Vitamin D counteracts fibrogenic TGF-β signalling in human hepatic stellate cells both receptor-dependently and independently

Vitamin D deficiency stratifies the risk of covert and overt hepatic encephalopathy in patients with cirrhosis: A retrospective cohort study

BACKGROUNDS & AIMS

This study aimed to investigate the association between vitamin D deficiency and covert hepatic encephalopathy (CHE), overt hepatic encephalopathy (OHE) occurrence, and mortality in patients with cirrhosis.

METHODS

This retrospective study reviewed 679 patients with cirrhosis. Vitamin D deficiency was defined as serum 25-hydorxyvitamin D (25-OHD) levels < 20 ng/mL. The associations between 25-OHD and CHE, OHE occurrence, and mortality were assessed using logistic regression, Fine-Gray competing risk regression, and Cox proportional hazards regression models, respectively.

RESULTS

Of 428 eligible patients, 75% had vitamin D deficiency and 23% had CHE. The prevalence of CHE was higher in patients with vitamin D deficiency than in those without vitamin D deficiency (28% vs. 13%, p = 0.002). During the median follow-up period of 2.3 years, 14% of the patients developed OHE and 27% died. Patients with vitamin D deficiency had a higher incidence of OHE (p = 0.002) and mortality (p = 0.006) than those without vitamin D deficiency. After adjustment for potential covariates, multivariate analyses showed that 25-OHE was associated with CHE (odds ratio, 0.95; 95% confidence interval [CI], 0.91-0.99; p = 0.023), OHE occurrence (sub-distribution hazard ratio, 0.92; 95% CI, 0.86-0.98; p = 0.013) and mortality (hazard ratio, 0.96; 95% CI, 0.93-0.99; p = 0.020) in patients with cirrhosis.

CONCLUSIONS

Vitamin D deficiency is highly prevalent and is associated with CHE, OHE, and mortality in patients with cirrhosis. Evaluation of vitamin D is essential to predict the outcomes of patients with cirrhosis.

Calcitriol ameliorates the progression of hepatic fibrosis through autophagy-related gene 16-like 1-mediated autophagy

BACKGROUND

Calcitriol has the potential to counteract fibrotic diseases beyond its classical action of maintaining calcium and bone metabolism; however, its functional mechanism remains unknown. Autophagy-related gene 16-like 1 (Atg16l1) is one of the genes related to autophagy and is involved in protecting against fibrotic diseases. The present study aimed to explore the contribution of autophagy to the inhibition of calcitriol-induced hepatic fibrosis, as well as its potential molecular mechanism.

METHODS

Carbon tetrachloride (Ccl4)-treated mice were established as hepatic fibrosis models and received calcitriol treatment for 6 weeks. Quantification of Sirius red staining and measurement of key fibrotic markers (collagen-1 and α-SMA) was performed to detect hepatic fibrosis. Chloroquine (CQ) treatment was used to observe autophagic flux, and 3-methyladenine (3-MA) was used to inhibit autophagy. Furthermore, the effects of calcitriol on transforming growth factor β1 (TGFβ1)-stimulated primary hepatic stellate cells (HSCs) were detected. Downregulation of Atg16l1 or vitamin D receptor (VDR) in LX-2 cells was used to explore the mechanism of action of calcitriol in fibrosis and autophagy. Additionally, the electrophoretic mobility shift assay (EMSA) was used to investigate the interactions between VDR and ATG16L1.

RESULTS

Calcitriol increased the expression of VDR and ATG16L1, enhanced autophagy and attenuated hepatic fibrosis. 3-MA treatment and VDR silencing abolished the protective effects of calcitriol against fibrosis. Calcitriol-induced anti-fibrosis effects were blocked by ATG16L1 suppression. Furthermore, VDR bound to the ATG16L1 promoter and downregulation of VDR decreased the expression of ATG16L1 in LX-2 cells.

CONCLUSION

Calcitriol mitigates hepatic fibrosis partly through ATG16L1-mediated autophagy.

Liver Diseases: Science, Fiction and the Foreseeable Future

This Editorial precedes the Special Issue entitled "Novel Challenges and Therapeutic Options for Liver Diseases". Following a historical outline of the roots of hepatology, we provide a brief insight into our colleagues' contributions in this issue on the current developments in this discipline related to the prevention of liver diseases, the metabolic dysfunction-associated steatotic liver disease (or non-alcoholic fatty liver disease, respectively), liver cirrhosis, chronic viral hepatitides, acute-on-chronic liver failure, liver transplantation, the liver-microbiome axis and microbiome transplantation, and telemedicine. We further add some topics not covered by the contributions herein that will likely impact future hepatology. Clinically, these comprise the predictive potential of organokine crosstalk and treatment options for liver fibrosis. With regard to promising developments in basic research, some current findings on the genetic basis of metabolism-associated chronic liver diseases, chronobiology, metabolic zonation of the liver, aspects of the aging liver against the background of demography, and liver regeneration will be presented. We expect machine learning to thrive as an overarching topic throughout hepatology. The largest study to date on the early detection of liver damage-which has been kicked off on 1 March 2024-is highlighted, too.

Vitamin D and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Novel Mechanistic Insights

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly prevalent condition characterized by abnormal fat accumulation in the liver, often associated with metabolic disorders. Emerging evidence suggests a potential link between vitamin D deficiency and the development and progression of MASLD. The current review provides a concise overview of recent studies uncovering novel mechanistic insights into the interplay between vitamin D and MASLD. Several epidemiological studies have highlighted a significant association between low vitamin D levels and an increased risk of MASLD. Vitamin D, traditionally known for its role in bone health, has now been recognized as a key player in various physiological processes, including immune regulation and inflammation. Experimental studies using animal models have demonstrated that vitamin D deficiency exacerbates liver steatosis and inflammation, suggesting a potential protective role against MASLD. Mechanistically, vitamin D appears to modulate MASLD through multiple pathways. Firstly, the vitamin D receptor (VDR) is abundantly expressed in liver cells, indicating a direct regulatory role in hepatic function. Activation of the VDR has been shown to suppress hepatic lipid accumulation and inflammation, providing a mechanistic basis for the observed protective effects. Additionally, vitamin D influences insulin sensitivity, a critical factor in MASLD pathogenesis. Improved insulin sensitivity may mitigate the excessive accumulation of fat in the liver, thus attenuating MASLD progression. In parallel, vitamin D exhibits anti-inflammatory properties by inhibiting pro-inflammatory cytokines implicated in MASLD pathophysiology. Experimental evidence suggests that the immunomodulatory effects of vitamin D extend to the liver, reducing inflammation and oxidative stress, key drivers of MASLD, and the likelihood of hepatocyte injury and fibrosis. Understanding the complex interplay between vitamin D and MASLD provides a basis for exploring targeted therapeutic strategies and preventive interventions. As vitamin D deficiency is a modifiable risk factor, addressing this nutritional concern may prove beneficial in mitigating the burden of MASLD and associated metabolic disorders.

Pathophysiological-Based Nutritional Interventions in Cirrhotic Patients with Sarcopenic Obesity: A State-of-the-Art Narrative Review

In recent decades, following the spread of obesity, metabolic dysfunction has come to represent the leading cause of liver disease. The classical clinical presentation of the cirrhotic patient has, therefore, greatly changed, with a dramatic increase in subjects who appear overweight or obese. Due to an obesogenic lifestyle (lack of physical activity and overall malnutrition, with an excess of caloric intake together with a deficit of proteins and micronutrients), these patients frequently develop a complex clinical condition defined as sarcopenic obesity (SO). The interplay between cirrhosis and SO lies in the sharing of multiple pathogenetic mechanisms, including malnutrition/malabsorption, chronic inflammation, hyperammonemia and insulin resistance. The presence of SO worsens the outcome of cirrhotic patients, affecting overall morbidity and mortality. International nutrition and liver diseases societies strongly agree on recommending the use of food as an integral part of the healing process in the comprehensive management of these patients, including a reduction in caloric intake, protein and micronutrient supplementation and sodium restriction. Based on the pathophysiological paths shared by cirrhosis and SO, this narrative review aims to highlight the nutritional interventions currently advocated by international guidelines, as well as to provide hints on the possible role of micronutrients and nutraceuticals in the treatment of this multifaceted clinical condition.

Steatosis regression assessed by cap after Vitamin 'D' supplementation in NAFLD patients with Vitamin 'D' deficiency

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, and previous studies suggested a relationship between vitamin D deficiency and NAFLD. It is suggested that vitamin D supplementation may have significant beneficial effect on liver biochemistry and histology.

OBJECTIVE

This study aims to assess the degree of possible steatosis regression using controlled attenuation parameter (CAP) in NAFLD patients with vitamin D deficiency after vitamin D supplementation and evaluating its effect on lipid profile and transaminases.

PATIENTS AND METHODS

This study was conducted on 100 NAFLD patients with vitamin D deficiency. They received 10000 IU/week of vitamin D orally for 3 months. CAP was used to assess hepatic steatosis and fibrosis before/after intervention. Transaminases, lipid profile, and vitamin D levels were evaluated before/after treatment.

RESULTS

Serum AST, ALT, cholesterol, TG, LDL and HDL showed a significant reduction posttreatment in patients with both normal and elevated baseline levels ( P < 0.001). The posttreatment mean CAP showed a significant reduction (300.44 ± 37.56 vs. 265 ± 36.19 dB/ml) ( P  < 0.001), and there was a significant improvement in the mean fibrosis values by LSM (5.32 ± 1.53 vs. 4.86 ± 1.28 KPa) ( P  = 0.001). After supplementation, serum vitamin D level was raised significantly in the majority of patients ( P  < 0.001); however, only 13% of them reached sufficient levels (>30 ng/ml), insufficient levels (20-29 ng/ml) was reached in 83% and 5% showed vitamin D deficiency (<20 ng/ml).

CONCLUSION

A significant improvement was detected in hepatic steatosis (by CAP); mean values of LSM, transaminases and lipid profile after three months of oral vitamin D supplementation.

Relevance of vitamin D on NAFLD and liver fibrosis detected by vibration controlled transient elastography in US adults: a cross-sectional analysis of NHANES 2017-2018

BACKGROUND

The connection between vitamin D to non-alcoholic fatty liver disease (NAFLD) is still unclear. Herein, the relationship of vitamin D with NAFLD and liver fibrosis (LF) detected by vibration controlled transient elastography was investigated in US adults.

METHODS

The National Health and Nutrition Examination Survey of 2017-2018 was employed for our analysis. Participants were categorized as having either vitamin D deficiency (<50 nmol/L) or vitamin D sufficiency (≥50 nmol/L). A controlled attenuation parameter score of ≥ 263 dB/m was employed to define NAFLD. Significant LF was identified by the liver stiffness measurement value of ≥ 7.9 kPa. Multivariate logistic regression was adopted to explore the relationships.

RESULTS

Among the 3407 participants, the prevalence of NAFLD and LF was 49.63% and 15.93% respectively. Compared to participants without NAFLD, no significant difference in serum vitamin D was observed in NALFD participants (74.26 vs. 72.24 nmol/L; p = 0.21). Using multivariate logistic regression analysis, no obvious connection of vitamin D status to NAFLD (sufficiency vs. deficiency, OR 0.89, 95%CI 0.70-1.13) was discovered. However, among NAFLD participants, the sufficiency of vitamin D represents a lower LF risk (OR 0.56, 95%CI 0.38-0.83). When evaluated in quartiles, in comparison to the lowest quartile, high vitamin D represents low LF risk in a dose-dependent manner (Q2 vs. Q1, OR 0.65, 95%CI 0.37-1.14; Q3 vs. Q1, OR 0.64, 95%CI 0.41-1.00; Q4 vs. Q1, OR 0.49, 95%CI 0.30-0.79).

CONCLUSIONS

No relationship was found between vitamin D and CAP-defined NAFLD. However, a positive connection of the high serum vitamin D to the reduced LF risk was found among NAFLD subjects.Key messages:Our study found no relationship between vitamin D and CAP-defined NAFLD in US adults.High serum vitamin D was inversely associated with liver fibrosis in a dose-dependent manner among NAFLD participants.

The Association between Vitamin D Deficiency and Hepatosteatosis in Children and Adolescents with Obesity

INTRODUCTION

Increasingly, research groups have been studying the association of serum vitamin D and metabolic health indicators, especially in patients with obesity. We compared the serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and adolescents who had obesity and hepatosteatosis with children and adolescents who had obesity without hepatosteatosis and investigated the relationship between serum 25(OH)D concentrations and severity of hepatosteatosis. We also aimed to assess the effect of vitamin D treatment after 6 months on hepatosteatosis and liver biochemistry.

METHODS

One hundred thirty-three patients with obesity (body mass index [BMI] >+2 standard deviations [SDs] for their age and gender) and vitamin D deficiency (serum 25(OH)D <12 ng/mL) were recruited. Anthropometric measurements, biochemical parameters (serum calcium, phosphate, alkaline phosphatase, parathyroid hormone, 25(OH)D, glucose and insulin concentrations), and ultrasonographic findings of hepatosteatosis were recorded before and 6 months after Vitamin D treatment. χ2, Student's t tests, and multivariate analysis were performed.

RESULTS

Grade 1, 2, and 3 hepatosteatosis at baseline was present in 51 (38.4%), 43 (32.3%), and 10 (7.5%) subjects, respectively. Mean (± SD) serum 25(OH)D concentrations were significantly lower in those with hepatosteatosis (8.4 ± 2.4 ng/mL) compared with those without hepatosteatosis (9.9 ± 2.4 ng/mL, p < 0.005). Multivariable logistic regression analysis showed serum 25(OH)D concentration was the independent predictor for hepatosteatosis (p < 0.005), whereas age, sex, weight SD, BMI SD, and homeostasis model of assessment (HOMA)-insulin resistance (IR) were not (p > 0.05). There was no significant difference in BMI SD, HOMA-IR, and liver enzymes between subjects with and without hepatosteatosis (p > 0.05). Despite improvement in serum 25(OH)D concentrations at 6 months post-treatment (34.7 ± 10.6 ng/mL vs. 8.7 ± 2.4 ng/mL; p < 0.0001), there was no significant difference in the proportion of patients with different severity of hepatosteatosis as compared to before treatment (p = 0.88).

CONCLUSION

Serum 25(OH)D concentrations were lower in children and adolescents with obesity and hepatic steatosis as compared to those without hepatic steatosis, with an inverse association between the severity of hepatosteatosis and serum 25(OH)D concentrations. Vitamin D treatment in children and adolescents with obesity and hypovitaminosis D did not improve severity of hepatic steatosis on ultrasonography at 6 months.

Vitamin D/vitamin D receptor pathway in non-alcoholic fatty liver disease

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, but underlying mechanisms are not fully understood. In recent years, a growing body of evidence has emphasized the therapeutic role of vitamin D in NAFLD, but the specific mechanism remains to be investigated.

AREAS COVERED

This review summarized the roles of vitamin D/VDR (vitamin D receptor) pathway in different types of liver cells (such as hepatocytes, hepatic stellate cells, liver macrophages, T lymphocytes, and other hepatic immune cells) in case of NAFLD. Meanwhile, the effects of pathways in the gut-liver axis, adipose tissue-liver axis, and skeletal muscle-liver axis on the development of NAFLD were further reviewed. Relevant literature was searched on PubMed for the writing of this review.

EXPERT OPINION

The precise regulation of regional vitamin D/VDR signaling pathway based on cell-specific or tissue-specific function will help clarify the potential mechanism of vitamin D in NAFLD, which may provide new therapeutic targets to improve the safety and efficacy of vitamin D based drugs.

Gene Polymorphisms and Biological Effects of Vitamin D Receptor on Nonalcoholic Fatty Liver Disease Development and Progression

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with increasing prevalence worldwide. The genetic and molecular background of NAFLD pathogenesis is not yet clear. The vitamin D/vitamin D receptor (VDR) axis is significantly associated with the development and progression of NAFLD. Gene polymorphisms may influence the regulation of the VDR gene, although their biological significance remains to be elucidated. VDR gene polymorphisms are associated with the presence and severity of NAFLD, as they may influence the regulation of adipose tissue activity, fibrosis, and hepatocellular carcinoma (HCC) development. Vitamin D binds to the hepatic VDR to exert its biological functions, either by activating VDR transcriptional activity to regulate gene expression associated with inflammation and fibrosis or by inducing intracellular signal transduction through VDR-mediated activation of Ca²⁺ channels. VDR activity has protective and detrimental effects on hepatic steatosis, a characteristic feature of NAFLD. Vitamin D-VDR signaling may control the progression of NAFLD by regulating immune responses, lipotoxicity, and fibrogenesis. Elucidation of the genetic and molecular background of VDR in the pathophysiology of NAFLD will provide new therapeutic targets for this disease through the development of VDR agonists, which already showed promising results in vivo.

The effect of high oral loading dose of cholecalciferol in non-alcoholic fatty liver disease patients. A randomized placebo controlled trial

Background and Aim: Non-alcoholic fatty liver (NAFLD) is one of the most common progressive metabolic disorders worldwide. There are increasing scientific interests nowadays for the association between vitamin D status and Non-alcoholic fatty liver. Earlier studies have revealed that vitamin D deficiency is highly prevalent in Non-alcoholic fatty liver patients that contributes to poor outcomes. Hence, the present study aimed to assess the efficacy and safety of oral cholecalciferol on Non-alcoholic fatty liver patients.

Subjects and Methods: This study was conducted on 140 patients that were randomized either to group 1 that received the standard conventional therapy in addition to placebo or group 2 that received the standard conventional therapy in addition to cholecalciferol during the 4 months study period.

Results: At the end of the study group 2 revealed significant decrease (p &lt; 0.05) in the mean serum level of TG, LDL-C, TC, hsCRP as compared to their baseline results and group 1 results. Additionally, a significant improvement in the serum levels of ALT (p = 0.001) was seen in group 2 at the end of the study when compared to group 1. Whereas group 1 did not show any change in these parameters when compared to group 2 and their baseline results.

Conclusion: Cholecalciferol was shown to have beneficial effects on serum ALT levels, hsCRP levels and lipid profile of NAFLD patients.

Clinical Trial Registration:https://prsinfo.clinicaltrials.gov/prs-users-guide.html, identifier NCT05613192

Efficacy of Submicron Dispersible Free Phytosterols on Non-Alcoholic Fatty Liver Disease: A Pilot Study

BACKGROUND

No pharmacological treatment is yet approved for non-alcoholic fatty liver disease (NAFLD). Plant sterols have shown healthy properties beyond lowering LDL-cholesterol, including lowering triglycerides and lipoprotein plasma levels. Despite pre-clinical data suggesting their involvement in liver fat control, no clinical study has yet been successful.

AIMS

Testing a sub-micron, free, phytosterol dispersion efficacy on NAFLD.

METHODS

A prospective, uncontrolled pilot study was carried out on 26 patients with ≥17.4% liver steatosis quantified by magnetic resonance imaging. Subjects consumed daily a sub-micron dispersion providing 2 g of phytosterols. Liver fat, plasma lipids, lipoproteins, liver enzymes, glycemia, insulinemia, phytosterols, liposoluble vitamins and C-reactive protein were assessed at baseline and after one year of treatment.

RESULTS

Liver steatosis relative change was -19%, and 27% of patients reduced liver fat by more than 30%. Statistically and clinically significant improvements in plasma triglycerides, HDL-C, VLDL and HDL particle number and C-reactive protein were obtained, despite the rise of aspartate aminotransferase, glycemia and insulinemia. Though phytosterol plasma levels were raised by >30%, no adverse effects were presented, and even vitamin D increased by 23%.

CONCLUSIONS

Our results are the first evidence in humans of the efficacy of submicron dispersible phytosterols for the treatment of liver steatosis, dyslipidemia and inflammatory status in NAFLD.

Ginsenoside AD-2 Ameliorating Lipopolysaccharide-Induced Activation in HSC-T6 Cells and Carbon Tetrachloride-Induced Hepatic Fibrosis in Mice via Regulation of VD-VDR Axis

Ginsenoside 25-hydroxy protopanaxadiol (AD-2) isolated from ginseng was proved to have anti-hepatic fibrosis (HF) effect in our previous study. But the mechanism is unknown. The present study investigated the anti-HF effects and mechanisms of AD-2 on the lipopolysaccharide (LPS)-induced activation in HSC-T6 cells and carbon tetrachloride (CCl4)-induced hepatic fibrosis (HF) in mice. Results showed that AD-2 significantly inhibited the LPS-induced activated HSC-T6 cells in vitro and markedly reduced the serum transaminase and hydroxyproline levels, pathological changes, and hepatic body ratio in CCl4-induced HF mice, indicating AD-2 ameliorated liver injury and reversed HF notably. Moreover, AD-2 decreased the expression of TGF-β1, α-SMA, and MMP2, and maintained TIMP1/MMP9 in balance with the level of vitamin D (VD) and the expression of VD nuclear receptor (VDR) and Sirt3 increased. In conclusion, the anti-HF mechanism of AD-2 is related to the inhibition of HSC activation, promotion of collagen degradation, and regulation of the VD/VDR axis.

Vitamin D-A prominent immunomodulator to prevent COVID-19 infection

COVID-19 remains a life-threatening infectious disease worldwide. Several bio-active agents have been tested and evaluated in an effort to contain this disease. Unfortunately, none of the therapies have been successful, owing to their safety concerns and the presence of various adverse effects. Various countries have developed vaccines as a preventive measure; however, they have not been widely accepted as effective strategies. The virus has proven to be exceedingly contagious and lethal, so finding an effective treatment strategy has been a top priority in medical research. The significance of vitamin D in influencing many components of the innate and adaptive immune systems is examined in this study. This review aims to summarize the research on the use of vitamin D for COVID-19 treatment and prevention. Vitamin D supplementation has now become an efficient option to boost the immune response for all ages in preventing the spread of infection. Vitamin D is an immunomodulator that treats infected lung tissue by improving innate and adaptive immune responses and downregulating the inflammatory cascades. The preventive action exerted by vitamin D supplementation (at a specific dose) has been accepted by several observational research investigations and clinical trials on the avoidance of viral and acute respiratory dysfunctions. To assess the existing consensus about vitamin D supplementation as a strategy to treat and prevent the development and progression of COVID-19 disease, this review intends to synthesize the evidence around vitamin D in relation to COVID-19 infection.

Higher Serum 25-Hydroxyvitamin D Is Associated with Lower All-Cause and Cardiovascular Mortality among US Adults with Nonalcoholic Fatty Liver Disease

Aims: We aimed to assess the association between serum 25-hydroxyvitamin D (25(OH)D) levels with all-cause and cardiovascular mortality in patients with nonalcoholic fatty liver disease (NAFLD). Methods: We performed a retrospective cohort study based on the US National Health and Nutrition Examination Survey 2001–2016 on adults aged ≥20 years. NAFLD was determined as a US Fatty Liver Index score ≥ 30 in the absence of other liver conditions. Weighted Cox proportional hazards regression models were applied to explore the relationship between serum 25(OH)D levels and mortality. Results: 898 all-cause deaths and 305 cardiovascular deaths were recorded over a median follow-up of 8.7 years. Compared with those in the severe deficiency group (below 25.0 nmol/L), the fully adjusted HRs and 95% CIs of NAFLD patients with sufficient serum 25(OH)D concentrations (≥75.0 nmol/L) were 0.36 (0.22, 0.60) for all-cause mortality and 0.14 (0.07, 0.29) for cardiovascular mortality. Each one-unit increase in the natural log-transformed serum 25(OH)D concentration was related to a 41% lower risk for all-cause deaths (HR = 0.59, 95% CI: 0.46, 0.77) and a 65% lower risk for cardiovascular deaths (HR = 0.35, 95% CI: 0.22, 0.58). Conclusions: Among NAFLD patients, increased serum 25(OH)D levels were independently associated with reduced risk for all-cause and cardiovascular deaths.

Communication in non-communicable diseases (NCDs) and role of immunomodulatory nutraceuticals in their management

Conveyance of pathogens between organisms causes communicable diseases. On the other hand, a non-communicable disease (NCD) was always thought to have no causative transmissible infective agents. Today, this clear distinction is increasingly getting blurred and NCDs are found to be associated with some transmissible components. The human microbiota carries a congregation of microbes, the majority and the most widely studied being bacteria in the gut. The adult human gut harbors ginormous inhabitant microbes, and the microbiome accommodates 150-fold more genes than the host genome. Microbial communities share a mutually beneficial relationship with the host, especially with respect to host physiology including digestion, immune responses, and metabolism. This review delineates the connection between environmental factors such as infections leading to gut dysbiosis and NCDs and explores the evidence regarding possible causal link between them. We also discuss the evidence regarding the value of appropriate therapeutic immunomodulatory nutritional interventions to reduce the development of such diseases. We behold such immunomodulatory effects have the potential to influence in various NCDs and restore homeostasis. We believe that the beginning of the era of microbiota-oriented personalized treatment modalities is not far away.

The role of Vitamin D3 in ocular fibrosis and its therapeutic potential for the glaucomatous trabecular meshwork

Glaucoma is the leading cause of irreversible blindness globally. The most prevalent subtype, Primary Open Angle Glaucoma (POAG), is characterized by increased intraocular pressure (IOP), damage to the optic nerve head and irreversible visual loss. IOP increases aqueous humor (AqH) outflow is reduced through the trabecular meshwork (TM) and Schlemm's canal (SC). Increased outflow resistance is partly due to TM/SC dysregulation, including loss of normal trabecular meshwork cell (TMC) function, following increased levels of oxidative stress within TMC, dysregulated extracellular matrix (ECM) deposition and remodeling alongside alterations in TMC phenotype and apoptosis. Current widely available POAG treatments do not target the aberrant expression of ECM in the TM directly. As a result, most drug treatments can fail as the underlying pathological process continues unabated. Rho-kinase inhibitors have demonstrated the benefit of restoring TM/SC function, however there is a clear need to develop further treatment strategies that can target the underlying cellular processes which become dysregulated within the TMC during POAG pathogenesis. Vitamin D is suggested to be beneficial in alleviating the symptoms of fibrosis and inflammation in soft tissues. It has important functions in many major organ systems, including regulation of calcium, phosphate and parathyroid hormone. Evidence suggests that Vitamin D3 modulates ECM turnover through the conventional TGFβ-SMAD signaling, which is associated with the development of POAG. The link between Vitamin D3, inflammation and fibrosis within ocular tissues will be discussed and the potential roles of Vitamin D3 in the management of POAG patients will be explored within this review.

Vitamin D–VDR Novel Anti-Inflammatory Molecules—New Insights into Their Effects on Liver Diseases

There is consistent evidence that vitamin D deficiency is strongly associated with liver dysfunction, disease severity, and poor prognosis in patients with liver disease. Vitamin D and its receptor (VDR) contribute to the regulation of innate and adaptive immune responses. The presence of genetic variants of vitamin D- and VDR-associated genes has been associated with liver disease progression. In our recent work, we summarized the progress in understanding the molecular mechanisms involved in vitamin D–VDR signaling and discussed the functional significance of VDR signaling in specific cell populations in liver disease. The current review focuses on the complex interaction between immune and liver cells in the maintenance of liver homeostasis and the development of liver injury, the interplay of vitamin D and VDR in the development and outcome of liver disease, the role of vitamin D- and VDR-associated genetic variants in modulating the occurrence and severity of liver disease, and the therapeutic value of vitamin D supplementation in various liver diseases. The association of the vitamin D–VDR complex with liver dysfunction shows great potential for clinical application and supports its use as a prognostic index and diagnostic tool.

Fibrogenic Pathways in Metabolic Dysfunction Associated Fatty Liver Disease (MAFLD)

The prevalence of nonalcoholic fatty liver disease (NAFLD), recently also re-defined as metabolic dysfunction associated fatty liver disease (MAFLD), is rapidly increasing, affecting ~25% of the world population. MALFD/NAFLD represents a spectrum of liver pathologies including the more benign hepatic steatosis and the more advanced non-alcoholic steatohepatitis (NASH). NASH is associated with enhanced risk for liver fibrosis and progression to cirrhosis and hepatocellular carcinoma. Hepatic stellate cells (HSC) activation underlies NASH-related fibrosis. Here, we discuss the profibrogenic pathways, which lead to HSC activation and fibrogenesis, with a particular focus on the intercellular hepatocyte–HSC and macrophage–HSC crosstalk.

Type I interferons and TGF-β cooperate to induce liver fibrosis during HIV-1 infection under antiretroviral therapy

Liver diseases have become a major comorbidity health concern for people living with HIV-1 (PLWH) treated with combination antiretroviral therapy (cART). To investigate if HIV-1 infection and cART interact to lead to liver diseases, humanized mice reconstituted with progenitor cells from human fetal livers were infected with HIV-1 and treated with cART. We report here that chronic HIV-1 infection with cART induced hepatitis and liver fibrosis in humanized mice, associated with accumulation of M2-like macrophages (M2LMs), elevated TGF-β, and IFN signaling in the liver. Interestingly, IFN-I and TGF-β cooperatively activated human hepatic stellate cells (HepSCs) in vitro. Mechanistically, IFN-I enhanced TGF-β–induced SMAD2/3 activation in HepSCs. Finally, blockade of IFN-I signaling reversed HIV/cART-induced liver diseases in humanized mice. Consistent with the findings in humanized mice with HIV-1 and cART, we detected elevated markers of liver injury, M2LMs, and of IFN signaling in blood specimens from PLWH compared with those of healthy individuals. These findings identify the IFN-I/M2LM/HepSC axis in HIV/cART-induced liver diseases and suggest that inhibiting IFN-I signaling or M2LM may provide a novel therapeutic strategy for treating HIV/cART-associated liver diseases in PLWH treated with antiretroviral therapy.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD often occurs associated with endocrinopathies. Evidence suggests that endocrine dysfunction may play an important role in NAFLD development, progression, and severity. Our work aimed to explore and summarize the crosstalk between the liver and different endocrine organs, their hormones, and dysfunctions. For instance, our results show that hyperprolactinemia, hypercortisolemia, and polycystic ovary syndrome seem to worsen NAFLD’s pathway. Hypothyroidism and low growth hormone levels also may contribute to NAFLD’s progression, and a bidirectional association between hypercortisolism and hypogonadism and the NAFLD pathway looks likely, given the current evidence. Therefore, we concluded that it appears likely that there is a link between several endocrine disorders and NAFLD other than the typically known type 2 diabetes mellitus and metabolic syndrome (MS). Nevertheless, there is controversial and insufficient evidence in this area of knowledge.

The Interplay Between TGF-β Signaling and Cell Metabolism

The transforming growth factor-β (TGF-β) signaling plays a critical role in the development and tissue homeostasis in metazoans, and deregulation of TGF-β signaling leads to many pathological conditions. Mounting evidence suggests that TGF-β signaling can actively alter metabolism in diverse cell types. Furthermore, metabolic pathways, beyond simply regarded as biochemical reactions, are closely intertwined with signal transduction. Here, we discuss the role of TGF-β in glucose, lipid, amino acid, redox and polyamine metabolism with an emphasis on how TGF-β can act as a metabolic modulator and how metabolic changes can influence TGF-β signaling. We also describe how interplay between TGF-β signaling and cell metabolism regulates cellular homeostasis as well as the progression of multiple diseases, including cancer.

Asthma Phenotype with Metabolic Dysfunction

Asthma is chronic eosinophilic bronchitis with the dominancy of T helper 2 (Th2) inflammation. However, patients with asthma and metabolic dysfunction have pathogenic and pathological differences from those with Th2 inflammation. Metabolic dysfunction, typically presented as metabolic syndrome, has several important clinical components including central obesity, insulin resistance or glucose intolerance, dyslipidemia, and vitamin D deficiency. Data from large epidemiological studies support the significance of these components in the control of asthma and their contribution to airway remodeling, suggesting the presence of an asthma phenotype with metabolic dysfunction. These components are quite interactive with each other, so it is difficult to reveal the individual role of each. It is well known that asthma is difficult to treat in patients with obesity, due in part to inadequate response to inhaled corticosteroids. Additionally, vitamin D deficiency and insulin resistance have been regarded as aggravating factors of asthma control and airway remodeling. Recent clinical and in vivo studies have revealed the specific mechanisms of these components, which may aggravate asthma control and airway remodeling. In this review article, I summarize the recent studies and unmet needs for patients with asthma and metabolic dysfunction.

Roles of nuclear receptors in hepatic stellate cells

Introduction: Hepatic stellate cells (HSCs) are essential for physiological homeostasis of the liver extracellular matrix (ECM). Excessive transdifferentiation of HSC from a quiescent to an activated phenotype contributes to disrupt this balance and can lead to liver fibrosis. Accumulating evidence has suggested that nuclear receptors (NRs) are involved in the regulation of HSC activation, proliferation, and function. Therefore, these NRs may be therapeutic targets to balance ECM homeostasis and inhibit HSC activation in liver fibrosis.Areas covered: In this review, the authors summarized the recent progress in the understanding of the regulatory role of NRs in HSCs and their potential as drug targets in liver fibrosis.Expert opinion: NRs are still potential therapy targets for inhibiting HSCs activation and liver fibrosis. However, the development of NRs agonists or antagonists to inhibit HSCs requires fully consideration of systemic effects.

Calcitriol promotes the maturation of hepatocyte-like cells derived from human pluripotent stem cells

Human hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) represent a promising cell source for the assessment of hepatotoxicity and pharmaceutical safety testing. However, the hepatic functionality of HLCs remains significantly inferior to primary human hepatocytes. The bioactive vitamin D (VD), calcitriol, promotes the differentiation of many types of cells, and its deficiency is correlated to the severity of liver diseases. Whether calcitriol contributes to the differentiation of HLCs needs to be explored. Here, we found that the supplementation of calcitriol improved the functionalities of hPSCs-derived HLCs in P450 activities, urea production, and albumin secretion. Moreover, calcitriol also enhanced mitochondrial respiratory function with increased protein expression levels of the subunit of respiratory enzyme complexes in HLCs. Further analyses showed that the mitochondrial biogenesis regulators and mitophagy were increased by calcitriol, thus improving the mitochondrial quality. These improvements in functionality and mitochondrial condition were dependent on vitamin D receptor (VDR) because the improvements were abolished under VDR-deficient conditions. Our finding provides a cost-effective chemical process for HLC maturation to meet the demand for basic research and potential clinic applications.

The Association between Vitamin D and Nonalcoholic Fatty Liver Disease Assessed by Controlled Attenuation Parameter

BACKGROUND

An association between nonalcoholic fatty liver disease (NAFLD) and low vitamin D levels has been suggested. We investigated the relationship between vitamin D and NAFLD assessed by controlled attenuation parameter (CAP).

METHODS

We conducted a retrospective cohort study of apparently healthy subjects who underwent Fibroscan during health screening tests. NAFLD was diagnosed using CAP values.

RESULTS

Among the 1202 subjects (mean age 57.2 years, 60.6% male), 630 (52.4%) subjects had NAFLD with CAP ≥ 248 dB/m. Multivariable analysis was conducted after adjusting for metabolic risk factors including diabetes, hypertension, hypercholesterolemia, body mass index, high-density lipoprotein cholesterol, triglyceride and smoking. Higher vitamin D levels showed a lower risk of NAFLD compared to the lowest quartile of vitamin D in a dose-dependent manner (OR 0.68, 95% CI 0.47-1.00 in Q2 vs. Q1; OR 0.65, 95% CI 0.44-0.94 in Q3 vs. Q1; and OR 0.64, 95% CI 0.44-0.94 in Q4 vs. Q1). The highest quartile of vitamin D showed a decreased risk of a severe grade of steatosis (CAP ≥ 302 dB/m) compared to the lowest quartile (OR 0.52, 95% CI 0.31-0.87 in Q4 vs. Q1).

CONCLUSIONS

Higher levels of serum vitamin D were associated with a decreased risk of CAP-defined NAFLD, compared to low levels of serum vitamin D. The association between NAFLD and vitamin D suggests that vitamin D may exert a protective role against NAFLD.

Paricalcitol inhibits oxidative stress-induced cell senescence of the bile duct epithelium dependent on modulating Sirt1 pathway in cholestatic mice

BACKGROUND

Clinical studies indicate that vitamin D receptor (VDR) expression is reduced in primary biliary cirrhosis patient livers. However, the mechanism by which activated VDR effect cholestatic liver injury remains unclear.

METHODS

Mice were injected intraperitoneally with the VDR agonist paricalcitol or a vehicle 3 days prior to bile duct ligation (BDL) and for 5 or 28 days after surgery. The analyses of liver morphology and necrotic areas were based on H&E staining. Serum biochemical indicators of liver damage were analyzed by commercial kits. The mechanisms of paricalcitol on cholestatic liver injury were determined by Western blot analysis.

RESULTS

Paricalcitol ameliorated the BDL-induced liver damage in mice. Paricalcitol increased the proliferation of BECs to promote the repair of the bile duct. Paricalcitol also reduced the BDL-induced oxidative stress level in the mice. Mechanistic analysis revealed that paricalcitol decreased the number of SA-β-gal-positive cells and downregulated the expression of p53, p21 and p16 proteins which was associated with reducing oxidative stress. Additionally, paricalcitol exerted the inhibitory effect of cell senescence was through reducing DNA damage and promoting DNA repair. Interesting, we found that paricalcitol prevented the downregulation of oxidative stress-induced Sirt1 expression in the BDL mice and t-BHP-induced BECs models. Moreover, paricalcitol suppressed cell senescence through a Sirt1-dependent pathway. These results were confirmed by antioxidant ALCAR and the Sirt1 inhibitor EX-527.

CONCLUSION

Paricalcitol alleviated cholestatic liver injury through promoting the repair of damaged bile ducts and reducing oxidative stress-induced cell senescence of the bile duct via modulating Sirt1 pathway.

Role of Steroid Hormones in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and may progress to cirrhosis or even hepatocellular carcinoma. A number of steroid hormones are important regulators of lipid homeostasis through fine tuning the expression of genes related to lipid synthesis, export, and metabolism. Dysregulation of such pathways has been implicated in the pathogenesis of NAFLD. The aim of this review is to clarify the potential impact of steroid hormones on NAFLD. We also highlight potential interventions through modulating steroid hormone levels or the activities of their cognate receptors as therapeutic strategies for preventing NAFLD.

Cyanocobalamin and/or calcitriol mitigate renal damage-mediated by tamoxifen in rats: Implication of caspase-3/NF-κB signaling pathways

AIM

Tamoxifen (TAMO) is a chemotherapeutic drug used for the treatment of breast cancer. Nevertheless, there is a lack of information available in regarding its nephrotoxicity. The purpose of this work was to investigate the impact of cyanocobalamin (COB) and/or calcitriol (CAL) injections on TAMO-induced nephrotoxicity.

MAIN METHODS

Animals were allocated into five groups as follows: normal control group; TAMO (45 mg/kg) administered group; TAMO+COB (6mg/kg, i.p) treated group; TAMO+CAL (0.3 μg/kg, i.p) treated group; TAMO+COB+CAL combination groups.

KEY FINDINGS

Renal injury induced by TAMO was confirmed by the alteration in renal function parameters in the serum (urea and creatinine), as well as in the urine (creatinine clearance, total protein and albumin). These results were supported by histopathological examination. Upregulation of renal inflammatory parameters; tumor necrosis factor (TNF)-α, interleukin (IL)-6, C-reactive protein (CRP); and transforming growth factor (TGF)-β1 as well as in protein expression of nuclear factor-kappa B (NF-κB) and cleaved caspase-3 were observed to a greater extent in the TAMO-treated rats compared with the control. Renal fibrosis was also evidenced by a elevation in renal L-hydroxyproline level as well as by histomorphological collagen deposition in TAMO-treated groups compared to the control group. Administration of COB and/or CAL concurrently with TAMO significantly ameliorated the deviation in the above-studied parameters and improved the histopathological renal picture.

SIGNIFICANCE

Inhibition of NF-κβ-mediated inflammation and caspase-3-induced apoptosis are possible renoprotective mechanisms of COB and/or CAL against TAMO nephrotoxicity, which was more noticeable in the TAMO group treated with the combination of the two vitamins in question.

Cholangiopathy aggravation is caused by VDR ablation and alleviated by VDR-independent vitamin D signaling in ABCB4 knockout mice

BACKGROUND & AIMS

Cholangiopathies are chronic liver diseases in which damaged cholangiocytes trigger a proinflammatory and profibrotic reaction. The nuclear vitamin D receptor (VDR) is highly expressed in cholangiocytes and exerts immune-regulatory functions in these cells. In the present study, we examined the protective function of VDR and other vitamin D signaling pathways in chronic cholangiopathy and cholangiocytes.

METHODS

Vdr was invalidated in Abcb4 knockout mice, a widely used animal model of chronic cholangiopathy. The impact of vitamin D signaling on cholangiopathy features was examined in vivo and in cholangiocytes (primary and cell lines).

RESULTS

Cholangiopathy features (i.e, cholestasis, ductular reaction and fibrosis) were aggravated in Vdr;Abcb4 double knockout mice compared to the Abcb4 simple knockout, and associated with an overexpression of proinflammatory factors. The proinflammatory phenotype of cholangiocytes was also exacerbated following VDR silencing in vitro. The expression of proinflammatory factors and the severity of cholangiopathy were reduced in the double knockout mice treated with the vitamin D analog calcipotriol or with vitamin D. In vitro, the inflammatory response to TNFα was significantly reduced by calcipotriol in biliary cells silenced for VDR, and this effect was abolished by co-silencing the plasma membrane receptor of vitamin D, protein disulfide-isomerase A3 (PDIA3).

CONCLUSIONS

Our results demonstrate an anti-inflammatory role of VDR signaling in cholangiocytes and cholangiopathy. They also provide evidence for PDIA3-mediated anti-inflammatory effects of vitamin D and vitamin D analog in these settings.

Effect of vitamin D supplementation in patients with chronic hepatitis C after direct-acting antiviral treatment: a randomized, double-blind, placebo-controlled trial

Background

Replacement of vitamin D (VD) among patients with chronic hepatitis C (CHC) before viral eradication has demonstrated a protective effect on serum markers associated with hepatic fibrogenesis. We therefore hypothesized that VD may facilitate further fibrosis amelioration following curative treatment with direct-acting antivirals (DAA).

Methods

This study was a randomized, double-blind, placebo-controlled trial conducted between February 2018 and August 2018. Patients with CHC and VD deficiency were randomized in a 1:1 ratio to either receive ergicalciferol or placebo over 6 weeks. Biochemical analysis indicators, including 25-hydroxyvitamin D (25(OH)D), fibrogenic markers [(transforming growth factor beta 1 (TGF-β1) and tissue inhibitors of matrix metalloproteinases 1 (TIMP-1)], and fibrolytic markers [matrix metalloproteinase 9 (MMP-9) and amino terminal type III procollagen peptide (P3NP)], were assessed at baseline and at 6 weeks. Serum 25(OH)D was analyzed by a chemiluminescence immunoassay. Serum hepatic fibrogenesis markers were measured using a quantitative sandwich enzyme-linked immunosorbent assay.

Results

Seventy-five patients with CHC and VD deficiency were randomly assigned to VD (n = 37) and placebo (n = 38) groups. At the end of the study, the mean serum 25(OH)D level had risen to a normal level in the VD group, but was still deficient in the placebo group (41.8 ±   9.1 vs. 18.1 ±  4.6 ng/mL, p < 0.001). Upon restoration of the VD level, there were no significant mean differences in the change from baseline for TGF-β1 (-0.6 ng/mL (95% confidence interval (95% CI) [-2.8-1.7]), p = 0.63), TIMP-1 (-5.5 ng/mL (95% CI [-26.4 -15.3]), p = 0.60), MMP-9 (122.9 ng/mL (95% CI [-69.0 -314.8]), p = 0.21), and P3NP (-0.1 ng/mL (95% CI [-2.4 -2.2]), p = 0.92) between the VD and placebo groups.

Conclusion

Short-term VD supplementation after DAA treatment in patients with CHC does not improve serum fibrogenesis markers and may not expedite the residual liver fibrosis healing process. Future studies are warranted to evaluate the long-term effect of VD supplementation on hepatic fibrosis regression.

Association between Nonalcoholic Fatty Liver Disease and Bone Mineral Density in HIV-Infected Patients Receiving Long-term TDF-Based Antiretroviral Therapy

BACKGROUND

Tenofovir (TDF) has a detrimental effect on bone mineral density (BMD), while nonalcoholic fatty liver disease (NAFLD) is associated with a lower BMD.

OBJECTIVE

To help understand the mutual effects of NAFLD and TDF on BMD, this study was designed to explore the potential association between NAFLD and BMD in HIV-infected patients receiving long-term TDF-based antiretroviral therapy (ART).

METHODS

A total of 89 HIV-infected patients who received TDF-based ART for more than three years were enrolled in this cross-sectional study. We measured BMD using an ultrasonic bone density apparatus, and liver ultrasonography was performed to determine the severity of the fatty liver. The association of NAFLD with BMD was examined using multiple logistic regression analyses.

RESULTS

Patients with NAFLD showed a worse BMD status than those without NAFLD. The incidence rates of osteopenia (42.86% versus 25.93%) and osteoporosis (17.14% versus 3.70%) were significantly higher in HIV-infected patients with NAFLD than in those without NAFLD. After multivariate adjustment, the odds ratio (OR) for patients with NAFLD exhibiting a worse BMD status compared with those without NAFLD was 4.49 (95% confidence interval [CI] 1.42, 14.15).

CONCLUSION

Based on our results, NAFLD was significantly associated with a worse BMD status, including osteopenia and osteoporosis, in HIV patients after receiving long-term TDF-based ART. Furthermore, we may want to avoid using TDF for ART in HIV-infected patients with NAFLD.

Serum vitamin D and vitamin-D-binding protein levels in children with chronic hepatitis B

BACKGROUND

Vitamin D is an essential fat-soluble secosteroid hydroxylated by the liver to form the intermediate metabolite calcidiol {25-hydroxy vitamin D [25(OH)D]}, which is a reliable indicator to investigate individual vitamin D status. Vitamin-D-binding protein (VDBP) is a multifunctional glycoprotein mainly synthesized in the liver and the major transport protein for vitamin D and its metabolites. Serum vitamin D and VDBP are both associated with hepatitis B. However, few studies have reported the relationship and clinical significance of vitamin D and VDBP with hepatitis B virus (HBV) replication and hepatic fibrosis in children with chronic hepatitis B (CHB).

AIM

To explore vitamin D and VDBP serum levels in children with CHB and the association of vitamin D and VDBP with HBV replication and hepatic fibrosis.

METHODS

We enrolled 204 children with CHB admitted to Hunan Children’ Hospital in summer and autumn between 2018 and 2019 and 170 healthy controls. CHB patients included: 164 hepatitis B e antigen (HBeAg) positive and 40 HBeAg negative; 193 hepatitis B surface antigen (HBsAg) positive and 11 HBsAg negative; 164 with detectable HBV deoxyribonucleic acid (DNA) and 40 with undetectable HBV DNA; 131 with HBV genotype B and 23 with HBV genotype C; and 27 without hepatic fibrosis and 97 with hepatic fibrosis. Serum levels of 25(OH)D, VDBP, liver function markers, and other clinical parameters were collected to analyze their association with vitamin D and VDBP. Mann-Whitney U test, Kruskal-Wallis H test, or t test was used to analyze serum 25(OH)D and VDBP levels in different groups. Spearman rank correlation test was utilized to analyze the correlation of 25(OH)D and VDBP with other markers. Statistically significant factors determined by univariate analysis were further analyzed by binary multivariate logistic regression analysis. P < 0.05 was considered statistically significant.

RESULTS

Children with CHB had lower serum 25(OH)D (56.64 ± 17.89 nmoL/L) and VDBP [122.40 (70.74-262.84 μg/L)] levels than healthy controls had (P < 0.001). Serum 25(OH)D and VDBP levels were significantly different among the different grades of hepatic fibrosis (P < 0.05). VDBP levels in children with HBV genotype C, HBsAg, HBeAg, and detectable HBV DNA were significantly lower than those in children with HBV genotype B, no HBsAg, no HBeAg, and undetectable HBV DNA (P < 0.05). Serum 25(OH)D level was negatively correlated with age and serum total bilirubin level (r = -0.396 and -0.280, respectively, P < 0.001). Serum VDBP level was negatively correlated with HBV DNA (log₁₀ IU/mL) (r = -0.272, P < 0.001). Serum 25(OH)D level was not correlated with VDBP level (P > 0.05). Univariate (P < 0.05) and multivariate logistic regression analysis showed that low level of 25(OH)D (odds ratio = 0.951, 95% confidence interval: 0.918-0.985) and high level of HBV DNA (odds ratio = 1.445, 95% confidence interval: 1.163-1.794) were independently correlated with hepatic fibrosis (P < 0.01).

CONCLUSION

Serum levels of 25(OH)D and VDBP are decreased in children with CHB. Serum VDBP level is negatively correlated with HBV replication. Low level of 25(OH)D is independently associated with hepatic fibrosis in children with CHB. There is no significant association between serum levels of 25(OH)D and VDBP.

The Impact of Vitamin D in Non-Alcoholic Fatty Liver Disease: A Cross-Sectional Study in Patients with Morbid Obesity

PURPOSE

We aimed to evaluate the association between vitamin D status and hepatic function parameters and scores: Fatty Liver Index (FLI, predictor of hepatic steatosis) and BARD (BMI, AST/ALT ratio and DM, predictor of hepatic fibrosis) in patients with morbid obesity.

PATIENTS AND METHODS

Cross-sectional study including patients with morbid obesity followed in our centre between January 2010 and July 2018. Patients with missing vitamin D levels or hepatic profile parameters were excluded. We divided the population according to two cut-offs of vitamin D levels (12ng/mL and 20ng/mL).

RESULTS

The included population (n=1124) had an average age of 43.3±10.7 years and 84.3% were female. Seventy-point eight percent of the population had vitamin D levels lower than 20ng/mL and 34.8% lower than 12ng/dL. Patients with lower vitamin D levels (<12ng/mL) had higher BMI, hip and waist circumferences and higher prevalence of hypertension. Higher FLI scores [OR= 0.77 (0.07), p<0.01] and ALP levels [β= -0.03 (-0.06, -0.01), p<0.01] associated to lower vitamin D levels.

CONCLUSION

Vitamin D deficiency is associated with a higher risk of hepatic steatosis in individuals with morbid obesity. Correction of vitamin D deficiency may have a beneficial role in the management of NAFLD in patients with morbid obesity.

Vitamin D alleviates liver fibrosis by inhibiting histidine-rich calcium binding protein (HRC)

BACKGROUND

Liver fibrosis may progress toward cirrhosis and cancer without effective therapy. Here, we investigated the underlying mechanism of Vitamin D as a therapeutic approach.

METHODS

Carbon tetrachloride (CCL4)-induced mice model and transforming growth factor-β1 (TGF-β1) induced human hepatic stellate cell line LX-2 were used in vivo and in vitro. The fibrotic profiles, degree of liver injury and HRC expression were assessed by histology, Western blot, immunohistochemistry and Real-Time PCR. The proliferation of cells transfected with HRC ^+/+ and HRC^-/- plasmids was detected by MTS and cell cycle methods.

RESULTS

Vitamin D significantly suppressed the expression of HRC in liver fibrosis model both in vivo and in vitro (P < 0.01). The cell with overexpression of HRC significantly increased TGF-β1/Smad3 expressions and the percentage of the S peak in cell cycle (P < 0.05). However, Vitamin D can significantly reverse the levels of TGF-β1, Smad3 and p-smad3 caused by HRC in vitro. Furthermore, the overexpression of HRC in cell lines can attenuate the function of Vitamin D, suggesting that VD played a role by regulating HRC. Mechanically, HRC as the target of VDR is detected by CHIP method.

CONCLUSIONS

Vitamin D can delay hepatic fibrosis by reducing activation of hepatic stellate cells and TGF-β/Smad signaling through negative regulation of HRC. The findings revealed the important regulatory effect of Vitamin D in hepatic stellate cells and provided new insights into the therapeutic function of Vitamin D on liver fibrosis.

Association of vitamin D supplementation with serum leptin and metabolic parameters in Egyptian patients with non-alcoholic steatohepatitis: a prospective study

Background

Nonalcoholic steatohepatitis (NASH) is the progressive form of NAFLD, a common cause of liver disease, with increased chance of progression to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Circulating leptin is increased in patients with NASH. It is an independent positive predictor of the severity of hepatic steatosis. Vitamin D is a lipophilic molecule essential to maintain calcium and phosphate balance. Moreover, it has antifibrotic, antiproliferative, and anti-inflammatory effects on the liver. Vitamin D deficiency is a worldwide condition and very common in patients with NASH. Low serum vitamin D has been shown to predispose to intrahepatic lipid accumulation leading to NAFLD. The aim of this study was to investigate the association of vitamin D supplementation with serum leptin and metabolic parameters in Egyptian patients with non-alcoholic steatohepatitis

Results

Patients with NASH group had statistically significant higher values of diastolic blood pressure (94.3 ± 11.9 mmHg, p < 0.0001), glycated hemoglobin (8.0 ± 2.4%, p < 0.0001), fasting blood sugar (165.6 ± 62.0 mg/dL, p < 0.0001), fasting insulin level (24.2 ± 3.0 μU/ml, p < 0.0001), homeostatic model assessment of insulin resistance (HOMA-IR) (1.8 ± 0.7, p < 0.0001), alanine transferase (ALT) (78.2 ± 36.7 U/L, p < 0.0001), aspartate transferase (AST) (108.6 ± 85.6 U/L, p < 0.0001), NAFLD fibrosis score (− 0.78 ± 0.9, p < 0.0001), total cholesterol (233.0 ± 40.9 mg/dL, p = 0.0011), low-density lipoprotein (117.5 ± 41.6 mg/dL, p = 0.0084), and triglycerides (229.7 ± 62.1 mg/dL, p < 0.0001) than the control group. Moreover, they had lower serum vitamin D level (15.6 ± 6.6 ng/ml, p = 0.0004) and higher serum leptin level (35.9 ± 28.4 ng/ml, p < 0.0001) than the control group. Following vitamin D supplementation, there was a statistically significant reduction in HbA1c (6.8 ± 1.3%, p = 0.0055), fasting blood sugar (136.1 ± 32.7 mg/dL, p = 0.0094), fasting insulin level (22.9 ± 1.8 μU/ml, p = 0.0236), HOMA-IR (1.4 ± 0.4, p = 0.0026), ALT (55.3 ± 21.3 U/L, p = 0.0010), AST (73.1 ± 54.2 U/L, p = 0.0297), and triglycerides (203.6 ± 49.8 mg/dL, p = 0.0415) in patients with NASH. There was a statistically significant increase in serum vitamin D level (33.0 ± 7.6 ng/ml, p < 0.0001) and decrease in serum leptin level (23.5 ± 12.9 ng/ml, p = 0.0140) after treatment.

Conclusions

Vitamin D supplementation in patients with NASH in a dose of 4000 IU/day for 12 weeks improves severity of hepatic inflammation, decreases insulin resistance, improves glycemic control, corrects dyslipidemia, and protects against lipotoxicity by inhibition of serum leptin.

Calcitriol alleviates ethanol-induced hepatotoxicity via AMPK/mTOR-mediated autophagy

Excessive ethanol consumption causes cellular damage, leading to fetal alcohol syndrome and alcohol liver diseases, which are frequently seen with vitamin D (VD) deficiency. A great deal of progress has been achieved in the mechanisms of ethanol-induced hepatocyte damage. However, there are limited intervention means to reduce or rescue hepatocytes damage caused by ethanol. On the basis of our preliminary limited screen process, calcitriol showed a positive effect on protecting hepatocyte viability. Therefore, the molecular basis is worth elucidating. We found that calcitriol pretreatment markedly improved the cell viability, decreased cell apoptosis and oxidative stress and alleviated the abnormal mitochondrial morphology and membrane potential of hepatocytes induced by ethanol. Notably, autophagy was significantly enhanced by calcitriol, as evident by the increasing number of autophagosomes and autolysosomes, upregulated LC3B-Ⅱ and ATG5 levels, and promotion of p62 degradation. Furthermore, calcitriol pretreatment increased the colocalization of GFP-LC3-labeled autophagosomes with mitochondria, suggesting that calcitriol effectively promoted ethanol-induced mitophagy in hepatocytes. In addition, the inhibition of autophagy attenuated the protective and preventive effect of calcitriol. Furthermore, the effect of calcitriol on autophagy was regulated by AMPK/mTOR signaling, and signaling transduction was dependent on the Vitamin D receptor (VDR). In conclusion, calcitriol ameliorates ethanol-induced hepatocyte damage by enhancing autophagy. It may offer a convenient preventive and hepatoprotective mean for people on occasional social drink.

Vitamin D3 as Potential Treatment Adjuncts for COVID-19

Severe acute respiratory syndrome coronavirus type (SARS-CoV2, also known as COVID-19), which is the latest pandemic infectious disease, constitutes a serious risk to human health. SARS-CoV2 infection causes immune activation and systemic hyperinflammation which can lead to respiratory distress syndrome (ARDS). ARDS victims are characterized by a significant increase in IL-6 and IL-1. Macrophage activation, associated with the "cytokine storm", promotes the dysregulation of the innate immunity. So far, without vaccines or specific therapy, all efforts to design drugs or clinical trials are worthwhile. Vitamin D and its receptor vitamin D receptor (VDR) exert a critical role in infections due to their remarkable impact on both innate and adaptive immune responses and on the suppression of the inflammatory process. The protective properties of vitamin D supplementation have been supported by numerous observational studies and by meta-analysis of clinical trials for prevention of viral acute respiratory infection. In this review, we compare the mechanisms of the host immune response to SARS-CoV2 infection and the immunomodulatory actions that vitamin D exerts in order to consider the preventive effect of vitamin D supplementation on SARS-CoV2 viral infection.

Vitamin D and Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD): An Update

Non-alcoholic fatty liver disease (NAFLD) is the first cause of chronic liver disease worldwide; it ranges from simple steatosis to steatohepatitis (NASH) and, potentially, cirrhosis and hepatocarcinoma. NAFLD is also an independent risk factor for type 2 diabetes, cardiovascular diseases, and mortality. As it is largely associated with insulin resistance and related disorders, NAFLD has been recently re-named as Metabolic dysfunction-Associated Fatty Liver Disease (MAFLD). At present, there are no approved pharmacological treatments for this condition. Vitamin D is a molecule with extensive anti-fibrotic, anti-inflammatory, and insulin-sensitizing properties, which have been proven also in hepatic cells and is involved in immune-metabolic pathways within the gut–adipose tissue–liver axis. Epidemiological data support a relationship hypovitaminosis D and the presence of NAFLD and steatohepatitis (NASH); however, results from vitamin D supplementation trials on liver outcomes are controversial. This narrative review provides an overview of the latest evidence on pathophysiological pathways connecting vitamin D to NAFLD, with emphasis on the effects of vitamin D treatment in MAFLD by a nonsystematic literature review of PubMed published clinical trials. This article conforms to the Scale for Assessment of Narrative Review Articles (SANRA) guidelines. Evidence so far available supports the hypothesis of potential benefits of vitamin D supplementation in selected populations of NAFLD patients, as those with shorter disease duration and mild to moderate liver damage.

Relationship between hepatic and systemic angiopoietin-like 3, hepatic Vitamin D receptor expression and NAFLD in obesity

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and an independent risk factor for cardiovascular mortality. Angiopoietin-like proteins (ANGPTLs) are targets for vitamin D receptor (VDR)-mediated gene transcription and this axis may promote NAFLD. ANGPTL3 is a hepatokine which inhibits lipoprotein lipase and its experimentally induced inactivation reduces hepatosteatosis. Little is known on ANGPTL3 in human NAFLD and no data exist on its relationship with hepatic VDR/VD-related genes. The aim of this research was to investigate hepatic ANGPTLs and VDR/VD-related gene expression in human obesity in relation to NAFLD.

METHODS

We conducted a cross-sectional investigation on forty obese subjects with/without NAFLD. We evaluated hepatic ANGPTL3, ANGPTL4, ANGPTL8, LPL, VDR, CYP27A1 and CYP2R1 mRNA expression in liver biopsies by RT-PCR; VDR expression was further investigated by immunohistochemistry; circulating ANGPTL3 was measured by Milliplex assay.

RESULTS

Compared to non-NAFLD, NAFLD individuals had significantly higher hepatic VDR, ANGPTL3 and LPL expression. ANGPTL3 correlated with steatosis grade, LPL, VDR, CYP27A1 and CYP2R1 expression. Plasma ANGPTL3 concentrations were positively associated with clinical/histological markers of NAFLD/NASH and with hepatic ANGPTL3 expression. Greater hepatic VDR expression was the main determinant of hepatic ANGPTL3 after adjusting for multiple confounders.

CONCLUSIONS

Hepatic ANGPTL3 expression correlates with greater VDR expression, presence and severity of NAFLD and translates in increased circulating ANGPTL3, likely as a result of its modulation by up-regulated hepatic VDR in NAFLD. This study provides novel insights to potential mechanisms underlying ANGPTLs-mediated ectopic fat accumulation and NAFLD development in obesity.

Calcipotriol Inhibits NLRP3 Signal Through YAP1 Activation to Alleviate Cholestatic Liver Injury and Fibrosis

Cholestasis is common in multiple clinical circumstances. The NOD-like receptor protein 3 (NLRP3) inflammasome pathway has been demonstrated to play an important role in liver injury and fibrosis induced by cholestasis. We previously proved that MCC950, a selective NLRP3 inhibitor, alleviates liver fibrosis and injury in experimental liver cholestasis induced by bile-duct ligation (BDL) in mice. Herein, we investigate the role of calcipotriol, a potent vitamin D receptor agonist, in experimental liver cholestasis, test its therapeutic efficacy, and explore its potential protective mechanism. C57BL/6 mice were made to undergo BDL or fed the 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet to establish two classic cholestatic models. Calcipotriol was administered intraperitoneally to these mice daily. Serum makers of liver damage and integrity, liver histological changes, levels of liver pro-fibrotic markers, bile acid synthetases and transporters were measured in vivo. The underlying mechanism by which calcipotriol alleviates cholestatic liver injury and fibrosis was further investigated. The results of the current study demonstrated that calcipotriol supplement significantly alleviate cholestatic liver injury and fibrosis. Moreover, calcipotriol supplement markedly inhibited NLRP3 inflammasome pathway activation to alleviate liver injury and fibrosis in vivo and inhibit hepatic stellate cell (HSC) activation in vitro. In addition, VDR agonist calcipotriol exert inhibitory effect on NLRP3 inflammasome activation through activating yes-associated protein 1 (YAP1). In conclusion, our findings proved that calcipotriol suppressed the NLRP3 signal by activating YAP1 to alleviate liver injury and retard fibrogenesis in cholestasis.

Serum 25-hydroxyvitamin-D and nonalcoholic fatty liver disease: Does race/ethnicity matter? Findings from the MESA cohort

BACKGROUND AND AIMS

Low serum 25-hydroxyvitamin D (25(OH)D) is associated with higher nonalcoholic fatty liver disease (NAFLD) risk in studies of mainly white participants. Significant racial/ethnic differences exist in serum 25(OH)D and NAFLD prevalence questioning extending this association to other racial/ethnic groups. We tested whether the association between serum 25(OH)D and NAFLD vary by race/ethnicity.

METHODS AND RESULTS

This was a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) that included 3484 participants (44% male; 38.4% Whites, 27.8% African-Americans, 23.5% Hispanics, and 10.3% Chinese-Americans) who had serum 25(OH)D and upper abdominal CT images available at baseline. Serum 25(OH)D was measured by high-performance liquid chromatography-tandem mass spectrometry. NAFLD was identified if liver-to-spleen Hounsfield-Unit ratio was <1. Whites had the highest 25(OH)D level and African-Americans had the lowest level (mean ± SD: 29.5 ± 10.4 vs.19.9 ± 9.1, respectively). Six hundred and eleven (17.5%) participants had NAFLD; Hispanics had the highest prevalence (26.2%) followed by Chinese-Americans (19.8%), Whites (15.8%) and African-Americans (11.7%), P < 0.0001. In adjusted model, the association of 25(OH)D with NAFLD differed by race/ethnicity (P < 0.0001). Negative association was only evident in Causations (OR (95% CI):1.23 (1.03, 1.47) per 1 SD lower serum 25(OH)D). For other racial/ethnic groups, BMI, triglycerides, diabetic status and/or smoking, but not serum 25(OH)D, were common independent risk factors for NAFLD.

CONCLUSIONS

The negative association between serum 25(OH)D and NAFLD in Whites may not be broadly generalizable to other racial/ethnic groups. Modifiable risk factors including BMI, triglycerides, diabetic status and/or smoking associate with NAFLD risk in non-white racial/ethnic groups beyond 25(OH)D.

Associations between Vitamin D and Liver Function and Liver Fibrosis in Patients with Biliary Atresia

Objectives

To detail the effects of vitamin D (VD) deficiency and assess the relationships between VD deficiency and liver function and liver fibrosis in patients with biliary atresia (BA).

Methods

In this study, BA patients confirmed by intraoperative cholangiography were enrolled between January 2017 and February 2019. Preoperative serum 25-(OH)D level, liver function, serum biomarker levels of liver fibrosis, and histopathologic features were recorded. Deficiency, insufficiency, and sufficiency of VD were defined as serum 25-(OH)D concentrations of <10, 10-20, and >20 ng/ml, respectively. Associations between serum 25-(OH)D level and liver function and liver fibrosis were analyzed.

Results

A total of 161 BA infants were included. The median (interquartile range (IQR)) serum 25-(OH)D level in all patients was 7.56 (IQR: 4.48–11.40) ng/ml. The rates of 25-(OH)D deficiency, insufficiency, and sufficiency were 67.1% (108/161), 29.2% (47/161), and 3.7% (6/161), respectively. Serum 25-(OH)D level was negatively correlated with alkaline phosphatase (r = ‐0.232, P = 0.003). After adjusting for age, a decrease in serum 25-(OH)D level was correlated with the increase of the Batts-Ludwig stage score (odds ratio (OR): 0.94, 95% confidence interval (CI): 0.88–0.99; P = 0.028). Serum 25-(OH)D level was also correlated with the N-terminal propeptide of type III procollagen (PIIINP) (r = ‐0.246, P = 0.002). Additionally, PIIINP (P = 0.038) and ALP (P = 0.031) were independently associated with serum 25-(OH)D level.

Conclusions

VD deficiency was common and inversely correlated with liver fibrosis in BA patients. Furthermore, VD was not correlated with liver function except alkaline phosphatase.

Vitamin D and nonalcoholic fatty liver disease

PURPOSE OF REVIEW

Vitamin D deficiency may impact disease progression of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to review recent studies examining either vitamin D status or the effects of supplementation in patients with NAFLD, along with investigating the roles of genetic polymorphisms and the gut microbiome.

RECENT FINDINGS

Six heterogeneous observational studies of vitamin D status, and four randomized controlled intervention trials of vitamin D supplementation in NAFLD were conflicting. All studies were hampered by the challenges of diagnosing NAFLD, were underpowered, and lacked data on clinically important outcomes. The results of three cross-sectional studies, including a Mendelian randomization study, provide limited evidence for a role for genetic modifiers of vitamin D status in NAFLD. Genetic and experimental evidence suggests that vitamin D and the vitamin D receptor (VDR) may influence the gut microbiome in health and disease.

SUMMARY

The evidence relating either lower vitamin D status to the prevalence and severity of NAFLD, or examining vitamin D supplementation in patients with NAFLD is inconclusive. Larger, higher quality trials with relevant endpoints are needed. Further mechanistic studies on the roles of vitamin D and VDR in influencing the gut-liver axis in NAFLD are warranted.

Evaluation of the Effect Derived from Silybin with Vitamin D and Vitamin E Administration on Clinical, Metabolic, Endothelial Dysfunction, Oxidative Stress Parameters, and Serological Worsening Markers in Nonalcoholic Fatty Liver Disease Patients

Nowadays, the nonalcoholic fatty liver disease represents the main chronic liver disease in the Western countries, and the correct medical therapy remains a big question for the scientific community. The aim of our study was to evaluate the effect derived from the administration for six months of silybin with vitamin D and vitamin E (RealSIL 100D®) on metabolic markers, oxidative stress, endothelial dysfunction, and worsening of disease markers in nonalcoholic fatty liver disease patients. We enrolled 90 consecutive patients with histological diagnosis of nonalcoholic fatty liver disease and 60 patients with diagnosis of reflux disease (not in therapy) as healthy controls. The nonalcoholic fatty liver disease patients were randomized into two groups: treated (60 patients) and not treated (30 patients). We performed a nutritional assessment and evaluated clinical parameters, routine home tests, the homeostatic model assessment of insulin resistance, NAFLD fibrosis score and fibrosis-4, transient elastography and controlled attenuation parameter, thiobarbituric acid reactive substances, tumor necrosis factor α, transforming growth factor β, interleukin-18 and interleukin-22, matrix metalloproteinase 2, epidermal growth factor receptor, insulin growth factor-II, cluster of differentiation-44, high mobility group box-1, and Endocan. Compared to the healthy controls, the nonalcoholic fatty liver disease patients had statistically significant differences for almost all parameters evaluated at baseline (p < 0.05). Six months after the baseline, the proportion of nonalcoholic fatty liver disease patients treated that underwent a statistically significant improvement in metabolic markers, oxidative stress, endothelial dysfunction, and worsening of disease was greater than not treated nonalcoholic fatty liver disease patients (p < 0.05). Even more relevant results were obtained for the same parameters by analyzing patients with a concomitant diagnosis of metabolic syndrome (p < 0.001). The benefit that derives from the use of RealSIL 100D could derive from the action on more systems able to advance the pathology above all in that subset of patients suffering from concomitant metabolic syndrome.

Current and Emerging Therapies for Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is the most common cause of chronic liver disease in the developed world and commonly associated with metabolic comorbidities such as diabetes mellitus, hypertension, dyslipidemia, and obesity. Non-alcoholic steatohepatitis is an aggressive form of non-alcoholic fatty liver disease, associated with an increased risk of liver and non-liver-related mortality. Currently there are no approved therapies for non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and standard-of-care lifestyle advice is rarely effective. This has spurned intense drug development efforts and several agents are in clinical trials to address this major gap in non-alcoholic fatty liver disease. Drug development efforts have focused on pathogenic mechanisms including pathways involving lipid metabolism, inflammation, and fibrosis. This review presents the overview of the trials and agents in the pipeline of emerging therapies for non-alcoholic fatty liver disease/non-alcoholic steatohepatitis.

Genetic associations of vitamin D receptor polymorphisms with advanced liver fibrosis and response to pegylated interferon-based therapy in chronic hepatitis C

Vitamin D receptor (VDR) modulates host immune responses to infections such as hepatitis C virus (HCV) infection, including interferon signaling. This study aimed to investigate the associations of VDR polymorphisms with advanced liver fibrosis and response to pegylated interferon (PEG-IFN)-based therapy in patients with chronic HCV infection. In total, 554 Thai patients with chronic HCV infection treated with a PEG-IFN-based regimen were enrolled. Six single-nucleotide polymorphisms (SNPs) were genotyped: the IL28B C > T (rs12979860) SNP and five VDR SNPs, comprising FokI T > C (rs2228570), BsmI C > T (rs1544410), Tru9I G > A (rs757343), ApaI C > A (rs7975232), and TaqI A > G (rs731236). In total, 334 patients (60.3%) achieved sustained virological response (SVR), and 255 patients (46%) were infected with HCV genotype 1. The bAt (CCA) haplotype, consisting of the BsmI rs1544410 C, ApaI rs7975232 C, and TaqI rs731236 A alleles, was associated with poor response (in terms of lack of an SVR) to PEG-IFN-based therapy. The IL28B rs12979860 CT/TT genotypes (OR = 3.44, 95% CI [2.12–5.58], p < 0.001), bAt haplotype (OR = 2.02, 95% CI [1.04–3.91], p = 0.03), pre-treatment serum HCV RNA (logIU/mL; OR = 1.73, 95% CI [1.31–2.28], p < 0.001), advanced liver fibrosis (OR = 1.68, 95% CI [1.10–2.58], p = 0.02), and HCV genotype 1 (OR = 1.59, 95% CI [1.07–2.37], p = 0.02) independently predicted poor response. Patients with the bAt haplotype were more likely to have poor response compared to patients with other haplotypes (41.4% vs 21.9%, p = 0.03). The FokI rs2228570 TT/TC genotypes (OR = 1.63, 95% CI [1.06–2.51], p = 0.03) and age ≥55 years (OR = 2.25; 95% CI [1.54–3.32], p < 0.001) were independently associated with advanced liver fibrosis, assessed based on FIB-4 score >3.25. VDR polymorphisms were not associated with pre-treatment serum HCV RNA. In Thai patients with chronic HCV infection, the bAt haplotype is associated with poor response to PEG-IFN-based therapy, and the FokI rs2228570 TT/TC genotypes are risk factors for advanced liver fibrosis.

Overview of studies of the vitamin D/vitamin D receptor system in the development of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. NAFLD is known to be associated with obesity, type 2 diabetes, metabolic syndrome and increased cardiovascular events: for these reasons, it is becoming a global public health problem and represents an important challenge in terms of prevention and treatment. The mechanisms behind the pathogenesis of NAFLD are multiple and have not yet been completely unraveled; consequently, at moment there are not effective treatments. In the past few years a large body of evidence has been assembled that attributes an important role in hepatic aberrant fat accumulation, inflammation and fibrosis, to the vitamin D/vitamin D receptor (VD/VDR) axis, showing a strong association between hypovitaminosis D and the diagnosis of NAFLD. However, the data currently available, including clinical trials with VD supplementation, still provides a contrasting picture. The purpose of this editorial is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to VD/VDR. Based on recent data from literature, we focused in particular on the hypothesis that VDR itself, independently from its traditional ligand VD, may have a crucial function in promoting hepatic fat accumulation. This might also offer new possibilities for future innovative therapeutic approaches in the management of NAFLD.

Vitamin D deficiency: prevalence and association with liver disease severity in pediatric nonalcoholic fatty liver disease

BACKGROUND/OBJECTIVES

To determine associations between serum 25-hydroxyvitamin D (25(OH)-D) concentrations and histologic nonalcoholic fatty liver disease (NAFLD) severity.

SUBJECTS/METHODS

Clinical, laboratory, and histology data were collected retrospectively in a pediatric cohort with biopsy-confirmed NAFLD. Serum 25(OH)-D concentrations were used to define vitamin D deficiency (≤20 ng/ml), insufficiency (21-30 ng/ml), and sufficiency (≥31 ng/ml).

RESULTS

In all, 234 patients (78% non-Hispanic, median age 14 years) were included. The majority (n = 193) were either vitamin D insufficient (50%) or deficient (32%). Eighty-four patients (36%) reported taking vitamin D supplements at the time of biopsy; serum 25(OH)-D concentrations were not higher in those supplemented. There were no differences in the demographic, clinical, and laboratory characteristics of the three vitamin D status groups. Severity of steatosis, ballooning, lobular/portal inflammation, and NAFLD activity score were also not different between the groups. The proportion of patients with significant fibrosis (stage ≥ 2) was higher in those with insufficiency (29%) compared to those who were sufficient (17%) or deficient (15%, p = 0.04). After controlling for important covariates selected from age, body mass index, ethnicity, vitamin D supplementation, and season, the insufficient group had increased odds of a higher fibrosis score compared to the sufficient group (adjusted OR, 2.04; 95%CI, 1.02-4.08).

CONCLUSIONS

Vitamin D deficiency and insufficiency are common in children with NAFLD, but not consistently related with histologic disease severity. Prospective longitudinal studies are needed to determine optimal dosing strategies to achieve sufficiency and to determine whether adequate supplementation has an impact on histology.