Cytomegalovirus Replication and “Herpesvirus Burden” as Risk Factor of Cardiovascular Events in the First Year After Renal Transplantation

Cytomegalovirus infection and cardiovascular outcomes in abdominal organ transplant recipients: A systematic review and meta-analysis

INTRODUCTION

Despite advancements in Cytomegalovirus (CMV) management, its impact on graft function, mortality, and cardiovascular (CV) health of organ transplant recipients (OTR) remains a significant concern. We investigated the association between CMV infection and CV events (CVE) in organ (other than heart) transplant recipients.

METHODS

We conducted a comprehensive literature search in PubMed and EMBASE, including studies that reported on CMV infection or disease and post-transplantation CVE. Studies of heart transplant recipients were excluded.

RESULTS

We screened 3875 abstracts and 12 clinical studies were included in the final analysis, mainly in kidney and liver transplant recipients. A significant association was observed between CMV infection and an increased risk of CVE, with a pooled unadjusted hazard ratio (HR) of 1.99 (95% Confidence Intervals [CI] 1.45-2.73) for CMV infection and 1.59 (95% CI 1.21-2.10) for CMV disease. Pooled adjusted HR were 2.17 (95% CI 1.47-3.20) and 1.77 (95% CI 0.83-3.76), respectively. Heterogeneity was low (I2 = 0%) for CMV infection, suggesting consistent association across studies, and moderate-to-high for CMVdisease (I2 = 50% for unadjusted, 53% for adjusted HR).

DISCUSSION

We found a significant association between CMV infection and CV risk in abdominal OTR, underscoring the importance of proactive CMV surveillance and early treatment. Future research should aim for more standardized methodologies to fully elucidate the relationship between CMV and CV outcomes, potentially informing novel preventive and therapeutic strategies that could benefit the CV health of OTR.

Coinfection of Dermal Fibroblasts by Human Cytomegalovirus and Human Herpesvirus 6 Can Boost the Expression of Fibrosis-Associated MicroRNAs

Tissue fibrosis can affect every type of tissue or organ, often leading to organ malfunction; however, the mechanisms involved in this process are not yet clarified. A role has been hypothesized for Human Cytomegalovirus (HCMV) and Human Herpesvirus 6 (HHV-6) infections as triggers of systemic sclerosis (SSc), a severe autoimmune disease causing progressive tissue fibrosis, since both viruses and antiviral immune responses toward them have been detected in patients. Moreover, HCMV or HHV-6A infection was reported to increase the expression of fibrosis-associated transcriptional factors and miRNAs in human dermal fibroblasts. However, it is unlikely that they have separate effects in the infected host, as both viruses are highly prevalent in the human population. Thus, our study aimed to investigate, by quantitative real-time PCR microarray, the impact of HCMV/HHV-6A coinfection on the expression of pro-fibrotic miRNAs in coinfected cells, compared to the effect of single viruses. The results showed a possible synergistic effect of the two viruses on pro-fibrotic miRNA expression, thus suggesting that HCMV and HHV-6 may enhance each other and cooperate at inducing enhanced miRNA-driven fibrosis. These data may also suggest a possible use of virus-induced miRNAs as novel diagnostic or prognostic biomarkers for SSc and its clinical treatment.

Role of cytomegalovirus infection after kidney transplantation on the subsequent risk of atherosclerotic and thrombotic events

Background and aims

Whether cytomegalovirus (CMV) infection increases the risk of cardiovascular complications after kidney transplantation (KT) through different indirect effects remains controversial.

Methods

We analyzed the incidence of post-transplant atherosclerotic (PAEs) and thrombotic events (PTEs) in 465 KT recipients according to the previous exposure to any level or high-level (≥1,000 IU/mL) CMV viremia (either asymptomatic or clinical disease) by means of landmark analysis beyond days 30, 180 and 360 after transplantation. Proportional hazards models were constructed with death and graft loss as competing risks.

Results

After a median of 722 days, the cumulative incidences of PAE and PTE were 6.0% each. Most PAEs (53.6%) occurred beyond post-transplant day 360, whereas most PTEs (60.7%) were diagnosed between days 30-180.The incidence of PAE beyond day 180 was higher among patients with previous CMV viremia compared to those without (two-year rates: 4.7% versus 0.4%; P-value = 0.035). This difference was more pronounced in recipients developing high-level viremia (6.3% versus 0.7%, respectively; P-value = 0.013). After multivariate adjustment for age, pre-transplant cardiovascular risk, antiplatelet and statin therapy and graft function, however, associations were not maintained either for any-level (hazard ratio [HR]: 1.84; 95% confidence interval [CI]: 0.48-7.05) or high-level CMV viremia (HR: 2.84; 95% CI: 0.78-10.36). No significant differences were found in the remaining landmark analyses (days 30 or 360) or for the outcome of PTE either.

Conclusions

Our study does not support that CMV infection independently contributes to the risk of PAE or PTE after KT.

Cytomegalovirus Disease, Short-Term Cardiovascular Events and Graft Survival in a Cohort of Kidney Transplant Recipients With High CMV IgG Seroprevalence

INTRODUCTION

Both cytomegalovirus (CMV) infection and CMV disease have been linked with several long-term indirect effects in kidney transplant recipients. Research questions: We conducted a retrospective study to assess the association between cytomegalovirus disease and risks of death, shortterm cardiovascular events and graft loss in a cohort of renal transplant recipients.

DESIGN

The associations between CMV disease and death and cardiovascular events were determined using Cox regression models, while the association between viral disease and graft loss risk was analyzed through a competing risks regression according to the Fine and Gray method. Death with a functioning graft was considered as a competing risk event.

RESULTS

A total of 865 consecutive renal transplant recipients were included. The prevalence of seropositive donor/seronegative recipient (D+/R-) group was 89.9% with the remaining patients classified as seropositive recipient (R+). After median follow-up time of 24.4 months, CMV disease was not a risk factor for all-causes mortality (HR = 1.75; 95% CI 0.94-3.25), early cardiovascular events (HR = 0.54; 95% CI 0.16-1.82) or graft loss (subhazard ratio [the HR adjusted for competing risk of death with functioning graft] = 0.99; 95% CI 0.53-1.84).

CONCLUSIONS

In this cohort with high prevalence of CMV IgG antibodies, we found no association between cytomegalovirus disease and risk of death or graft loss. The relationship between CMV and cardiovascular disease remains to be unraveled and probably corresponds to a multifactorial phenomenon involving individual risk factors and the immune response to infection rather than the virus effect itself.

A critical review of the relationship between post-transplant atherosclerotic events and cytomegalovirus exposure in kidney transplant recipients

Introduction: Cytomegalovirus (CMV) infection after kidney transplantation (KT) has been implicated in the so-called 'indirect effects' attributable to the viral ability to evade host's immunity and trigger sustained inflammation. Whether CMV exposure contributes to the development of post-transplant atherosclerotic events (AEs) remains controversial.Areas covered: This review (based on a PubMed/MEDLINE search from database inception to October 2019) summarizes the proposed mechanisms for the role of CMV in atherogenesis, including accelerated immunosenescence, endothelial injury and inflammatory milieu in the vessel wall. Sero-epidemiological evidence linking CMV exposure and cardiovascular disease in the general population is discussed. Finally, we performed a comprehensive review of observational studies investigating the impact of CMV infection on the occurrence of AE after KT, as well as the potential protective effect of antiviral prophylaxis.Expert opinion: Reviewed studies provide biological plausibility and preliminary clinical evidence pointing to the pathogenic role of CMV in post-transplant atherogenesis. However, no definitive recommendations can be made regarding the use of antiviral prophylaxis to prevent post-transplant AE, since existing evidence is mainly founded on inadequately powered post hoc analysis. Well-designed observational studies should clarify the differential impact of prophylactic or preemptive approaches on the occurrence of CMV-associated post-transplant AE among KT recipients.

Valganciclovir Prophylaxis Versus Preemptive Therapy in Cytomegalovirus-Positive Renal Allograft Recipients: Long-term Results After 7 Years of a Randomized Clinical Trial

BACKGROUND

The VIPP study compared valganciclovir prophylaxis with preemptive treatment regarding efficacy, safety, and long-term graft outcome in cytomegalovirus (CMV)-positive (R+) renal transplant recipients.

METHODS

Multicenter, open-label, randomized clinical study with a 12-month study phase and a follow-up of up to 84 months. Patients in the prophylaxis group received 2 × 450 mg/d oral valganciclovir for 100 days adjusted to renal function. Preemptive treatment with 2 × 900 mg/d valganciclovir was initiated at a viral load of 400 CMV copies/mL or greater (polymerase chain reaction) and maintained over ≥14 days, followed by secondary prophylaxis. Patients were stratified by donor CMV IgG serostatus (donor CMV IgG positive [D+]/R+, donor CMV IgG negative [D-]/R+).

RESULTS

The 12-month results were reported previously (Witzke et al Transplantation 2012). The intent-to-treat/safety population comprised 148 patients in the prophylaxis (61.5% D+/R+) and 151 patients in the preemptive group (52.3% D+/R+). Overall, 47% patients completed the follow-up. Significantly fewer patients in the prophylaxis compared with preemptive group experienced a CMV infection or disease up to month 84 (11.5%; 95% confidence interval [95% CI], 6.8-17.8%] vs 39.7%; 95% CI, 31.9-48.0%; P < 0.0001 and 4.7%; 95% CI, 1.9-9.5% vs 15.9%; 95% CI, 10.5-22.7%; P = 0.002). Incidences of graft loss (7.4% vs 8.6%), death (9.5% vs 11.3%), rejection (29.1% vs 28.5%), and renal function (estimated glomerular filtration rate [mean ± SD]: 58.2 ± 26.3 vs 59.9 ± 25.7 mL/min per 1.73 m) were not significantly different between prophylaxis and preemptive treatment. Tolerability was comparable between groups.

CONCLUSIONS

Prophylaxis was more effective than the preemptive approach, applying a low-intense surveillance protocol in preventing CMV infection and disease in intermediate-risk patients. Both strategies were similarly effective in preventing graft loss and death under the conditions of this long-term trial with a threshold of 400 copies/mL for initiation of anti-CMV treatment.

Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation

Cytomegalovirus (CMV) continues to be one of the most common infections after solid-organ transplantation, resulting in significant morbidity, graft loss, and adverse outcomes. Management of CMV varies considerably among transplant centers but has been become more standardized by publication of consensus guidelines by the Infectious Diseases Section of The Transplantation Society. An international panel of experts was reconvened in October 2012 to revise and expand evidence and expert opinion-based consensus guidelines on CMV management, including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues. The following report summarizes the recommendations.

CMV: Prevention, Diagnosis and Therapy

Cytomegalovirus (CMV) is the most common infection after organ transplantation and has a major impact on morbidity, mortality and graft survival. Optimal prevention, diagnosis and treatment of active CMV infection enhance transplant outcomes, and are the focus of this section. Methods to prevent CMV include universal prophylaxis and preemptive therapy; each has its merits, and will be compared and contrasted. Diagnostics have improved substantially in recent years, both in type and quality, allowing for more accurate and savvy treatment; advances in diagnostics include the development of an international standard, which should allow comparison of results across different methodologies, and assays for cellular immune function against CMV. Therapy primarily involves ganciclovir, now rendered more versatile by data suggesting oral therapy with valganciclovir is not inferior to intravenous therapy with ganciclovir. Treatment of resistant virus remains problematic, but is enhanced by the availability of multiple novel therapeutic agents.

The impact of prophylactic antiviral agents and statin administration on graft longevity in kidney allograft recipients

CONTEXT

In an earlier study, we compared the duration of kidney graft survival between two groups of recipients; one on triple (cyclosporine, prednisone and mycophenolate mofetil) and the other on quadruple (cyclosporine, prednisone, mycophenolate mofetil, and sirolimus) immunosuppressive therapy.

OBJECTIVE

The aim of this study was to examine the impact of antiviral and statin therapy on graft longevity.

MATERIALS AND METHODS

One hundred five kidney allograft recipients were preoperatively assessed for serological markers of infection with various viral agents. All patients were on a prophylactic antiviral regimen of acyclovir and gancyclovir. Seventeen patients were on a statin. Patients were monitored for viral infections and graft rejection or loss for period of 3 years posttransplantation.

RESULTS

We detected a high preoperative prevalence rate of IgG immunoglobulins versus the latency-establishing Herpesviridae viruses. Two patients who were preoperatively IgG positive for CMV had cytomegalovirus disease after transplantation. One patient who was preoperatively IgG positive for VZV had shingles after the surgery. No other confirmed viral infections were reported. Thirteen of 88 patients (14.77%) whose treatment regimen did not include a statin suffered a rejection episode or lost the graft whereas 1 of 17 patients (5.88%) on a statin had a rejection episode.

CONCLUSIONS

The low rate of viral infections observed in our study population supports the utility of prophylactic administration of antiviral agents to transplant recipients. However, statins seem to have a protective effect on graft longevity (odds ratio [OR] = 0.361, 95% confidence interval [CI] = 0.044-2.957).

Increased risk of stroke after a herpes zoster attack: a population-based follow-up study

BACKGROUND AND PURPOSE

Varicella zoster virus-induced vasculopathy and postherpes zoster attack stroke syndromes have been reported previously; nevertheless, data regarding the exact prevalence and risk of stroke occurring postherpes zoster attack are still lacking. This study aims to investigate the frequency and risk of stroke after a herpes zoster attack using a nationwide, population-based study of a retrospective cohort design. Method- A total of 7760 patients who had received treatment for herpes zoster between 1997 and 2001 were included and matched with 23 280 randomly selected subjects. A 1-year stroke-free survival rate was then estimated using the Kaplan-Meier method. After adjusting for potential confounders, Cox proportional hazard regressions were carried out to compute the adjusted 1-year survival rate.

RESULTS

Of the sampled patients, 439 patients (1.41%) developed strokes within the 1-year follow-up period, that is, 133 individuals (1.71% of the patients with herpes zoster) from the study cohort and 306 individuals (1.31% of patients in the comparison cohort) from the comparison cohort. The log rank test indicated that patients with herpes zoster had significantly lower 1-year stroke-free survival rates than the control (P<0.001). The adjusted hazard ratios of stroke after herpes zoster and herpes zoster ophthalmicus during the 1-year follow-up period were 1.31 and 4.28, respectively.

CONCLUSIONS

The risk for stroke increased after a zoster attack. Although varicella zoster virus vasculopathy is a well-documented complication that may induce a stroke postherpes zoster attack, it does not fully account for the unexpectedly high risk of stroke in these patients.

The Association Between Cytomegalovirus Infection and Atherosclerotic Events in Renal Transplant Recipients

Cytomegalovirus (CMV) infection is a risk factor for arteriosclerosis in renal transplant recipients. We sought to investigate the effects of CMV infection on atherosclerotic events (AE) in renal transplant recipients. This retrospective analysis included 200 patients: 52 women and 148 men of overall mean age of 36.18 +/- 10.23 years who were transplanted at our center between 1998 and 2001. We analyzed demographic features, dialysis duration, diabetes, blood pressure level, body mass index (BMI), medications, and lipid parameters. CMV infection was diagnosed in 23.5% of patients in the first 2 years after transplantation; these patients were followed for 4 years. All patients had been assessed for AE, including previous myocardial infarction, angina, revascularization procedures, intermittent claudication, stroke, or transient ischemic attack. AE occurred in 13% during the follow-up period. CMV infection was more frequent among these patients compared to those without AE, namely 42.3% versus 20.6%, respectively. Although the gender, dialysis duration, serum cholesterol level, presence of acute rejection, and BMI were not associated with AE, age, hypertension, and CMV infection did show a relation. A multivariate analysis by logistic regression revealed mean age and CMV infection to be independent risk factors for AE: odds ratio (OR)=5.6, 95% confidence interval (CI)=1.3 to 24.6 (P=0.02) and OR=4, 95% CI = 1.3 to 12.3 (P=.01). This study suggested that the presence of CMV infection may be a triggering factor for AE in renal transplant recipients.