Fibroblast growth factor 21 is a hepatokine involved in MASLD progression.

AIM: We aimed to assess the role of FGF21 in metabolic dysfunction-associated steatotic liver disease (MASLD) at a multi-scale level. METHODS: We used human MASLD pathology samples for FGF21 gene expression analyses (qPCR and RNAseq), serum to measure circulating FGF21 levels and DNA for genotyping the FGF21 rs838133 variant in both estimation and validation cohorts. A hepatocyte-derived cell line was exposed to free fatty acids at different timepoints. Finally, C57BL/6J mice were fed a high-fat and choline-deficient diet (CDA-HFD) for 16 weeks to assess hepatic FGF21 protein expression and FGF21 levels by ELISA. RESULTS: A significant upregulation in FGF21 mRNA expression was observed in the liver analysed by both qPCR (fold change 5.32 ± 5.25 vs. 0.59 ± 0.66; p = 0.017) and RNA-Seq (3.5 fold; FDR: 0.006; p < 0.0001) in MASLD patients vs. controls. Circulating levels of FGF21 were increased in patients with steatohepatitis vs. bland steatosis (386.6 ± 328.9 vs. 297.9 ± 231.5 pg/mL; p = 0.009). Besides, sex, age, A-allele from FGF21, GG genotype from PNPLA3, ALT, type 2 diabetes mellitus and BMI were independently associated with MASH and significant fibrosis in both estimation and validation cohorts. In vitro exposure of Huh7.5 cells to high concentrations of free fatty acids (FFAs) resulted in overexpression of FGF21 (p < 0.001). Finally, Circulating FGF21 levels and hepatic FGF21 expression were found to be significantly increased (p < 0.001) in animals under CDA-HFD. CONCLUSIONS: Hepatic and circulating FGF21 expression was increased in MASH patients, in Huh7.5 cells under FFAs and in CDA-HFD animals. The A-allele from the rs838133 variant was also associated with an increased risk of steatohepatitis and significant and advanced fibrosis in MASLD patients.

Beneficial effects of hepatic cyclooxygenase-2 expression against cholestatic injury after common bile duct ligation in mice.

BACKGROUND AND AIMS: Cyclooxygenase-2 (COX-2) is involved in different liver diseases, but little is known about the significance of COX-2 in cholestatic injury. This study was designed to elucidate the role of COX-2 expression in hepatocytes during the pathogenesis of obstructive cholestasis. METHODS: We used genetically modified mice constitutively expressing human COX-2 in hepatocytes. Transgenic mice (hCOX-2-Tg) and their wild-type (Wt) littermates were either subjected to a mid-abdominal laparotomy or common bile duct ligation (BDL) for 2 or 5 days. Then, we explored the mechanisms underlying the role of COX-2 and its derived prostaglandins in liver function, and the synthesis and excretion of bile acids (BA) in response to cholestatic liver injury. RESULTS: After BDL, hCOX-2-Tg mice showed lower grades of hepatic necrosis and inflammation than Wt mice, in part by a reduced hepatic neutrophil recruitment associated with lower mRNA levels of pro-inflammatory cytokines. Furthermore, hCOX-2-Tg mice displayed a differential metabolic pattern of BA synthesis that led to an improved clearance after BDL-induced accumulation. In addition, an enhanced response to the BDL-induced oxidative stress and hepatic apoptosis was observed. In vitro experiments using hepatic cells that stably express hCOX-2 confirmed the cytoprotective role of prostaglandin E2 against BA toxicity. CONCLUSIONS: Taken together, our data indicate that constitutive expression of COX-2 in hepatocytes ameliorates cholestatic liver injury in mice by reducing inflammation and cell damage and by modulating BA metabolism, pointing to a role for COX-2 as a defensive response against cholestasis-derived BA accumulation and injury.

The biochemical pattern defines MASLD phenotypes linked to distinct histology and prognosis.

BACKGROUND: MASLD can manifest as hepatocellular damage, which can result in mild elevation of aminotransferases. However, in some patients, MASLD presents with cholestatic pattern. OBJECTIVE: To assess the impact of the biochemical pattern on the natural course of MASLD, including liver damage in histology, the accuracy of non-invasive tests(NITs), and prognosis. METHODS: Multicenter study enrolling 2156 patients with biopsy-proven MASLD, who were classified based on their[ALT/ULN)]/[(ALP/ULN)] levels at the time of biopsy: (a) hepatocellular pattern(H), > 5; (b) mixed pattern(M),2-5; (c) cholestatic pattern(C), < 2. OUTCOMES: (a) histological evaluation of the single components of NAS, MASH, and fibrosis; (b) NITs and transient elastography assessing advanced fibrosis; (c) prognosis determined by the appearance of decompensated cirrhosis and death. RESULTS: Out of the 2156 patients, 22.9% exhibited the H-pattern, whilst 31.7% exhibited the C-pattern. Severe steatosis, ballooning, lobular inflammation, and MASH (56.4% H vs. 41.9% M vs. 31.9% C) were more common in H-pattern (p = 0.0001),whilst C-pattern was linked to cirrhosis (5.8% H vs. 5.6% M vs. 10.9% C; p = 0.0001). FIB-4(0.74(95% CI 0.69-0.79) vs. 0.83 (95% CI 0.80-0.85); p = 0.005) and Hepamet Fibrosis Score(0.77 (95% CI 0.69-0.85) vs. 0.84 (95% CI 0.80-0.87); p = 0.044)exhibited lower AUROCs in the H-pattern. The C-pattern[HR 2.37 (95% CI 1.12-5.02); p = 0.024], along with age, diabetes, and cirrhosis were independently associated with mortality. Most patients maintained their initial biochemical pattern during the second evaluation. CONCLUSIONS: The H-pattern exhibited greater necro-inflammation in the histology than the C-pattern, whereas the latter showed more cirrhosis. The accuracy of NITs in detecting fibrosis was decreased in H-pattern. The occurrence of decompensated events and mortality was predominant in C-pattern. Therefore, identifying MASLD phenotypes based on the biochemical presentation could be relevant for clinical practice.

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury.

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

Hospital-based screening outperforms primary care screening as a means of achieving hepatitis C virus micro-elimination.

AIM: To assess the respective performances of a HCV screening program in a hospital setting and a HCV screening model applied concomitantly in a primary care centre. METHODS: Adult patients consecutively admitted to hospital for ambulatory surgery were screened for anti-HCV antibodies (hospital screening cohort, HPSC), as were patients receiving blood tests for medical reasons in a primary care centre (primary care screening cohort, PCSC). Serum anti-HCV and HCV RNA levels were tested by ELISA and real-time PCR, respectively. RESULTS: Seroprevalence of HCV infection was 2.2 % in the HPSC and 1.4 % in the PCSC (p = 0.044). All viraemic patients (0.2 % in HPSC and 0.1 % in PCSC) were treated with direct-acting antivirals and 85.7 % experienced a sustained virological response. CONCLUSIONS: Hospital-based HCV screening outperformed primary care-centered screening, significantly increasing HCV case findings.

Papel del servicio de prevención en el diagnóstico de la patología mental para una adecuada integración laboral / Role of the prevention service in the diagnosis of mental pathology for an adequate occupational integration

Las enfermedades mentales tienen especial relevancia tanto por su elevada prevalencia en el momento actual como por sus consecuencias en diferentes ámbitos de la vida. En este artículo se presenta un caso clínico de un trabajador diagnosticado de trastorno conversivo que es evaluado por parte del servicio de prevención con el fin de establecer la aptitud laboral. El conocimiento de la clínica, diagnóstico y abordaje de estos trastornos conjunta y coordinadamente por el servicio de prevención de riesgos labores, mandos directos y otros especialistas es el pilar fundamental para conseguir una adecuada adaptación del puesto de trabajo, así como una integración laboral siempre que se cumplan las restricciones especificadas en el informe de aptitud. (AU)

Mental illnesses are particularly relevant both because of their high prevalence at the present time and because of their consequences in different areas of life. This article presents a clinical case of a worker diagnosed with conversion disorder who is evaluated by the prevention service in order to establish work aptitude. Knowledge of the clinic, diagnosis and approach to these joint and coordinated disorders by the occupational risk prevention service, direct managers and other specialists is the fundamental pillar to achieve an adequate adaptation of the job, as well as labor integration whenever the restrictions specified in the suitability report are met. (AU)

Influence of epidemiological and clinical factors in the reactogenicity to Comirnaty® vaccine in health care workers of a Spanish university teaching hospital (COVIVAC study) / Influencia de factores epidemiológicos y clínicos en la reactogenicidad a la vacuna Comirnaty® en trabajadores sanitarios de un hospital universitario español (estudio COVIVAC)

Introduction. Comirnaty® is an mRNA vaccine against COVID-19 which has been administered to millions of people since the end of 2020. Our aim was to study epidemiological and clinical factors influencing reactogenicity and functional limitation after the first two doses of the vaccine in health care workers (HCWs). Material and methods. Prospective post-authorization cohort study to monitor safety and effectiveness of the vaccine. Results. Local side effects were mild and presented both with first and second dose of Comirnaty. Systemic side effects were more frequent after 2nd dose. Nevertheless, previous SARS-CoV-2 infection was associated with systemic effects after the first dose of the vaccine (OR ranging from 2 to 6). No severe adverse effects were reported. According to multivariate analysis, the degree of self-reported functional limitation after the first dose increased with age, female sex, previous COVID-19 contact, previous SARS-CoV-2 infection, and Charlson Comorbidity Index (CCI). After the second dose, the degree of functional limitation observed was lower in those with previous SARS-CoV-2 infection, and it was positively associated to the degree of functional limitation after the first dose. Conclusion. Systemic adverse effects were more frequent after the second dose of Comirnaty. Previous SARS-CoV-2 infection was associated with systemic effects after the first dose. Age, female sex, previous COVID-19, previous isolation due to COVID-19 contact, and CCI showed to be independent predictors of the degree of functional limitation after the 1st dose of Comirnaty®. After the 2nd dose, the degree of functional limitation was lower in those who previously had SARS-CoV-2 infection (AU)

Introducción. Comirnaty® es una vacuna de ARNm contra el COVID-19 que se ha administrado a millones de personas desde finales de 2020. Nuestro objetivo fue estudiar los factores epidemiológicos y clínicos que influyen en la reactogenicidad y la limitación funcional asociadas tras las dos primeras dosis de la vacuna en trabajadores de la salud. Metodología. Estudio de cohorte prospectivo post-autorización para evaluar la seguridad y eficacia de la vacuna. Resultados. Los efectos secundarios locales fueron leves y se presentaron tanto con la primera como con la segunda dosis de Comirnaty. Los efectos secundarios sistémicos fueron más frecuentes después de la segunda dosis. No obstante, la infección previa por SARS-CoV-2 se asoció con efectos sistémicos tras la primera dosis de la vacuna (OR de 2 a 6). No se informaron efectos adversos graves. El análisis multivariante demostró que el grado de limitación funcional tras la primera dosis aumentó con la edad, el sexo femenino, contacto previo con COVID-19, la infección previa por SARS CoV-2 y el índice de comorbilidad de Charlson (ICC). Tras la segunda dosis, el grado de limitación funcional observado fue menor en aquellos con infección previa por SARS-CoV-2, y se asoció positivamente al grado de limitación funcional tras la primera dosis.Conclusión. Los efectos adversos sistémicos fueron más frecuentes después de la segunda dosis de Comirnaty. La infección previa por SARS-CoV-2 se asoció con efectos sistémicos después de la primera dosis. La edad, el sexo femenino, infección por COVID-19 previa, el aislamiento previo por contacto de COVID-19 y el ICC se mostraron como predictores independientes del grado de limitación funcional tras la 1ª dosis de Comirnaty®. Después de la 2.ª dosis, el grado de limitación funcional fue menor en los que previamente tenían infección por SARS-CoV-2 (AU)

Sleep apnea-COPD overlap syndrome is associated with larger left carotid atherosclerotic plaques.

Background: Little is known about whether the overlap syndrome (OS) combining features of chronic obstructive pulmonary disease (COPD) and sleep apnea-hypopnea syndrome increases the risk of stroke associated with COPD itself. Methods: We prospectively studied 74 COPD patients and 32 subjects without lung disease. Spirometry and cardiorespiratory polygraphy were used to assess the pulmonary function of the study population and ultrasound measurements of intima media thickness (IMT) as well as the volume of plaques in both carotid arteries were also evaluated. Results: Polygraphic criteria of OS were met in 51% of COPD patients. We found that 79% of patients with OS and 50% of COPD patients without OS had atherosclerotic plaques in the left carotid artery (p = 0.0509). Interestingly, the mean volume of atherosclerotic plaques was significantly higher in the left carotid artery of COPD patients with OS (0.07 ± 0.02 ml) than in those without OS (0.04 ± 0.02 ml, p = 0.0305). However, regardless of the presence of OS, no significant differences were observed in both presence and volume of atherosclerotic plaques in the right carotid artery of COPD patients. Adjusted-multivariate linear regression revealed age, current smoking and the apnea/hypopnea index (OR = 4.54, p = 0.012) as independent predictors of left carotid atherosclerotic plaques in COPD patients. Conclusions: This study suggests that the presence of OS in COPD patients is associated with larger left carotid atherosclerotic plaques, indicating that OS might be screened in all COPD patients to identify those with higher risk of stroke.

Increased let-7d-5p in non-alcoholic fatty liver promotes insulin resistance and is a potential blood biomarker for diagnosis.

BACKGROUND AND AIMS: The molecular mechanisms driving non-alcoholic fatty liver disease (NAFLD) are poorly understood; however, microRNAs might play a key role in these processes. We hypothesize that let-7d-5p could contribute to the pathophysiology of NAFLD and serve as a potential diagnostic biomarker. METHODS: We evaluated let-7d-5p levels and its targets in liver biopsies from a cross-sectional study including patients with NAFLD and healthy donors, and from a mouse model of NAFLD. Moreover, the induction of let-7d-5p expression by fatty acids was evaluated in vitro. Further, we overexpressed let-7d-5p in vitro to corroborate the results observed in vivo. Circulating let-7d-5p and its potential as a NAFLD biomarker was determined in isolated extracellular vesicles from human plasma by RT-qPCR. RESULTS: Our results demonstrate that hepatic let-7d-5p was significantly up-regulated in patients with steatosis, and this increase correlated with obesity and a decreased expression of AKT serine/threonine kinase (AKT), insulin-like growth factor 1 (IGF1), IGF-I receptor (IGF1R) and insulin receptor (INSR). These alterations were corroborated in a NAFLD mouse model. In vitro, fatty acids increased let-7d-5p expression, and its overexpression decreased AKT, IGF-IR and IR protein expression. Furthermore, let-7d-5p hindered AKT phosphorylation in vitro after insulin stimulation. Finally, circulating let-7d-5p significantly decreased in steatosis patients and receiver operating characteristic (ROC) analyses confirmed its utility as a diagnostic biomarker. CONCLUSIONS: Our results highlight the emerging role of let-7d-5p as a potential therapeutic target for NAFLD since its overexpression impairs hepatic insulin signalling, and also, as a novel non-invasive biomarker for NAFLD diagnosis.

Circulating bone morphogenetic protein 8A is a novel biomarker to predict advanced liver fibrosis.

BACKGROUND & AIMS: Advanced hepatic fibrosis is the main risk factor of liver-related morbidity and mortality in patients with chronic liver disease. In this study, we assessed the potential role of bone morphogenetic protein 8A (BMP8A) as a novel target involved in liver fibrosis progression. METHODS: Histological assessment and BMP8A expression were determined in different murine models of hepatic fibrosis. Furthermore, serum BMP8A was measured in mice with bile duct ligation (BDL), in 36 subjects with histologically normal liver (NL) and in 85 patients with biopsy-proven non-alcoholic steatohepatitis (NASH): 52 with non- or mild fibrosis (F0-F2) and 33 with advanced fibrosis (F3-F4). BMP8A expression and secretion was also determined in cultured human hepatocyte-derived (Huh7) and human hepatic stellate (LX2) cells stimulated with transforming growth factor ꞵ (TGFꞵ). RESULTS: Bmp8a mRNA levels were significantly upregulated in livers from fibrotic mice compared to control animals. Notably, serum BMP8A levels were also elevated in BDL mice. In addition, in vitro experiments showed increased expression and secretion to the culture supernatant of BMP8A in both Huh7 and LX2 cells treated with TGFꞵ. Noteworthy, we found that serum BMP8A levels were significantly higher in NASH patients with advanced fibrosis than in those with non- or mild fibrosis. In fact, the AUROC of circulating BMP8A concentrations to identify patients with advanced fibrosis (F3-F4) was 0.74 (p˂0.0001). Moreover, we developed an algorithm based on serum BMP8A levels that showed an AUROC of 0.818 (p˂0.0001) to predict advanced fibrosis in NASH patients. CONCLUSION: This study provides experimental and clinical evidence indicating that BMP8A is a novel molecular target linked to liver fibrosis and introduces an efficient algorithm based on serum BMP8A levels to screen patients at risk for advanced hepatic fibrosis.

Influence of epidemiological and clinical factors in the reactogenicity to Comirnaty® vaccine in health care workers of a Spanish university teaching hospital (COVIVAC study).

OBJECTIVE: Comirnaty® is an mRNA vaccine against COVID-19 which has been administered to millions of people since the end of 2020. Our aim was to study epidemiological and clinical factors influencing reactogenicity and functional limitation after the first two doses of the vaccine in health care workers (HCWs). METHODS: Prospective post-authorization cohort study to monitor safety and effectiveness of the vaccine. RESULTS: Local side effects were mild and presented both with first and second dose of Comirnaty. Systemic side effects were more frequent after 2nd dose. Nevertheless, previous SARS-CoV-2 infection was associated with systemic effects after the first dose of the vaccine (OR ranging from 2 to 6). No severe adverse effects were reported. According to multivariate analysis, the degree of self-reported functional limitation after the first dose increased with age, female sex, previous COVID-19 contact, previous SARS-CoV-2 infection, and Charlson Comorbidity Index (CCI). After the second dose, the degree of functional limitation observed was lower in those with previous SARS-CoV-2 infection, and it was positively associated to the degree of functional limitation after the first dose. CONCLUSIONS: Systemic adverse effects were more frequent after the second dose of Comirnaty. Previous SARS-CoV-2 infection was associated with systemic effects after the first dose. Age, female sex, previous COVID-19, previous isolation due to COVID-19 contact, and CCI showed to be independent predictors of the degree of functional limitation after the 1st dose of Comirnaty®. After the 2nd dose, the degree of functional limitation was lower in those who previously had SARS-CoV-2 infection.

Mitochondrial respiratory chain activity is associated with severity, corticosteroid response and prognosis of alcoholic hepatitis.

BACKGROUND AND AIMS: Little is known about the extent of mitochondrial respiratory chain (MRC) activity dysfunction in patients with alcoholic hepatitis (AH). We aimed to assess the hepatic MRC activity in AH patients and its potential impact on the severity and prognosis of this life-threatening liver disease. METHODS: MRC complexes were measured in liver biopsies of 98 AH patients (non-severe, 17; severe, 81) and in 12 histologically normal livers (NL). Severity was assessed according to Maddrey's Index and MELD score. Corticosteroid response rate and cumulative mortality were also evaluated. RESULTS: The activity of the five MRC complexes was markedly decreased in the liver of AH patients compared with that of NL subjects, being significantly lower in patients with severe AH than in those with non-severe AH. There was a negative correlation between the activity of all MRC complexes and the severity of AH. Interestingly, only complex I and III activities showed a significant positive correlation with the corticosteroid response rate and a significant negative correlation with the mortality rate at all-time points studied. In a multivariate regression analysis, besides the MELD score and the corticosteroid response rate, complex I activity was significantly associated with 3-month mortality (OR = 6.03; p = 0.034) and complex III activity with 6-month mortality (OR = 4.70; p = 0.041) in AH patients. CONCLUSION: Our results indicate that MRC activity is markedly decreased in the liver of AH patients, and, particularly, the impairment of MRC complexes I and III activity appears to have a significant impact on the clinical outcomes of patients with AH.

Impaired Function of Solute Carrier Family 19 Leads to Low Folate Levels and Lipid Droplet Accumulation in Hepatocytes.

Low serum folate levels are inversely related to metabolic associated fatty liver disease (MAFLD). The role of the folate transporter gene (SLC19A1) was assessed to clarify its involvement in lipid accumulation during the onset of MAFLD in humans and in liver cells by genomic, transcriptomic, and metabolomic techniques. Genotypes of 3 SNPs in a case-control cohort were initially correlated to clinical and serum MAFLD markers. Subsequently, the expression of 84 key genes in response to the loss of SLC19A1 was evaluated with the aid of an RT2 profiler-array. After shRNA-silencing of SLC19A1 in THLE2 cells, folate and lipid levels were measured by ELISA and staining techniques, respectively. In addition, up to 482 amino acids and lipid metabolites were semi-quantified in SLC19A1-knockdown (KD) cells through ultra-high-performance liquid chromatography coupled with mass spectrometry. SNPs, rs1051266 and rs3788200, were significantly associated with the development of fatty liver for the single-marker allelic test. The minor alleles of these SNPs were associated with a 0.6/-1.67-fold decreased risk of developing MAFLD. When SLC19A1 was KD in THLE2 cells, intracellular folate content was four times lower than in wild-type cells. The lack of functional SLC19A1 provoked significant changes in the regulation of genes associated with lipid droplet accumulation within the cell and the onset of NAFLD. Metabolomic analyses showed a highly altered profile, where most of the species that accumulated in SLC19A1-KD-cells belong to the chemical groups of triacylglycerols, diacylglycerols, polyunsaturated fatty acids, and long chain, highly unsaturated cholesterol esters. In conclusion, the lack of SLC19A1 gene expression in hepatocytes affects the regulation of key genes for normal liver function, reduces intracellular folate levels, and impairs lipid metabolism, which entails lipid droplet accumulation in hepatocytes.

Rhamnan sulfate reduces atherosclerotic plaque formation and vascular inflammation.

OBJECTIVE: While lipid-lowering drugs have become a mainstay of clinical therapy these treatments only slow the progression of the disease and can have side effects. Thus, new treatment options are needed to supplement the effects of lipid lowering therapy for treating atherosclerosis. We examined the use of an inexpensive and widely available marine polysaccharide rhamnan sulfate as an oral therapeutic for limiting vascular inflammation and atherosclerosis. METHODS AND RESULTS: We found rhamnan sulfate enhanced the barrier function of endothelial cells, preventing the deposition of LDL and maintaining barrier function even in the presence of glycocalyx-degrading enzymes. Rhamnan sulfate was also found to bind directly to FGF-2, PDGF-BB and NF-κB subunits with high affinity. In addition, rhamnan sulfate was a potent inhibitor of NF-κB pathway activation in endothelial cells by TNF-α. We treated ApoE-/- mice with a high fat diet for 4 weeks and then an addition 9 weeks of high fat diet with or without rhamnan sulfate. Rhamnan sulfate reduced vascular inflammation and atherosclerosis in both sexes of ApoE-/- mice but had a stronger therapeutic effect in female mice. Oral consumption of rhamnan sulfate induced a significant decrease in cholesterol plasma levels in female mice but not in male mice. In addition, there was a marked reduction in inflammation for female mice in the liver and aortic root in comparison to male mice. CONCLUSIONS: Rhamnan sulfate has beneficial effects in reducing inflammation, binding growth factors and NF-κB, enhancing endothelial barrier function and reducing atherosclerotic plaque formation in ApoE-/- mice.

Ptpn1 deletion protects oval cells against lipoapoptosis by favoring lipid droplet formation and dynamics.

Activation of oval cells (OCs) has been related to hepatocyte injury during chronic liver diseases including non-alcoholic fatty liver disease (NAFLD). However, OCs plasticity can be affected under pathological environments. We previously found protection against hepatocyte cell death by inhibiting protein tyrosine phosphatase 1B (PTP1B). Herein, we investigated the molecular and cellular processes involved in the lipotoxic susceptibility in OCs expressing or not PTP1B. Palmitic acid (PA) induced apoptotic cell death in wild-type (Ptpn1+/+) OCs in parallel to oxidative stress and impaired autophagy. This lipotoxic effect was attenuated in OCs lacking Ptpn1 that showed upregulated antioxidant defences, increased unfolded protein response (UPR) signaling, higher endoplasmic reticulum (ER) content and elevated stearoyl CoA desaturase (Scd1) expression and activity. These effects in Ptpn1-/- OCs concurred with an active autophagy, higher mitochondrial efficiency and a molecular signature of starvation, favoring lipid droplet (LD) formation and dynamics. Autophagy blockade in Ptpn1-/- OCs reduced Scd1 expression, mitochondrial fitness, LD formation and restored lipoapoptosis, an effect also recapitulated by Scd1 silencing. PTP1B immunostaining was detected in OCs from mouse liver and, importantly, LDs were found in OCs from Ptpn1-/- mice with NAFLD. In conclusion, we demonstrated that Ptpn1 deficiency restrains lipoapoptosis in OCs through a metabolic rewiring towards a "starvation-like" fate, favoring autophagy, mitochondrial fitness and LD formation. Dynamic LD-lysosomal interations likely ensure lipid recycling and, overall, these adaptations protect against lipotoxicity. The identification of LDs in OCs from Ptpn1-/- mice with NAFLD opens therapeutic perspectives to ensure OC viability and plasticity under lipotoxic liver damage.

Bone morphogenetic protein 2 is a new molecular target linked to non-alcoholic fatty liver disease with potential value as non-invasive screening tool.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease worldwide, being non-alcoholic steatohepatitis (NASH) its most clinically relevant form. Given the risks associated with taking a liver biopsy, the design of accurate non-invasive methods to identify NASH patients is of upmost importance. BMP2 plays a key role in metabolic homeostasis; however, little is known about its involvement in NAFLD onset and progression. This study aimed to elucidate the impact of BMP2 in NAFLD pathophysiology. METHODS: Hepatic and circulating levels of BMP2 were quantified in serum and liver specimens from 115 biopsy-proven NAFLD patients and 75 subjects with histologically normal liver (NL). In addition, BMP2 content and release was determined in cultured human hepatocytes upon palmitic acid (PA) overload. RESULTS: We found that BMP2 expression was abnormally increased in livers from NAFLD patients than in subjects with NL and this was reflected in higher serum BMP2 levels. Notably, we observed that PA upregulated BMP2 expression and secretion by human hepatocytes. An algorithm based on serum BMP2 levels and clinically relevant variables to NAFLD showed an AUROC of 0.886 (95%CI, 0.83-0.94) to discriminate NASH. We used this algorithm to develop SAN (Screening Algorithm for NASH): a SAN < 0.2 implied a low risk and a SAN ≥ 0.6 indicated high risk of NASH diagnosis. CONCLUSION: This proof-of-concept study shows BMP2 as a new molecular target linked to NAFLD and introduces SAN as a simple and efficient algorithm to screen individuals at risk for NASH.

Liver injury in non-alcoholic fatty liver disease is associated with urea cycle enzyme dysregulation.

The main aim was to evaluate changes in urea cycle enzymes in NAFLD patients and in two preclinical animal models mimicking this entity. Seventeen liver specimens from NAFLD patients were included for immunohistochemistry and gene expression analyses. Three-hundred-and-eighty-two biopsy-proven NAFLD patients were genotyped for rs1047891, a functional variant located in carbamoyl phosphate synthetase-1 (CPS1) gene. Two preclinical models were employed to analyse CPS1 by immunohistochemistry, a choline deficient high-fat diet model (CDA-HFD) and a high fat diet LDLr knockout model (LDLr -/-). A significant downregulation in mRNA was observed in CPS1 and ornithine transcarbamylase (OTC1) in simple steatosis and NASH-fibrosis patients versus controls. Further, age, obesity (BMI > 30 kg/m2), diabetes mellitus and ALT were found to be risk factors whereas A-allele from CPS1 was a protective factor from liver fibrosis. CPS1 hepatic expression was diminished in parallel with the increase of fibrosis, and its levels reverted up to normality after changing diet in CDA-HFD mice. In conclusion, liver fibrosis and steatosis were associated with a reduction in both gene and protein expression patterns of mitochondrial urea cycle enzymes. A-allele from a variant on CPS1 may protect from fibrosis development. CPS1 expression is restored in a preclinical model when the main trigger of the liver damage disappears.

Increased Oxygen Desaturation Time During Sleep Is a Risk Factor for NASH in Patients With Obstructive Sleep Apnea: A Prospective Cohort Study.

Introduction: Given that obstructive sleep apnea (OSA) is commonly associated with metabolic disorders, in this prospective study, we sought to determine the prevalence and risk factors for hepatosteatosis, non-alcoholic steatohepatitis (NASH), and advanced liver fibrosis in patients with clinical and polygraphic criteria of OSA (n = 153) and in subjects with normal lung function parameters (NLP, n = 43). Methods: Hepatosteatosis, NASH, and advanced liver fibrosis were determined by blood-based non-invasive tools, such as the fatty liver index and the hepatic steatosis index, a serum lipidomic (OWLiver™) test, and three distinct fibrosis algorithms, respectively. Logistic regression models adjusted by potential confounders were performed to evaluate risk factors. Results: Insulin resistance and dyslipidemia were more frequent in patients with OSA than in subjects with NLP. The prevalence of hepatosteatosis was significantly higher in patients with OSA than in subjects with NLP. NASH was also found more frequently in patients with OSA than in subjects with NLP. In contrast, advanced liver fibrosis was rarely detected in the entire study population, and no significant differences were observed between patients with OSA and subjects with NLP. Besides male gender, increased body mass index (BMI), and presence of type 2 diabetes, percentage of sleep time with oxygen saturation <90% (Tc90%) was the only polygraphic variable significantly associated with NASH in patients with OSA. Conclusions: This study shows that hepatosteatosis and NASH are highly prevalent in patients with OSA and indicates that those with a Tc90% higher than 10% are at increased risk for NASH.

Inhibition of ATG3 ameliorates liver steatosis by increasing mitochondrial function.

BACKGROUND & AIMS: Autophagy-related gene 3 (ATG3) is an enzyme mainly known for its actions in the LC3 lipidation process, which is essential for autophagy. Whether ATG3 plays a role in lipid metabolism or contributes to non-alcoholic fatty liver disease (NAFLD) remains unknown. METHODS: By performing proteomic analysis on livers from mice with genetic manipulation of hepatic p63, a regulator of fatty acid metabolism, we identified ATG3 as a new target downstream of p63. ATG3 was evaluated in liver samples from patients with NAFLD. Further, genetic manipulation of ATG3 was performed in human hepatocyte cell lines, primary hepatocytes and in the livers of mice. RESULTS: ATG3 expression is induced in the liver of animal models and patients with NAFLD (both steatosis and non-alcoholic steatohepatitis) compared with those without liver disease. Moreover, genetic knockdown of ATG3 in mice and human hepatocytes ameliorates p63- and diet-induced steatosis, while its overexpression increases the lipid load in hepatocytes. The inhibition of hepatic ATG3 improves fatty acid metabolism by reducing c-Jun N-terminal protein kinase 1 (JNK1), which increases sirtuin 1 (SIRT1), carnitine palmitoyltransferase 1a (CPT1a), and mitochondrial function. Hepatic knockdown of SIRT1 and CPT1a blunts the effects of ATG3 on mitochondrial activity. Unexpectedly, these effects are independent of an autophagic action. CONCLUSIONS: Collectively, these findings indicate that ATG3 is a novel protein implicated in the development of steatosis. LAY SUMMARY: We show that autophagy-related gene 3 (ATG3) contributes to the progression of non-alcoholic fatty liver disease in humans and mice. Hepatic knockdown of ATG3 ameliorates the development of NAFLD by stimulating mitochondrial function. Thus, ATG3 is an important factor implicated in steatosis.