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Abstract

GH and its principal mediator IGF1 have important effects on metabolic and cardiovascular (CV) status. While acquired GH deficiency (GHD) is often associated with increased CV risk, the consequences of congenital GHD are not known. We have described a large group of patients with isolated GHD (IGHD) due to a homozygous mutation (c.57+1G>A) in the GH releasing hormone receptor gene, and shown that adult GH-naïve individuals have no evidence of clinically evident premature atherosclerosis. To test whether subclinical atherosclerosis is anticipated in untreated IGHD, we performed a cross-sectional study of 25 IGHD and 27 adult controls matched for age and gender. A comprehensive clinical and biochemical panel and coronary artery calcium scores were evaluated by multi-detector tomography. Height, weight, IGF1, homeostasis model assessment of insulin resistance, creatinine and creatininekinase were lower in the IGHD group. Median and interquartile range of calcium scores distribution was similar in the two groups: IGHD 0(0) and control 0(4.9). The vast majority of the calcium scores (20 of 25 IGHD (80%) and 18 of 27 controls (66.6%)) were equal to zero (difference not significant). There was no difference in the calcium scores classification. None of IGHD subjects had minimal calcification, which were present in four controls. Three IGHD and four controls had mild calcification. There were two IGHD individuals with moderate calcification and one control with severe calcification. Our study provides evidence that subjects with congenital isolated lifetime and untreated severe IGHD do not have accelerated subclinical coronary atherosclerosis.

Nonalcoholic fatty liver disease (NAFLD) is known to be associated with insulin resistance, atherosclerosis, and low serum IGF1 levels. We have described a large cohort of patients with isolated GH deficiency (IGHD) due to the c.57+1G→A mutation in the GHRH receptor gene. These subjects have increased insulin sensitivity (IS), delayed atherosclerosis, and normal longevity. We hypothesized that, despite visceral obesity, NAFLD would be absent or mild due to the increased IS. To assess the prevalence and severity of NAFLD in adult subjects with lifetime, congenital, untreated IGHD, we studied 22 IGHD adults and 25 controls (COs) matched for age and sex. NAFLD was assessed by a comprehensive liver function panel, and ultrasonographic pattern (hyperechogenic pattern, HP) coded as follows: 0, absent; 1, mild; 2, moderate; and 3, severe. Compared with COs, IGHD individual had lower serum IGF1 (P<0.0001), higher total cholesterol (P=0.027), lower prothrombin time (P=0.017), and similar activated partial thromboplastin time and fibrinogen values. Alanine transaminase (ALT) values were similar in the two groups, but aspartate transaminase was higher in IGHD (P=0.013). However, more IGHD subjects (7/22) than COs (3/23) had ALT above the upper limit of normal (P=0.044). The prevalence of NAFLD was higher in IGHD than COs (61 vs 29%, P=0.032), and the HP score was higher in IGHD than COs (P=0.041), but severe NAFLD was not observed in any IGHD (or CO) individual. Liver HP score is increased in lifetime, untreated, congenital IGHD, but the increase in transaminases is mild, suggesting a lack of advanced forms of NAFLD.