Estrogen Stimulation of Kiss1 Expression in the Medial Amygdala Involves Estrogen Receptor-α But Not Estrogen Receptor-β.

The neuropeptide kisspeptin, encoded by Kiss1, regulates reproduction by stimulating GnRH secretion. Neurons synthesizing kisspeptin are predominantly located in the hypothalamic anteroventral periventricular (AVPV) and arcuate nuclei, but smaller kisspeptin neuronal populations also reside in extrahypothalamic brain regions, such as the medial amygdala (MeA). In adult rodents, estradiol (

Examination of the influence of leptin and acute metabolic challenge on RFRP-3 neurons of mice in development and adulthood.

BackgroundThe neuropeptide RFamide-related peptide-3 (RFRP-3; mammalian ortholog to gonadotropin-inhibiting hormone) can inhibit luteinizing hormone (LH) release and increases feeding, but the regulation and development of RFRP-3 neurons remains poorly characterized, especially in mice.Methods and resultsWe first confirmed that peripheral injections of murine RFRP-3 peptide could markedly suppress LH secretion in adult mice, as in other species. Second, given RFRP-3's reported orexigenic properties, we performed double-label in situ hybridization for metabolic genes in Rfrp neurons of mice. While Rfrp neurons did not readily coexpress neuropeptide Y, thyrotropin-releasing hormone, or MC4R, a small subset of Rfrp neurons did express the leptin receptor in both sexes. Surprisingly, we identified no changes in Rfrp expression or neuronal activation in adult mice after acute fasting. However, we determined that Rfrp mRNA levels in the dorsal-medial nucleus were significantly reduced in adult obese (Ob) mice of both sexes. Given the lower Rfrp levels observed in adult Ob mice, we asked whether leptin might also regulate RFRP-3 neuron development. Rfrp gene expression changed markedly over juvenile development, correlating with the timing of the juvenile 'leptin surge' known to govern hypothalamic feeding circuit development. However, the dramatic developmental changes in juvenile Rfrp expression did not appear to be leptin driven, as the pattern and timing of Rfrp neuron development were unaltered in Ob juveniles.ConclusionLeptin status modulates RFRP-3 expression in adulthood, but is not required for normal development of the RFRP-3 system. Leptin's regulation of adult RFRP-3 neurons likely occurs primarily via indirect signaling, and may be secondary to obesity, as only a small subset of RFRP-3 neurons express the long form of the leptin receptor (LepRb)

Examination of the Influence of Leptin and Acute Metabolic Challenge on RFRP-3 Neurons of Mice in Development and Adulthood

BACKGROUND: The neuropeptide RFamide-related peptide-3 (RFRP-3; mammalian ortholog to GnIH) can inhibit LH release and increases feeding, but the regulation and development of RFRP-3 neurons remains poorly characterized, especially in mice. METHODS AND RESULTS: We first confirmed that peripheral injections of murine RFRP-3 peptide could markedly suppress luteinizing hormone secretion in adult mice, as in other species. Second, given RFRP-3′s reported orexigenic properties, we performed double-label in situ hybridization for metabolic genes in Rfrp neurons of mice. While Rfrp neurons did not readily co-express NPY, TRH, or MC4R, a small subset of Rfrp neurons did express leptin receptor in both sexes. Surprisingly, we identified no changes in Rfrp expression or neuronal activation in adult mice after acute fasting. However, we determined that Rfrp mRNA levels in the DMN were significantly reduced in adult Obese (Ob) mice of both sexes. Given the lower Rfrp levels observed in adult Ob mice, we asked whether leptin might also regulate RFRP-3 neuron development. Rfrp gene expression changed markedly over juvenile development, correlating with the timing of the juvenile “leptin surge” known to govern hypothalamic feeding circuit development. However, the dramatic developmental changes in juvenile Rfrp expression did not appear to be leptin-driven, as the pattern and timing of Rfrp neuron development were unaltered in Ob juveniles. CONCLUSION: Leptin status modulates RFRP-3 expression in adulthood, but is not required for normal development of the RFRP-3 system. Leptin's regulation of adult RFRP-3 neurons likely occurs via primarily indirect signaling, and may be secondary to obesity, as only a small subset of RFRP-3 neurons express LepRb

Systematic review with network meta‐analysis: comparative efficacy of pharmacologic therapies for fibrosis improvement and resolution of NASH

BackgroundNonalcoholic steatohepatitis (NASH) is a common cause of chronic liver disease. There is a major need to understand the efficacy of different pharmacological agents for the treatment of NASH.AimTo assess the relative rank-order of different pharmacological interventions in fibrosis improvement and NASH resolution.MethodsA comprehensive search of several databases was conducted by an experienced librarian. We included randomised controlled-trials (RCTs) comparing pharmacological interventions in patients with biopsy-proven NASH. The primary outcome was ≥1 stage improvement in fibrosis. The secondary outcome was NASH resolution.ResultsA total of 26 RCTs with 23 interventions met the eligibility criteria. Lanifibranor and obeticholic acid had the highest probability of being ranked the most effective intervention for achieving ≥1 stage of fibrosis improvement (SUCRA 0.78) and (SUCRA 0.77), respectively. For NASH resolution, semaglutide, liraglutide and vitamin E plus pioglitazone had the highest probability of being ranked the most effective intervention for achieving NASH resolution (SUCRA 0.89), (SUCRA 0.84) and (SUCRA 0.83), respectively. Lanifibranor, obeticholic acid, pioglitazone and vitamin E were significantly better than placebo in achieving ≥1 stage of fibrosis improvement. Conversely, semaglutide, liraglutide, vitamine E plus pioglitazone, pioglitazone, lanifibranor and obeticholic acid were significantly better than placebo in achieving NASH resolution.ConclusionThese data provide relative rank-order efficacy of various NASH therapies in terms of their improvements in liver fibrosis and NASH resolution. Therapies that have been shown to improve NASH resolution may be combined with therapies that have an antifibrotic effect to further boost treatment response rate in future

Corticosterone Blocks Ovarian Cyclicity and the LH Surge via Decreased Kisspeptin Neuron Activation in Female Mice.

Stress elicits activation of the hypothalamic-pituitary-adrenal axis, which leads to enhanced circulating glucocorticoids, as well as impaired gonadotropin secretion and ovarian cyclicity. Here, we tested the hypothesis that elevated, stress-levels of glucocorticoids disrupt ovarian cyclicity by interfering with the preovulatory sequence of endocrine events necessary for the LH surge. Ovarian cyclicity was monitored in female mice implanted with a cholesterol or corticosterone (Cort) pellet. Cort, but not cholesterol, arrested cyclicity in diestrus. Subsequent studies focused on the mechanism whereby Cort stalled the preovulatory sequence by assessing responsiveness to the positive feedback estradiol signal. Ovariectomized mice were treated with an LH surge-inducing estradiol implant, as well as Cort or cholesterol, and assessed several days later for LH levels on the evening of the anticipated surge. All cholesterol females showed a clear LH surge. At the time of the anticipated surge, LH levels were undetectable in Cort-treated females. In situ hybridization analyses the anteroventral periventricular nucleus revealed that Cort robustly suppressed the percentage of Kiss1 cells coexpressing cfos, as well as reduced the number of Kiss1 cells and amount of Kiss1 mRNA per cell, compared with expression in control brains. In addition, Cort blunted pituitary expression of the genes encoding the GnRH receptor and LHβ, indicating inhibition of gonadotropes during the blockage of the LH surge. Collectively, our findings support the hypothesis that physiological stress-levels of Cort disrupts ovarian cyclicity, in part, through disruption of positive feedback mechanisms at both the hypothalamic and pituitary levels which are necessary for generation of the preovulatory LH surge

Clinical Utility of Change in Nonalcoholic Fatty Liver Disease Activity Score and Change in Fibrosis in NAFLD.

The Nonalcoholic fatty liver disease (NAFLD) Activity Score (NAS) has been applied as a method for evaluating treatment response, and a ≥2-point improvement in NAS has been commonly used as an accepted end point in phase 2b clinical trials in nonalcoholic steatohepatitis.1,2 Although liver fibrosis is the strongest histologic predictor of liver-related outcome and all-cause mortality in NAFLD,3,4 the association between change in NAS and change in fibrosis stage has not been fully verified. Therefore, we aimed to examine the association between change in NAS and change in fibrosis stage in well-characterized patients with NAFLD who had a paired liver biopsy assessment

Change in MRI-PDFF and Histologic Response in Patients With Nonalcoholic Steatohepatitis: A Systematic Review and Meta-Analysis.

Background & aimsMagnetic resonance imaging proton density fat fraction (MRI-PDFF) offers promise as a non-invasive biomarker of treatment response in early-phase nonalcoholic steatohepatitis (NASH) trials. We performed a systematic review to quantify the association between a ≥ 30% reduction in MRI-PDFF and histologic response in NASH.MethodsWe searched the Cochrane Library, Embase, Medline and trial registries through May 2020 for early-phase clinical trials that incorporated MRI-PDFF and examined histologic response following intervention in adults with NASH. Subjects were classified as MRI-PDFF responders (relative decline in liver fat ≥30%) or non-responders (relative decline in liver fat <30%). MRI-PDFF responders versus non-responders were compared. Primary outcome was histologic response defined as a 2-point improvement in NAFLD Activity Score with at least 1-point improvement in lobular inflammation or ballooning. Secondary outcome was NASH resolution. Proportions and random effects odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated.ResultsSeven studies met inclusion criteria, comprising 346 subjects (median age 51 years; 59% female; 46% with diabetes). MRI-PDFF responders were significantly more likely to have a histologic response (51% vs 14%, P < .001; OR 6.98, 95% CI 2.38-20.43, P < .001) and NASH resolution (41% vs 7%, P < .001; OR 5.45, 95% CI 1.53-19.46, P = .009) compared to non-responders.ConclusionsThis meta-analysis demonstrates that a ≥30% relative decline in MRI-PDFF is associated with higher odds of histologic response and NASH resolution. These results support the use of MRI-PDFF in non-invasive monitoring of treatment response in early-phase NASH clinical trials and provide helpful data for sample-size estimation for histology-based assessment

Clinical utility of 30% relative decline in MRI-PDFF in predicting fibrosis regression in non-alcoholic fatty liver disease.

ObjectiveEmerging data suggest that a 30% relative decline in liver fat, as assessed by MRI-proton density fat fraction (MRI-PDFF), may be associated with Non-Alcoholic Fatty Liver Disease Activity Score improvement, but the association between decline in MRI-PDFF and fibrosis regression is not known. Therefore, we aimed to examine the association between ≥30% relative decline in MRI-PDFF and fibrosis regression in non-alcoholic fatty liver disease (NAFLD).DesignThis prospective study included 100 well-characterised patients with biopsy-proven NAFLD with paired contemporaneous MRI-PDFF assessment at two time points. MRI-PDFF response was defined as ≥30% relative decline in MRI-PDFF. The primary outcome was ≥1 stage histological fibrosis regression.ResultsThe median (IQR) age was 54 (43-62) years and body mass index was 31.9 (29-36) kg/m2. In multivariable-adjusted logistic regression analysis (adjusted for age, gender, diabetes status, race/ethnicity, interval between biopsies, gamma-glutamyl transferase, liver stiffness by magnetic resonance elastography and change in platelet counts), MRI-PDFF response was an independent predictor of fibrosis regression with an adjusted OR of 6.46 (95% CI 1.1 to 37.0, p=0.04). The proportion of patients with MRI-PDFF response with fibrosis regression, no change in fibrosis and fibrosis progression was 40.0%, 24.6% and 13.0%, respectively, and the proportion of patients with MRI-PDFF response increased with fibrosis regression (p=0.03).Conclusion≥30% reduction in MRI-PDFF in early phase trials can provide a useful estimate of odds of ≥1 stage improvement in fibrosis. These data may be helpful in sample size estimation in non-alcoholic steatohepatitis trials