Background

Cardiac allograft vasculopathy (CAV) is the principal cause of long-term graft failure following heart transplantation. Early identification of patients at risk of CAV is essential to target invasive follow-up procedures more effectively and to establish appropriate therapies. We evaluated the prognostic value of the first heart biopsy (median: 9 days post-transplant) versus all biopsies obtained within the first three months for the prediction of CAV and graft failure due to CAV.

Methods and Findings

In a prospective cohort study, we developed multivariate regression models evaluating markers of atherothrombosis (fibrin, antithrombin and tissue plasminogen activator [tPA]) and endothelial activation (intercellular adhesion molecule-1) in serial biopsies obtained during the first three months post-transplantation from 172 patients (median follow-up = 6.3 years; min = 0.37 years, max = 16.3 years). Presence of fibrin was the dominant predictor in first-biopsy models (Odds Ratio [OR] for one- and 10-year graft failure due to CAV = 38.70, p = 0.002, 95% CI = 4.00–374.77; and 3.99, p = 0.005, 95% CI = 1.53–10.40) and loss of tPA was predominant in three-month models (OR for one- and 10-year graft failure due to CAV = 1.81, p = 0.025, 95% CI = 1.08–3.03; and 1.31, p = 0.001, 95% CI = 1.12–1.55). First-biopsy and three-month models had similar predictive and discriminative accuracy and were comparable in their capacities to correctly classify patient outcomes, with the exception of 10-year graft failure due to CAV in which the three-month model was more predictive. Both models had particularly high negative predictive values (e.g., First-biopsy vs. three-month models: 99% vs. 100% at 1-year and 96% vs. 95% at 10-years).

Conclusions

Patients with absence of fibrin in the first biopsy and persistence of normal tPA in subsequent biopsies rarely develop CAV or graft failure during the next 10 years and potentially could be monitored less invasively. Presence of early risk markers in the transplanted heart may be secondary to ischemia/reperfusion injury, a potentially modifiable factor.

Background

Placenta growth factor (PlGF) plays an important role in pathological angiogenesis and is thought to be an independent biomarker in patients with coronary artery disease. However, little is known regarding the regulation of PlGF expression in heart tissue.

Methods

We determined expression changes in PlGF and its receptor, VEGFR1, in normal and abnormal biopsies from human cardiac allografts and in cardiomyocytes cultured under hypoxia or cyclical stretch conditions.

Results

Human donor myocardium and biopsies from allografts without fibrin deposits expressed PlGF and VEGFR1 mRNA. Biopsies (n = 7) with myocardial fibrin, elevated serum cardiac troponin I titers (p < 0.03) and cellular infiltrates (p < 0.05), expressed 1.6-fold more PlGF mRNA than biopsies from allografts without fibrin (n=11; p < 0.05). PlGF protein was localized in cardiomyocytes, extracellular matrix and some microvessels in areas with fibrin deposition. VEGFR1 mRNA expression was not different between groups. Cultured neonatal rat cardiomyocytes constitutively expressed PlGF/VEGFR1 under normoxia. PlGF expression was increased 3.88 ± 0.62 fold after 12 hours (n = 6; p ≤ 0.05) and 3.64 ± 0.41 fold after 24 hours of hypoxia (n = 6; p ≤ 0.05). Shorter periods of hypoxia, conditioned media from hypoxic cells and cyclical stretch did not significantly alter PlGF or VEGFR1 expression.

Conclusion

Cardiomyocyte PIGF expression is upregulated by hypoxia in vitro and its expression increases significantly in allografts with myocardial damage. Collectively, these results provide important temporal and spatial evidence that endogenous PlGF could facilitate cardiac healing following myocardial hypoxia/ischemia.

Background/Aims

Several inflammatory biomarkers have been found to be associated with cardiovascular disease or all-cause mortality in dialysis patients, but their usefulness in clinical practice or as surrogate endpoints is not certain. The purpose of the present study was to determine the intrapatient variation of C-reactive protein, IL-6, fetuin-A and albumin in a population of dialysis patients.

Methods

Apparently healthy dialysis patients with either a tunneled dialysis catheter or fistula had monthly assessments of these biomarkers for a total of four determinations, and the intraclass correlation coefficients were calculated as measures of intersubject variance.

Results

Our results showed large within-subject variation relative to the total variation in the measurements (31-46%). Having a tunneled catheter as opposed to a fistula was not significantly associated with mean levels, suggesting that chronic subclinical catheter infection does not explain the variation seen in the biomarkers. In contrast, there was a rapid change in these biomarkers with a clinically apparent acute infection.

Conclusion

These results suggest that these biomarkers have limitations for use as surrogate endpoints in clinical trials due to wide fluctuations, even in apparently clinically healthy individuals.

Background/Aims

Several inflammatory biomarkers have been found to be associated with cardiovascular disease or all-cause mortality in dialysis patients, but their usefulness in clinical practice or as surrogate endpoints is not certain. The purpose of the present study was to determine the intrapatient variation of C-reactive protein, IL-6, fetuin-A and albumin in a population of dialysis patients.

Methods

Apparently healthy dialysis patients with either a tunneled dialysis catheter or fistula had monthly assessments of these biomarkers for a total of four determinations, and the intraclass correlation coefficients were calculated as measures of intersubject variance.

Results

Our results showed large within-subject variation relative to the total variation in the measurements (31–46%). Having a tunneled catheter as opposed to a fistula was not significantly associated with mean levels, suggesting that chronic subclinical catheter infection does not explain the variation seen in the biomarkers. In contrast, there was a rapid change in these biomarkers with a clinically apparent acute infection.

Conclusion

These results suggest that these biomarkers have limitations for use as surrogate endpoints in clinical trials due to wide fluctuations, even in apparently clinically healthy individuals.