Inflammation-associated graft loss in renal transplant recipients

Association between oral nutrition and inflammation after intestinal transplantation

Intestinal transplantation (Itx) can be a life-saving treatment for certain patient populations, including those patients with intestinal failure (IF) who develop life-threatening complications due to the use of parenteral nutrition (PN). Most patients who have undergone Itx are eventually able to tolerate a full oral diet. However, little guidance or consensus exists regarding optimizing the specific components of an oral diet for Itx patients, including macronutrients, micronutrients and dietary patterns. While oral dietary prescriptions have moved to the forefront of primary and preventive care, this movement has yet to occur across the field of organ transplantation. Evidence to date points to the role of systemic chronic inflammation (SCI) in a wide variety of chronic diseases as well as post-transplant graft dysfunction. This review will discuss current trends in oral nutrition for Itx patients and also offer novel insights into nutritional management techniques that may help to decrease SCI and chronic disease risk as well as optimize graft function.

Effect of pretransplant sarcopenia on patient and graft outcomes in solid organ transplant recipients: A systematic review and meta-analysis

The relationship between sarcopenia and prognosis in solid organ transplantation recipients (SOTr) remains unverified. We aimed to quantify the prevalence of pretransplant sarcopenia and its effect on patient and graft survival in SOTr. We used PubMed, EMBASE, Cochrane Library and Web of Science to search relevant studies published in English (from inception to December 31, 2021). Prospective and retrospective cohort studies that reported the prevalence of sarcopenia before transplant or the association between sarcopenia and clinical outcomes in SOTr were included. Primary outcomes were the prevalence of sarcopenia and its impact on patient and graft survival. Secondary outcomes included perioperative complications, acute rejection, length of hospital stay, length of intensive care unit stay (ICU LOS) and early readmission. Thirty-nine studies involving 5792 patients were included. Pooled prevalence of sarcopenia amongst SOTr candidates was 40 % (95 % confidence interval [CI]: 34%-47 % and I2 = 97 %). Sarcopenia was associated with increased risk of death (hazard ratio [HR] = 1.87, 95 % CI: 1.46-2.41 and I2 = 60 %), poor graft survival (HR = 1.71, 95 % CI: 1.16-2.54 and I2 = 57 %) and increased liver graft loss (HR = 1.43, 95 % CI: 1.03-1.99 and I2 = 38 %). Patients with sarcopenia demonstrated increased incidence of perioperative complications (risk ratio [RR] = 1.34, 95 % CI: 1.17-1.53 and I2 = 40 %), long ICU LOS (mean difference = 2.31 days, 95 % CI: 0.58-4.04 and I2 = 97 %) and decreased risk of acute rejection (RR = 0.61, 95 % CI: 0.42-0.89 and I2 = 0 %). In Conclusion, sarcopenia is prevalent in SOTr candidates and associated with death and graft loss. Identifying sarcopenia before transplantation and intervening may improve long-term outcomes.

Systemic inflammation early after kidney transplantation is associated with long-term graft loss: a cohort study

Background

Early graft loss following kidney transplantation is mainly a result of acute rejection or surgical complications, while long-term kidney allograft loss is more complex. We examined the association between systemic inflammation early after kidney transplantation and long-term graft loss, as well as correlations between systemic inflammation scores and inflammatory findings in biopsies 6 weeks and 1 year after kidney transplantation.

Methods

We measured 21 inflammatory biomarkers 10 weeks after transplantation in 699 patients who were transplanted between 2009 and 2012 at Oslo University Hospital, Rikshospitalet, Norway. Low-grade inflammation was assessed with predefined inflammation scores based on specific biomarkers: one overall inflammation score and five pathway-specific scores. Surveillance or indication biopsies were performed in all patients 6 weeks after transplantation. The scores were tested in Cox regression models.

Results

Median follow-up time was 9.1 years (interquartile range 7.6-10.7 years). During the study period, there were 84 (12.2%) death-censored graft losses. The overall inflammation score was associated with long-term kidney graft loss both when assessed as a continuous variable (hazard ratio 1.03, 95% CI 1.01-1.06, P = 0.005) and as a categorical variable (4th quartile: hazard ratio 3.19, 95% CI 1.43-7.10, P = 0.005). In the pathway-specific analyses, fibrogenesis activity and vascular inflammation stood out. The vascular inflammation score was associated with inflammation in biopsies 6 weeks and 1 year after transplantation, while the fibrinogenesis score was associated with interstitial fibrosis and tubular atrophy.

Conclusion

In conclusion, a systemic inflammatory environment early after kidney transplantation was associated with biopsy-confirmed kidney graft pathology and long-term kidney graft loss. The systemic vascular inflammation score correlated with inflammatory findings in biopsies 6 weeks and 1 year after transplantation.

Assessment of the Relationship Between Inflammation and Glomerular Filtration Rate

Background

Chronic kidney disease (CKD) is a global health problem. As it progresses to end stages, renal replacement therapy is required but ultimately, the best treatment is transplantation. Decreased renal function has been associated with an inflammatory state associated to primary CKD and in kidney transplant recipients (KTRs).

Objective

To establish how the serum concentrations of some cytokines, such as interleukin (IL)-2, IL-8, IL-22, IL-17α, interferon-gamma, IL-4, and transforming growth factor-β, correlate with various CKD stages.

Methods

One hundred and forty-one KTRs between the ages of 18 and 75 years were included in the study. We also included 112 live kidney donors, 37 CKD PG_CKD+3, and 76 GP_healthy. Participants were grouped according to their glomerular filtration rate (GFR) and their circulating cytokine levels, previously quantified by ELISA.

Results

By linear regression analysis, we established the relation of each cytokine with the GFR. Transforming growth factor-β correlated positively with the GFR in the study population, except in healthy individuals. A negative correlation of IL-8 and IL-17α and GFR was found in all cases.

Conclusions

Whether these cytokines (IL-8 and IL-17α) could be used as inflammatory biomarkers indicating CKD progression, regardless of the type of population, remains to be prospectively determined.

Effect of allopurinol drug use on GFR and proteinuria in patients with renal transplant recipients (ADOPTR study)

BACKGROUND

Hyperuricemia has been associated with the development of hypertension, cardiovascular, and renal disease. However, there is no data about the effect of lowering uric acid level on renal functions and proteinuria in renal transplant recipients. This study aimed to investigate the effect of allopurinol treatment on renal functions in renal transplant recipients (RTR).

METHODS

A total of 245 patients with renal transplantation were included in this randomized, placebo-controlled study. Patients were randomized to receive either placebo (121 patients) or 300 mg/day allopurinol (124 patients). We have examined uric acid, urinary protein creatinin ratio, MDRD (the modification of diet in renal diseases) and CRP (C-reactive protein) before and 24 weeks after treatment in both group.

RESULTS

In the allopurinol group, the mean serum uric acid levels, eGFR (estimated glomerular filtration rate), and creatinine urinary albumin creatinin ratio (UACR) significantly improved (p < 0.001). Also uric acid level was positively correlated with the UACR (r = 0,645 p < 0.001) and negatively correlated with MDRD (r = -0,387 p < 0.05) in allopurinol treatment group. A statistically significant increase in CRP level was observed (p < 0,05) in plasebo group. Multivariate regression analysis showed that uric acid was positively correlated with UACR (r = 0,473, β = 0.021, p = 0.002) and negatively correlated with MDRD (r = -0554 β = 0.016, P = 0.001) in allopurinol treatment RTR.

CONCLUSION

Urate, a salt of uric acid, is lowered by allopurinol treatment resulting in improved eGFR and decreased proteinuria, when compared to the placebo group. Therefore, we suggest that allopurinol therapy should be part of the management of kidney transplant patients with normal kidney function. Long-term follow-up studies will be useful in revealing the effect of uric acid management on kidney functions and proteinuria.

Advanced Tertiary Lymphoid Tissues in Protocol Biopsies are Associated with Progressive Graft Dysfunction in Kidney Transplant Recipients

BACKGROUND

Tertiary lymphoid tissues (TLTs) are ectopic lymphoid tissues found in chronically inflamed organs. Although studies have documented TLT formation in transplanted kidneys, the clinical relevance of these TLTs remains controversial. We examined the effects of TLTs on future graft function using our histologic TLT maturity stages and the association between TLTs and Banff pathologic scores. We also analyzed the risk factors for the development of TLTs.

METHODS

Serial protocol biopsy samples (0 hour, 1, 6, and 12 months) without rejection were retrospectively analyzed from 214 patients who underwent living donor kidney transplantation. TLTs were defined as lymphocyte aggregates with signs of proliferation and their stages were determined by the absence (stage I) or presence (stage II) of follicular dendritic cells.

RESULTS

Only 4% of patients exhibited TLTs at the 0-hour biopsy. Prevalence increased to almost 50% at the 1-month biopsy, and then slightly further for 12 months. The proportion of advanced stage II TLTs increased gradually, reaching 19% at the 12-month biopsy. Presence of stage II TLTs was associated with higher risk of renal function decline after transplantation compared with patients with no TLT or stage I TLTs. Stage II TLTs were associated with more severe tubulitis and interstitial fibrosis/tubular atrophy at 12 months and predicted poorer graft function independently from the degree of interstitial inflammation. Pretransplantation rituximab treatment dramatically attenuated the development of stage II TLTs.

CONCLUSIONS

TLTs are commonly found in clinically stable transplanted kidneys. Advanced stage II TLTs are associated with progressive graft dysfunction, independent of interstitial inflammation.

Endothelial Dysfunction and 6-Year Risk of Mortality in Kidney Transplant Recipients

Background

Endothelial dysfunction is an early and potentially reversible stage in the atherosclerotic process. We assessed endothelial dysfunction noninvasively in kidney transplant recipients (KTRs) and evaluated the association with mortality and graft outcomes.

Methods

Flow-mediated dilation (FMD) was measured in arteria brachialis by ultrasound, with baseline diameters obtained at rest and maximal diameters obtained during reactive hyperemia occurring after 5 min of forearm occlusion. FMD% is the percentage difference of flow-mediated dilation relative to baseline. Endpoints on mortality and graft outcomes were collected from The Norwegian Renal Registry. The distribution of risk according to FMD levels was assessed in Cox regression using a restricted cubic spline function. FMD was dichotomized using receiver operating characteristic analysis to identify optimal cut points at maximal sensitivity and specificity.

Results

From a total of 269 KTRs in 2012, 152 (56.5%) were eligible and examined 10 wk after transplantation, and 145 had successful FMD measurements. During a mean follow-up of 6.5 y, 26 patients died, 11 lost their graft, and 34 experienced either graft loss or death. Mortality increased with lower FMD levels until about 5% dilation and did not change with further reduction in FMD% (P for nonlinearity <0.01). An optimal cut point of FMD ≤5.36% defined impaired endothelial function and FMD% below this level, was associated with fatal outcome, hazard ratio (HR), 9.80 (1.29-74.62), P = 0.03, uncensored graft loss, HR, 7.80 (1.83-33.30), P = 0.01, but an association with death-censored graft loss was lost after adjusting for pulse pressure, HR, 4.58 (0.55-37.92), P = 0.16.

Conclusions

We found that impaired FMD is strongly associated with mortality in KTRs.

Development and Validation of an Inflammatory-Frailty Index for Kidney Transplantation

BACKGROUND

Physical frailty phenotype is characterized by decreased physiologic reserve to stressors and associated with poor outcomes, such as delirium and mortality, that may result from post-kidney transplant (KT) inflammation. Despite a hypothesized underlying pro-inflammatory state, conventional measures of frailty typically do not incorporate inflammatory biomarkers directly. Among KT candidates and recipients, we evaluated the inclusion of inflammatory biomarkers with traditional physical frailty phenotype components.

METHODS

Among 1154 KT candidates and recipients with measures of physical frailty phenotype and inflammation (interleukin 6 [IL6], tumor necrosis factor alpha [TNFα], C-reactive protein [CRP]) at 2 transplant centers (2009-2017), we evaluated construct validity of inflammatory-frailty using latent class analysis. Inflammatory-frailty measures combined 5 physical frailty phenotype components plus the addition of an individual inflammatory biomarkers, separately (highest tertiles) as a sixth component. We then used Kaplan-Meier methods and adjusted Cox proportional hazards to assess post-KT mortality risk by inflammatory-frailty (n = 378); Harrell's C-statistics assessed risk prediction (discrimination).

RESULTS

Based on fit criteria, a 2-class solution (frail vs nonfrail) for inflammatory-frailty was the best-fitting model. Five-year survival (frail vs nonfrail) was: 81% versus 93% (IL6-frailty), 87% versus 89% (CRP-frailty), and 83% versus 91% (TNFα-frailty). Mortality was 2.07-fold higher for IL6-frail recipients (95% CI: 1.03-4.19, p = .04); there were no associations between the mortality and the other inflammatory-frailty indices (TNFα-frail: 1.88, 95% CI: 0.95-3.74, p = .07; CRP-frail: 1.02, 95% CI: 0.52-2.03, p = .95). However, none of the frailty-inflammatory indices (all C-statistics = 0.71) improved post-KT mortality risk prediction over the physical frailty phenotype (C-statistics = 0.70).

CONCLUSIONS

Measurement of IL6-frailty at transplantation can inform which patients should be targeted for pre-KT interventions. However, the traditional physical frailty phenotype is sufficient for post-KT mortality risk prediction.

The triglyceride to HDL-cholesterol ratio and chronic graft failure in renal transplantation

BACKGROUND

Transplant vasculopathy (TV) is a major contributing factor to chronic graft failure in renal transplant recipients (RTR). TV lesions resemble atherosclerosis in several ways, and it is plausible to believe that some risk factors influence both atherosclerotic plaque formation and formation of TV.

OBJECTIVE

The objective of this prospective longitudinal study was to determine if dyslipidemia reflected by the triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio is prospectively associated with death censored chronic graft failure in RTR.

METHOD

454 prospectively included RTR with a functioning graft for at least one year, were followed for a median of 7 years. RTR were matched based on propensity scores to avoid potential confounding and subsequently the association of the TG/HDL-C ratio with the endpoint chronic graft failure, defined as return to dialysis or re-transplantation, was investigated.

RESULTS

Linear regression analysis showed that concentration of insulin, male gender, BMI and number of antihypertensives predict the TG/HDL-C ratio. Cox regression showed that the TG/HDL-C ratio is associated with chronic graft failure (HR = 1.43, 95%CI = 1.12-1.84, p = 0.005) in competing risk analysis for mortality. Interaction testing indicated that the relationship of the TG/HDL-C ratio with graft failure is stronger in subjects with a higher insulin concentration.

CONCLUSION

Our results demonstrate that the TG/HDL-C ratio has the potential to act as a predictive clinical biomarker. Furthermore, there is a need for closer attention to lipid management in RTR in clinical practice with a focus on triglyceride metabolism.

Understanding and using AlloSure donor derived cell-free DNA

Renal transplant is a lifesaving and cost-effective intervention for patients with End Stage Renal Failure. Yet it is often regarded as replacement therapy rather than a cure given the overall failure rate over time. With a shortage of organs, this global issue has been further compounded by increased incidences of obesity, hypertension and diabetes, such that the disease burden and need for transplantation continues to increase. Considering the lifetime of immunosupression in transplant patients, there will also be significant associated co-morbidities By leveraging the advances in innovation in Next Generation Sequencing, the field of transplant can now monitor patients with an optimized surveillance schedule, and change the care paradigm in the post-transplant landscape. Notably, low grade inflammation is an independent risk for mortality across different disease states. In transplantation, sub-clinical inflammation enhances acute and chronic rejection, as well as accelerates pathologies that leads to graft loss. Cell free DNA has been shown to be increased in inflammatory processes as we all as provide an independent predictor of all-cause mortality. This review considers the utility of AlloSure, a donor derived cell free DNA molecular surveillance tool, which has shown new clinical insights on how best to manage renal transplant patients, and how to improve patient outcomes.

IL-10-specific autoantibodies predict major adverse cardiovascular events in kidney transplanted patients - a retrospective cohort study

End-stage renal failure is associated with persistent systemic inflammation. The aim of this study was to investigate if systemic inflammation at the time of kidney transplantation is linked to poor graft survival, major adverse cardiovascular events (MACE), and increased mortality, and if these processes are modulated by naturally occurring cytokine-specific autoantibodies (c-aAbs), which have been shown to regulate cytokine activity in vitro. Serum levels of cytokines, high-sensitivity C-reactive protein (hsCRP) and c-aAbs specific for interleukin (IL)-1α, tumor necrosis factor (TNF)-α, IL-6, and IL-10 were measured at the time of transplantation in a retrospective cohort study of 619 kidney transplanted patients with a median follow-up of 4.9 years (range 1.2-8.2 years). Systemic inflammation was associated with all-cause mortality in simple and multiple Cox regression analyses. IL-10-specific c-aAbs were associated with MACE after transplantation, suggesting that IL-10 may be a protective factor. Similarly, patients with a history of MACE before transplantation had lower levels of TNF-α-specific c-aAbs, hence we hypothesized that TNF may be a risk factor of MACE. These findings support that pro-inflammatory activity before transplantation is a pathological driver of MACE and all-cause mortality after transplantation. This information adds to pretransplantation risk estimation in renal transplant candidates.

The level of intracellular tacrolimus in T cell is affected by CD44+ABCB1+activities triggered by inflammation

Rejection is an important issue in kidney transplant. Although with adequate trough level of tacrolimus, acute rejection occurs, and we are focused on these cases. We hypothesized that the lower concentration of tacrolimus in the peripheral blood mononuclear cell would be a cause of rejection; in this regard, we describe ABCB1, which regulates intracellular concentration of tacrolimus. The effect of inflammation on the intracellular concentration of tacrolimus was evaluated, as was the association between that concentration and ABCB1 and CD44 activities. Seven kidney recipients experiencing acute rejection were prospectively enrolled. Both the whole blood concentration of tacrolimus and intracellular concentration of tacrolimus were measured at the time of enrollment and after stabilization. A human T lymphoblastoid cell line (Jurkat T cell) was treated with various concentrations of tacrolimus for 21 h and then stimulated for 3 h. The levels of mRNA interleukin-2, interleukin-8, and interferon-γ decreased dose dependently by tacrolimus. Furthermore, a fluorescence-activated cell sorter was used to count cells expressing CD44 and ABCB1; changes in intracellular concentration of tacrolimus were explored after tacrolimus treatment and stimulation. Also, B6 splenocytes were tested in the same manner as previous Jurkat T cell experiments. The tacrolimus ratio of three patients was lower at the time of acute rejection than when patients were stabilized. In vitro, the intracellular concentration of tacrolimus decreased after stimulation. Under the same conditions, CD44+ABCB1+cells increased in proportion on tacrolimus treatment and stimulation. This work supports the hypothesis that inflammation reduces the intracellular tacrolimus level, possibly via drug efflux mediated by CD44+ABCB1+and inflammation could lead to acute rejection.

Cytokine Profiles Associated With Angiotensin II Type 1 Receptor Antibodies

Introduction

Angiotensin II type 1 receptor antibody (AT1R-Ab), is a non–human leukocyte antigen (HLA) antibody implicated in poor renal allograft outcomes, although its actions may be mediated through a different pathway than HLA donor-specific antibodies (DSAs). Our aim was to examine serum cytokine profiles associated with AT1R-Ab and distinguish them from those associated with HLA DSA in serially collected blood samples from a cohort of pediatric renal transplant recipients.

Methods

Blood samples from 65 pediatric renal transplant recipients drawn during the first 3 months posttransplant, at 6, 12, and 24 months posttransplant, and during suspected episodes of kidney transplant rejection were tested for AT1R-Ab, HLA DSA, and a panel of 6 cytokines (tumor necrosis factor [TNF]-α, interferon [IFN]-γ, interleukin [IL]-8, IL-1β, IL-6, and IL-17). Associations between antibodies and cytokines were evaluated.

Results

AT1R-Ab, but not HLA DSA, was associated with elevations in TNF-α, IFN-γ, IL-8, IL-1β, IL-6, and IL-17. This relationship remained significant even after controlling for relevant clinical factors and was consistent across all time points. In contrast to HLA DSA, AT1R-Ab was associated with elevations in vascular inflammatory cytokines in the first 2 years posttransplant.

Conclusions

This profile of vascular cytokines may be informative for clinical monitoring and designing future studies to delineate the distinct pathophysiology of AT1R-Ab–mediated allograft injury in kidney transplantation.

Serum amyloid a as an indicator of impending xenograft failure: Experimental studies

BACKGROUND

There is well-documented systemic inflammatory response in xenograft recipients to the presence of a pig graft. Serum amyloid A (SAA) is an inflammatory marker that is elevated in various pathological states. The assay used to measure it is (i) simple, (ii) relatively inexpensive, and (iii) provides an answer within minutes.

METHOD

The levels of SAA (n = 11) and C-reactive protein (C-RP) (n = 8) were measured retrospectively in the serum of baboons with pig kidney transplants, who received therapy with an IL-6R inhibitor and a TNF-α antagonist. Immunohistochemistry (IHC) was used to identify amyloid A and C-RP expression in the native livers and deposition in the pig kidney grafts.

RESULTS

One kidney graft underwent hyperacute rejection, 6 (55%) underwent acute antibody-mediated rejection, 3 baboons (27%) were euthanized for serious systemic infections, and one was euthanized for acute gastric dilatation. The SAA increased temporarily after kidney transplantation, and increased again by the day of euthanasia, indicating moderate (n = 3) or significant (severe) (n = 8) inflammation. In contrast, as the baboons were receiving tocilizumab, C-RP did not increase. There was greater expression of amyloid A in baboon livers (by IHC) than of C-RP (mean OD 53 vs 1, p < 0.01), and greater deposition of amyloid A than C-RP in the pig kidney grafts (mean OD 24 vs 2, p < 0.001). Plasma fibrinogen negatively correlated with the expression of amyloid A in the liver (r = -0.72, p < 0.05). The results of the SAA assay correlated with amyloid A expression in the liver and deposition in the kidney grafts.

CONCLUSIONS

SAA is a sensitive, but non-specific, marker for inflammation in baboons with pig kidney grafts, and is not affected by therapy that suppresses the response of C-RP. The SAA assay is a rapid, reliable, and relatively inexpensive method of following the inflammatory state of baboons with pig xenografts.

Paricalcitol versus placebo for reduction of proteinuria in kidney transplant recipients: a double-blind, randomized controlled trial

Proteinuria after kidney transplantation is accompanied by an increased risk of graft failure. In this single-center, placebo-controlled, double-blind trial we studied whether vitamin D receptor activator paricalcitol might reduce proteinuria. Patients with urinary protein-to-creatinine ratio (UPCR) ≥20 mg/mmol despite optimization of the renin angiotensin aldosterone system (RAAS) blockade were randomly assigned to receive 24 weeks' treatment with 2 μg/day paricalcitol or placebo. Primary endpoint was change in UPCR, and main secondary endpoints were change in urinary albumin-to-creatinine ratio (UACR) and 24-h proteinuria. Analysis was by intention to treat. One hundred and sixty-eight patients undergo randomization, and 83 were allocated to paricalcitol, and 85 to placebo. Compared with baseline, UPCR declined in the paricalcitol group (-39%, 95% CI -45 to -31) but not in the placebo group (21%, 95% CI 9 to 35), with a between group difference of -49% (95% CI -57 to -41; P < 0.001). UACR and 24-h proteinuria decreased only on paricalcitol therapy and significantly differed between groups at end-of-treatment (P < 0.001). Paricalcitol was well tolerated but incidence of mild hypercalcemia was higher than in placebo. In conclusion, addition of 2 μg/day paricalcitol lowers residual proteinuria in kidney transplant recipients. Long-term studies are needed to determine if the reduction in proteinuria improves transplant outcomes (ClinicalTrials.gov, number NCT01436747).

Donor biomarkers as predictors of organ use and recipient survival after neurologically deceased donor organ transplantation

PURPOSE

We sought to build prediction models for organ transplantation and recipient survival using both biomarkers and clinical information.

MATERIALS AND METHODS

We abstracted clinical variables from a previous randomized trial (n = 556) of donor management. In a subset of donors (n = 97), we measured two candidate biomarkers in plasma at enrollment and just prior to explantation.

RESULTS

Secretory leukocyte protease inhibitor (SLPI) was significant for predicting liver transplantation (C-statistic 0.65 (0.53, 0.78)). SLPI also significantly improved the predictive performance of a clinical model for liver transplantation (integrated discrimination improvement (IDI): 0.090 (0.009, 0.210)). For other organs, clinical variables alone had strong predictive ability (C-statistic >0.80). Recipient 3-years survival was 80.0% (71.9%, 87.0%). Donor IL-6 was significantly associated with recipient 3-years survival (adjusted Hazard Ratio (95%CI): 1.26(1.08, 1.48), P = .004). Neither clinical variables nor biomarkers showed strong predictive ability for 3-year recipient survival.

CONCLUSIONS

Plasma biomarkers in neurologically deceased donors were associated with organ use. SLPI enhanced prediction within a liver transplantation model, whereas IL-6 before transplantation was significantly associated with recipient 3-year survival. Clinicaltrials.gov: NCT00987714.

Kidney allograft subclinical rejection modulates systemic inflammation measured by C-reactive protein at 1 year after transplantation

Kidney allograft inflammation is associated with proinflammatory modifications of peripheral blood mononuclear cells, suggesting that renal inflammation contributes to systemic inflammation. Thus, the aim of this study was to evaluate the relationship between subclinical inflammation in surveillance biopsies performed at 1 year and systemic inflammation assessed by C-reactive protein (CRP) levels at the time of biopsy. We analyzed 544 surveillance biopsies performed at 1 year that were classified as normal (n = 368), borderline (n = 148), or subclinical rejection (SCR) (n = 28). CRP levels were divided into quartiles. Patients in 1st, 2nd, and 3rd quartile were classified as low CRP (n = 408) and patients in the 4th quartile as high CRP (n = 136). Univariate analysis showed that the proportion of patients with SCR was higher in the high CRP group (10.3% vs 3.4%, P = 0.0067). Multivariate analysis showed that independent predictors of high CRP were body mass index (odds ratio [OR] 1.072 and 95% confidence interval [CI] 1.027-1.119), a positive urine culture at the day of the biopsy (OR 2.760 and 95% CI 1.205-6.323), and the presence of SCR at 1-year surveillance biopsy (OR 7.260 and 95% CI 3.530-14.935). In summary, we describe that subclinical acute rejection constitutes an independent predictor of systemic inflammation as measured by CRP.

The Associations of Endotoxemia With Systemic Inflammation, Endothelial Activation, and Cardiovascular Outcome in Kidney Transplantation

OBJECTIVE

Cardiovascular disease is the leading cause of death in kidney transplant recipients (KTRs), yet incompletely accountable by traditional risk factors. Inflammation is an unconventional cardiovascular risk factor, with gut-derived endotoxemia potentially driving inflammation and endothelial disease. Comparable data are lacking in kidney transplantation. This study investigated the associations of endotoxemia with inflammation, endothelial activation, and 5-year cardiovascular events in KTRs. Determinants of endotoxemia were also explored.

DESIGN AND METHODS

This is a single-center cross-sectional study with prospective follow-up from a prevalent cohort of 128 KTRs.

MAIN OUTCOME MEASURES

Demographic, nutritional and clinical predictors of inflammation (high-sensitivity C-reactive protein [hsCRP]), endothelial activation (sE-selectin), and endotoxemia (endotoxin) were assessed. Follow-up data on 5-year cardiovascular event rates were collected.

RESULTS

Endotoxemia (P = .03), reduced 25-hydroxyvitamin D (P = .04), high fructose intake (P < .001), decreased fiber intake (P < .001), and abdominal obesity (P = .002) were independently associated with elevated hsCRP. In turn, endotoxemia (P = .007) and increasing hsCRP (P = .02) were both independently associated with raised sE-selectin. Furthermore, endotoxemia predicted increased cardiovascular event rate (P = .02), independent of hsCRP and a global measure of cardiovascular risk estimated by a validated algorithm of 7-year risk for major adverse cardiac events in kidney transplantation. Determinants of endotoxemia included reduced 25-hydroxyvitamin D (P < .001), hypertriglyceridemia (P < .001), increased fructose intake (P = .01), and abdominal obesity (P = .01).

CONCLUSIONS

Endotoxemia in KTRs contributes to inflammation, endothelial activation, and increased cardiovascular events. This study highlights the clinical relevance of endotoxemia in KTRs, suggesting future interventional targets.

Anti-inflammatory profile of paricalcitol in kidney transplant recipients

BACKGROUND AND OBJECTIVES

Paricalcitol, a selective vitamin D receptor activator, is used to treat secondary hyperparathyroidism in kidney transplant patients. Experimental and clinical studies in non-transplant kidney disease patients have found this molecule to have anti-inflammatory properties. In this exploratory study, we evaluated the anti-inflammatory profile of paricalcitol in kidney-transplant recipients.

METHODS

Thirty one kidney transplant recipients with secondary hyperparathyroidism completed 3 months of treatment with oral paricalcitol (1μg/day). Serum concentrations and gene expression levels of inflammatory cytokines in peripheral blood mononuclear cells were analysed at the beginning and end of the study.

RESULTS

Paricalcitol significantly decreased parathyroid hormone levels with no changes in calcium and phosphorous. It also reduced serum concentrations of interleukin (IL)-6 and tumour necrosis factor-alpha (TNF-α) by 29% (P<0.05) and 9.5% (P<0.05) compared to baseline, respectively. Furthermore, gene expression levels of IL-6 and TNF-α in peripheral blood mononuclear cells decreased by 14.1% (P<0.001) and 34.1% (P<0.001), respectively. The ratios between pro-inflammatory cytokines (TNF-α and IL-6) and anti-inflammatory cytokines (IL-10), both regarding serum concentrations and gene expression, also experienced a significant reduction.

CONCLUSIONS

Paricalcitol administration to kidney transplant recipients has been found to have beneficial effects on inflammation, which may be associated with potential clinical benefits.

Effect of Paricalcitol on FGF-23 and Klotho in Kidney Transplant Recipients

BACKGROUND

Paricalcitol decreases intact parathyroid hormone and the frequency of secondary hyperparathyroidism after kidney transplantation. This proof-of-concept study aimed to assess the effect of paricalcitol on fibroblast growth factor-23/KLOTHO axis in renal transplants.

METHODS

Twenty-nine subjects with secondary hyperparathyroidism received oral paricalcitol 1 μg/d for 3 months, and 8 patients matched by age, sex, and creatinine clearance, but with intact parathyroid hormone less than 100 pg/mL, were included as controls.

RESULTS

Intact parathyroid hormone decreased in paricalcitol-treated patients (P < 0.0001). Serum fibroblast growth factor-23 enhanced (P < 0.01), whereas KLOTHO concentrations showed a trend to increase (P = 0.067). KLOTHO gene expression in peripheral blood mononuclear cells increased by 45.7% in paricalcitol-treated patients (P < 0.01), without change in controls. Paricalcitol administration resulted in a median percent decrease of 56% in methylated DNA levels of KLOTHO promoter (P < 0.001). The ratio of the unmethylated/methylated KLOTHO promoter DNA did not change in controls, but it increased by 177% in paricalcitol-treated subjects (P < 0.0001). The increase in this ratio was independently associated with the change in serum KLOTHO (r = 0.55, P < 0.01) and messenger RNA expression levels (r = 0.40, P < 0.05).

CONCLUSIONS

Paricalcitol administration to renal transplant patients significantly reduced intact parathyroid hormone and increased fibroblast growth factor-23, with a trend to increase in serum KLOTHO. Paricalcitol-treated patients showed a decrease in the methylation of the KLOTHO promoter with an increment in the ratio of un-methyated/methylated DNA, which was associated with an increase of KLOTHO gene expression levels and serum KLOTHO concentrations. Long-term studies are needed to assess whether paricalcitol-induced increase in KLOTHO gene expression and serum concentrations may translate into beneficial clinical effects.

Anemia and low-grade inflammation in pediatric kidney transplant recipients

BACKGROUND

Anemia and low-grade inflammation are reported to be associated with impaired long-term graft outcome in renal transplant (RTx) recipients. In this study, hemoglobin (Hb) and inflammation marker levels were correlated with measured glomerular filtration rate (GFR) in 128 pediatric RTx recipients over a median follow-up period of 10 years.

METHODS

Serum levels of erythropoietin (EPO), hepcidin-25, high-sensitivity C-reactive protein (CRP) (hsCRP) and interleukin-6 (IL-6) were analyzed by enzyme-linked immunosorbent assays, and GFR was analyzed by ⁵¹Cr-EDTA clearance.

RESULTS

The median levels of Hb (115 g/L), hsCRP (0.4 mg/L) and IL-6 (1.4 pg/mL) and the median erythrocyte sedimentation rate (ESR; 19 mm/h) remained stable after the first post-operative year. However, approximately half of the patients had a normocytic, normochromic anemia, and one-third had elevated levels of hsCRP (>1 mg/L) and ESR (>25 mm/h), indicating continuous low-grade inflammation. Low Hb levels preceded increased fibrosis in protocol biopsies taken at 1.5 and 3 years after transplantation and preceded decreased GFR by several years. Hb levels showed an inverse correlation with EPO levels (r = -0.206, p = 0.038) and ESR (r = -0.369, p < 0.001), but not with hepcidin-25, hsCRP or IL-6 levels. The levels of the major inflammatory markers IL-6 and hsCRP did not show a significant correlation with GFR at either the early maintenance phase or later. In the multivariable analysis, low Hb levels performed better than any other marker with respect to predicting concomitant and subsequent GFR.

CONCLUSIONS

Anemia, but not elevated inflammatory indices, was associated with poor concomitant and subsequent graft function during a 10-year follow-up in pediatric RTx patients.

Plasma Levels of Marine n-3 Fatty Acids Are Inversely Correlated With Proinflammatory Markers sTNFR1 and IL-6 in Renal Transplant Recipients

OBJECTIVE

Marine n-3 polyunsaturated fatty acids (PUFAs) exert potential anti-inflammatory effects and might improve long-term outcomes after renal transplantation. We assessed associations between plasma phospholipid levels of marine n-3 PUFAs and plasma inflammatory biomarkers 10 weeks after renal transplantation.

DESIGN

Cross-sectional single-center study.

SUBJECTS

A study population of 861 renal transplant recipients transplanted at Oslo University Hospital between 2007 and 2011.

METHODS AND MAIN OUTCOME MEASURE

Plasma phospholipid fatty acids were determined by gas chromatography. Marine n-3 PUFA levels were defined as the sum of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid levels in weight percentage of total plasma phospholipid fatty acids. Plasma inflammatory biomarkers were measured by enzyme immunoassays. We used multivariable linear regression analysis to assess associations between levels of marine n-3 PUFAs and inflammatory biomarkers in plasma.

RESULTS

Plasma marine n-3 PUFA levels were inversely associated with plasma levels of proinflammatory biomarkers soluble tumor necrosis factor receptor 1 (standardized regression coefficient -0.11, P < .001) and interleukin-6 (standardized regression coefficient -0.09, P = .01). In contrast, there was no association between plasma levels of marine n-3 PUFAs and the anti-inflammatory mediator interleukin-10.

CONCLUSIONS

In this renal transplant cohort, inverse associations between plasma levels of marine n-3 PUFAs and markers of inflammation were demonstrated.

Early Kidney Allograft Dysfunction (Threatened Allograft): Comparative Effectiveness of Continuing Versus Discontinuation of Tacrolimus and Use of Sirolimus to Prevent Graft Failure: A Retrospective Patient-Centered Outcome Study

Supplemental digital content is available in the text.

Background

Due to lack of treatment options for early acute allograft dysfunction in the presence of tubular-interstitial injury without histological features of rejection, kidney transplant recipients are often treated with sirolimus-based therapy to prevent cumulative calcineurin inhibitor exposure and to prevent premature graft failure.

Methods

We analyzed transplant recipients treated with sirolimus-based (n = 220) compared with continued tacrolimus-based (n = 276) immunosuppression in recipients of early-onset graft dysfunction (threatened allograft) with the use of propensity score-based inverse probability treatment weighted models to balance for potential confounding by indication between 2 nonrandomized groups.

Results

Weighted odds for death-censored graft failure (odds ratio [OR], 1.20; 95% confidence interval [95% CI], 0.66-2.19, P = 0.555) was similar in the 2 groups, but a trend for increased risk of greater than 50% loss in estimated glomerular filtration rate from baseline in sirolimus group (OR, 1.90; 95% CI, 0.96-3.76; P = 0.067) compared with tacrolimus group. Sirloimus group compared with tacrolimus group had increased risk for death with functioning graft (OR, 2.01; 95% CI, 1.29-3.14; P = 0.002) as well as increased risk of late death (death after graft failure while on dialysis) (OR, 2.39; 95% CI, 1.59-3.59; P < 0.001). Analysis of subgroups based on the absence or presence of T cell–mediated rejection or tubulointerstitial inflammation in the index biopsy, or the use of different types of induction agents, and all subgroups had increased risk of death with functioning graft and late death if exposed to sirolimus-based therapy.

Conclusions

Use of sirolimus compared with tacrolimus in recipients with early allograft dysfunction during the first year of transplant may not prevent worsening of allograft function and could potentially lead to poor survival along with increased risk of late death.

Cytomegalovirus-Associated CD4(+) CD28(null) Cells in NKG2D-Dependent Glomerular Endothelial Injury and Kidney Allograft Dysfunction

Emerging data suggest that expansion of a circulating population of atypical, cytotoxic CD4(+) T cells lacking costimulatory CD28 (CD4(+) CD28(null) cells) is associated with latent cytomegalovirus (CMV) infection. The purpose of the current study was to increase the understanding of the relevance of these cells in 100 unselected kidney transplant recipients followed prospectively for a median of 54 months. Multicolor flow cytometry of peripheral blood mononuclear cells before transplantation and serially posttransplantation was undertaken. CD4(+) CD28(null) cells were found predominantly in CMV-seropositive patients and expanded in the posttransplantation period. These cells were predominantly effector-memory phenotype and expressed markers of endothelial homing (CX3CR1) and cytotoxicity (NKG2D and perforin). Isolated CD4(+) CD27(-) CD28(null) cells proliferated in response to peripheral blood mononuclear cells previously exposed to CMV-derived (but not HLA-derived) antigens and following such priming incubation with glomerular endothelium resulted in signs of endothelial damage and apoptosis (release of fractalkine and von Willebrand factor; increased caspase 3 expression). This effect was mitigated by NKG2D-blocking antibody. Increased CD4(+) CD28(null) cell frequencies were associated with delayed graft function and lower estimated glomerular filtration rate at end follow-up. This study suggests an important role for this atypical cytotoxic CD4(+) CD28(null) cell subset in kidney transplantation and points to strategies that may minimize the impact on clinical outcomes.

Hyperviscosity in renal transplant recipients

OBJECTIVE

The resistance of blood to flow is called plasma viscosity. Increased blood viscosity has been described in patients with coronary and peripheral arterial disease. In this study, we evaluated the influence of clinical and laboratory findings on plasma viscosity in renal transplant recipients.

METHODS

Eighty-one kidney transplant recipients (37.8 ± 11.3 years old, 50.38 ± 16.8 months post-transplantation period, 27 female) with normal graft functions were enrolled. The biochemical and clinical parameters in the 1st year after transplantation were retrospectively recorded, and graft function was evaluated by means of the yearly decline in eGFR. Plasma viscosity was measured and searched for the association with cross-sectionally analyzed cardiovascular parameters including body composition analyses, ambulatory blood pressure monitoring (ABPM) data, and pulse-wave velocity.

RESULTS

Patients were divided into 2 groups according to the median value of serum viscosity. Patients with high viscosity had higher serum low-density lipoprotein (P = .042) and C-reactive protein (P = .046) levels than lower viscosity group. In ABPM, daytime (P = .047) and office systolic (P = .046) blood pressure levels and left ventricular mass index (LVMI; P = .012) were significantly higher in patients with hyperviscosity. Patients with high viscosity had higher hip circumference (P = .038) and fat mass (P = .048). Estimated glomerular filtration rate decline was significantly higher in high-viscosity patients than in patients with low viscosity levels (12.9% vs 17.2%; P = .001) at 2 years' follow-up.

CONCLUSIONS

We suggest that the hyperviscous state of the renal transplant recipients may arise from the inflammatory state, hypertension, and increased fat mass and increased LVMI. Hyperviscosity is also closely related to renal allograft dysfunction.

Cardiovascular risk factors following renal transplant

Kidney transplantation is the gold-standard treatment for many patients with end-stage renal disease. Renal transplant recipients (RTRs) remain at an increased risk of fatal and non-fatal cardiovascular (CV) events compared to the general population, although rates are lower than those patients on maintenance haemodialysis. Death with a functioning graft is most commonly due to cardiovascular disease (CVD) and therefore this remains an important therapeutic target to prevent graft failure. Conventional CV risk factors such as diabetes, hypertension and renal dysfunction remain a major influence on CVD in RTRs. However it is now recognised that the morbidity and mortality from CVD are not entirely accounted for by these traditional risk-factors. Immunosuppression medications exert a deleterious effect on many of these well-recognised contributors to CVD and are known to exacerbate the probability of developing diabetes, graft dysfunction and hypertension which can all lead on to CVD. Non-traditional CV risk factors such as inflammation and anaemia have been strongly linked to increased CV events in RTRs and should be considered alongside those which are classified as conventional. This review summarises what is known about risk-factors for CVD in RTRs and how, through identification of those which are modifiable, outcomes can be improved. The overall CV risk in RTRs is likely to be multifactorial and a complex interaction between the multiple traditional and non-traditional factors; further studies are required to determine how these may be modified to enhance survival and quality of life in this unique population.

The 82-plex plasma protein signature that predicts increasing inflammation

The objective of the study was to define the specific plasma protein signature that predicts the increase of the inflammation marker C-reactive protein from index day to next-day using proteome analysis and novel bioinformatics tools. We performed a prospective study of 91 incident kidney transplant recipients and quantified 359 plasma proteins simultaneously using nano-Liquid-Chromatography-Tandem Mass-Spectrometry in individual samples and plasma C-reactive protein on the index day and the next day. Next-day C-reactive protein increased in 59 patients whereas it decreased in 32 patients. The prediction model selected and validated 82 plasma proteins which determined increased next-day C-reactive protein (area under receiver-operator-characteristics curve, 0.772; 95% confidence interval, 0.669 to 0.876; P < 0.0001). Multivariable logistic regression showed that 82-plex protein signature (P < 0.001) was associated with observed increased next-day C-reactive protein. The 82-plex protein signature outperformed routine clinical procedures. The category-free net reclassification index improved with 82-plex plasma protein signature (total net reclassification index, 88.3%). Using the 82-plex plasma protein signature increased net reclassification index with a clinical meaningful 10% increase of risk mainly by the improvement of reclassification of subjects in the event group. An 82-plex plasma protein signature predicts an increase of the inflammatory marker C-reactive protein.

Symmetric dimethylarginine as predictor of graft loss and all-cause mortality in renal transplant recipients

Supplemental digital content is available in the text.

Background

Elevated symmetric dimethylarginine (SDMA) has been shown to predict cardiovascular events and all cause mortality in diverse populations. The potential role of SDMA as a risk marker in renal transplant recipients (RTR) has not been investigated.

Methods

We analyzed SDMA in the placebo arm of the Assessment of Lescol in Renal Transplantation study, a randomized controlled trial of fluvastatin in RTR. Mean follow-up was 5.1 years. Patients were grouped into quartiles based on SDMA levels at study inclusion. Relationships between SDMA and traditional risk factors for graft function and all-cause mortality were analyzed in 925 RTR using univariate and multivariate survival analyses.

Results

In univariate analysis, SDMA was significantly associated with renal graft loss, all-cause death, and major cardiovascular events. After adjustment for established risk factors including estimated glomerular filtration rate, an elevated SDMA-level (4th quartile, >1.38 μmol/L) was associated with renal graft loss; hazard ratio (HR), 5.51; 95% confidence interval (CI), 1.95–15.57; P=0.001, compared to the 1st quartile. Similarly, SDMA in the 4th quartile was independently associated with all-cause mortality (HR, 4.56; 95% CI, 2.15–9.71; P<0.001), and there was a strong borderline significant trend for an association with cardiovascular mortality (HR, 2.86; 95% CI, 0.99–8.21; P=0.051).

Conclusion

In stable RTR, an elevated SDMA level is independently associated with increased risk of all-cause mortality and renal graft loss.

Inflammatory biomarkers, glycemic variability, hypoglycemia, and renal transplant outcomes: results of a randomized controlled trial

BACKGROUND

We previously reported that compared to standard glycemic control [blood glucose (BG): 70-180 mg/dL], patients randomized to intensive glycemic control (BG: 70-110 mg/dL) were at increased risk of graft rejection in renal transplantation. However, the underlying mechanisms that associate the effect of intensive glycemic control with renal transplant outcomes have not been identified.

METHODS

A secondary data analysis of 93 participants (n=44 intensive, n=49 control) was conducted using data from a previous randomized controlled clinical trial. We examined inflammatory biomarkers, glycemic variability, hypoglycemia, and hyperglycemia as potential contributing etiologies by assessing the effect of intensive glycemic control on these characteristics, and evaluate the association of these variables with graft rejection.

RESULTS

Intensive glycemic control had no appreciable effect on highly sensitive C-reactive protein, interleukin (IL)-6, tumor necrosis factor alpha, IL-1β, or IL-10 levels at all time points after transplantation. Moreover, neither inflammatory biomarkers nor increased glycemic variability were associated with graft rejection. However, intensive treatment increased the risk of hypoglycemia (BG <70 mg/dL, 84% vs. 25%, P<0.001). In sub-analysis, compared to non-rejecters, rejecters demonstrated higher rates of blood glucose below 70 mg/dL (90% vs. 49%, P=0.02).

CONCLUSION

Inflammatory biomarkers and increased glycemic variability lack correlation with clinical outcomes in renal transplant, but importantly, increased perioperative hypoglycemic episodes (BG <70mg/dL) may be a salient etiology that contributed to the increased risk for acute allograft rejection related to intensive glycemic control. Further research is needed to confirm a causal association.

Systemic inflammation in xenograft recipients precedes activation of coagulation

BACKGROUND

Dysregulation of coagulation is considered a major barrier against successful pig organ xenotransplantation in non-human primates. Inflammation is known to promote activation of coagulation. The role of pro-inflammatory factors as well as the relationship between inflammation and activation of coagulation in xenograft recipients is poorly understood.

METHODS

Baboons received kidney (n=3), heart (n=4), or artery patch (n=8) xenografts from α1,3-galactosyltransferase gene-knockout (GTKO) pigs or GTKO pigs additionally transgenic for human complement-regulatory protein CD46 (GTKO/CD46). Immunosuppression (IS) was based on either CTLA4Ig or anti-CD154 costimulation blockade. Three artery patch recipients did not receive IS. Pro-inflammatory cytokines, chemokines, and coagulation parameters were evaluated in the circulation after transplantation. In artery patch recipients, monocytes and dendritic cells (DC) were monitored in peripheral blood. Expression of tissue factor (TF) and CD40 on monocytes and DC were assessed by flow cytometry. C-reactive protein (C-RP) levels in the blood and C-RP deposition in xenografts as well as native organs were evaluated. Baboon and pig C-RP mRNA in heart and kidney xenografts were evaluated.

RESULTS

In heart and kidney xenograft recipients, the levels of INFγ, TNF-α, IL-12, and IL-8 were not significantly higher after transplantation. However, MCP-1 and IL-6 levels were significantly higher after transplantation, particularly in kidney recipients. Elevated C-RP levels preceded activation of coagulation in heart and kidney recipients, where high levels of C-RP were maintained until the time of euthanasia in both heart and kidney recipients. In artery patch recipients, INFγ, TNF-α, IL-12, IL-8, and MCP-1 were elevated with no IS, while IL-6 was not. With IS, INFγ, TNF-α, IL-12, IL-8, and MCP-1 were reduced, but IL-6 was elevated. Elevated IL-6 levels were observed as early as 2 weeks in artery patch recipients. While IS was associated with reduced thrombin activation, fibrinogen and C-RP levels were increased when IS was given. There was a significant positive correlation between C-RP, IL-6, and fibrinogen levels. Additionally, absolute numbers of monocytes were significantly increased when IS was given, but not without IS. This was associated with increased CD40 and TF expression on CD14+ monocytes and lineage(neg) CD11c+ DC, with increased differentiation of the pro-inflammatory CD14+ CD11c+ monocyte population. At the time of euthanasia, C-RP deposition in kidney and heart xenografts, C-RP positive cells in artery patch xenograft and native lungs were detected. Finally, high levels of both pig and baboon C-RP mRNA were detected in heart and kidney xenografts.

CONCLUSIONS

Inflammatory responses precede activation of coagulation after organ xenotransplantation. Early upregulation of C-RP and IL-6 levels may amplify activation of coagulation through upregulation of TF on innate immune cells. Prevention of systemic inflammation in xenograft recipients (SIXR) may be required to prevent dysregulation of coagulation and avoid excessive IS after xenotransplantation.

Neopterin is associated with cardiovascular events and all-cause mortality in renal transplant patients

BACKGROUND

Inflammatory markers show significant associations with cardiovascular events and all-cause mortality after kidney transplantation. Neopterin, reflecting interferon-γ-release, may better reflect the proinflammatory state of recipients than less specific markers.

METHODS

Kidney transplant recipients in the Assessment of LEscol in Renal Transplant (ALERT) trial were examined and investigated for an association between serum neopterin and subsequent clinical events: graft loss, major cardiovascular events (MACE) and all-cause mortality.

RESULTS

After adjustment for established and emerging risk factors neopterin expressed as neopterin-to-creatinine ratio was significantly associated with MACE (p = 0.009) and all-cause mortality (p = 0.002). Endpoints were more frequent with increasing quartiles of neopterin-to-creatinine ratio. The incidence rates of MACE and all-cause mortality were significantly increased in the upper quartiles compared with the first.

CONCLUSIONS

This long-term prospective analysis in stable kidney allograft recipients suggests that neopterin is associated with long-term risk of cardiovascular events and all-cause mortality, but not renal outcomes.

Evidence of enhanced systemic inflammation in stable kidney transplant recipients with low Framingham risk scores

BACKGROUND

While the Framingham risk score (FRS) predicts cardiovascular risk in the general population, it underestimates cardiovascular events in renal transplant recipients (RTR). Inflammation is common in RTR, and it is also a hallmark of vascular injury contributing to cardiovascular events.

OBJECTIVE

To explore the relationship between inflammatory chemokines (CCL family) and FRS in a stable RTR.

METHODS

The modified FRS (2009) was used to calculate the 10-yr probability of CVE in 150 RTR. A cross-sectional study measured plasma levels of 14 CCLs by Luminex technique in 53% (79/150) of the cohort and 28 controls.

RESULTS

43.3% of RTR was classified as low, 16% moderate, and 40.7% high FRS. FRS correlated with eGFR and all CCLs with R of <0.2(p = n.s). Compared with controls, CCL 1,4,8,15, and 27 were equally increased in both the high and low FRS groups (p < 0.04 and 0.03, respectively). The percentage of patients with low FRS and CCL 8,15, and 27 values above the 95% cutoff control levels was 46.1%, 76.9%, and 53.8%, respectively.

CONCLUSIONS

Over one half of stable RTR, including those with low FRS, have increased inflammatory chemokine levels. Inflammation is not accounted for in the FRS, and this may explain the poor performance of FRS in transplant patients.

Biomarkers in native and transplant kidneys: opportunities to improve prediction of outcomes in chronic kidney disease

PURPOSE OF REVIEW

Predicting the outcomes of patients with chronic kidney disease (CKD) is important from both patient and healthcare system perspectives. This review examines the current state of conventional and nonconventional biomarkers as noninvasive tools to improve risk-stratification and outcome prediction in CKD.

RECENT FINDINGS

Conventional biomarkers (serum creatinine, urine albumin, and clinical variables such as sex, age, and diabetes) have been the cornerstone of most prediction models for CKD progression to end-stage renal disease (ESRD), and adverse cardiovascular outcomes including death. With better understanding of the pathophysiology of CKD and the evolution of molecular diagnostics, numerous novel or nonconventional markers have emerged. They have been examined individually and in combination to predict specific outcomes. We highlight these markers and studies, conducted primarily in patients with native kidneys. In those with transplant kidneys, markers of both acute and chronic kidney dysfunction have been examined, although to a lesser extent. Similarities and differences in knowledge derived from these two populations are highlighted.

SUMMARY

Improving prediction of outcomes in CKD patients with either native or transplant kidneys remains an important goal. Increasingly sophisticated biomarkers may potentially identify targets for clinical research, improve the nature and timing of therapeutic interventions, and guide resource allocation.

Model comparisons of competing risk and recurrent events for graft failure in renal transplant recipients

BACKGROUND AND OBJECTIVES

Risk factor analysis of long-term graft survival in kidney transplant recipients is usually based on Cox regression models of time to first occurrence of doubling of serum creatinine or graft loss (DSCGL). However, death is a competing cause of failure, and censoring patients who die could bias estimates. We therefore compared estimates of time to first event versus estimates that included death as a competing risk and recurrent events.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A Cox regression analysis of 1997-2002 data from the Assessment of Lescol in Renal Transplant (ALERT) trial population identified an eight-factor risk model, by analyzing time to first occurrence of DSCGL. The same factors were re-analyzed, allowing for death as competing. The probability of survival free of DSCGL was estimated; and two recurrent models (marginal and conditional) were used for time to events.

RESULTS

Creatinine, systolic BP, and HLA-DR mismatches lost 33%-46% of their strength of association with DSCGL when death was included as a competing risk. Small changes were observed if recurrent events were analyzed in the marginal model.

CONCLUSION

The relationship between serum creatinine and DSCGL was attenuated when death was considered as a competing risk; inclusion of recurrent events had little effect. These findings have important implications for analysis and trial design in populations at high mortality risk.

Chronic bile duct hyperplasia is a chronic graft dysfunction following liver transplantation

AIM: To investigate pathological types and influential factors of chronic graft dysfunction (CGD) following liver transplantation (LT) in rats.

METHODS: The whole experiment was divided into three groups: (1) normal group (n = 12): normal BN rats without any drug or operation; (2) syngeneic transplant group (SGT of BN-BN, n = 12): both donors and recipients were BN rats; and (3) allogeneic transplant group (AGT of LEW-BN, n = 12): Donors were Lewis and recipients were BN rats. In the AGT group, all recipients were subcutaneously injected by Cyclosporin A after LT. Survival time was observed for 1 year. All the dying rats were sampled, biliary tract tissues were performed bacterial culture and liver tissues for histological study. Twenty-one day after LT, 8 rats were selected randomly in each group for sampling. Blood samples from caudal veins were collected for measurements of plasma endotoxin, cytokines and metabonomic analysis, and faeces were analyzed for intestinal microflora.

RESULTS: During the surgery of LT, no complications of blood vessels or bile duct happened, and all rats in each group were still alive in the next 2 wk. The long term observation revealed that a total of 8 rats in the SGT and AGT groups died of hepatic graft diseases, 5 rats in which died of chronic bile duct hyperplasia. Compared to the SGT and normal groups, survival ratio of rats significantly decreased in the AGT group (P < 0.01). Moreover, liver necrosis, liver infection, and severe chronic bile duct hyperplasia were observed in the AGT group by H and E stain. On 21 d after LT, compared with the normal group (25.38 ± 7.09 ng/L) and SGT group (33.12 ± 10.26 ng/L), plasma endotoxin in the AGT group was remarkably increased (142.86 ± 30.85 ng/L) (both P < 0.01). Plasma tumor necrosis factor-α and interleukin-6 were also significantly elevated in the AGT group (593.6 ± 171.67 pg/mL, 323.8 ± 68.30 pg/mL) vs the normal (225.5 ± 72.07 pg/mL, 114.6 ± 36.67 pg/mL) and SGT groups (321.3 ± 88.47 pg/mL, 205.2 ± 53.06 pg/mL) (P < 0.01). Furthermore, Bacterial cultures of bile duct tissues revealed that the rats close to death from the SGT and AGT groups were strongly positive, while those from the normal group were negative. The analysis of intestinal microflora was performed. Compared to the normal group (7.98 ± 0.92, 8.90 ± 1.44) and SGT group (8.51 ± 0.46, 9.43 ± 0.69), the numbers of Enterococcus and Enterobacteria in the AGT group (8.76 ± 1.93, 10.18 ± 1.64) were significantly increased (both P < 0.01). Meanwhile, compared to the normal group (9.62 ± 1.60, 9.93 ± 1.10) and SGT group (8.95 ± 0.04, 9.02 ± 1.14), the numbers of Bifidobacterium and Lactobacillus in the AGT group (7.83 ± 0.72, 8.87 ± 0.13) were remarkably reduced (both P < 0.01). In addition, metabonomics analysis showed that metabolic profiles of plasma in rats in the AGT group were severe deviated from the normal and SGT groups.

CONCLUSION: Chronic bile duct hyperplasia is a pathological type of CGD following LT in rats. The mechanism of this kind of CGD is associated with the alterations of inflammation, intestinal barrier function and microflora as well as plasma metabolic profiles.