ResearchPad - from-bedside-to-bench-and-back-again:-lipid-metabolism-vascular-disease Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[OR17-02 Changes in Hepatokines and Apolipoproteins Are Associated with Metabolic Response to Metreleptin in Partial Lipodystrophy]]> Introduction Metreleptin treatment may improve the metabolic aspects of partial lipodystrophy; however, the treatment response is heterogeneous. This study aimed to explore changes in circulating apolipoprotein concentrations, as well as ANGPLT3, ANGPLT4, and IGF-1 levels in patients treated with Metreleptin as part of a clinical study investigating the efficacy of Metreleptin in nonalcoholic steatohepatitis (NASH) associated with partial lipodystrophy ( identifier: NCT01679197). Methods Serum samples of 18 patients with partial lipodystrophy who underwent a full metabolic evaluation and paired liver biopsies before and after Metreleptin were studied. Patients were tested at baseline, month (M) 3, M6, and M12. Glycemic response was defined as “more than 1% HbA1c reduction from baseline”. Lipid response was defined as “more than 30% decrease in triglycerides from baseline”. The hepatic response was defined as “a decrease of 2 points or more from baseline in NASH score, without an increase in fibrosis”. Patients with “any 2 of 3 above” at M12 were defined as metabolic responders. Results Metreleptin treatment resulted in significant reductions in triglycerides (346 mg/dL vs. 253 mg/dL; F: 8.474; p < 0.001), apo B (145.24 mg/dL vs. 111.09 mg/dL; F: 9.266: p < 0.001), apo CII (18.65 mg/dL vs. 15.95 mg/dL; F: 6.663: p = 0.001), apo CIII (62.95 mg/dL vs. 49.33 mg/dL; F: 5.640, p = 0.002), apo E (8.16 mg/dL vs. 6.52 mg/dL; F: 11.056, p < 0.001), and ANGPLT3 (14.36 ng/mL vs. 12.00 mg/dL; F: 4.348; p = 0.008) over time. IGF-1 levels significantly increased at M3 (134 ng/mL vs. 139 ng/mL; p = 0.001), however the difference was not significant over time. Metabolic responders had lower baseline leptin (12.4 ng/mL vs. 27.8 ng/mL; p = 0.024) and IGF-1 (95 ng/ml vs. 151 ng/mL; p = 0.008), and higher apo CII (39.06 mg/dL vs. 17.90 mg/dL; p = 0.011), apo CIII (173.57 mg/dL vs. 51.51 mg/dL; p = 0.015), apo E (18.41 mg/dL vs. 5.89 mg/dL; p = 0.002), and ANGPLT3 (17.33 ng/mL vs. 10.06 ng/mL; p = 0.04). Metabolic responders had a significant increase in IGF-1 (95 ng/mL vs. 134 ng/mL; p = 0.019), which was statistically distinguished from non-responders (p = 0.004). Responders also had a greater reduction in apo CII (20.51 mg/dL vs. -1.84 mg/dL; p = 0.001), apo CIII (32.59 mg/dL vs. -7.83 mg/dL; p = 0.007), apo E (8.17 mg/dL vs. 0.22 mg/dL; p = 0.001), and ANGPLT3 (6.08 ng/mL vs. -0.16 ng/mL; p = 0.005) early after treatment at M3. Conclusions Metreleptin treatment lowers levels of apolipoproteins associated with triglyceride metabolism as well as ANGPLT3 in patients with partial lipodystrophy. Metabolic response to Metreleptin appears to be correlated with early changes in these factors and an increase in IGF-1 levels.

<![CDATA[OR17-01 Leptin Decreases De Novo Lipogenesis in Lipodystrophic Patients]]> De novo lipogenesis (DNL) plays a role in the development of hepatic steatosis and non-alcoholic fatty liver disease (NAFLD). In rodent models of both health and lipodystrophy (LD), leptin decreases DNL. In human patients with LD, reduced adipose tissue results in adipokine deficiencies, including lower plasma leptin, which contributes to insulin resistance, dyslipidemia and ectopic accumulation of triglycerides (TG). The mechanisms by which leptin regulates serum and hepatic-TG are not well elucidated. Studying patients with LD before and after leptin therapy provides an important clinical model for understanding leptin’s effect on DNL. We hypothesized that leptin treatment in lipodystrophic patients would decrease DNL by decreasing insulin resistance and glycemia, resulting in reduced circulating and hepatic-TG.

Leptin-naïve patients with LD (n=11) were treated with recombinant leptin (metreleptin) for 6 months. All measurements were performed after an 8–12 hr fast. The % of TG in TG-rich lipoproteins (TRLP-TG) derived from DNL (% DNL) was measured using body water labeling (oral D2O) of TG and mass spectrometry analysis. Absolute DNL was calculated as the product of TRLP-TG and % DNL. HbA1c and serum-TG were measured biochemically, hepatic-TG by MRI, and total body and hepatic insulin sensitivity measured during a hyperinsulinemic-euglycemic clamp.

DNL decreased after metreleptin: % DNL from 22.8±6.8 to 9.1±5.1% (p=0.0008) and absolute DNL from 54.2±32.1 to 8.6±6.5 mg/dl (p=0.003). TRLP-TG decreased from (median [interquartile range]) 160 [107, 280] to 98 [66, 147] mg/dl (p=0.01). Total body and hepatic insulin sensitivity increased from 3.7 [3.0, 7.3] to 8.4 [5.1,10.6] mg/kgFFM/min (p=0.03) and from 61.0 [48.5, 69.3] to 84.7 [75.2, 107.6] % (p =0.01), respectively. HbA1c decreased from 8.6±1.8 to 7.1±1.4% (p=0.04), hepatic-TG decreased from 17.6±11.9 to 10.3±9.1% (p=0.02), and serum-TG from 386 [216, 686] to 223 [118, 497] mg/dl (p=0.06). DNL correlated negatively with insulin sensitivity both before (r=-0.73, p=0.03) and after (r=-0.85, p=0.004) metreleptin. DNL correlated positively with hepatic-TG before (r=0.70 p=0.03) and tended to correlate after metreleptin (r=0.65, p=0.06). The change in DNL correlated with change in serum-TG (r=0.77, p=0.04) but not the change in hepatic-TG (p=0.80).

We show here for the first time that 6 months of metreleptin treatment in humans with LD decreased DNL by 84% and was associated with reductions in glycemia and improved peripheral and hepatic insulin sensitivity. These data indicate a strong link between metreleptin’s effects to increase clearance of blood glucose by peripheral tissues and reduce hepatic carbohydrate flux, resulting in DNL reductions. This led to lowered hepatic steatosis and dyslipidemia and suggests treatments that target multi-organ insulin resistance may lead to decreased NAFLD and cardiovascular risk.

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