D-livering the message: The importance of vitamin D status in chronic liver disease

Abstract

Vitamin D is synthesized predominantly in the liver and functions as an important secosteroid hormone with pleiotropic effects. While its key regulatory role in calcium and bone homeostasis is well established, recently there is increasing recognition that vitamin D also regulates cell proliferation and differentiation, and has immunomodulatory, anti-inflammatory and anti-fibrotic properties. These non-skeletal effects are relevant in the pathogenesis and treatment of many causes of chronic liver disease. Vitamin D deficiency is frequently present in chronic liver disease and may predict non-response to antiviral therapy in chronic hepatitis C. Small studies suggest that vitamin D supplementation improves sustained viral response rates, while 1α-hydroxylase polymorphisms and vitamin D-binding protein are also implicated in therapeutic outcomes. Vitamin D deficiency also closely relates to the severity of non-alcoholic fatty liver disease (NAFLD) and is implicated in the pathogenesis of insulin resistance, a key factor in the development of NAFLD. In preclinical studies, phototherapy and vitamin D supplementation ameliorate NAFLD histopathology, while vitamin D is a powerful anti-fibrotic against thioacetamide liver injury. In liver transplant recipients severe vitamin D deficiency predicts, and vitamin D supplementation prevents, acute cellular rejection. The role of vitamin D in the activation and regulation of both innate and adaptive immune systems may explain its importance in the above liver diseases. Further prospective studies are therefore warranted to investigate the therapeutic impact of vitamin D supplementation in chronic liver disease.

A vitamin D protocol post‐liver transplantation

“…Some of the major effects of optimized VD levels post transplantation include the decreased incidence of acute cellular rejection, decreased rate of infection, and reduced incidence of fracture (Kitson & Roberts, 2012;Moromizato et al, 2014;Nakchbandi, 2014). Vitamin D supplementation using ergocalciferol was the current approach at project site among liver transplant providers.…”

“…The intention is to supplement these patients who are especially at risk for complications of the VDD. The pre-transplant population has advanced disease, and the post population is vulnerable to infections and graft rejection (Kitson & Roberts, 2012).…”

“…Non-alcoholic fatty liver disease (NAFLD) is one result of metabolic syndrome (Kitson & Roberts, 2012). It is a relatively benign condition, and one result of the obesity epidemic that involves some fat infiltration into the liver without inflammation (Chopra, 2016).…”

“…It is a relatively benign condition, and one result of the obesity epidemic that involves some fat infiltration into the liver without inflammation (Chopra, 2016). With a prevalence of up to 30%, NAFLD is rapidly becoming the most common etiology of chronic liver disease in developed western countries (Eliades & Spyrou, 2015;Iruzubieta et al, 2014;Kitson & Roberts, 2012;Lim & Chalasani, 2012). Of the patients with NAFLD, 30% have histological evidence of non-alcoholic steatohepatitis (NASH), the complicated form of NAFLD, risking a high rate of disease progression to cirrhosis (Kitson & Roberts, 2012).…”

“…Clinical practice guidelines endorse a minimal level of 30ng/mL for serum 25-hydroxy vitamin D for patients prior to and after liver transplantation (Holick et al, 2011;Kitson & Roberts, 2012). This DNP project proposed a VDS protocol with the intention of fulfilling clinical practice guideline recommendations.…”