Blood Pressure and Vascular Effects of Leptin in Humans

Background: Leptin may play a role in mediating obesity-related hypertension. However, its effects on the vasculature and blood pressure (BP) remain poorly defined in humans. Methods: In the first study, we performed a short-term, placebo-controlled, randomized, double-blind, cross-over experiment investigating the actions of recombinant human leptin (r-metHuLeptin) in 15 nonobese adults. To compliment the acute study, we retrospectively analyzed available BP results from a previously performed 85–day, placebo-controlled, randomized, double-blind, parallel weight-loss study using r-metHuLeptin in 284 obese adults. Results: In the acute study, conduit artery endothelial function determined by brachial flow-mediated dilatation (FMD) increased 2 hours following 0.2 mg · Kg−1 subcutaneously (SC) of r-metHuLeptin versus placebo (+3.3% versus −2.8%, P = .02). BP remained unchanged 4 hours after injections. In the retrospective analysis of the weight loss study data, 10 mg every day before noon (QAM), 10 mg every day after noon (QPM), or 10 mg twice a day (BID) SC of r-metHuLeptin was found to not alter the degree of weight loss (−3.2 ± 3.7 versus −2.9 ± 3.2 Kg, P = .54), change in systolic (−1.6 + 12.9 versus −2.0 ± 13.9 mmHg, P = .85) and diastolic BP (−0.2 ± 8.7 versus −1.5 ± 8.6, P = .30), as well as heart rate (−1.4 ± 10.7 versus −1.4 ± 10.4 beats/min, P = .98) compared to placebo. Conclusions: In our acute study, marked hyperleptinemia rapidly enhanced endothelial function and did not alter BP. The available data from a longer-term study in healthy obese adults did not demonstrate a significant effect of hyperleptinemia upon BP. These combined findings do not support a direct role for leptin in linking obesity to hypertension, however more studies are required to corroborate these observations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63121/1/met.2006.0023.pd

Circulating Citrate Is Associated with Liver Fibrosis in Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is associated with mitochondrial damage. Circulating mitochondrial metabolites may be elevated in NAFLD but their associations with liver damage is not known. This study aimed to assess the association of key mitochondrial metabolites with the degree of liver fibrosis in the context of NAFLD and nonalcoholic steatohepatitis (NASH). Cross-sectional analyses were performed on two cohorts of biopsy-proven NAFLD and/or NASH subjects. The association of circulating mitochondrial metabolite concentrations with liver fibrosis was assessed using linear regression analysis. In the single-center cohort of NAFLD subjects (n = 187), the mean age was 54.9 ±13.0 years, 40.1% were female and 86.1% were White. Type 2 diabetes (51.3%), hypertension (43.9%) and obesity (72.2%) were prevalent. Those with high citrate had a higher proportion of moderate/significant liver fibrosis (stage F ≥ 2) (68.4 vs. 39.6%, p = 0.001) and advanced fibrosis (stage F ≥ 3) (31.6 vs. 13.6%, p = 0.01). Citrate was associated with liver fibrosis independent of age, sex, NAFLD activity score and metabolic syndrome (per 1 SD increase: β = 0.19, 95% CI: 0.03–0.35, p = 0.02). This association was also observed in a cohort of NASH subjects (n = 176) (β = 0.21, 95% CI: 0.07–0.36, p = 0.005). The association of citrate with liver fibrosis was observed in males (p = 0.005) but not females (p = 0.41). In conclusion, circulating citrate is elevated and associated with liver fibrosis, particularly in male subjects with NAFLD and NASH. Mitochondrial function may be a target to consider for reducing the progression of liver fibrosis and NASH.</p

The Commensal Microbe Veillonella as a Marker for Response to an FGF19 Analog in NASH

Background and aimsThe composition of the human gut microbiota is linked to health and disease, and knowledge of the impact of therapeutics on the microbiota is essential to decipher their biological roles and to gain new mechanistic insights. Here we report the effect of aldafermin, an analog of the gut hormone FGF19, versus placebo on the gut microbiota in a prospective, phase 2 study in patients with NASH.Approach and resultsA total of 176 patients with biopsy-confirmed nonalcoholic steatohepatitis (NASH) (nonalcoholic fatty liver disease activity score ≥ 4), fibrosis (F1-F3 by NASH Clinical Research Network criteria), and elevated liver fat content (≥ 8% by magnetic resonance imaging-proton density fat fraction) received 0.3&nbsp;mg (n&nbsp;=&nbsp;23), 1&nbsp;mg (n&nbsp;=&nbsp;49), 3&nbsp;mg (n&nbsp;=&nbsp;49), and 6&nbsp;mg (n&nbsp;=&nbsp;28) aldafermin or placebo (n&nbsp;=&nbsp;27) for 12&nbsp;weeks. Stool samples were collected on day 1 and week 12 and profiled using 16S ribosomal RNA gene sequencing; 122 patients had paired stool microbiome profiles at both day 1 and week 12. Overall, the state of the gut microbial community was distinctly stable in patients treated with aldafermin, with all major phyla and genera unaltered during therapy. Patients treated with aldafermin showed a significant, dose-dependent enrichment in the rare genus Veillonella, a commensal microbe known to have lactate-degrading and performance-enhancing properties, which correlated with changes in serum bile acid profile.ConclusionsVeillonella may be a bile acid-sensitive bacteria whose enrichment is enabled by aldafermin-mediated suppression of bile acid synthesis and, in particular, decreases in toxic bile acids. This study provides an integrated analysis of gut microbiome, serum bile acid metabolome, imaging, and histological measurements in clinical trials testing aldafermin for NASH. Our results provide a better understanding of the intricacies of microbiome-host interactions (clinicaltrials.gov trial No. NCT02443116)

Potent suppression of hydrophobic bile acids by aldafermin, an FGF19 analogue, across metabolic and cholestatic liver diseases

Background & Aims: Higher serum bile acid levels are associated with an increased risk of cirrhosis and liver-related morbidity and mortality. Herein, we report secondary analyses of aldafermin, an engineered analogue of the gut hormone fibroblast growth factor 19, on the circulating bile acid profile in prospective, phase II studies in patients with metabolic or cholestatic liver disease. Methods: One hundred and seventy-six patients with biopsy-confirmed non-alcoholic steatohepatitis (NASH) and fibrosis and elevated liver fat content (≥8% by magnetic resonance imaging-proton density fat fraction) received 0.3 mg (n = 23), 1 mg (n = 49), 3 mg (n = 49), 6 mg (n = 28) aldafermin or placebo (n = 27) for 12 weeks. Sixty-two patients with primary sclerosing cholangitis (PSC) and elevated alkaline phosphatase (>1.5× upper limit of normal) received 1 mg (n = 21), 3 mg (n = 21) aldafermin or placebo (n = 20) for 12 weeks. Serum samples were collected on day 1 and week 12 for determination of bile acid profile and neoepitope-specific N-terminal pro-peptide of type III collagen (Pro-C3), a direct measure of fibrogenesis. Results: Treatment with aldafermin resulted in significant dose-dependent reductions in serum bile acids. In particular, bile acids with higher hydrophobicity indices, such as deoxycholic acid, lithocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, and glycocholic acid, were markedly lowered by aldafermin in both NASH and PSC populations. Moreover, aldafermin predominantly suppressed the glycine-conjugated bile acids, rather than the taurine-conjugated bile acids. Changes in levels of bile acids correlated with changes in the novel fibrogenesis marker Pro-C3, which detects a neo-epitope of the type III collagen during its formation, in the pooled NASH and PSC populations. Conclusions: Aldafermin markedly reduced major hydrophobic bile acids that have greater detergent activity and cytotoxicity. Our data provide evidence that bile acids may contribute to sustaining a pro-fibrogenic microenvironment in the liver across metabolic and cholestatic liver diseases. Lay summary: Aldafermin is an analogue of a gut hormone, which is in development as a treatment for patients with chronic liver disease. Herein, we show that aldafermin can potently and robustly suppress the toxic, hydrophobic bile acids irrespective of disease aetiology. The therapeutic strategy utilising aldafermin may be broadly applicable to other chronic gastrointestinal and liver disorders. Clinical Trials Registration: The study is registered at Clinicaltrials.gov NCT02443116 and NCT02704364