Evaluación del ffecto modulador del factor de cecimiento similar a la insulinaa tipo i (igf-i) en linfocitos t de bazo de ratas sometidas a estrés nutricional / Evaluation of the modulating effect of type-i insulin-like growthfactor (igf-i) in rat spleen-t lymphocytes under nutritional stress / Avaliacáo doefeiito modulador do factor de cescimento similar a insulina tiipo i (igf-i) em linfócitos t de baço de ratos submetidos a stress nutricional

En este trabajo se estudió el papel del factor de crecimiento similar a la insulina tipo I (IGF-I) como factormodulador del estrés inducido por una restricción proteica en la dieta, en linfocitos T de bazo de rata. Se encontró que la restricción proteica disminuye el peso corporal en un 15%, el peso del bazo en un 32% y la población total de linfocitos T en un 42%. Igualmente, se observó en la población restringida un incremento en los porcentajes de las subpoblaciones T-CD4, T-CD8 y linfocitos B, y una relación T-CD4/T-CD8 disminuida, lo que sugiere una función inmune afectada por la malnutrición. También se halló que los cultivos de linfocitos provenientes de bazo de ratas en restricción proteica presentanmenor proliferación que los provenientes de ratas bien alimentadas; dicha proliferación se incrementa al adicionar IGF-I de manera dependiente de la dosis. Esta respuesta depende, también, del contenido de proteína en la dieta, observándose una mayor y más pronta respuesta a IGF-I en el grupo bien nutrido. La concanavalina A incrementó, igualmente, la proliferación en ambos grupos de animales, y al combinarla con IGF-I se presentó un sinergismo en la respuesta. En este trabajo se encontró, también, que la restricción proteica incrementa la apoptosis de los linfocitos T, y que la adición de IGF-I logra proteger dichas células de la apoptosis soportando el papel inmunomodulador de esta hormona en estrés nutricional.

In this work we studied the role of Insulin- like Growth Factor-I (IGF-I) as stress modulator in spleen T-lymphocytes from protein restricted rats. In protein restriction we found 15% lowered body weight, 32% lowered spleen weight and a reduction of 42% in total T-cell population. Also, increased percentages of T-CD4, T-CD8 and B cell populations and lowered T-CD4/T-CD8 ratio was observed, suggesting an impaired immune function due to malnutrition. Cultures of spleen T-lymphocytes from protein restricted rats showed less proliferation than the ones from well fed rats, this proliferation was increased after the addition of IGF-I in a dose depending manner. This answer depends, also, from the protein content of the diet, since the well fed animals showed a higher and faster answer. Concanavaline A, also, increased proliferation in both groups of rats and when combined with IGF-I a synergistic answer was found. In this work we also found that protein restriction increased apoptosis of T-lymphocytes, and the addition of IGF-I helped in the recovery of those cells supporting the immunomodulator role of IGF-I in nutritional stress.

Neste trabalho foi estudado o papel de Factor de Crescimento Similar à Insulina Tipo I (IGF-I) como factor modulador do stress induzido por uma restrição proteica em linfócitos T de baço de rato. Encontrou- se que a restrição proteica diminui o peso corporal em 15%, o peso do baço dos animais em 32% e a população total de linfócitos T em 42%. Igualmente, se observou uma alteração nas percentagens das subpopulações T-CD4, T-CD8 e linfócitos B, e uma relação T-CD4/T-CD8 diminuída que sugere uma função imune afectada pela má nutrição. Foi encontrado que os cultivos de linfócitos provenientes do baço de rato em restrição proteica apresentam menor proliferação que os provenientes de ratos bem alimentados; dita proliferação incrementa ao adicionar IGF-I de maneira dependente da dose. Esta resposta depende, também, do conteúdo de proteína na dieta, observando- se uma maior e mais rápida resposta a IGF-I no grupo bem nutrido. A concavalina A incrementou, igualmente, a proliferação em ambos grupos de animais, e ao combiná-la com IGF-I apresentou-se um sinergismo na resposta. Nesta investigação também foi encontrado que a restrição proteica incrementa a apoptose dos linfócitos T e que a adição de IGF-I permite proteger estas células da apoptose dando suporte ao papel imunomodulador desta hormona em stress nutricional.

Insulin-like Growth Factor(IGF)-I and IGF-Binding Protein-3 in Relation to Hemoglobin Concentration in Healthy Infants

PURPOSE: Insulin-like growth factor(IGF-I) and IGF binding protein(IGFBP)-3 is thought to play an important role in fetal erythropoiesis. The objective of this study was to establish a relation between IGF-I, free IGF-I, IGFBP-1, and -3 with hemoglobin level in healthy term, 3-month, and 12-month old infants. METHODS: Healthy term infants(n=20)were enrolled at birth, as well as 3 months

Growth Status and Levels of Growth Factors in Children with Insulin-dependent Diabetes Mellitus

PURPOSE: It is well known that the linear growth velocity in children with insulin-dependent diabetes mellitus (type 1 DM) is closely related to metabolic control and onset age of the disease. Many studies have demonstrated growth impairment in children with type 1 DM, regardless of the degree of metabolic control, whereas other studies have found no growth retardation. Therefore, we examined the growth status and the level of growth factors in children with type 1 DM, and compared them with healthy children. METHODS: Thirty-six patients with type 1 DM (21 female, 15 male; mean age, 10.8 years : range, 5-15 years)were studied. The mean duration of type 1 DM in these patients was 2.7 years (range, 0.1-7.0 years). Their growth status in height standard deviation score (HTSDS) and levels of insulin-like growth factor (IGF)-I, free IGF-I, IGF-II and IGF-binding protein (IGFBP)-3 were compared with age and sex matched normal children (21 female, 15 male; mean age, 10.3 years; range, 5-15 years). RESULTS: As HTSDS in type 1 DM, children were 0.4 +/- 1.1, no prominent growth impairment was observed in type 1 DM children. IGF-I and IGF-II levels decreased significantly in type 1 DM, but no significant differences in free IGF-I and IGFBP-3 levels compared to normal. Height in type 1 DM children was in direct correlation with free IGF-I (r=0.35, P<0.05) and IGFBP-3 (r= 0.45, P<0.01), respectively. CONCLUSION: This study reveals that the levels of IGF-I and -II are decreased in children with type 1 DM, whereas free IGF-I levels are not. These findings may be related to the decreased IGFBP-3 levels in diabetic children, and may explain no growth impairment, except in cases of extremely poor metabolic control.

Growth Status and Levels of Growth Factors in Children with Insulin-dependent Diabetes Mellitus

PURPOSE: It is well known that the linear growth velocity in children with insulin-dependent diabetes mellitus (type 1 DM) is closely related to metabolic control and onset age of the disease. Many studies have demonstrated growth impairment in children with type 1 DM, regardless of the degree of metabolic control, whereas other studies have found no growth retardation. Therefore, we examined the growth status and the level of growth factors in children with type 1 DM, and compared them with healthy children. METHODS: Thirty-six patients with type 1 DM (21 female, 15 male; mean age, 10.8 years : range, 5-15 years)were studied. The mean duration of type 1 DM in these patients was 2.7 years (range, 0.1-7.0 years). Their growth status in height standard deviation score (HTSDS) and levels of insulin-like growth factor (IGF)-I, free IGF-I, IGF-II and IGF-binding protein (IGFBP)-3 were compared with age and sex matched normal children (21 female, 15 male; mean age, 10.3 years; range, 5-15 years). RESULTS: As HTSDS in type 1 DM, children were 0.4 +/- 1.1, no prominent growth impairment was observed in type 1 DM children. IGF-I and IGF-II levels decreased significantly in type 1 DM, but no significant differences in free IGF-I and IGFBP-3 levels compared to normal. Height in type 1 DM children was in direct correlation with free IGF-I (r=0.35, P<0.05) and IGFBP-3 (r= 0.45, P<0.01), respectively. CONCLUSION: This study reveals that the levels of IGF-I and -II are decreased in children with type 1 DM, whereas free IGF-I levels are not. These findings may be related to the decreased IGFBP-3 levels in diabetic children, and may explain no growth impairment, except in cases of extremely poor metabolic control.