A non-interventional study of the genetic polymorphisms of NOD2 associated with increased mortality in non-alcoholic liver transplant patients

Presence of NOD2 mutations is not associated with hepatic or systemic hemodynamic abnormalities of cirrhosis

BACKGROUND

Patients with cirrhosis who carry NOD2 mutations are susceptible to bacterial infections. The aim was to evaluate the association of NOD2 mutations with hepatic and systemic hemodynamics in cirrhosis.

PATIENTS AND METHODS

This is a secondary analysis of a prospectively collected database in the context of the screening for the INCA trial (EudraCT 2013-001626-26). This cross-sectional study compared hemodynamic findings according to NOD2 status in 215 patients. Patients were genotyped for NOD2 variants (p.N289S, p.R702W, p.G908R, c.3020insC, rs72796367). Hepatic hemodynamic study and right heart catheterization were performed.

RESULTS

Patients had a median age of 59 (IQR 53-66) years, and 144 (67%) were men. Most patients (64%) were Child-Pugh stage B. Sixty-six patients (31%) carried a NOD2 mutation, which was slightly more common among Child-Pugh stage C (p = 0.05), without differences in MELD [wild-type: 13 (10-16); NOD2 variants 13 (10-18)]. No differences in hepatic and systemic hemodynamics were observed according to NOD2 status. If excluding patients on prophylactic or therapeutic antibiotics, again no association between hepatic or systemic hemodynamics and NOD2 status could be observed.

CONCLUSION

NOD2 mutations are not associated with hepatic or systemic hemodynamic abnormalities in patients with decompensated cirrhosis, suggesting that other mechanisms leading to bacterial translocation predominate.

Immunosuppressive Agents and Infectious Risk in Transplantation: Managing the "Net State of Immunosuppression"

Successful solid organ transplantation reflects meticulous attention to the details of immunosuppression, balancing risks for graft rejection against risks for infection. The 'net state of immune suppression' is a conceptual framework of all factors contributing to infectious risk. Assays which measure immune function in the immunosuppressed transplant recipient relative to infectious risk and allograft function are lacking. The best measures of integrated immune function may be quantitative viral loads to assess the individual's ability to control latent viral infections. Few studies address adjustment of immunosuppression during active infections. Thus, confronted with infection in solid organ recipients, the management of immunosuppression is based largely on clinical experience. This review examines known measures of immune function and the immunologic effects of common immunosuppressive drugs and available studies reporting modification of drug regimens for specific infections. These data provide a conceptual framework for the management of immunosuppression during infection in organ recipients.

Intestinal Fibrosis and Liver Fibrosis: Consequences of Chronic Inflammation or Independent Pathophysiology?

Background

Intestinal fibrosis and liver fibrosis represent a significant burden for our patients and health-care systems. Despite the severe clinical problem and the observation that fibrosis is reversible, no specific antifibrotic therapies exist.

Summary

In this review, using an 'East-West' scientific collaboration, we summarize the current knowledge on principal mechanisms shared by intestinal fibrosis and liver fibrosis. We furthermore discuss inflammation as the cause of fibrogenesis in both entities, depict unique features of intestinal and hepatic fibrosis, and provide a future outlook on the development of antifibrotic therapies.

Key Messages

A collaborative effort in the field of fibrosis, covering multiple organ systems, will have the highest chance of leading to the development of a successful antifibrotic intervention.

A variant in the nuclear dot protein 52kDa gene increases the risk for spontaneous bacterial peritonitis in patients with alcoholic liver cirrhosis

BACKGROUND

Spontaneous bacterial peritonitis is frequently a fatal infection in patients with liver cirrhosis. We investigated if nuclear dot protein 52kDa (NDP52), a negative regulator of toll-like receptor (TLR) signalling and autophagy adaptor protein, might be involved.

METHODS

Two cohorts comprising 152 (derivation cohort) and 198 patients (validation cohort) with decompensated liver cirrhosis and 168 healthy controls were genotyped for the rs2303015 polymorphism in the NDP52 gene and prospectively followed-up for spontaneous bacterial peritonitis.

RESULTS

Overall, 57 (38%) patients in the derivation cohort and 77 (39%) in the validation cohort had spontaneous bacterial peritonitis. Cirrhosis was due to alcohol abuse in 57% of the derivation and 66% of the validation cohort. In patients with alcoholic cirrhosis, patients with spontaneous bacterial peritonitis had an increased frequency of the NDP52 rs2303015 minor variant in the derivation (p=0.04) and in the validation cohort (p=0.01). Multivariate analysis confirmed this minor variant (odds ratio 4.7, p=0.002) and the TLR2 -16934 TT variant (odds ratio 2.5, p=0.008) as risk factors for spontaneous bacterial peritonitis. In addition, presence of the NDP52 minor variant affected survival negatively.

CONCLUSION

Presence of the NDP52 rs2303015 minor variant increases the risk for spontaneous bacterial peritonitis in patients with alcoholic cirrhosis.

Impact of Single Nucleotide Polymorphisms (SNPs) on Immunosuppressive Therapy in Lung Transplantation

Lung transplant patients present important variability in immunosuppressant blood concentrations during the first months after transplantation. Pharmacogenetics could explain part of this interindividual variability. We evaluated SNPs in genes that have previously shown correlations in other kinds of solid organ transplantation, namely ABCB1 and CYP3A5 genes with tacrolimus (Tac) and ABCC2, UGT1A9 and SLCO1B1 genes with mycophenolic acid (MPA), during the first six months after lung transplantation (51 patients). The genotype was correlated to the trough blood drug concentrations corrected for dose and body weight (C0/Dc). The ABCB1 variant in rs1045642 was associated with significantly higher Tac concentration, at six months post-transplantation (CT vs. CC). In the MPA analysis, CT patients in ABCC2 rs3740066 presented significantly lower blood concentrations than CC or TT, three months after transplantation. Other tendencies, confirming previously expected results, were found associated with the rest of studied SNPs. An interesting trend was recorded for the incidence of acute rejection according to NOD2/CARD15 rs2066844 (CT: 27.9%; CC: 12.5%). Relevant SNPs related to Tac and MPA in other solid organ transplants also seem to be related to the efficacy and safety of treatment in the complex setting of lung transplantation.

The gut microbiota and liver disease

The leaky gut hypothesis links translocating microbial products with the onset and progression of liver disease, and for a long time was considered one of its major contributors. However, a more detailed picture of the intestinal microbiota contributing to liver disease started to evolve. The gut is colonized by trillions of microbes that aid in digestion, modulate immune response, and generate a variety of products that result from microbial metabolic activities. These products together with host-bacteria interactions influence both normal physiology and disease susceptibility. A disruption of the symbiosis between microbiota and host is known as dysbiosis and can have profound effects on health. Qualitative changes such as increased proportions of harmful bacteria and reduced levels of beneficial bacteria, and also quantitative changes in the total amount of bacteria (overgrowth) have been associated with liver disease. Understanding the link between the pathophysiology of liver diseases and compositional and functional changes of the microbiota will help in the design of innovative therapies. In this review, we focus on factors resulting in dysbiosis, and discuss how dysbiosis can disrupt intestinal homeostasis and contribute to liver disease.