Effects of vitamin D supplementation on liver fibrogenic factors in non-alcoholic fatty liver patients with steatohepatitis: study protocol for a randomized clinical trial

The relationship between advanced liver fibrosis and osteoporosis in type 2 diabetes patients with MAFLD

PURPOSE

To investigate the relationship between advanced liver fibrosis and osteoporosis in metabolic-associated fatty liver disease (MAFLD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 1144 T2DM patients were divided into the MAFLD and non-MAFLD groups, 460 T2DM patients with MAFLD (277 males aged ≥50 years and 183 postmenopausal females) were divided into N1 (advanced liver fibrosis excluded), N2 (indeterminate advanced liver fibrosis), and N3 (advanced liver fibrosis) groups according to the non-alcoholic fatty liver fibrosis score (NFS), the differences in bone mineral density (BMD) levels and prevalence of osteoporosis were compared. Based on the tertile levels of BMD of the lumbar spine (L), T2DM patients were divided into three groups (T1, T2, and T3), and the differences in the prevalence of advanced liver fibrosis were compared.

RESULTS

The BMD levels of the L4, and L1-4 in the MAFLD group were lower than those of the non-MAFLD groups in male and female T2DM patients .The BMD levels of the total hip, L4, and L1-4 in the N3 group were lower than those of the N2 and N1 groups in male and female T2DM patients with MAFLD, and the prevalence of osteoporosis in the N3 group of males was higher than that in the N1 group. The BMD levels of the total hip, L4, and L1-4 were negatively correlated with NFS in both males and females. The BMD levels of the total hip and L4 in males, and the BMD level of L4 in females were negatively associated with NFS. The prevalence of advanced liver fibrosis was higher in the T1 group than in the T2 and T3 groups in T2DM patients with MAFLD.

CONCLUSION

The BMD levels in male aged ≥50 years or postmenopausal female diabetic patients with MAFLD were negatively correlated with the degree of advanced liver fibrosis, which means an increased risk of liver fibrosis with decreasing BMD.

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.

Effects of vitamin D supplementation on liver fibrogenic factors, vitamin D receptor and liver fibrogenic microRNAs in metabolic dysfunction-associated steatotic liver disease (MASLD) patients: an exploratory randomized clinical trial

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global metabolic problem which can lead to irreversible liver fibrosis. It has been shown that vitamin D and its receptors contribute to fibrogenic pathways in the liver. However, the effect of vitamin D supplementation on liver fibrosis related factors have not been examined. This double blinded placebo controlled clinical trial was designed to investigate the effects on vitamin D supplementation on serum levels of VDR, fibrogenic factors and fibrogenic MicroRNAs in MASLD patients.

METHODS

Forty six MASLD patients after block matching for sex and BMI were randomly assigned to receive 4000 IU/d vitamin D or placebo for 12 weeks. Weight, height and waist circumference were measured. Serum fibrogenic microRNAs, laminin, collagen type IV, hyaluronic acid, vitamin D, VDR, PTH, blood fasting glucose, serum fasting insulin, lipid profile, ALT and AST were determined at the baseline and at the end of the trial. Insulin resistance and insulin sensitivity were calculated using the HOMA-IR and QUICKI equation.

RESULTS

Supplementation with vitamin D for 12 weeks led to the significant increases in serum 25(OH) vitamin D, VDR and HDL-C compared to placebo (P < 0.001, P = 0.008 and P < 0.001). There were significant decreases in ALT, AST, FBS and LDL-C levels in the vitamin D group as compared to the placebo (P < 0.05). Laminin and hyaluronic acid concentrations were significantly decreased in the vitamin D group as compared to the placebo group, by -10.6 and - 28.7 ng/mL, respectively. Supplementation with vitamin D for 12 weeks resulted in a significant lower MiR-21 and MiR-122 gene expressions compared to the placebo group (P = 0.01 and P < 0.001, respectively).

DISCUSSION

As the first randomized controlled trial on the effect of vitamin D supplementation on serum levels of VDR, fibrogenic factors and fibrogenic MicroRNAs in MASLD patients, we found a significant reduction in some liver fibrogenic factors, in liver transaminases and corresponding changes in some fibrosis-related MiRs and some metabolic factors. Further clinical trials with larger sample sizes and direct measures of liver fibrosis are needed to confirm these findings.

TRIAL REGISTRATION NUMBER

(available at: http://www.irct.ir , identifier: IRCT201405251485N13), Registration date: 14-03-2017.

Comprehensive molecular mechanisms and clinical therapy in nonalcoholic steatohepatitis: An overview and current perspectives

Our understanding of nonalcoholic steatohepatitis (NASH) pathophysiology continues to advance rapidly. Given the complexity of the pathogenesis of NASH, the field has moved from describing the single pathogenesis of NASH to deeply phenotyping with a description of the multi-mechanism and multi-target pathogenesis that includes glucose, lipid and cholesterol metabolism, fibrotic progression, inflammation, immune reaction and apoptosis. To make the picture more complex, the pathogenesis of NASH involves pathological connections between the liver and several organs such as the adipose, pancreas, kidney and gut. Numerous pharmacologic candidates have been tested in clinical trials and have generated some positive results. Importantly, PPAR as triglyceride synthesis inhibitor and FXR as bile acids synthesis inhibitor have displayed beneficial effects on candidates for lipid and cholesterol metabolism. Although the efficacy of these drugs has been affirmed, serious side effects hinder their further development. It is a particularly important task to carry out the in-depth long-term research. Additionally, drug combination increases response rate and reduces side effects of a single drug. Mastering the advantages and limitations of clinical candidate drugs and continuous improvement and innovation are necessary to formulate a new strategy for the future treatment of NASH.

Effect of Oral and parenteral routes of vitamin D supplementation on serum 25(OH) vitamin D levels in patients with non-alcoholic fatty liver disease

BACKGROUND

Due to the interruption of the EHC pathway in NAFLD patients, we hypothesized that parenteral vitamin D supplementation is superior to oral in vitamin D insufficient patients with NAFLD. Therefore, this study aimed to compare the efficacy of oral and parenteral routes of vitamin D supplementation on serum 25(OH) vitamin D levels in patients with NAFLD.

METHODS

In this prospective randomized trial, 66 NAFLD cases with vitamin D deficiency were studied. For 33 cases, oral vitamin D was supplemented, whereas the other 33 patients were given an intramuscular injection of vitamin D. Laboratory tests and liver ultrasound were performed at the beginning and the end of the trial for each subject.

RESULTS

Regardless of the drug administration route, at the end of this trial the mean of serum 25-hydroxy vitamin D level increased from 8.74±2.47 to 33.16±17.61 (P=0.00), and the mean±SD for serum triglyceride decreased from 191.46±92.79 to 166.00±68.30 (P=0.02), both were statistically significant. Liver ultrasound reported statistically significant changes in the grade of fatty liver disease (P=0.003). In the comparison between the two groups, serum 25-hydroxy vitamin D level changes were not statistically significant (P=0.788).

CONCLUSION

The intramuscular method of supplementation was not better than the oral route in improving serum 25(OH) vitamin D levels in NAFLD patients. In this study, the impaired EHC and vitamin D absorption inhibitor factors in NAFLD patients did not affect the final result of serum vitamin D levels significantly.

NAFLD and Vitamin D: Evidence for Intersection of MicroRNA Regulated Pathways

Non-alcoholic fatty liver disease (NAFLD) is now the most common cause of chronic liver disease, worldwide. The molecular pathogenesis of NAFLD is complex, involving numerous signalling molecules including microRNAs (miRNAs). Dysregulation of miRNA expression is associated with hepatic inflammation, fibrosis and hepatocellular carcinoma. Although miRNAs are also critical to the cellular response to vitamin D, mediating regulation of the vitamin D receptor (VDR) and vitamin D’s anticancer effects, a role for vitamin D regulated miRNAs in NAFLD pathogenesis has been relatively unexplored. Therefore, this review aimed to critically assess the evidence for a potential subset of miRNAs that are both dysregulated in NAFLD and modulated by vitamin D. Comprehensive review of 89 human studies identified 25 miRNAs found dysregulated in more than one NAFLD study. In contrast, only 17 studies, including a protocol for a trial in NAFLD, had examined miRNAs in relation to vitamin D status, response to supplementation, or vitamin D in the context of the liver. This paper summarises these data and reviews the biological roles of six miRNAs (miR-21, miR-30, miR-34, miR-122, miR-146, miR-200) found dysregulated in multiple independent NAFLD studies. While modulation of miRNAs by vitamin D has been understudied, integrating the data suggests seven vitamin D modulated miRNAs (miR-27, miR-125, miR-155, miR-192, miR-223, miR-375, miR-378) potentially relevant to NAFLD pathogenesis. Our summary tables provide a significant resource to underpin future hypothesis-driven research, and we conclude that the measurement of serum and hepatic miRNAs in response to vitamin D supplementation in larger trials is warranted.

Effect and mechanism of vitamin D activation disorder on liver fibrosis in biliary atresia

To investigate the mechanism of 25 hydroxyvitamin D (25(OH)D) deficiency in children with biliary atresia (BA) and its effect on liver fibrosis. The serum vitamin D and 25(OH)D, and expression of 25 hydroxylase (CYP2R1 and CYP27A1) in the liver of BA patients were detected and compared with those in the control group. We investigated the effect of differential expression of CYP2R1 in hepatocytes on the expression of genes related to liver fibrosis in primary hepatic stellate cells (HSCs) of BA and animal models of cholestasis. The ratio of 25(OH)D/vitamin D in the BA group was significantly lower than that in the control group. The mRNA and protein expression of CYP2R1 and CYP27A1 in liver tissue of the BA group was significantly lower than that in the control group. Exogenous active vitamin D (calcitriol) inhibited the proliferation and migration of primary HSCs isolated from BA patients, and reduced the expression of fibrosis-related genes in vitro. Downregulation of expression of CYP2R1 in hepatocytes increased expression of transforming growth factor (TGF)-β1, collagen (Col)-1α1 and tissue inhibitor of metalloproteinase (TIMP)-1, and decreased the expression of matrix metalloproteinase (MMP)-2 in cocultured primary HSCs of BA. Upregulation of expression of CYP2R1 in mice with bile duct ligation significantly increased the level of 25(OH)D, decreased the expression of TGF-β1, Col-1α1 and TIMP-1, and increased the expression of MMP-2. Children with BA have impaired vitamin D activation due to CYP2R1 deficiency. The dysactivation of vitamin D can promote the proliferation and activation of HSCs and participate in the development of hepatic fibrosis in BA.

Mitochondrial Mutations and Genetic Factors Determining NAFLD Risk

NAFLD (non-alcoholic fatty liver disease) is a widespread liver disease that is often linked with other life-threatening ailments (metabolic syndrome, insulin resistance, diabetes, cardiovascular disease, atherosclerosis, obesity, and others) and canprogress to more severe forms, such as NASH (non-alcoholic steatohepatitis), cirrhosis, and HCC (hepatocellular carcinoma). In this review, we summarized and analyzed data about single nucleotide polymorphism sites, identified in genes related to NAFLD development and progression. Additionally, the causative role of mitochondrial mutations and mitophagy malfunctions in NAFLD is discussed. The role of mitochondria-related metabolites of the urea cycle as a new non-invasive NAFLD biomarker is discussed. While mitochondria DNA mutations and SNPs (single nucleotide polymorphisms) canbe used as effective diagnostic markers and target for treatments, age and ethnic specificity should be taken into account.

It's all about the spaces between cells: role of extracellular matrix in liver fibrosis

Liver fibrosis is one of the leading complications of a variety of chronic liver disorders, including the nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, liver cirrhosis and liver failure. The progression of liver fibrosis is driven by chronic inflammation, which activates the secretory fibroblasts to the myofibroblast phenotype. These specialized liver cells are called as hepatic stellate cells (HSCs). The excessive extracellular matrix (ECM) secretion creates a large number of complications. Fibrosis is the result of imbalance between the matrix synthesizing and matrix degrading factors. The major ECM proteins include the matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), lysyl oxidases (LOX), lysyl oxidase-like (LOXLs) enzymes, tenascins and others. These ECM proteins present novel avenues for the therapeutics of liver fibrosis. The current review highlights the major role played by these critical matrix proteins in liver fibrosis. Further, some of the targeted formulations used against these proteins are discussed and suggestions are provided to select the course of research for successful clinical translation of basic research findings for the amelioration of liver fibrosis.