Preclinical markers of atherosclerosis in acromegaly: a systematic review and meta-analysis

OBJECTIVE

Multiple studies investigated preclinical markers of peripheral vascular damage in acromegaly (ACRO) reporting discordant results. The aim of this study was to run a meta-analysis to examine whether intima media thickness (IMT), flow mediated dilation (FMD) and arterial pulse wave velocity (PWV) are affected in acromegalic patients and to assess the impact of effective treatment of growth hormone excess on these outcomes.

STUDY SELECTION

Twenty-seven studies comparing ACRO vs control (CON) populations and active (ACT) vs inactive (INACT) ACRO were included in the meta-analysis.

DATA SYNTHESIS

ACRO compared to CON have higher IMT (ES = 0.83, 95% C.I. 0.35-1.30), p = 0.001, impaired FMD (ES = - 1.59, 95% C.I. - 2.33 to - 0.85, p < 0.0001) and higher PWV (ES = 0.76 95% C.I. 0.37-1.16, p = 0.0001). When patients with ACT vs INACT disease were considered IMT was higher (ES = 0.43, 95% C.I. 0.02-0.84, p = 0.041) and FMD was impaired (ES = - 0.66, 95% C.I. - 1.28 to 0.04, p = 0.038) in ACT patients. Meta-regression analysis of studies comparing IMT in ACT vs INACT acromegalic patients showed a significant and inverse association between the effect size and the percent of hypertensive (p = 0.025) and diabetic (p = 0.041) patients.

CONCLUSIONS

IMT, FMD and arterial stiffness are impaired in acromegaly showing that these patients may be at increased risk of atherosclerosis. In patients with active disease these preclinical markers of atherosclerosis are worse compared to patients with inactive disease but the role of diabetes and hypertension is prevailing on growth hormone excess.

Chronic limb-threatening ischemia could benefit from growth hormone therapy for wound healing and limb salvage

Revascularization for chronic limb-threatening ischemia (CLTI) is necessary to alleviate symptoms and wound healing. When it fails or is not possible, there are few alternatives to avoid limb amputation in these patients. Although experimental studies with stem cells and growth factors have shown promise, clinical trials have demonstrated inconsistent results because CLTI patients generally need arteriogenesis rather than angiogenesis. Moreover, in addition to the perfusion of the limb, there is the need to improve the neuropathic response for wound healing, especially in diabetic patients. Growth hormone (GH) is a pleiotropic hormone capable of boosting the aforementioned processes and adds special benefits for the redox balance. This hormone has the potential to mitigate symptoms in ischemic patients with no other options and improves the cardiovascular complications associated with the disease. Here, we discuss the pros and cons of using GH in such patients, focus on its effects on peripheral arteries, and analyze the possible benefits of treating CLTI with this hormone.

Elevated systolic blood pressure in male GH transgenic mice is age dependent

Acromegaly is associated with an increased incidence of cardiovascular disease. Transgenic mice expressing bovine GH (bGH) gene have previously been used to examine the effects of chronic GH stimulation on cardiovascular function. Results concerning systolic blood pressure (SBP) in bGH mice are conflicting. We hypothesized that these discrepancies may be the result of the various ages of the mice used in previous studies. In the current study, SBP was assessed monthly in male bGH mice from 3-12 months of age. Factors known to alter blood pressure were assessed during this time and included: levels of brain natriuretic peptide (BNP) and glucose homeostasis markers, and renal levels of angiotensin-converting enzyme 2 and endothelial nitric oxide synthase. Beginning at 6 months of age bGH had increased SBP compared with wild-type controls, which remained elevated through 12 months of age. Despite having increased blood pressure and cardiac BNP mRNA, bGH mice had decreased circulating levels of BNP. Additionally, bGH mice had an age-dependent decline in insulin levels. For example, they were hyperinsulinemic at 3 months, but by 11 months of age were hypoinsulinemic relative to wild-type controls. This decrease in insulin was accompanied by improved glucose tolerance at 11 months. Finally, both angiotensin-converting enzyme 2 and endothelial nitric oxide synthase expression were severely depressed in kidneys of 11-month-old bGH mice. These results indicate that elevated SBP in bGH mice is dependent on age, independent of insulin resistance, and related to alterations in both the natriuretic peptide and renin-angiotensin systems.