Neutrophil extracellular traps activate hepatic stellate cells and monocytes via NLRP3 sensing in alcohol-induced acceleration of MASH fibrosis.

OBJECTIVE: Alcohol use in metabolic dysfunction-associated steatohepatitis (MASH) is associated with an increased risk of fibrosis and liver-related death. Here, we aimed to identify a mechanism through which repeated alcohol binges exacerbate liver injury in a high fat-cholesterol-sugar diet (MASH diet)-induced model of MASH. DESIGN: C57BL/6 mice received either chow or the MASH diet for 3 months with or without weekly alcohol binges. Neutrophil infiltration, neutrophil extracellular traps (NETs) and fibrosis were evaluated. RESULTS: We found that alcohol binges in MASH increase liver injury and fibrosis. Liver transcriptomic profiling revealed differential expression of genes involved in extracellular matrix reorganisation, neutrophil activation and inflammation compared with alcohol or the MASH diet alone. Alcohol binges specifically increased NET formation in MASH livers in mice, and NETs were also increased in human livers with MASH plus alcohol use. We discovered that cell-free NETs are sensed via Nod-like receptor protein 3 (NLRP3). Furthermore, we show that cell-free NETs in vitro induce a profibrotic phenotype in hepatic stellate cells (HSCs) and proinflammatory monocytes. In vivo, neutrophil depletion using anti-Ly6G antibody or NET disruption with deoxyribonuclease treatment abrogated monocyte and HSC activation and ameliorated liver damage and fibrosis. In vivo, inhibition of NLRP3 using MCC950 or NLRP3 deficiency attenuated NET formation, liver injury and fibrosis in MASH plus alcohol diet-fed mice (graphical abstract). CONCLUSION: Alcohol binges promote liver fibrosis via NET-induced activation of HSCs and monocytes in MASH. Our study highlights the potential of inhibition of NETs and/or NLRP3, as novel therapeutic strategies to combat the profibrotic effects of alcohol in MASH.

Alcohol-induced extracellular ASC specks perpetuate liver inflammation and damage in alcohol-associated hepatitis even after alcohol cessation.

BACKGROUND AIMS: Prolonged systemic inflammation contributes to poor clinical outcomes in severe alcohol-associated hepatitis (AH) even after the cessation of alcohol use. However, mechanisms leading to this persistent inflammation remain to be understood. APPROACH RESULTS: We show that while chronic alcohol induces nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation in the liver, alcohol binge results not only in NLRP3 inflammasome activation but also in increased circulating extracellular apoptosis-associated speck-like protein containing a caspase recruitment domain (ex-ASC) specks and hepatic ASC aggregates both in patients with AH and in mouse models of AH. These ex-ASC specks persist in circulation even after the cessation of alcohol use. Administration of alcohol-induced-ex-ASC specks in vivo in alcohol-naive mice results in sustained inflammation in the liver and circulation and causes liver damage. Consistent with the key role of ex-ASC specks in mediating liver injury and inflammation, alcohol binge failed to induce liver damage or IL-1ß release in ASC-deficient mice. Our data show that alcohol induces ex-ASC specks in liver macrophages and hepatocytes, and these ex-ASC specks can trigger IL-1ß release in alcohol-naive monocytes, a process that can be prevented by the NLRP3 inhibitor, MCC950. In vivo administration of MCC950 reduced hepatic and ex-ASC specks, caspase-1 activation, IL-1ß production, and steatohepatitis in a murine model of AH. CONCLUSIONS: Our study demonstrates the central role of NLRP3 and ASC in alcohol-induced liver inflammation and unravels the critical role of ex-ASC specks in the propagation of systemic and liver inflammation in AH. Our data also identify NLRP3 as a potential therapeutic target in AH.

Altered ethanol metabolism and increased oxidative stress enhance alcohol-associated liver injury in farnesoid X receptor-deficient mice.

BACKGROUND & AIMS: Pharmacological activation of farnesoid X receptor (FXR) ameliorates liver injury, steatosis and inflammation in mouse models of alcoholic liver disease (ALD), but the underlying mechanisms of the protective effect of FXR against ALD remain unclear. METHODS: To investigate the role of FXR in ALD, we used the NIAAA model of chronic plus binge ethanol feeding in FXR-deficient knockout (FXR KO) mice. RESULTS: Ethanol-mediated liver injury and steatosis were increased in FXR KO mice, while both WT and FXR KO mice consumed the same amount of alcohol. Ethanol feeding induced liver inflammation and neutrophil infiltration that were further increased in FXR KO mice. In addition, collagen accumulation and expression of profibrotic genes were markedly elevated in the liver of alcohol-fed FXR KO compared to wild-type mice, suggesting that ethanol-induced liver fibrosis is enhanced in the absence of FXR. Surprisingly, FXR KO mice showed reduced blood alcohol levels post-binge, while CYP2E1 and ALDH1A1 were upregulated compared to WT mice, suggesting that alcohol metabolism is altered in FXR KO mice. Notably, exacerbated liver injury in FXR KO mice was associated with increased oxidative stress. ALDH1A1 activity was upregulated in FXR-deficient mouse primary hepatocytes, contributing to reactive oxygen species (ROS) generation, in vitro. Finally, using an ALDH1A1 inhibitor, we showed that ALDH1A1 activity is a key contributor to alcohol-induced ROS generation in FXR-deficient hepatocytes, in vitro. CONCLUSION: ALD pathogenesis in FXR KO mice correlates with altered ethanol metabolism and increased oxidative stress, providing new insights into the protective function of FXR in ALD.

Protective role of cGAS in NASH is related to the maintenance of intestinal homeostasis.

BACKGROUND & AIMS: Various intracellular pathways regulate inflammation in NASH. Cyclic GMP-AMP synthase (cGAS) is a DNA sensor that activates STING and plays a role in inflammatory diseases. Here, we explored the role of cGAS in hepatic damage, steatosis, inflammation, and liver fibrosis in mouse models of NASH. METHODS: cGAS deficient (cGAS-KO) and STING deficient (STING-KO) mice received high fat-high cholesterol-high sugar diet (HF-HC-HSD) or relevant control diets. Livers were evaluated after 16 or 30 weeks. RESULTS: HF-HC-HSD diet, both at 16 and 30 weeks, resulted in increased cGAS protein expression as well as in increased ALT, IL-1ß, TNF-α and MCP-1 in wild-type (WT) mice compared to controls. Surprisingly, liver injury, triglyceride accumulation, and inflammasome activation were greater in HF-HC-HSD cGAS-KO compared to WT mice at 16 and to a lesser extent at 30 weeks. STING, a downstream target of cGAS was significantly increased in WT mice after HF-HC-HSD. In STING-KO mice after HF-HC-HSD feeding, we found increased ALT and attenuated MCP1 and IL-1ß expression compared to WT mice. Markers of liver fibrosis were increased in cGAS- and STING-KO mice compared to WT on HF-HC-HSD. We discovered that cGAS-KO mice had a significant increase in circulating endotoxin levels on HF-HC-HSD that correlated with changes in intestinal morphology which was exacerbated by HF-HC-HSD compared to WT mice. CONCLUSION: Our findings indicate that cGAS or STING deficiency exacerbate liver damage, steatosis, and inflammation in HF-HC-HSD diet-induced NASH, which might be linked to the disruption of the gut barrier.

Uncovering the mechanisms of exertional dyspnoea in combined pulmonary fibrosis and emphysema.

The prevailing view is that exertional dyspnoea in patients with combined idiopathic pulmonary fibrosis (IPF) and emphysema (CPFE) can be largely explained by severe hypoxaemia. However, there is little evidence to support these assumptions.We prospectively contrasted the sensory and physiological responses to exercise in 42 CPFE and 16 IPF patients matched by the severity of exertional hypoxaemia. Emphysema and pulmonary fibrosis were quantified using computed tomography. Inspiratory constraints were assessed in a constant work rate test: capillary blood gases were obtained in a subset of patients.CPFE patients had lower exercise capacity despite less extensive fibrosis compared to IPF (p=0.004 and 0.02, respectively). Exertional dyspnoea was the key limiting symptom in 24 CPFE patients who showed significantly lower transfer factor, arterial carbon dioxide tension and ventilatory efficiency (higher minute ventilation (V'E)/carbon dioxide output (V'CO2 ) ratio) compared to those with less dyspnoea. However, there were no between-group differences in the likelihood of pulmonary hypertension by echocardiography (p=0.44). High dead space/tidal volume ratio, low capillary carbon dioxide tension emphysema severity (including admixed emphysema) and traction bronchiectasis were related to a high V'E/V'CO2 ratio in the more dyspnoeic group. V'E/V'CO2 nadir >50 (OR 9.43, 95% CI 5.28-13.6; p=0.0001) and total emphysema extent >15% (2.25, 1.28-3.54; p=0.01) predicted a high dyspnoea burden associated with severely reduced exercise capacity in CPFEContrary to current understanding, hypoxaemia per se is not the main determinant of exertional dyspnoea in CPFE. Poor ventilatory efficiency due to increased "wasted" ventilation in emphysematous areas and hyperventilation holds a key mechanistic role that deserves therapeutic attention.

Macrophage-Specific Hypoxia-Inducible Factor-1α Contributes to Impaired Autophagic Flux in Nonalcoholic Steatohepatitis.

Inflammatory cell activation drives diverse cellular programming during hepatic diseases. Hypoxia-inducible factors (HIFs) have recently been identified as important regulators of immunity and inflammation. In nonalcoholic steatohepatitis (NASH), HIF-1α is upregulated in hepatocytes, where it induces steatosis; however, the role of HIF-1α in macrophages under metabolic stress has not been explored. In this study, we found increased HIF-1α levels in hepatic macrophages in methionine-choline-deficient (MCD) diet-fed mice and in macrophages of patients with NASH compared with controls. The HIF-1α increase was concomitant with elevated levels of autophagy markers BNIP3, Beclin-1, LC3-II, and p62 in both mouse and human macrophages. LysMCre HIFdPA fl/fl mice, which have HIF-1α levels stabilized in macrophages, showed higher steatosis and liver inflammation compared with HIFdPA fl/fl mice on MCD diet. In vitro and ex vivo experiments reveal that saturated fatty acid, palmitic acid (PA), both induces HIF-1α and impairs autophagic flux in macrophages. Using small interfering RNA-mediated knock-down and overexpression of HIF-1α in macrophages, we demonstrated that PA impairs autophagy via HIF-1α. We found that HIF-1α mediates NF-κB activation and MCP-1 production and that HIF-1α-mediated impairment of macrophage autophagy increases IL-1ß production, contributing to MCD diet-induced NASH. Conclusion: Palmitic acid impairs autophagy via HIF-1α activation in macrophages. HIF-1α and impaired autophagy are present in NASH in vivo in mouse macrophages and in human blood monocytes. We identified that HIF-1α activation and decreased autophagic flux stimulate inflammation in macrophages through upregulation of NF-κB activation. These results suggest that macrophage activation in NASH involves a complex interplay between HIF-1α and autophagy as these pathways promote proinflammatory overactivation in MCD diet-induced NASH.

Carotid chemoreflex activity restrains post-exercise cardiac autonomic control in healthy humans and in patients with pulmonary arterial hypertension.

KEY POINTS: Dysfunction of post-exercise cardiac autonomic control is associated with increased mortality risk in healthy adults and in patients with cardiorespiratory diseases. The afferent mechanisms that regulate the post-exercise cardiac autonomic control remain unclear. We found that afferent signals from carotid chemoreceptors restrain the post-exercise cardiac autonomic control in healthy adults and patients with pulmonary arterial hypertension (PAH). Patients with PAH had higher carotid chemoreflex sensitivity, and the magnitude of carotid chemoreceptor restraint of autonomic control was greater in patients with PAH as compared to healthy adults. The results demonstrate that the carotid chemoreceptors contribute to the regulation of post-exercise cardiac autonomic control, and suggest that the carotid chemoreceptors may be a potential target to treat post-exercise cardiac autonomic dysfunction in patients with PAH. ABSTRACT: Dysfunction of post-exercise cardiac autonomic control predicts mortality, but its underlying mechanisms remain unclear. We tested whether carotid chemoreflex activity restrains post-exercise cardiac autonomic control in healthy adults (HA), and whether such restraint is greater in patients with pulmonary arterial hypertension (PAH) who may have both altered carotid chemoreflex and altered post-exercise cardiac autonomic control. Twenty non-hypoxaemic patients with PAH and 13 age- and sex-matched HA pedalled until 90% of peak work rate observed in a symptom-limited ramp-incremental exercise test. Recovery consisted of unloaded pedalling for 5 min followed by seated rest for 6 min. During recovery, subjects randomly inhaled either 100% O2 (hyperoxia) to inhibit the carotid chemoreceptor activity, or 21% O2 (normoxia) as control. Post-exercise cardiac autonomic control was examined via heart rate (HR) recovery (HRR; HR change after 30, 60, 120 and 300 s of recovery, using linear and non-linear regressions of HR decay) and HR variability (HRV; time and spectral domain analyses). As expected, the PAH group had higher carotid chemosensitivity and worse post-exercise HRR and HRV than HA. Hyperoxia increased HRR at 30, 60 and 120 s and absolute spectral power HRV in both groups. Additionally, hyperoxia resulted in an accelerated linear HR decay and increased time domain HRV during active recovery only in the PAH group. In conclusion, the carotid chemoreceptors restrained recovery of cardiac autonomic control from exercise in HA and in patients with PAH, with the restraint greater for some autonomic indexes in patients with PAH.

Ischemic preconditioning boosts post-exercise but not resting cardiac vagal control in endurance runners.

PURPOSE: High cardiac vagal control in endurance athletes has been generally associated with adequate recovery from training and readiness to cope high-intensity training. A method that improves cardiac vagal control in endurance athletes could therefore be advantageous. Accordingly, we sought to test whether ischemic preconditioning (IPC) could enhance cardiac vagal control in endurance runners. METHODS: Fifteen subjects underwent IPC, sham ultrasound (SHAM) or control (CT), in random order. Subjects were informed both IPC and SHAM would be beneficial vs. CT (i.e., similar placebo induction), and IPC would be harmless despite ischemia sensations (i.e., nocebo avoidance). Resting cardiac vagal control was assessed via respiratory sinus arrhythmia (RSA) and heart rate variability (HRV) indexes. Post-exercise cardiac vagal control was assessed via heart rate recovery [HR time constant decay (T30) and absolute HR decay (HRR30s)] during 30-s breaks of a discontinuous incremental test. Capillary blood samples were collected for lactate threshold identification. RESULTS: RSA and HRV were similar among interventions at pre- and post-intervention assessments. Lactate threshold occurred at 85 ± 4% of maximal effort. T30 was similar among interventions, but IPC increased HRR30s at 70% and 75% of maximal effort vs. SHAM and CT (70%: IPC = 31 ± 2 vs. SHAM = 26 ± 3 vs. CT = 26 ± 2 bpm, mean ± SEM, P < 0.01; 75%: IPC = 29 ± 2 vs. SHAM = 25 ± 2 vs. CT = 24 ± 2 bpm, P < 0.01). CONCLUSION: IPC did not change resting cardiac vagal control, but boosted fast post-exercise cardiac vagal reactivation at exercise intensities below lactate threshold in endurance runners.

Can sexual transmission support the enzootic cycle of Trypanosoma cruzi?

BACKGROUND: Trypanosoma cruzi circulates in sylvatic habitats, mainly through blood-feeding triatomines, although other routes also contribute to its dispersion. Sexual transmission of T. cruzi is an understudied topic, especially among wild mammals. Because of the difficulties inherent to field work, experimentally infected mice are frequently used to evaluate the transmission of T. cruzi. OBJECTIVE: This study aimed to evaluate the sexual transmission of T. cruzi in acutely infected mice. METHODS: Male and female mice in the acute phase of Chagas disease were mated with naïve partners. Then, parasitological tests, immunohistochemistry, serological assays, and polymerase chain reaction (PCR) assays were used to detect infection. FINDINGS: Parasitological analysis showed trypomastigotes in the blood of 20% of the naïve mice after mating with infected partners. Serological assays detected anti-T. cruzi antibodies in all naïve females mated with infected males and in 60% of naïve males mated with infected females. PCR showed T. cruzi nDNA bands for all naïve mice mated with infected partners. The possibility of sexual transmission was also confirmed by visualisation of amastigotes in the testes. MAIN CONCLUSIONS: Our results demonstrate that sexual transmission of T. cruzi is an ordinary event that may contribute to maintenance of the parasite's enzootic cycle.

Sexual transmission of Trypanosoma cruzi in murine model.

Trypanosoma cruzi is mainly transmitted by blood-sucking triatomines, but other routes also have epidemiological importance, such as blood transfusion and congenital transmission. Although the possibility of sexual transmission of T. cruzi has been suggested since its discovery, few studies have been published on this subject. We investigated acquisition of T. cruzi by sexual intercourse in an experimental murine model. Male and female mice in the chronic phase of Chagas disease were mated with naive partners. Parasitological, serological and molecular tests demonstrated the parasites in tissues and blood of partners. These results confirm the sexual transmission of T. cruzi in mice.

Water intake accelerates parasympathetic reactivation after high-intensity exercise.

UNLABELLED: It has been shown that water intake (WI) improves postexercise parasympathetic recovery after moderate-intensity exercise session. However, the potential cardiovascular benefit promoted by WI has not been investigated after high-intensity exercise. PURPOSE: To assess the effects of WI on post high-intensity parasympathetic recovery. METHODS: Twelve recreationally active young men participated in the study (22 ± 1.4 years, 24.1 ± 1.6 kg.m(-2)). The experimental protocol consisted of two visits to the laboratory. Each visit consisted in the completion of a 30-min high-intensity [~80% of maximal heart rate (HR)] cycle ergometer aerobic session performing randomly the WI or control (CON, no water consumption) intervention at the end of the exercise. HR and RR intervals (RRi) were continuously recorded by a heart rate monitor before, during and after the exercise. Differences in HR recovery [e.g., absolute heart rate decrement after 1 min of recovery (HRR60s) and time-constant of the first order exponential fitting curve of the HRR (HRRτ)] and in postexercise vagal-related heart rate variability (HRV) indexes (rMSSD30s, rMSSD, pNN50, SD1 and HF) were calculated and compared for WI and CON. RESULTS: A similar HR recovery and an increased postexercise HRV [SD1 = 9.4 ± 5.9 vs. 6.0 ± 3.9 millisecond, HF(ln) = 3.6 ± 1.4 vs. 2.4 ± 1.3 millisecond(2), for WI and CON, respectively; p < .05] was observed in WI compared with CON. CONCLUSION: The results suggest that WI accelerates the postexercise parasympathetic reactivation after high-intensity exercise. Such outcome reveals an important cardioprotective effect of WI.

A novel experimental model of MetALD in male mice recapitulates key features of severe alcohol-associated hepatitis.

BACKGROUND: The recent increase in the incidence of alcohol-associated hepatitis (AH) coincides with the obesity epidemic in the United States. However, current mouse models do not fully replicate the combined insults of obesity, metabolic dysfunction-associated steatohepatitis, and alcohol. The aim of this study was to develop a new mouse model that recapitulates the robust inflammatory and fibrotic phenotype characteristic of human MetALD. METHODS: Eight- to 10-week-old male C57BL/6 mice were fed chow or high fat-cholesterol-sugar diet (metabolic dysfunction-associated steatohepatitis diet) and in each group, some received alcohol in drinking water (ad libitum) and weekly alcohol binges (EtOH) for 3 months. The liver was assessed for features of AH. RESULTS: MetALD mice displayed increased liver damage indicated by highly elevated ALT and bilirubin levels compared to all other groups. Liver steatosis was significantly greater in the MetALD mice compared to all other experimental groups. The inflammatory phenotype of MetALD was also recapitulated, including increased IL-6 and IL-1ß protein levels as well as increased CD68+ macrophages and Ly6G+ neutrophils in the liver. Sirius red staining and expression of collagen 1, alpha-smooth muscle actin indicated advanced fibrosis in the livers of MetALD mice. In addition, indicators of epithelial-to-mesenchymal transition markers were increased in MetALD mice compared to all other groups. Furthermore, we found increased ductular reaction, dysregulated hedgehog signaling, and decreased liver synthetic functions, consistent with severe AH. CONCLUSIONS: Alcohol administration in mice combined with metabolic dysfunction-associated steatohepatitis diet recapitulates key characteristics of human AH including liver damage, steatosis, robust systemic inflammation, and liver immune cell infiltration. This model results in advanced liver fibrosis, ductular reaction, decreased synthetic function, and hepatocyte dedifferentiation, suggesting a robust model of MetALD in mice.

Respiratory, cardiovascular and musculoskeletal mechanisms involved in the pathophysiology of pulmonary hypertension: An updated systematic review of preclinical and clinical studies.

BACKGROUND: Progressive exercise intolerance is a hallmark of pulmonary hypertension (pH), severely impacting patients' independence and quality of life (QoL). Accumulating evidence over the last decade shows that combined abnormalities in peripheral reflexes and target organs contribute to disease progression and exercise intolerance. OBJECTIVE: The aim of this study was to review the literature of the last decade on the contribution of the cardiovascular, respiratory, and musculoskeletal systems to pathophysiology and exercise intolerance in pH. METHODS: A systematic literature search was conducted using specific terms in PubMed, SciELO, and the Cochrane Library databases for original pre-clinical or clinical studies published between 2013 and 2023. Studies followed randomized controlled/non-randomized controlled and pre-post designs. RESULTS: The systematic review identified 25 articles reporting functional or structural changes in the respiratory, cardiovascular, and musculoskeletal systems in pH. Moreover, altered biomarkers in these systems, lower cardiac baroreflex, and heightened peripheral chemoreflex activity seemed to contribute to functional changes associated with poor prognosis and exercise intolerance in pH. Potential therapeutic strategies acutely explored involved manipulating the baroreflex and peripheral chemoreflex, improving cardiovascular autonomic control via cardiac vagal control, and targeting specific pathways such as GPER1, GDF-15, miR-126, and the JMJD1C gene. CONCLUSION: Information published in the last 10 years advances the notion that pH pathophysiology involves functional and structural changes in the respiratory, cardiovascular, and musculoskeletal systems and their integration with peripheral reflexes. These findings suggest potential therapeutic targets, yet unexplored in clinical trials, that could assist in improving exercise tolerance and QoL in patients with pH.

Impact of an active lifestyle on cardiovascular autonomic modulation and oxidative stress in males with overweight and parental history of hypertension.

Family history of hypertension is associated with early autonomic dysfunction and increased oxidative stress. These alterations have been found to be reinforced by the overweight factor. Conversely, an active lifestyle is effective in improving the mechanisms regulating blood pressure control. Hence, we ought to investigate the effects of an active lifestyle on the hemodynamic, autonomic and oxidative stress parameters in individuals carrying both family history of hypertension and overweight risk factors. Fifty-six normotensive males were divided into four groups: eutrophic offspring of normotensive parents (EN, n = 12), eutrophic and inactive with hypertensive parents (EH, n = 14), overweight and inactive with hypertensive parents (OH, n = 13), and overweight and physically active with hypertensive parents (OAH, n = 17). Cardiovascular autonomic modulation was assessed by heart rate (HRV) and blood pressure (BPV) variability indexes. Oxidative stress included pro/antioxidant markers and nitrite concentration. Inactive offspring of hypertensive parents (EH and OH) showed higher LFSBP (vs EN), an indicator of sympathetic outflow to the vasculature and reduced anti-oxidant activity (vs EN), while higher pro-oxidant markers were found exclusively in OH (vs EN and EH). Conversely, the OAH group showed bradycardia, higher vagally-mediated HFabs index (vs OH and EN), lower sympathovagal balance (vs OH) and preserved LFSBP. Yet, the OAH showed preserved pro/antioxidant markers and nitrite levels. Our findings indicates that overweight offspring of hypertensive parents with an active lifestyle have improved hemodynamic, cardiac autonomic modulation and oxidative stress parameters compared to their inactive peers.

Post-exercise heart rate variability recovery: a time-frequency analysis.

OBJECTIVE: Most studies investigating the effects of non-pharmacological interventions, such as physical training (PT), on cardiac autonomic control, assessed the HRV only in resting conditions. Recently, a new time-frequency mathematical approach based on the short-time Fourier transform (STFT) method has been validated for the assessment of HRV in non-stationary conditions such as the immediate post-exercise period. The aim of this study was to evaluate the effects of the PT on post-exercise cardiac autonomic control using the time-frequency STFT analysis of the HRV. METHODS: Twenty-one healthy male volunteers participated in this study. The subjects were initially evaluated for their physical exercise/sport practice and allocated to groups of low physical training ((Low)PT, n = 13) or high physical training (H(igh)PT, n = 8). The post-exercise HRV was assessed by the STFT method, which provides the analysis of dynamic changes in the power of the low- and high-frequency spectral components (LF and HF, respectively) of the HRV during the whole recovery period. RESULTS: Greater LF (from the min 5 to 10) and HF (from the min 6 to 10) in the post-exercise period in the H(igh)PT compared to the (Low)PT group (P < 0.05) was observed. CONCLUSION: These results indicate that exercise training exerts beneficial effects on post-exercise cardiac autonomic control.

Role of the Inflammasome in Liver Disease.

The involvement of inflammasomes in the proinflammatory response observed in chronic liver diseases, such as alcohol-associated liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD), is widely recognized. Although there are different types of inflammasomes, most studies to date have given attention to NLRP3 (nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3) in the pathogenesis of ALD, NAFLD/nonalcoholic steatohepatitis, and fibrosis. Canonical inflammasomes are intracellular multiprotein complexes that are assembled after the sensing of danger signals and activate caspase-1, which matures interleukin (IL)-1ß, IL-18, and IL-37 and also induces a form of cell death called pyroptosis. Noncanonical inflammasomes activate caspase-11 to induce pyroptosis. We discuss the different types of inflammasomes involved in liver diseases with a focus on (a) signals and mechanisms of inflammasome activation, (b) the role of different types of inflammasomes and their products in the pathogenesis of liver diseases, and (c) potential therapeutic strategies targeting components of the inflammasomes or cytokines produced upon inflammasome activation.

Granulocyte colony-stimulating factor attenuates liver damage by M2 macrophage polarization and hepatocyte proliferation in alcoholic hepatitis in mice.

Massive inflammation and liver failure are main contributors to the high mortality in alcohol-associated hepatitis (AH). In recent clinical trials, granulocyte colony-stimulating factor (G-CSF) therapy improved liver function and survival in patients with AH. However, the mechanisms of G-CSF-mediated beneficial effects in AH remain elusive. In this study, we evaluated effects of in vivo G-CSF administration, using a mouse model of AH. G-CSF treatment significantly reduced liver damage in alcohol-fed mice even though it increased the numbers of liver-infiltrating immune cells, including neutrophils and inflammatory monocytes. Moreover, G-CSF promoted macrophage polarization toward an M2-like phenotype and increased hepatocyte proliferation, which was indicated by an increased Ki67-positive signal colocalized with hepatocyte nuclear factor 4 alpha (HNF-4α) and cyclin D1 expression in hepatocytes. We found that G-CSF increased G-CSF receptor expression and resulted in reduced levels of phosphorylated ß-catenin in hepatocytes. In the presence of an additional pathogen-associated molecule, lipopolysaccharide (LPS), which is significantly increased in the circulation and liver of patients with AH, the G-CSF-induced hepatoprotective effects were abolished in alcohol-fed mice. We still observed increased Ki67-positive signals in alcohol-fed mice following G-CSF treatment; however, Ki67 and HNF-4α did not colocalize in LPS-challenged mice. Conclusion: G-CSF treatment increases immune cell populations, particularly neutrophil counts, and promotes M2-like macrophage differentiation in the liver. More importantly, G-CSF treatment reduces alcohol-induced liver injury and promotes hepatocyte proliferation in alcohol-fed mice. These data provide new insights into the understanding of mechanisms mediated by G-CSF and its therapeutic effects in AH.

Cell-to-Cell Communications in Alcohol-Associated Liver Disease.

This review covers some important new aspects of the alcohol-induced communications between liver parenchymal and non-parenchymal cells leading to liver injury development. The information exchange between various cell types may promote end-stage liver disease progression and involves multiple mechanisms, such as direct cell-to-cell interactions, extracellular vesicles (EVs) or chemokines, cytokines, and growth factors contained in extracellular fluids/cell culture supernatants. Here, we highlighted the role of EVs derived from alcohol-exposed hepatocytes (HCs) in activation of non-parenchymal cells, liver macrophages (LM), and hepatic stellate cells (HSC). The review also concentrates on EV-mediated crosstalk between liver parenchymal and non-parenchymal cells in the settings of HIV- and alcohol co-exposure. In addition, we overviewed the literature on the crosstalk between cell death pathways and inflammasome activation in alcohol-activated HCs and macrophages. Furthermore, we covered highly clinically relevant studies on the role of non-inflammatory factors, sinusoidal pressure (SP), and hepatic arterialization in alcohol-induced hepatic fibrogenesis. We strongly believe that the review will disclose major mechanisms of cell-to-cell communications pertained to alcohol-induced liver injury progression and will identify therapeutically important targets, which can be used for alcohol-associated liver disease (ALD) prevention.