Renal function is independently associated with circulating betatrophin.

OBJECTIVE: Betatrophin has been identified as a marker linking liver with beta cell function and lipid metabolism in murine models. Until now, the regulation of circulating betatrophin in humans is not entirely clear. We here analyzed the relation of betatrophin levels to phenotypes of the metabolic syndrome and speculated that renal function might influence circulating betatrophin levels and explain age-dependent changes of betatrophin. SUBJECTS: We analyzed blood samples from 535 individuals participating in the Metabolic Syndrome Berlin Potsdam study. RESULTS: In a crude analysis we found a positive correlation between betatrophin levels and HbA1c (r = 0.24; p < 0.001), fasting glucose (r = 0.20; p < 0.001) and triglycerides (r = 0.12; p = 0.007). Furthermore betatrophin was positively correlated with age (r = 0.47; p <0.001), systolic blood pressure (r = 0.17; p < 0.001), intima media thickness (r = 0.26; p < 0.001) and negatively correlated with CKD-EPI eGFR (r = -0.33; p < 0.001) as an estimate of renal function. Notably, eGFR remained highly associated with betatrophin after adjustment for age, waist circumference, gender, HbA1c and lipid parameters in a multivariate linear regression model (ß = -0.197, p< 0.001). CONCLUSIONS: Our data suggest that circulating levels of betatrophin depend on age, gender, waist circumference, total/HDL cholesterol ratio and renal function. Especially the association to eGFR highlights the importance for future studies to address renal function as possible influence on betatrophin regulation and consider eGFR as potential confounder when analyzing the role of betatrophin in humans.

Metabolic actions of natriuretic peptides and therapeutic potential in the metabolic syndrome.

Natriuretic peptides (NPs) are a group of peptide-hormones mainly secreted from the heart, signaling via c-GMP coupled receptors. NP are well known for their renal and cardiovascular actions, reducing arterial blood pressure as well as sodium reabsorption. Novel physiological functions have been discovered in recent years, including activation of lipolysis, lipid oxidation, and mitochondrial respiration. Together, these responses promote white adipose tissue browning, increase muscular oxidative capacity, particularly during physical exercise, and protect against diet-induced obesity and insulin resistance. Exaggerated NP release is a common finding in congestive heart failure. In contrast, NP deficiency is observed in obesity and in type-2 diabetes, pointing to an involvement of NP in the pathophysiology of metabolic disease. Based upon these findings, the NP system holds the potential to be amenable to therapeutical intervention against pandemic diseases such as obesity, insulin resistance, and arterial hypertension. Various therapeutic approaches are currently under development. This paper reviews the current knowledge on the metabolic effects of the NP system and discusses potential therapeutic applications.

Non-invasive measurement of liver and pancreas fibrosis in patients with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis (CF) have a relevant morbidity and mortality caused by CF-related liver-disease. While transient elastography (TE) is an established elastography method in hepatology centers, Acoustic-Radiation-Force-Impulse (ARFI)-Imaging is a novel ultrasound-based elastography method which is integrated in a conventional ultrasound-system. The aim of the present study was to evaluate the prevalence of liver-fibrosis in patients with CF using TE, ARFI-imaging and fibrosis blood tests. METHODS: 106 patients with CF were prospectively included in the present study and received ARFI-imaging of the left and right liver-lobe, ARFI of the pancreas TE of the liver and laboratory evaluation. RESULTS: The prevalence of liver-fibrosis according to recently published best practice guidelines for CFLD was 22.6%. Prevalence of significant liver-fibrosis assessed by TE, ARFI-right-liver-lobe, ARFI-left-liver-lobe, Fibrotest, Fibrotest-corrected-by-haptoglobin was 17%, 24%, 40%, 7%, and 16%, respectively. The best agreement was found for TE, ARFI-right-liver-lobe and Fibrotest-corrected-by-haptoglobin. Patients with pancreatic-insufficiency had significantly lower pancreas-ARFI-values as compared to patients without. CONCLUSIONS: ARFI-imaging and TE seem to be promising non-invasive methods for detection of liver-fibrosis in patients with CF.