The novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection has been predominantly linked to respiratory distress syndrome, but gastrointestinal symptoms and hepatic injury have also been reported. The mechanism of liver injury is poorly understood and may result as a consequence of viral hepatitis, systemic inflammatory response, gut barrier and microbiome alterations, intensive care treatment or drug toxicity. The incidence of hepatopathy among patients with coronavirus disease 2019 (COVID-19) is unclear, but studies have reported liver injury in patients with SARS and Middle East respiratory syndrome (MERS). We aimed to systematically review data on the prevalence of hepatic impairments and their clinical course in SARS and MERS Coronaviridae infections. A systematic literature search (PubMed/Embase/Cinahl/Web of Science) according to preferred reporting items for systematic review and meta-analysis protocols (PRISMA) was conducted from database inception until 17/03/2020 for studies that evaluated the incidence of hepatic abnormalities in SARS CoV-1, SARS CoV-2 and MERS infected patients with reported liver-related parameters. A total of forty-three studies were included. Liver anomalies were predominantly mild to moderately elevated transaminases, hypoalbuminemia and prolongation of prothrombin time. Histopathology varied between non-specific inflammation, mild steatosis, congestion and massive necrosis. More studies to elucidate the mechanism and importance of liver injury on the clinical course and prognosis in patients with novel SARS-CoV-2 infection are warranted.

This study shows for the first time that chemerin and vaspin serum concentrations are altered in patients with NAFLD. The analyzed adipokines appear to play a pivotal role in the pathogenesis of NAFLD, not only as regulators of insulin sensitivity, but also as mediators of the inflammatory process.

Adipocytokine profile seems to play a distinct role in the pathogenesis of chronic hepatitis C (CHC). Chemerin and vaspin are recently described adipocytokines with various suggested functions and potential to modulate inflammatory response and insulin resistance (IR). We assessed chemerin, vaspin and leptin serum concentration and studied their association with IR laboratory and morphological features in patients with hepatitis C. The study included 40 patients with hepatitis C and 20 healthy volunteers, similar in age and body mass index (43.6 +/- 11.6 vs 40.9 +/- 11.8 years and 25.0 +/- 4.1 vs 23.9 +/- 3.3 kg/m(2), respectively). Patients had to have a normal lipid profile, and diabetes was an exclusion criteria. Serum chemerin and leptin levels and IR were significantly higher in patients with hepatitis C when compared to the controls (P = 0.02, P = 0.02 and P = 0.02, respectively), whereas vaspin level was significantly decreased (P = 0.01). Serum chemerin was negatively associated with necro-inflammatory grade (r = (-0.49), P = 0.01). The lowest levels of serum chemerin were found in patients with moderate/severe inflammation (P = 0.03). Serum leptin tended to be up-regulated in patients with minimal inflammatory activity. Serum vaspin was higher, although not significantly, when fibrosis was more advanced. IR was positively associated with fibrosis stage (r = 0.33, P = 0.03). Serum chemerin and leptin were related to each other (r = 0.45, P = 0.02).Our findings support a complex interaction between the analysed adipokines and pathogenesis of inflammatory process in CHC. The role of chemerin and vaspin in pathogenesis of inflammatory response should be further investigated.

Chronic hepatitis C (CHC) is generally a slowly progressive disease, but some factors associated with rapid progression have been identified. Steatosis, independently of its metabolic or viral origin, leads to liver injury and fibrosis. It is suggested that hepatitis C virus may contribute to a wide spectrum of metabolic disturbances-namely, steatosis, insulin resistance, increased prevalence of impaired glucose tolerance, type 2 diabetes mellitus and lipid metabolism abnormalities. Adipokines, which are produced mainly by adipose tissue, may influence the inflammatory response and insulin sensitivity and contribute to the development of metabolic abnormalities in CHC and also regulate fibrogenesis and angiogenesis. Visfatin was described as an adipokine with immunomodulating and proinflammatory properties that promotes B-cell maturation and enhances activation of leukocytes, synthesis of adhesion molecules and production of proinflammatory cytokines. Visfatin exerts insulin-mimetic effects, decreases plasma glucose levels and regulates cell energy balance. Chemerin stimulates chemotaxis of dendritic cells, macrophages and natural killer (NK) cells toward the site of inflammation. On the other hand, it inhibits synthesis of proinflammatory mediators and enhances adiponectin production, influences adipocyte differentiation and maturation and regulates glucose uptake in adipocytes. Vaspin expression in human adipose tissue seems to be a compensatory mechanism associated with obesity and insulin resistance. Vaspin suppresses leptin, tumor necrosis factor (TNF)-α and resistin expression. Leptin protects against liver steatosis but accelerates fibrosis progression and exacerbates the inflammatory process. In contrast, adiponectin exerts a hepatoprotective effect. In this report, data indicating a possible role of these adipokines in the pathogenesis of chronic hepatitis are summarized.