Direct databases from 1966 to Jun of 2015. We included randomized trials of at least 4 weeks duration that compared groups with diabetes before and after the treatment with metformin or metformin plus other drugs, and evaluated body mass index, blood glucose, HbA1c and inflammatory parameters such as C-reactive protein, tumor necrosis factor and adiponectin. Results: Pooled results of the 26 trials, with 1760 participants at the end of treatment reduce BMI in 0.9% p=0,0043, as well as, decrease of blood glucose level [SMD -0,411 mg/dL, 95%CI -0,463 to -0,369, I2= 56.62%], HbA1c [SMD -0.479%, 95%CI -0,568 to -0,390, I2= 55.02%], CRP levels [SMD -0,274mg/dL, 95%CI -0,419 to -0,129, I2= 72.78%], TNFα concentration [SMD -0,103pg/ml, 95%CI -0,514 to 0,309, I2= 87.67%] and increase of adiponectin [SMD 0,171μg/ml, 95%CI 0,098 to 0,440, I2= 81.09%] compared with pretreatment. Conclusion: The long-treatment with metformin monotherapy or metformin plus other drugs improves metabolic parameters and induced changes in inflammatory markers in diabetic subject. CHAPTER III: Background: Metformin increases insulin sensitivity by decreasing hepatic glucose production and increasing glucose disposal in skeletal muscle. However, modulation of inflammatory response and CaMKKβ/AMPK/Myosin V activation in gastrocnemius muscle by metformin treatment has not been demonstrated in hypoinsulinemic diabetic rats. Objective: The present study investigated how the metformin improve insulin sensitivity in skeletal muscle of hypoinsulinemic diabetic rats. Methods: Diabetes was induced by streptozotocin (45 mg/kg, intraperitoneally) 10 days prior treatments. On 11th day, diabetic rats were treated with metformin (500 mg/kg, oral gavage), insulin (2U at 08:00 h and 4U at 17:00 h, subcutaneously) or untreated. After 20 days, glycemia was measured and insulin sensitivity was determined by KITT. Serum Insulin, GLUT4, IRSthr, inflammatory markers (NF-κB, IκB, TNF-α and p-JNK) and CAMKK, AMPK and Myosin V in gastrocnemius muscle were determined by ELISA. Results: As expected, insulin and metformin improved the insulin sensitivity. Besides, metformin treatment promoted reduction in inflammatory response mediated by NF-κB, IκB, TNF-α and p-JNK, and that was accompanied by increased CaMKKβ/AMPK/Myosin V/GLUT4 pathway activity in gastrocnemius muscle of diabetic rats. Conclusion: Our findings suggest that metformin induces significant reductions in several inflammatory markers in skeletal muscle of diabetic rats. Metformin-induced increase in CaMKKβ/AMPK/Myosin V/GLUT4 pathway activity was associated with higher insulin sensitivity. CHAPTER IV: Diabetes is characterized by a proinflammatory state which can activate TLR2 and TLR4, and these receptors could induce NF-κB and JNK activation in skeletal muscle. In this study, we investigated the inflammatory and apoptotic signaling pathways triggered by TLRs/NF-κB and JNK activation in skeletal muscle of diabetic rats treated with metformin before and after an insulin tolerance test. Metformin treatment decreased p-JNK and NF-κB, and increased IκB concentrations. This attenuation leads to a decrease of TNFα and CXCL1/KC, and an increase of p-AMPK, BAX and Bcl2 concentration. Furthermore, KITT revealed an improvement of the insulin sensitivity in the diabetic rats treated with metformin. In addition, metformin was not capable of attenuating the changes in the inflammatory pathway triggered by insulin injection as the increase of TNFα and TLR4 in metformin treated rats, and IκB, CXCL1/KC, TNFα and p-AMPK increase in the untreated group. Taken together, these results point out that metformin may attenuate the activation of the inflammatory pathway TLRs/NF-κB/TNFα/CXCL1/KC and the apoptotic signaling BAX/Bcl2/p-JNK, which could be accompanied by a reduction of the inflammatory damage caused by hyperglycemia and an improvement of insulin sensitivity in diabetic rats.