The aromatase inhibitor letrozole increases epiphyseal growth plate height and tibial length in peripubertal male mice

Sex hormones may influence longitudinal growth, either indirectly, by affecting the growth-hormone-insulin-like growth factor I (IGF-I) axis, or directly, by affecting changes within the epiphyseal growth plate (EGP). The aim of the present study was to investigate the effects of letrozole, an aromatase inhibitor, on longitudinal growth and changes in the EGP in vivo. Eighteen peripubertal male mice were divided into three groups. The first group was killed at baseline, the second was injected with letrozole (Femara) s.c., 2 mg/kg body weight/day, for 10 days, and the third was injected with the vehicle alone. Serum testosterone levels were found to be significantly higher in the treated group than in the controls. Letrozole induced a significant increase in body weight, tail length and serum growth hormone level, but had no significant effect on the level of serum IGF-I. On histomorphometric study, there was a significant increase (12%) in EGP height in the treated animals compared with controls. Immunohistochemistry showed a 3.4-fold letrozole-induced increase in the proliferation of the EGP chondrocytes, as estimated by the number of proliferation cell nuclear antigen-stained cells, and a decrease in the differentiation of the EGP chondrocytes, as estimated by type X collagen staining. Letrozole did not interfere with type II collagen levels. The study group also showed a twofold increase in the number of IGF-I receptor-positive cells compared with controls. In conclusion, the aromatase inhibitor, letrozole, appears to increase the linear growth potential of the EGP in mice.

Prepubertal gynaecomastia: aetiology, course and outcome

BACKGROUND

Palpable and measurable glandular breast tissue is a rare finding in prepubertal boys and warrants thorough evaluation to rule out an underlying pathology.

OBJECTIVE

To characterize the course and outcome of prepubertal gynaecomastia, examine its effect on puberty, and try to identify its underlying cause.

PATIENTS AND METHODS

Twenty-nine out of 581 (5%) boys referred to our clinic for evaluation of gynaecomastia between 1980 and 2000 were prepubertal at diagnosis. Data on age at appearance of gynaecomastia, general and endocrine evaluation, course of growth and puberty, and treatment were collected from the medical files.

RESULTS

Prepubertal gynaecomastia was diagnosed at mean age of 8.9 +/- 2.2 years. In 27 of the 29 boys (93.2%) no underlying cause was identified. The remaining two boys (6.8%) had hyperaromatase syndrome. Nine boys (31%) were obese. Spontaneous resolution was recorded in six boys (20.5%), no change in 15 (52%), and further breast enlargement in eight (including the two with hyperaromatase syndrome) (27.5%). Accelerated growth and bone maturation rates were noted only in the two boys with hyperaromatase syndrome. Pubertal onset was documented in 13 boys at 11.8 +/- 1.1 years.

CONCLUSIONS

According to our large single tertiary care centre experience, 5% of boys referred for evaluation of gynaecomastia were prepubertal. The development of gynaecomastia was the only abnormality and was not associated with other pubertal signs or accelerated growth rate. In most cases, the gynaecomastia was idiopathic. Further prospective studies are needed to evaluate the pathophysiological mechanisms responsible for this phenomenon.

Why pumps? Continuous subcutaneous insulin infusion for children and adolescents with type 1 diabetes

CSII is a feasible, safe and well-accepted mode of therapy for many children with type 1 diabetes. For a significant number of patients and parents, it serves as a much easier means of coping with the huge daily burden of diabetes. Therefore, we believe that both CSII and MDI should be made available to the diabetic team and the patients to better tailor therapy, improve satisfaction and decrease the fear of hypoglycemia.

Insulin pump therapy for 1-6 year old children with type 1 diabetes

BACKGROUND

The management of diabetes in preschool children poses unique difficulties for both the families and the medical team.

OBJECTIVE

To test the feasibility and safety of insulin pump therapy in the 1-6 year age group in order to improve quality of life and metabolic control.

METHODS

The study group comprised 15 type 1 diabetic children aged 1-6 years old (mean +/- SD, 3.8 +/- 1.2 years) from three diabetes centers. Insulin pump therapy was applied for 12 months. Data, including insulin dose, hemoglobin A1c, hypoglycemic events, as well as scores on the Diabetes Quality of Life Measure Questionnaire and the Diabetes Treatment Satisfaction Questionnaire, were collected and compared with the multiple daily injection treatment prior to entry into the study,

RESULTS

HbA1c was measured at the beginning of the study and at 2, 4, 8 and 12 months later; the respective levels (mean +/- SD) were 8.82 +/- 0.98, 8.45 +/- 1.05, 8.37 +/- 0.85, 8.32 +/- 0.71, 8.18 +/- 0.90%. HbA1c measurements after 12 months were significantly lower than at the beginning of the study (P < 0.05). There were no significant differences in insulin dose and the total number of hypoglycemic events. In both the DQOL and DTSQ scales there were significant differences in scores in favor of the insulin pump period (43.7 +/- 8.0 versus 33.7 +/- 7.9, P < 0.001; and 10.9 +/- 2.3 versus 14.5 +/- 2.3, P < 0.001), respectively.

CONCLUSIONS

For very young diabetic children, insulin pump therapy improves quality of life and is feasible and safe. It should be considered as an optional mode of therapy for this age group.

Familial central precocious puberty suggests autosomal dominant inheritance

The prevalence of precocious puberty is higher in certain ethnic groups, and some cases may be familial. The aim of this study was to investigate the mode of inheritance of familial precocious puberty and to identify characteristics that distinguish familial from isolated precocious puberty. Of the 453 children referred to our center for suspected precocious puberty between January 1, 1997, and December 31, 2000, 156 (147 girls and 9 boys) were found to have idiopathic central precocious puberty, which was familial in 43 (42 girls and 1 boy) (27.5%). Data of the familial and sporadic cases were compared. The familial group was characterized by a significantly lower maternal age at menarche than the sporadic group (mean, 11.47 +/- 1.96 vs. 12.66 +/- 1.18 yr; P = 0.0001) and more advanced puberty at admission (Tanner stage 2, 56.5% vs. 78.1%; P = 0.006). Segregation analysis was used to study the mode of inheritance. The segregation ratio for precocious puberty was 0.38 (0.45 after exclusion of young siblings) assuming incomplete penetrance and 0.58 (0.65 after exclusion of young siblings) assuming complete ascertainment. These results suggest autosomal dominant transmission with incomplete, sex-dependent penetrance.

Continuous glucose monitoring for the evaluation and improved control of gestational diabetes mellitus

OBJECTIVES

To compare the daily glycemic profile reflected by continuous versus self-monitoring of blood glucose in women with gestational diabetes mellitus (GDM), and to evaluate possible differences in treatment strategy based on the two monitoring methods.

MATERIALS AND METHODS

The study sample consisted of 57 women with gestational diabetes, 47 in Israel and ten in California. Gestational age ranged from 24 to 32 weeks in the Israeli women, and 32 to 36 weeks in the American women. Data derived from the Continuous Glucose Monitoring (CGM) System (MiniMed) for 72 h were compared to fingerstick glucose measurements (6-8 times a day). During continuous monitoring, patients documented the timing of food intake, insulin injections and hypoglycemic events.

RESULTS

In the Israeli group, 23 women were treated by diet alone, and 24 by diet plus insulin. An average of 763 +/- 62 glucose measurements was recorded for each patient with continuous glucose monitoring. The mean total time of hyperglycemia (glucose level > 140 mg/dl) undetected by the fingerstick method was 132 +/- 31 min/day in the insulin-treated group and 94 +/- 23 min/day in the diet-treated group. Nocturnal hypoglycemic events (glucose levels < 50 mg/dl) were recorded in 14 patients, all insulin-treated. On the basis of the additional information provided by continuous monitoring, the therapeutic regimen (insulin therapy, diet adjustment, or both) was changed in 36 of the 47 patients. All ten American women were treated with insulin. The mean time of undetected hyperglycemia for a total group monitoring time of 30 days was 78 +/- 13 min/day. Eight women had nocturnal hypoglycemia on at least one of the three nights of monitoring for a total of 12 nights. A change in insulin dosage was made in all women on the basis of the data provided by continuous glucose monitoring.

CONCLUSION

Continuous glucose monitoring is helpful for monitoring women with GDM and for adjusting diabetes therapy. It can accurately detect high postprandial blood glucose levels and nocturnal hypoglycemic events that may go unrecognized by intermittent blood glucose monitoring. A large prospective study on maternal and neonatal outcome is needed to determine the clinical implications of this new monitoring technique.

Leptin reverses the inhibitory effect of caloric restriction on longitudinal growth

Caloric imbalance, particularly in critical periods of growth and development, is often the underlying cause of growth abnormalities. Serum levels of leptin are elevated in obesity and are low in malnutrition and malabsorption. The aim of the present study was to determine whether leptin integrates energy levels and growth in vivo, as shown previously in our ex vivo experiments, even in the presence of caloric restriction. In the first part of the study, mice were divided into three groups. Two groups were fed ad libitum and received leptin or vehicle only, and the third group was pair-fed with the group injected with leptin to dissociate leptin's effect on growth from its effect on food consumption. Mice given leptin had a significantly greater tibial length than untreated pair-fed animals and a similar tibial length as control mice fed ad libitum despite their lower weight. In addition, leptin significantly increased the overall size of the epiphyseal growth plate by 11%. On immunohistochemistry and in situ hybridization studies, leptin stimulated both the proliferation and differentiation of tibial growth plate chondrocytes without affecting the overall organization of the plate. There was also a marked increase in the expression and level of IGF-IR. In the second part of the study, two groups of mice were fed only 60% of their normal chow; one was injected with leptin, and the other was injected with vehicle alone. Caloric deprivation by itself reduced serum levels of IGF-I by 70% and the length of the tibia by 5%. Leptin treatment corrected the fasting-induced growth deficiency, but further reduced the level of serum IGF-I. These results indicate that leptin stimulates growth even in the presence of caloric restriction independently of peripheral IGF-I.

Modulation of Brain Insulin-Like Growth Factor I (IGF-I) Binding Sites and Hypothalamic GHRH and Somatostatin Levels by Exogenous Growth Hormone and IGF-I in Juvenile Rats

The effect of exogenous growth hormone (GH) and insulin-like growth factor I (IGF-I) on brain IGF-I binding sites (IGF-IR), and on the levels of growth hormone-releasing hormone (GHRH) and somatostatin was studied in hypophysectomized and intact juvenile male rats. Animals were injected subcutaneously twice daily (n = 5 each) with recombinant GH (rGH) (2.5 U/kg per day) or rIGF-I (500 microg/kg per day). In the hypophysectomized rats, serum GH and IGF-I levels were markedly suppressed and IGF-I levels were partially restored by GH treatment. There was a significant increase in IGF-IR binding capacity in the IGF-I-treated hypophysectomized rats compared to the saline-treated hypophysectomized animals (150.61 +/- 45.66 vs 41.32 +/- 12.42 fmol/mg, p < 0.05) but no significant difference in IGF-IR mRNA levels. GHRH levels in the saline-treated hypophysectomized group were significantly lower than in the saline-treated intact rats (31.2 +/- 11.2 vs 140.6 +/- 48.1 pg/mg tissue, respectively, p < 0.01); no effect was induced by GH or IGF-I (37.5 +/- 26.8 and 53.8 +/- 22.5 pg/mg tissue, respectively). However, in the intact rats, GH and IGF-I injection led to a decrease in GHRH content, which was significant in the GH-treated compared to the saline-treated animals (33.1 +/- 16.2 vs 140.6 +/- 48.1 pg/mg tissue, p < 0.01). No difference was found in somatostatin levels between intact and hypophysectomized rats (631.2 +/- 81.2 and 625.0 +/- 62.5 pg/mg tissue, respectively). However, in the hypophysectomized animals, GH and IGF-I treatment induced a significant increase in somatostatin levels (1300 +/- 193.7 pg/mg tissue, p < 0.01, and 912.5 +/- 81.2 pg/mg tissue, p < 0.05, respectively). Our findings suggest that the bioavailability of exogenous IGF-I is greater than that of GH-stimulated endogenous IGF-I. Because IGF-I is a potent neurotrophic agent, this effect may have important implications for states of neurodegenerative diseases.

PROP-1 Gene Mutation (R120C) Causing Combined Pituitary Hormone Deficiencies with Variable Clinical Course in Eight Siblings of One Jewish Moroccan Family

BACKGROUND

PROP-1 gene mutations have been described in patients with combined pituitary hormone deficiencies (CPHD).

METHODS

Clinical follow-up and molecular analysis of the PROP-1 gene were performed in 4 affected sisters of one consanguineous family, in whom 8 members had CPHD.

RESULTS

The 4 sisters were homozygous for the same R120C mutation. Growth hormone and thyroid-stimulating hormone deficiencies were diagnosed concomitantly in all subjects, but at different ages (5.5-10.8 years). All 8 subjects exhibited complete gonadotropin deficiency with failure of spontaneous sexual maturation. Adrenocorticotropic hormone deficiency developed in only 2 sisters in the 3rd and 4th decades of life.

CONCLUSIONS

The CPHD in this family, caused by an R120C mutation, was characterized by clinical phenotypic variability in terms of the severity of hormonal deficiencies and the time of their development. Identifying the mutation does not predict the clinical course. Therefore, continuous follow-up with repeated endocrine evaluations is mandatory to provide proper hormone substitution therapy.

Pubertal course of persistently short children born small for gestational age (SGA) compared with idiopathic short children born appropriate for gestational age (AGA)

OBJECTIVE

Few data are available on the pubertal development of children born small for gestational age (SGA) who fail to show catch-up growth.

DESIGN

A longitudinal analysis compared the pubertal course of persistently short children born SGA compared to children with idiopathic short stature who were appropriate for gestational age (AGA). One hundred and twenty-eight short children (height SDS<-1.7), including 76 (31 boys) born SGA and 52 (22 boys) born AGA, were regularly followed from early childhood to completion of puberty.

RESULTS

Puberty was attained at normal age (10.5-14 Years in boys, 9.5-13 Years in girls) for most children in both the SGA and AGA groups (boys, 80% and 77%; girls, 76% and 78% respectively). The duration of puberty was similar in the SGA and AGA groups. Menarche occurred at normal age range but was significantly earlier in the SGA girls (P<0.01 by ANOVA). Despite the similar total pubertal growth, the patterns of growth differed significantly: SGA group - accelerated growth and bone maturation rates from onset of puberty with peak height velocity at Tanner stages 2-3, followed by a decelerated growth rate and earlier fusion of the epiphyses; AGA group - steady progression of bone elongation and maturation throughout puberty (pubertal growth, P<0.05 in both sexes; bone maturation, P<0.001 in both sexes). Final height in the SGA group was compromised compared with their target height (P<0.001).

CONCLUSION

Children born SGA have a normal pubertal course with a distinct pubertal growth pattern. This pattern may represent an altered regulation of their growth modalities.

Comparison of continuous subcutaneous insulin infusion and multiple daily injection regimens in children with type 1 diabetes: a randomized open crossover trial

OBJECTIVE

To compare the efficacy and feasibility of continuous subcutaneous insulin infusion (CSII) with multiple daily insulin injections (MDI) in children with type 1 diabetes.

METHODS

The study sample included 23 children (10 males) aged 9.4 to 13.9 years with type 1 diabetes. An open randomized crossover design was used to compare 3.5 months of CSII to 3.5 months of MDI therapy for the following variables: diabetic control, incidence of adverse events, daily insulin requirement, body mass index standard deviation scores, treatment satisfaction, and quality of life.

RESULTS

The changes in HbA(1c) and fructoseamine values were similar in the 2 arms over time. At the end of the study, mean HbA(1c) level measured 8.05 +/- 0.78%. There were no differences between the treatment modes in frequency of symptomatic hypoglycemic or hyperglycemic events. There was 1 event of severe hypoglycemia during pump therapy and 3 during MDI, yielding a rate of 0.26 events per patient-year. There were no episodes of diabetic ketoacidosis. Body mass index standard deviation scores decreased during CSII and increased during MDI, as did mean insulin dose. Patients expressed a higher treatment satisfaction from CSII than MDI, although there was no difference in quality of life between the 2 modes.

CONCLUSIONS

Intensive insulin therapy by either insulin pump or MDI is safe in children and young adolescents with type 1 diabetes, with similar diabetes control and a very low rate of adverse events. We suggest that both modes be available to the diabetic team to better tailor therapy.

Role of obesity and leptin in the pubertal process and pubertal growth--a review

The prevalence of obesity is increasing alarmingly to epidemic proportions in children and adolescents, especially in industrialized countries. The finding that overweight children, especially girls, tend to mature earlier than lean children has led to the hypothesis that the degree of body fatness may trigger the neuroendocrine events that lead to the onset of puberty. Obese children have high leptin levels, and these may play a role in their earlier onset of puberty. Leptin receptors have been identified in the hypothalamus, gonadotrope cells of the anterior pituitary, and ovarian follicular cells, as well as Leydig cells. Leptin accelerates gonadotropin-releasing hormone (GnRH) pulsatility in hypothalamic neurons, and it has a direct effect on the anterior pituitary. Leptin administration at low doses may have a permissive, threshold effect on the central networks that regulate gonadotropin secretion. However, at high levels, such as those in obese people, it can have an inhibitory effect on the gonads. Children with obesity also have increased adrenal androgen levels, which may be involved in the accelerated growth of these children before puberty. Recent data indicate that leptin has a specific role in stimulating the activity of enzymes essential for the synthesis of adrenal androgens. Children with exogenous obesity frequently show an increase in height velocity with tall stature for age despite low growth hormone levels. Our group has shown that leptin acts as a skeletal growth factor, with a direct effect on skeletal growth centers, in the mice mandibular condyle, a model of endochondral ossification. In summary, obesity is associated with early puberty. Elevated leptin levels might have a permissive effect on the pubertal process and pubertal growth.

Continuous glucose monitoring for treatment adjustment in diabetic pregnancies--a pilot study

AIMS

To examine the efficacy of a continuous glucose monitoring (CGM) system for treatment adjustment in patients with diabetic pregnancy treated with insulin.

METHODS

The study sample consisted of eight women with diabetic pregnancy, six with pre-pregnancy Type 1 diabetes mellitus and two with gestational diabetes (GDM), all being treated with multiple daily insulin injections. Gestational age ranged from 24 to 32 weeks. Data derived from the Continuous Glucose Monitoring System (MiniMed) for 72 h were compared with fingerstick glucose measurements (six to eight times a day), and treatment was adjusted on the basis of the findings. Two to four weeks later, the patients were re-evaluated with CGM.

RESULTS

In the first part of the study, an average of 744+/-33 glucose measurements was recorded for each patient with CGM. The mean total time of hyperglycaemia (glucose level >7.7 mmol/l) undetected by the fingerstick method was 152+/-33 min/day. Nocturnal hypoglycaemic events (glucose level <2.7 mmol/l) were recorded in seven patients. Based on the additional information obtained by continuous monitoring, the insulin regimen was changed in all patients. CGM re-evaluation after treatment adjustment showed a reduction in undetected hyperglycaemia to 89+/-17 min/day and in nocturnal hypoglycaemic events, which were recorded in only one patient.

CONCLUSIONS

Continuous glucose monitoring may diagnose high blood glucose levels and nocturnal hypoglycaemic events that are unrecognized by intermittent blood glucose monitoring and could serve as a useful tool for the long-term management of diabetic pregnancies. A large prospective study is needed to determine the clinical implications of this new monitoring technique.

Growth without growth hormone: growth pattern and final height of five patients with idiopathic combined pituitary hormone deficiency

BACKGROUND

Growth without GH has been reported in patients with organic combined pituitary hormone deficiency (CPHD) after resection of craniopharyngiomas and hypothalamic tumours or in septo-optic dysplasia.

METHODS

This study describes the growth pattern and final height of five children (four boys, one girl) with idiopathic CPHD (GH, TSH, ACTH, LH and FSH) who maintained normal growth despite persistent GH deficiency throughout the growth period.

RESULTS

Presenting findings were borderline small penis in two children diagnosed at ages 3 and 9 years, and absence of pubertal signs in three adolescents diagnosed at age 12.8-13.7 years. The latter three patients also exhibited acromegaloid features. The height of all patients was within the 10-25th percentiles, and weight at the 25-50th percentiles. Although they were moderately overweight, accelerated weight gain was not observed. Prepubertal growth rate was 4-5 cm/year. The pubertal growth period, starting after initiation of sex hormone therapy (chronological age 15.9-16.3 years and bone age 12.5-14.5 years) continued for 4-5.5 years. Total pubertal growth was 6-11.7 cm with reduced growth spurt. Final height, which was attained at an advanced age (19-22 years), was 170-179 cm in the boys and 164 cm in the girl, equal to or exceeding the target height range. Repeated hormonal evaluations revealed undetectable GH and IGF-I levels, and no evidence of hyperprolactinaemia or hyperinsulinism.

CONCLUSIONS

Final height attainment within or above target height range may occur in patients with idiopathic CPHD despite persistent GHD. As this was not mediated by GH, IGF-I, insulin or prolactin, some other growth factors probably played a growth-promoting role.

Craniopharyngioma: presentation and endocrine sequelae in 36 children

We studied the clinical presentation by age of 36 children with craniopharyngioma, and outcome by height and body mass index (BMI). Presenting symptoms included headache (51.4%), vomiting (31%), visual disturbances (22.9%), polyuria and/or polydipsia (17.1%), delayed puberty (19.4%), short stature (13.8%), and precocious puberty (2.7%). Growth deceleration was overlooked, as was diabetes insipidus (actual rate, 52% for both). Delayed puberty was observed in all patients of appropriate age. Mean height standard deviation score (SDS) at admission was significantly lower than mean target height SDS (p = 0.004), while mean final height SDS was similar (p = 0.14). BMI SDS at last follow-up was similar to mean parental BMI SDS. We conclude that although endocrinopathies are present in most patients with craniopharyngioma, they are rarely the reason for referral. While affected prepubertal children have non-endocrine complaints, most adolescents are referred because of delayed puberty. Diabetes insipidus may be more prevalent in craniopharyngioma than previously reported. When patients with hypothalamic obesity are excluded, mean BMI SDS remains within normal range and is influenced mostly by parental BMI SDS.

Leptin: obesity, diabetes and other peripheral effects--a review

There is an increasing epidemic of obesity in the Western and developing world that has not spared children and, hence, is of great concern. Obesity presents numerous physiological and psychosocial problems for the child. Childhood obesity not only increases the risk of obesity in adulthood, it is associated with type 2 diabetes mellitus; is the leading cause of pediatric hypertension; increases the risk of coronary heart disease; and increases stress on the weight-bearing joints. Social and psychological problems are also significant consequences of obesity in children, with lowering of self-esteem and its effects on relationships with peers. Obesity is clearly associated with increased levels of the recently discovered hormone, leptin. Leptin, secreted from adipocytes, is involved in the regulation of food intake, energy expenditure, and energy balance in humans. This review focuses on the hormone, leptin, in an effort to document some of its many local and systemic effects on the body and, specifically, its potential role in obesity-induced diabetes.

Continuous glucose monitoring for the evaluation of gravid women with type 1 diabetes mellitus

OBJECTIVE

To compare the daily glycemic profile reflected by continuous and intermittent blood glucose monitoring in pregnant women with type 1 diabetes and to compare the treatment protocols based on the two monitoring methods.

METHODS

The study sample consisted of 34 gravid patients at gestational weeks 16-32, with type 1 diabetes being treated by multiple insulin injections. Data derived from the continuous glucose monitoring system for 72 hours were compared with finger stick glucose measurements performed 6-8 times per day. During the study period, patients documented the time of food intake, insulin injections, and hypoglycemic events. Data on demographics, gravidity, parity, body mass index, hemoglobin A1c, and fructosamine levels were collected for each patient.

RESULTS

An average (+/- standard deviation) of 780 +/- 54 glucose measurements was recorded for each patient with continuous glucose monitoring. The mean total time of hyperglycemia (glucose level greater than 140 mg/dL) undetected by the finger stick method was 192 +/- 28 minutes per day. Nocturnal hypoglycemic events (glucose level less than 50 mg/dL) were recorded in 26 patients; in all cases, there was an interval of 1-4 hours before clinical manifestations appeared or the event was revealed by random blood glucose examination. Based on the additional information obtained by continuous monitoring, the insulin therapeutic regimen was adjusted in 24 patients (70%).

CONCLUSION

Continuous glucose monitoring can diagnose high postprandial blood glucose levels and nocturnal hypoglycemic events that are unrecognized by intermittent blood glucose monitoring and may serve as a basis for determining treatment regimens. A large, prospective study on maternal and neonatal outcome is needed to evaluate the clinical implications of this new monitoring technique.

The effect of growth hormone on the development of diabetic kidney disease in rats

BACKGROUND

Nephropathy is the most severe complication of diabetes mellitus. We investigated the effect of exogenous growth hormone (GH) administration on renal function and matrix deposition in the streptozotocin (STZ) model of type I-diabetic rat.

METHODS

Adult female STZ-diabetic rats (D), non-diabetic control rats injected with saline (C) and control and diabetic rats injected with bovine GH for 3 months (CGH and DGH, respectively) were used.

RESULTS

The usual renal hypertrophy seen in D animals was more pronounced in the DGH group. Creatinine clearance increased only in the D rats, but not in the other groups, including DGH. Albuminuria was observed in the D animals but was significantly elevated in the DGH group. Glomeruli from DGH animals showed more extensive matrix accumulation (manifested as an increase in mesangial/glomerular area ratio). Renal extractable insulin-like growth factor (IGF-I) mRNA was decreased in the D and DGH groups, but renal IGF-I protein was not significantly increased. Renal IGF binding protein-1 was increased in the D groups and further increased in the DGH group, at both the mRNA and protein levels.

CONCLUSIONS

GH-treated diabetic rats had less hyperfiltration and more albuminuria, concomitant with more glomerular matrix deposition, when compared with regular diabetic animals. This was associated with a significant increase in renal IGFBP-1, and dissociated from IGF-I changes. Thus, in this model, GH exacerbates the course of diabetic kidney disease.

Greater prevalence of iron deficiency in overweight and obese children and adolescents

OBJECTIVE

To assess whether overweight children and adolescents, who often have poor dietary habits, are at increased risk of iron deficiency (ID).

METHODS

The study sample included 321 children and adolescents followed in two endocrine centers in Israel between 1999 and 2001. The subjects were divided into three groups on the basis of body mass index (BMI) for age and gender as follows: group 1-BMI below 85th percentile (normal weight); group 2-BMI above 85th, but below 97th percentile (overweight); and group 3-BMI above 97th percentile (obese). ID was defined as iron levels <8 micromol/l (45 mcg/dl), and iron-deficiency anemia (IDA) was defined as ID and hemoglobin level below 2 standard deviation score (SDS) for the mean for age and gender.

RESULTS

Iron levels below 8 micromol/l (45 mcg/dl) were noted in 38.8% of the obese children and 12.1% of the overweight children, compared with 4.4% of the normal-weight group (P<0.001). There was a significant negative correlation of low iron levels with BMI SDS (r=-0.44, P<0.001), but not with age or gender. Among the children with ID, 26.6% also had IDA. Groups 1, 2, and 3 accounted for 6.7%, 35%, and 58.3% of the children with IDA, respectively.

CONCLUSIONS

ID is common in overweight and obese children. A significantly greater proportion of obese than normal-weight children have IDA. Insufficient dietary intake of iron, whether absolute or relative to body mass, and increased iron needs may be a result of unbalanced nutrition or repeated short-term restrictive diets. Because of potentially harmful effects of ID, obese children should be routinely screened and treated as necessary.