Platelet-Derived Growth Factor Gene Polymorphism in Recurrent Hepatitis C Infection after Liver Transplantation

Effects of acetazolamide combined with remote ischemic preconditioning on risk of acute mountain sickness: a randomized clinical trial

BACKGROUND

We aimed to determine whether and how the combination of acetazolamide and remote ischemic preconditioning (RIPC) reduced the incidence and severity of acute mountain sickness (AMS).

METHODS

This is a prospective, randomized, open-label, blinded endpoint (PROBE) study involving 250 healthy volunteers. Participants were randomized (1:1:1:1:1) to following five groups: Ripc (RIPC twice daily, 6 days), Rapid-Ripc (RIPC four times daily, 3 days), Acetazolamide (twice daily, 2 days), Combined (Acetazolamide plus Rapid-Ripc), and Control group. After interventions, participants entered a normobaric hypoxic chamber (equivalent to 4000 m) and stayed for 6 h. The primary outcomes included the incidence and severity of AMS, and SpO2 after hypoxic exposure. Secondary outcomes included systolic and diastolic blood pressure, and heart rate after hypoxic exposure. The mechanisms of the combined regime were investigated through exploratory outcomes, including analysis of venous blood gas, complete blood count, human cytokine antibody array, ELISA validation for PDGF-AB, and detection of PDGF gene polymorphisms.

RESULTS

The combination of acetazolamide and RIPC exhibited powerful efficacy in preventing AMS, reducing the incidence of AMS from 26.0 to 6.0% (Combined vs Control: RR 0.23, 95% CI 0.07-0.70, P = 0.006), without significantly increasing the incidence of adverse reactions. Combined group also showed the lowest AMS score (0.92 ± 1.10). Mechanistically, acetazolamide induced a mild metabolic acidosis (pH 7.30 ~ 7.31; HCO3- 18.1 ~ 20.8 mmol/L) and improved SpO2 (89 ~ 91%) following hypoxic exposure. Additionally, thirty differentially expressed proteins (DEPs) related to immune-inflammatory process were identified after hypoxia, among which PDGF-AB was involved. Further validation of PDGF-AB in all individuals showed that both acetazolamide and RIPC downregulated PDGF-AB before hypoxic exposure, suggesting a possible protective mechanism. Furthermore, genetic analyses demonstrated that individuals carrying the PDGFA rs2070958 C allele, rs9690350 G allele, or rs1800814 G allele did not display a decrease in PDGF-AB levels after interventions, and were associated with a higher risk of AMS.

CONCLUSIONS

The combination of acetazolamide and RIPC exerts a powerful anti-hypoxic effect and represents an innovative and promising strategy for rapid ascent to high altitudes. Acetazolamide improves oxygen saturation. RIPC further aids acetazolamide, which synergistically regulates PDGF-AB, potentially involved in the pathogenesis of AMS.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05023941.

Correlation between platelet-derived growth factor-B gene polymorphism and coronary heart disease

OBJECT

The aim of the present work was to investigate the correlation of plasma platelet-derived growth factor (PDGF)-BB level and single nucleotide polymorphism (SNP, rs1800817 and rs2285094) of PDGF-B gene with the onset and stability condition of coronary heart disease (CHD).

METHODS

Totally, 335 subjects were included in and divided into CHD (n = 247) and control group (n = 88) according to coronary angiography. Besides, the patients in the CHD group were divided into acute coronary syndrome (ACS) group (n = 165) and stable angina pectoria (SAP) group (n = 82), based on CHD stability condition. The plasma PDGF-BB level was measured by ELISA, and the genotype of PDGF-B was examined through qPCR assay.

RESULTS

The PDGF-BB level was positively correlated with hsCRP level (r = 0.149, p < 0.05). The genotype frequencies of SNP rs1800817 and rs2285094 match Hardy-Weinberg equilibrium. There was weak linkage disequilibrium between SNP rs1800817 and rs2285094: D' = 0.419, r²  = 0.04, which has no correlation with CHD. There was no statistical difference in plasma PDGF-BB level among different genotypes in rs1800817 and rs2285094. There were no differences in the plasma PDGF-BB level among patients with any genotype of SNP rs1800817 and rs2285094, no matter how it was grouped. Logistic regression results indicated that the plasma PDGF-BB level was the independent risk factor of CHD onset (OR = 1.003, 95% CI 1.001-1.006, p = 0.014).

CONCLUSIONS

High plasma PDGF-BB level is the risk factor of CHD and has correlation with instability of CHD. The plasma PDGF-BB level change may be related to inflammatory response. PDGF-B gene rs1800817 and rs2285094 polymorphisms are not correlated with CHD.

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

The platelet derived growth factor-B polymorphism is associated with risk of severe fever with thrombocytopenia syndrome in Chinese individuals

Background

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a novel bunyavirus named SFTS virus (SFTSV). We hypothesize that host genetic variations may contribute to susceptibility to SFTS.

Results

Compared with the rs1800818 AA genotype, AG + GG genotypes were significantly associated with increased susceptibility to SFTS (odds ratio, 1.66, 95% confidence interval = 1.28-2.16; P < 0.001). By using the ELISA assay, we observed that PDGF-BB concentration was significantly reduced in acute phase of patients than in the controls (P < 0.001) and recovered patients at 6 month (P = 0.007) and 12 month (P = 0.003). A persistently reduced PDGF-BB was also revealed from the SFTSV-infected C57BL/6J mice (P < 0.001). The rs1800818 G allele was associated with decreased serum PDGF-BB levels in SFTS patients at their early infection (P = 0.015). In accordance, the relative mRNA levels of the at-risk G allele of 1800818 were lower than those of the A allele in heterozygous cell from acute phase of SFTS patients. PDGF-B rs1800818 conferred no susceptibility to severe or fatal outcome in SFTS patients.

Materials and Methods

An initially small-scale case-control association study guided the selection of platelet derived growth factor-B (PDGF-B) rs1800818 in 1020 SFTS patients and 1353 controls. Functional analyses were conducted to verify the biological significance of rs1800818 polymorphism.

Conclusions

Our findings suggest that the PDGF-B rs1800818 polymorphism might play a role in mediating the susceptibility to SFTS.

Role of fibrogenic and inflammatory cytokines in HCV-induced fibrosis

HCV is one of the main causative agents of liver fibrosis and hepatocellular carcinoma. Liver inflammation resulting from HCV infection triggers fibrosis. In HCV-related fibrosis, differentiated hepatic stellate cells (HSCs) known as myofibroblasts participate in the fibrogenic and inflammatory response. TGF-β1 and CTGF, released from these HSCs, have been implicated as master cytokines mediating HCV induced hepatic fibrosis. PDGF is another potent mitogen, which facilitates the progression of liver fibrosis by enhancing the proliferation and migration of HSCs. In addition to these major cytokines, the release of TNF-α, IL-6, IL-1b and IL-10 by immune cells also promotes the effect of HCV induced fibrosis. Targeting these cytokines may offer the potential for treatments to prevent or cure fibrosis.

Platelet Derived Growth Factor-B and Human Epidermal Growth Factor Receptor-2 Polymorphisms in Gall Bladder Cancer

Gall bladder cancer (GBC) is a gastro-intestinal cancer with high prevalence among north Indian women. Platelet derived growth factor-B (PDGFB) and human epidermal growth factor receptor-2 (HER2) may play roles in the etiology of GBC through the inflammation-hyperplasia-dysplasia-carcinoma pathway. To study the association of PDGFB and HER2 polymorphisms with risk of GBC, 200 cases and 300 controls were considered. PDGFB +286A>G and +1135A>C polymorphisms were investigated with an amplification refractory mutation system and the HER2 Ile655Val polymorphism by restriction fragment length polymorphism. Significant risk associations for PDGFB +286 GG (OR=5.25) and PDGFB +1135 CC (OR=3.19) genotypes were observed for GBC. Gender wise stratification revealed susceptibility for recessive models of PDGFB +1135A>C (OR=3.00) and HER2 Ile655Val (OR=2.52) polymorphisms among female GBC cases. GBC cases with gall stones were predisposed to homozygous +286 GG and +1135 CC genotypes. Significant risk associations were found for ACIle (OR=1.48), GAVal (OR=1.70), GAIle (OR=2.00) haplotypes with GBC cases and GCIle haplotype with female GBC cases (OR=10.37, P=<0.0001). Pair-wise linkage disequilibrium revealed negative associations among variant alleles. On multi-dimensional reduction analysis, a three factor model revealed significant gene-gene interaction for PDGFB +286A>G, PDGFB +1135A>C and HER2 Ile165Val SNPs with GBC. Protein-protein interaction showed significant association of PDGFB and HER2 with the epidermal growth factor receptor signaling pathway.

Serum aspartate aminotransferase levels and previous histopathological findings enable reduction of protocol liver biopsies after liver transplantation for hepatitis C

BACKGROUND

Hepatitis C virus (HCV) infection remains the leading indication for liver transplantation (LT) worldwide. Recurrent hepatitis C following LT is universal, and significant fibrosis (SF, Metavir fibrosis stage ≥2) apparent on protocol biopsy typically prompts antiviral therapy.

OBJECTIVE

To determine the optimal timing of protocol liver biopsies in this setting.

METHODS

A total of 151 patients who underwent LT related to HCV infection between July 2004 and December 2009 were analyzed retrospectively. Data regarding protocol liver biopsies at six, 12 and 24 months post-LT, conventional laboratory parameters and demographic information were obtained.

RESULTS

The 151 patients included in the present study had significantly lower serum aspartate aminotransferase (AST) levels than the four patients who progressed to receive antiviral treatment for SF before six months post-LT (P<0.001). AST level, but not alanine aminotransferase level, histological activity or fibrosis stage at the six-month biopsy was independently associated with the progression to SF at 12 months (P<0.05). However, AST level, histological activity and fibrosis stage at the 12-month biopsy emerged as independent parameters associated with progression to SF at 24 months (P<0.05).

CONCLUSION

The protocol liver biopsy at six months could be eliminated, especially in patients who consistently exhibit low AST levels. Histological activity, the presence or absence of fibrosis, and AST values at the 12-month biopsy may lead to the decision to defer the protocol biopsy at 24 months or result in earlier introduction of antiviral therapy.

YKL-40-gene polymorphism affects acute cellular rejection and fibrosis progression after transplantation for hepatitis C virus-induced liver disease

BACKGROUND AND AIM

The development of end-stage graft disease is suspected to be partially determined by an individual genetic background. The aim of our study was to determine the prevalence of YKL-40-gene polymorphism in hepatitis C virus (HCV)-positive patients and its impact on the incidence of acute cellular rejection (ACR), graft fibrosis and antiviral treatment response.

METHODS

A total of 149 patients, who underwent liver transplantation for HCV-induced liver disease, were genotyped for YKL-40 (rs4950928; G/C) by TaqMan Genotyping Assay. The results were correlated with 616 post-transplant graft biopsies regarding inflammation, fibrosis and evidence for ACR.

RESULTS

No association of YKL-40-genotypes was observed regarding mean inflammation grade (P = 0.216) and antiviral treatment outcome (P = 0.733). However, the development of advanced fibrosis (F3-4) was significantly faster in patients with YKL-40-G-allele: t(CC) = 4.6 versus t(CG/GG) = 2.4 years; P = 0.006. Patients with lower fibrosis (F0-2) compared to advanced fibrosis (F3-4) received significantly more frequent dual immunosuppression (calcineurin inhibitors [CNIs]/mofetile mycophenolate [MMF] vs CNIs; P = 0.003). ACR-occurrence was associated with YKL-40-genotypes (ACR: CC = 60.4%, CG = 25.0% and GG = 14.6% vs non-ACR: CC = 74.2%, CG = 23.8% and GG = 2.0%; P = 0.009) and with gender compatibility between donor and recipient (P = 0.012).

CONCLUSION

Fibrosis progression and ACR-incidence after transplantation for HCV-induced liver disease seem to be under genetic control. The negative impact of G-allele on post-transplant events observed in our study, deserves attention and should be verified in larger liver transplantation-cohorts.

Role of mannose-binding lectin-2 polymorphism in the development of acute cellular rejection after transplantation for hepatitis C virus-induced liver disease

The development of liver and graft disease is suspected to be affected by genetic diversity. Mannose-binding lectin-2 (MBL-2) is an important immunomodulatory factor that is involved in complement activation. The aim of our study was to elucidate the role of MBL-2 genotypes after liver transplantation (LT) for hepatitis C virus (HCV)-induced liver disease regarding the incidence of acute cellular rejection (ACR), graft inflammation, fibrosis development, and antiviral treatment response.

METHODS

A group of 149 patients who underwent LT for HCV-induced liver disease were genotyped for MBL-2 (rs7096206; G/C) by TaqMan genotyping assay. We evaluated 518 post-LT protocol biopsies and at least 98 urgent liver biopsies regarding graft fibrosis stages, inflammation grades, and evidence for rejection within MBL-2 genotype groups.

RESULT

No association of MBL-2 polymorphisms was observed regarding inflammation, fibrosis, and antiviral treatment outcome. However, the C allele of the MBL-2 gene (P = 0.001) and gender compatibility (P = 0.012) were factors significantly associated with the incidence of ACR.

CONCLUSION

MBL-2 polymorphisms and gender are involved in the development of ACR after LT. CC genotype and gender match may be regarded as risk factors for ACR in HCV-positive graft recipients. Further studies are needed to confirm and verify this observation in non-HCV groups as well.

Role of IL28B polymorphism in the development of hepatitis C virus-induced hepatocellular carcinoma, graft fibrosis, and posttransplant antiviral therapy

BACKGROUND

The development of liver graft disease is partially determined by individual genetic background. Interleukin 28B (IL28B) is strongly suspected to be involved in susceptibility for hepatitis C virus (HCV) infection, inflammation, and antiviral treatment response before and after liver transplantation (LT). Currently, the role of IL28B polymorphism (rs12979860) in the development of hepatocellular carcinoma (HCC) is unclear, and only limited data are available on the course of HCV recurrence.

METHODS

One hundred sixty-seven HCV-positive patients after LT were genotyped for IL28B (C→T; rs12979860). Sixty-one patients with histologically confirmed HCC in the explanted liver were compared with 106 patients without HCC regarding IL28B genotypes. Among patients with HCC, IL28B genotypes were correlated with tumor histology and pretransplant α-fetoprotein (AFP) levels. Furthermore, the role of IL28B polymorphism was evaluated regarding interferon-based treatment success and fibrosis progression after LT.

RESULTS

The prevalence of HCC in explanted livers was significantly higher among patients with TT genotype, suggesting a protective role of the C allele in HCC development (P=0.041). Median AFP level was closely to significance higher in the presence of T allele (P=0.052). Significant differences in IL28B genotype distribution were detected between AFP-negative and AFP-positive HCCs (<15 μg/L vs. >15 μg/L; P=0.008). Although no impact could be observed regarding acute cellular rejection (P=0.940), T allele was significantly associated with antiviral therapy failure (P=0.028) and faster development of advanced fibrosis (P=0.017) after LT.

CONCLUSION

IL28B polymorphism seems to be involved in the development of HCV-induced HCC and in the course of HCV recurrence after LT. T allele may be regarded as a genetic risk factor for HCV-related carcinogenesis, posttransplant fibrosis progression, and antiviral therapy failure.

A 7-gene signature of the recipient predicts the progression of fibrosis after liver transplantation for hepatitis C virus infection

Fibrosis recurrence after liver transplantation (LT) for hepatitis C virus (HCV) is a universal event and strongly determines a patient's prognosis. The recipient risk factors for fibrosis recurrence are still poorly defined. Here we assess a genetic risk score as a predictor of fibrosis after LT. The cirrhosis risk score (CRS), which comprises allele variants in 7 genes (adaptor-related protein complex 3 S2, aquaporin 2, antizyme inhibitor 1, degenerative spermatocyte homolog 1 lipid desaturase, syntaxin binding protein 5-like, toll-like receptor 4, and transient receptor potential cation channel M5), was calculated for 137 patients who underwent LT for HCV infection and experienced HCV reinfection of the graft. The patients were stratified into 3 CRS categories: <0.5, 0.5 to 0.7, and >0.7. All patients underwent protocol biopsy after LT (median follow-up = 5 years), and liver fibrosis was assessed according to the Desmet and Scheuer score. The data were analyzed with univariate and multivariate analyses. The results showed that the highest CRS category was strongly associated with the presence of F2 or F3 fibrosis in protocol biopsy samples 1, 3, and 5 years after LT (P = 0.006, P = 0.001, and P = 0.02, respectively). Overall, 75.0% of the patients with a CRS > 0.7 developed at least F2 fibrosis, whereas 51.5% developed F3 fibrosis during follow-up. The predictive value of the CRS for fibrosis progression was independent of known clinical risk factors, including the age of the donor, the sex of the recipient, and the occurrence of acute rejection. A Kaplan-Meier analysis confirmed the prognostic value of the CRS with respect to the recurrence of severe liver fibrosis in HCV-infected patients after LT (log rank = 6.23, P = 0.03). In conclusion, the genetic signature of the recipient predicts the likelihood of severe liver fibrosis in the graft after HCV recurrence. The CRS might help with early clinical decision making (eg, the selection of patients for antiviral therapy after LT).

Explanted liver inflammatory grade predicts fibrosis progression in hepatitis C recurrence

Factors present prior to liver transplantation (LT) that predict fibrosis progression in recurrent hepatitis C infection (HCV) after LT would be important to identify. This study sought to determine if histologic grade of HCV in the explant predicts fibrosis progression in recurrent HCV. The clinical and histologic data of all 159 patients undergoing their first LT for HCV at our center from 1998 to 2001 were retrospectively reviewed with follow-up through June 2008. Twenty-five cases were excluded for: non-HCV-related graft loss <90 days (19), recidivism (4), or unavailable explant or follow-up biopsies (2). A single pathologist scored (Ishak) explants in a blinded fashion. Patients were grouped by explant inflammatory grade ≤ 4 (group1) and >4 (group 2). Prospectively scored liver biopsies (protocol months 1 and 4, annually, and as indicated clinically) were reviewed for development of advanced fibrosis (bridging or cirrhosis). Cox proportional hazard regression was used to analyze the association of explant grade, donor, viral and LT factors with progression to advanced fibrosis. The groups were well-matched for patient, viral, donor, and transplant factors. Five-year advanced fibrosis-free survival in group 1 versus group 2 was 63% versus 28%, P < 0.001. Explant grade >4 was associated with increased HCV-related graft loss at 1 (6% versus 3%) and 5 (36% versus 14%) years post-LT (P = 0.003). On univariate and multivariate Cox regression analysis, predictors of advanced fibrosis were explant grade >4 (hazard ratio [HR] = 3.3, 95% confidence interval [CI] = 1.9-5.6, P < 0.001) donor age >50 (HR = 3.3, 95% CI = 1.9-5.7, P < 0.001) and viral load at LT of >158,730 IU/mL (HR = 1.8, 95% CI = 1.05-3.1, P = 0.03).

CONCLUSION

Explant histologic grade can identify patients requiring more aggressive monitoring and intervention for HCV recurrence post-LT.

Are genetic variants in the platelet-derived growth factor [beta] gene associated with chronic pancreatitis?

OBJECTIVES

Platelet-derived growth factor [beta] (PDGF-[beta]) is a major signal in proliferation and matrix synthesis through activated pancreatic stellate cells, leading to fibrosis of the pancreas. Recurrent acute pancreatitis (RAP) seems to predispose to chronic pancreatitis (CP) in some patients but not others. We tested the hypothesis that 2 known PDGF-[beta] polymorphisms are associated with progression from RAP to CP. We also tested the hypothesis that PDGF-[beta] polymorphisms in combination with environmental risk factors such as alcohol and smoking are associated with CP.

METHODS

Three hundred eighty-two patients with CP (n = 176) and RAP (n = 206) and 251 controls were evaluated. Platelet-derived growth factor [beta] polymorphisms +286 A/G (rs#1800818) seen in 5'-UTR and +1135 A/C (rs#1800817) in first intron were genotyped using single-nucleotide polymorphism polymerase chain reaction approach and confirmed by DNA sequencing.

RESULTS

The genotypic frequencies for PDGF-[beta] polymorphisms in positions +286 and +1135 were found to be similar in controls and patients with RAP and CP. There was no difference in genotypic frequencies among RAP, CP, and controls in subjects in the alcohol and smoking subgroups.

CONCLUSIONS

Known variations in the PDGF-[beta] gene do not have a significant effect on promoting or preventing fibrogenesis in pancreatitis. Further evaluation of this important pathway is warranted.

Recurrent viral liver disease (hepatitis B and C) after liver transplantation

Hepatitis C represents more than 35% of liver transplant candidates worldwide. Meanwhile, hepatitis B continues to be an important cause of end-stage liver disease and hepatocellular carcinoma in Asia and Africa. Recurrent viral liver disease is a significant event after liver transplantation and continues to be one of the main causes of graft dysfunction and loss in the middle and long-term follow-up. Mechanisms of liver reinfection and disease recurrence vary between these two viruses and pre-emptive as well as the therapeutic approaches are different. Hepatitis B patients can be managed with immune globulin immediately after liver transplant and various agents such as nucleotide and nucleoside analogues can be associated. As a result, disease recurrence has been delayed or prevented in these patients. Individuals transplanted for hepatitis C are known to have universal reinfection and a high rate of disease recurrence has been reported in the literature. Strategies to treat hepatitis C recurrence are limited to the use of pegylated interferon and ribavirin when disease is demonstrated histologically and biochemically, although other strategies have been described with limited or no success. We herein review the mechanisms of disease recurrence and the current as well as the future therapeutic approaches to prevent and to treat these diseases.

Liver fibrosis and chronic viral hepatitis

Liver fibrosis results from chronic damage to the liver in conjunction with the progressive accumulation of fibrillar extracellular matrix proteins. Fibrosis progression in patients with chronic viral hepatitis is a dynamic process where hepatic stellate cells, the most important contributor cell type, respond to a variety of host genetic factors and viral proteins. The abuse of alcohol, superimposed fatty liver disease, and age at the time of viral infection are some of the factors that accelerate liver fibrosis. Liver biopsy remains the gold standard to diagnose fibrosis and significant advances have been made to develop noninvasive markers for liver fibrosis.