Progressive chronic kidney disease after pediatric lung transplantation

Interstitial lung disease as an indication for pediatric lung transplant

Interstitial lung disease can be an indication for lung transplant at any age, but it is a particularly common indication for lung transplant in infants. Nevertheless, not all interstitial lung diseases will lead to lung transplant in childhood. Genetic testing has aided the identification of these diseases in children. In severely affected patients, however, definitive diagnosis is not always necessary to consider referral to a transplant center. At experienced transplant centers, a multidisciplinary team educates patient families and aids in the transplant evaluation of children with interstitial lung disease. Children who have undergone transplant require lifetime immunosuppression and close surveillance, but can enjoy good quality of life for years following surgery.

Identification of prognostic biomarkers for antibiotic associated nephrotoxicity in cystic fibrosis

BACKGROUND

Our objective was to discover novel urinary biomarkers of antibiotic-associated nephrotoxicity using an ex-vivo human microphysiological system (MPS) and to translate these findings to a prospectively enrolled cystic fibrosis (CF) population receiving aminoglycosides and/or polymyxin E (colistin) for a pulmonary exacerbation.

METHODS

We populated the MPS with primary human kidney proximal tubule epithelial cells (PTECs) from three donors and modeled nephrotoxin injury through exposure to 50 µg/mL polymyxin E for 72 h. We analyzed gene transcriptional responses by RNAseq and tested MPS effluents. We translated candidate biomarkers to a CF cohort via analysis of urine collected prior to, during and two weeks after antibiotics and patients were followed for a median of 3 years after antibiotic use.

RESULTS

Polymyxin E treatment resulted in a statistically significant increase in the pro-apoptotic Fas gene relative to control in RNAseq of MPS: fold-change = 1.63, FDR q-value = 7.29 × 10-5. Effluent analysis demonstrated an acute rise of soluble Fas (sFas) concentrations that correlated with cellular injury. In 16 patients with CF, urinary sFas concentrations were significantly elevated during antibiotic treatment, regardless of development of AKI. Over a median of three years of follow up, we identified seven cases of incident chronic kidney disease (CKD). Urinary sFas concentrations during antibiotic treatment were significantly associated with subsequent development of incident CKD (unadjusted relative risk = 2.02 per doubling of urinary sFas, 95 % CI = 1.40, 2.90, p < 0.001).

CONCLUSIONS

Using an ex-vivo MPS, we identified a novel biomarker of proximal tubule epithelial cell injury, sFas, and translated these findings to a clinical cohort of patients with CF.

Cardiovascular Burden Is High in Pediatric Lung Transplant Recipients

BACKGROUND

Cardiovascular morbidity is common in adults after lung transplantation (LTx) but has not been described for pediatric LTx recipients. Early subclinical cardiovascular damage is reflected by increases in pulse wave velocity (PWV; indicating arteriosclerosis), intima-media thickness (IMT; indicating atherosclerosis), and left ventricular mass index (LVMI; indicating left ventricular hypertrophy).

METHODS

We annually assessed 47 pediatric LTx recipients in a prospective longitudinal study (144 observations, mean 3.1 visits/patient, range of 1-4 visits, mean follow-up 2.2 y).

RESULTS

At inclusion, increased PWV and IMT were detected in 13% and 30%, respectively, and elevated LVMI was detected in 33%. Higher PWV was associated with male sex, longer time since LTx, higher diastolic blood pressure, and lower glomerular filtration rate. Male sex and lower hemoglobin levels were associated with higher IMT, and the presence of diabetes was associated with higher LVMI.

CONCLUSIONS

Pediatric LTx recipients suffer from a high and sustained burden of subclinical cardiovascular damage. In light of improving long-term outcomes, cardiovascular morbidity needs to be addressed. Our analysis identified classical and nonclassical risk factors to be associated with the measures for cardiovascular damage, which could serve as targets for intervention.

Risks associated with lung transplantation in cystic fibrosis patients

INTRODUCTION

Survival after lung transplantation lags behind outcomes of other solid organ transplants, and complications from lung transplant are the second most common cause of death in cystic fibrosis. Evolving surgical techniques, therapeutics, and perioperative management have improved short-term survival after lung transplantation, yet have not translated into significant improvement in long-term mortality. Areas covered: We review risk factors for poor long-term outcomes among patients with cystic fibrosis undergoing lung transplantation to highlight areas for improvement. This includes reasons for organ dysfunction, complications of immunosuppression, further exacerbation of extrapulmonary complications of cystic fibrosis, and quality of life. A literature search was performed using PubMed-indexed journals. Expert commentary: There are multiple medical and socioeconomic barriers that threaten long-term survival following lung transplant for patients with cystic fibrosis. An understanding of the causes of each could elucidate treatment options. There is a lack of prospective, multicenter, randomized control trials due to cost, complexity, and feasibility. Ongoing prospective studies should be reserved for the most promising interventions identified in retrospective studies in order to improve long-term outcomes.

Patterns of kidney injury in pediatric nonkidney solid organ transplant recipients

The incidence of acute kidney injury (AKI) and its impact on chronic kidney disease (CKD) following pediatric nonkidney solid organ transplantation is unknown. We aimed to determine the incidence of AKI and CKD and examine their relationship among children who received a heart, lung, liver, or multiorgan transplant at the Hospital for Sick Children between 2002 and 2011. AKI was assessed in the first year posttransplant. Among 303 children, perioperative AKI (within the first week) occurred in 67% of children, and AKI after the first week occurred in 36%, with the highest incidence among lung and multiorgan recipients. Twenty-three children (8%) developed CKD after a median follow-up of 3.4 years. Less than 5 children developed end-stage renal disease, all within 65 days posttransplant. Those with 1 AKI episode by 3 months posttransplant had significantly greater risk for developing CKD after adjusting for age, sex, and estimated glomerular filtration rate at transplant (hazard ratio: 2.77, 95% confidence interval, 1.13-6.80, P trend = .008). AKI is common in the first year posttransplant and associated with significantly greater risk of developing CKD. Close monitoring for kidney disease may allow for earlier implementation of kidney-sparing strategies to decrease risk for progression to CKD.

Outcomes of Lung Transplantation for Infants and Children with Genetic Disorders of Surfactant Metabolism

OBJECTIVE

To compare outcomes of infants and children who underwent lung transplantation for genetic disorders of surfactant metabolism (SFTPB, SFTPC, ABCA3, and NKX2-1) over 2 epochs (1993-2003 and 2004-2015) at St Louis Children's Hospital.

STUDY DESIGN

We retrospectively reviewed clinical characteristics, mortality, and short- and long-term morbidities of infants (transplanted at <1 year; n = 28) and children (transplanted >1 year; n = 16) and compared outcomes by age at transplantation (infants vs children) and by epoch of transplantation.

RESULTS

Infants underwent transplantation more frequently for surfactant protein-B deficiency, whereas children underwent transplantation more frequently for SFTPC mutations. Both infants and children underwent transplantation for ABCA3 deficiency. Compared with children, infants experienced shorter times from listing to transplantation (P = .014), were more likely to be mechanically ventilated at the time of transplantation (P < .0001), were less likely to develop bronchiolitis obliterans post-transplantation (P = .021), and were more likely to have speech and motor delays (P ≤ .0001). Despite advances in genetic diagnosis, immunosuppressive therapies, and supportive respiratory and nutritional therapies, mortality did not differ between infants and children (P = .076) or between epochs. Kaplan-Meier analyses demonstrated that children transplanted in epoch 1 (1993-2003) were more likely to develop systemic hypertension (P = .049) and less likely to develop post-transplantation lymphoproliferative disorder compared with children transplanted in epoch 2 (2004-2015) (P = .051).

CONCLUSION

Post-lung transplantation morbidities and mortality remain substantial for infants and children with genetic disorders of surfactant metabolism.

Risk factors for acute kidney injury during aminoglycoside therapy in patients with cystic fibrosis

BACKGROUND

Aminoglycoside (AG) therapy is a common cause of acute kidney injury (AKI) in cystic fibrosis (CF) patients. The aim of this study was to identify factors associated with AKI during intravenous AG courses in this population.

METHODS

This was a matched case-control study utilizing two independent cohorts of hospitalized CF patients receiving ≥ 3 days of intravenous AG at Cincinnati Children's Hospital Medical Center and Children's of Alabama. All admissions with AKI (cases, N = 82) were matched to two randomly selected admissions without AKI (controls, N = 164) by center, gender, and age ±3 years of the case. AKI was defined as a 1.5-fold increase in the baseline serum creatinine (SCr) level or by an increase in SCr level of 0.3 mg/dL within 48 h. Admissions with AKI before day 4 or without at least weekly SCr monitoring were excluded from the analysis. Factors were compared between cases and controls using simple and multiple conditional logistic regression.

RESULTS

Multivariable analysis identified receipt of an AG within 90 days prior to admission, longer duration of AG therapy, low serum albumin, and receipt of trimethoprim/sulfamethoxazole as independent risk factors for developing AKI. Infection with Staphylococcus aureus diminished the odds of developing AKI.

CONCLUSIONS

This study identifies risk factors contributing to AG-associated AKI in CF patients. These findings can be used to anticipate high-risk scenarios and limit AKI in CF patients under clinical care.

Peri-operative kidney injury and long-term chronic kidney disease following orthotopic heart transplantation in children

Significant advances in cardiac intensive care including extracorporeal life support have enabled children with complex congenital heart disease and end-stage heart failure to be supported while awaiting transplantation. With an increasing number of survivors after heart transplantation in children, the complications from long-term immunosuppression, including renal insufficiency, are becoming more apparent. Severe renal dysfunction after heart transplant is defined by a serum creatinine level >2.5 mg/dL (221 μmol/L), and/or need for dialysis or renal transplant. The degree of renal dysfunction is variable and is progressive over time. About 3-10 % of heart transplant recipients will go on to develop severe renal dysfunction within the first 10 years post-transplantation. Multiple risk factors for chronic kidney disease post-transplant have been identified, which include pre-transplant worsening renal function, recipient demographics and morbidity, peri-transplant haemodynamics and long-term exposure to calcineurin inhibitors. Renal insufficiency increases the risk of post-transplant morbidity and mortality. Hence, screening for renal dysfunction pre-, peri- and post-transplantation is important. Early and timely detection of renal insufficiency may help minimize renal insults, and allow prompt implementation of renoprotective strategies. Close monitoring and pre-emptive management of renal dysfunction is an integral aspect of peri-transplant and subsequent post-transplant long-term care.

Renal complications following lung and heart-lung transplantation

As survival improves after lung and heart-lung transplants, the long term detrimental impact of current management on renal function becomes more apparent as the number of non-renal solid organ transplant recipients on renal transplant waiting lists increases. Progressive chronic kidney disease (CKD) is a significant cause of morbidity and mortality in the transplant population. In this review we discuss the specific problems prior to lung or heart-lung transplant that predispose to CKD, as well as potential renal complications encountered during the peri- and post-transplant period. Significant acute and chronic nephrotoxicity is caused by calcineurin inhibitors (CNI). Mechanisms to decrease CNI exposure exist but have yet to be adopted in routine clinical care. Modifiable risk factors and the current screening and management approach taken at our institution are described. Pediatric nephrologists should be involved from an early stage. Future work will need to focus on identifying more accurate measures of renal function, given the limitations of current glomerular filtration rate estimation equations in a population where nutritional status may rapidly change post transplant. Multicentre studies of CNI minimisation strategies are required to guide future therapy that aims to minimise CKD development and progression in this vulnerable population.

Risk factors for chronic kidney disease in adults with cystic fibrosis

RATIONALE

Adults with cystic fibrosis (CF) possess multiple potential risk factors for chronic kidney disease, including CF-related diabetes (CFRD) and lifetime nephrotoxic drug exposure.

OBJECTIVES

To determine whether cumulative intravenous (IV) aminoglycoside exposure and CFRD increase the risk of chronic kidney disease in adults with CF.

METHODS

This was a cohort study using adults (≥ 18 yr) in the CF Foundation registry from 2001-2008. Chronic kidney disease (stage 3 or greater) was defined by an estimated glomerular filtration rate of less than 60 ml/min/1.73 m(2). Time-dependent multivariable Cox proportional hazards models were used to determine whether cumulative number of acute pulmonary exacerbations (surrogate for IV aminoglycoside exposure) and CFRD requiring insulin increase the risk of chronic kidney disease, adjusting for confounders.

MEASUREMENTS AND MAIN RESULTS

The study cohort included 11,912 adults with a median follow-up of 4 years. During the study period, 204 subjects had chronic kidney disease, with an annual disease prevalence of 2.3%. Disease prevalence doubled with every 10-year increase in age. CFRD requiring insulin therapy substantially increased the risk of chronic kidney disease (1-4 yr of CFRD requiring insulin vs. no CFRD, hazard ratio [HR] = 2.40, 95% confidence interval [CI] 1.74-3.32; ≥ 5 yr, HR = 4.56, 95% CI 2.84-7.31). Pulmonary exacerbations did not significantly increase the risk of chronic kidney disease (one to five exacerbations vs. none, HR = 0.79, 95% CI 0.56-1.11; six to nine exacerbations, HR = 0.92, 95% CI 0.58-1.46; ≥ 10 exacerbations, HR = 1.16, 95% CI 0.75-1.81).

CONCLUSIONS

CF-related diabetes is a significant risk factor for chronic kidney disease in adults with CF, but additional studies examining IV aminoglycoside exposure directly are required.

Solid-organ transplantation in childhood: transitioning to adult health care

Pediatric solid-organ transplantation is an increasingly successful treatment for solid-organ failure. With dramatic improvements in patient survival rates over the last several decades, there has been a corresponding emergence of complications attributable to pretransplant factors, transplantation itself, and the management of transplantation with effective immunosuppression. The predominant solid-organ transplantation sequelae are medical and psychosocial. These sequelae have a substantial effect on transition to adult care; as such, hurdles to successful transition of care arise from the patients, their families, and pediatric and adult health care providers. Crucial to successful transitioning is the ongoing development of a sense of autonomy and responsibility for one's own care. In this article we address the barriers to transitioning that occur with long-term survival in pediatric solid-organ transplantation. Although a particular transitioning model is not promoted, practical tools and strategies that contribute to successful transitioning of pediatric patients who have received a transplant are suggested.

Renal function in pediatric cystic fibrosis patients in the first decade of life

With increasing life expectancy and the need for lung transplantation in the cystic fibrosis (CF) population, there are increasing reports of chronic kidney disease (CKD). However, values for baseline or longitudinal glomerular filtration rate (GFR) as measured by exogenous clearance markers are lacking in this population. Retrospective cross-sectional study in 2 to 18-year-olds cared for at a single CF center who had a GFR measured by plasma disappearance of Technetium-99 m diethylenetriaminepentaacetic acid (mGFR). The primary outcome was evidence of renal dysfunction as defined by CKD stage II or below (mGFR <90 ml/min/1.73 m(2), persistent abnormalities in urinary sediment, abnormal renal imaging). Of 63 patients evaluated, four had apparent renal dysfunction, one demonstrated decreased mGFR, and three others had persistent microscopic hematuria. The mean mGFR was substantially higher (140 ± 24 ml/min/1.73 m(2)) than expected or previously reported for healthy children. We did not demonstrate the presence of significant renal impairment after limited aminoglycoside exposure in the first decade following diagnosis with CF. However, we did document the presence of glomerular hyperfiltration in a significant proportion of our CF patients.

Outcomes in pediatric solid-organ transplantation

LaR Pediatric solid-organ transplantation is an increasingly successful treatment for organ failure. Five- and 10-yr patient survival rates have dramatically improved over the last couple of decades, and currently, over 80% of pediatric patients survive into adolescence and young adulthood. Waiting list mortality has been a concern for liver, heart, and intestinal transplantation, illustrating the importance of transplant as a life-saving therapy. Unfortunately, the success of pediatric transplantation comes at the cost of long-term or late complications that arise as a result of allograft rejection or injury, immunosuppression-related morbidity, or both. As transplant recipients enter adolescence treatment, non-adherence becomes a significant issue, and the medical and psychosocial impacts transition to adulthood not only with regard to healthcare but also in terms of functional outcomes, economic potential, and overall QoL. This review addresses the clinical and psychosocial challenges encountered by pediatric transplant recipients in the current era. A better understanding of pediatric transplant outcomes and adult morbidity and mortality requires further ongoing assessment.

Peritoneal dialysis after nonrenal solid organ transplantation: clinical outcomes and practical considerations

The incidence of end-stage renal disease following nonrenal solid organ transplantation (NRSOT) is increasing and is associated with a poor prognosis. The etiology of end-stage renal disease is multifactorial, with calcineurin inhibitor (CNI) nephrotoxicity being primarily responsible. The impact of dialysis modality on the survival of these patients remains unclear. Peritoneal dialysis appears to be a feasible and safe option for renal replacement therapy in NRSOT patients. Concerns that NRSOT patients are at a higher risk of infectious and noninfectious complications necessitate practical considerations when prescribing and planning for peritoneal dialysis in these patients. While nephrotoxicity is a well-recognized complication of long-term CNI use, "peritoneotoxic" effects with significant alterations in peritoneal membrane structure and function have recently been described. Further study including the role of CNI-free immunotherapy protocols to optimize the outcomes of NRSOT recipients is needed.

Biopsy-diagnosed renal disease in patients after transplantation of other organs and tissues

Renal function deteriorates in about half of patients undergoing other transplants. We report the results of 105 renal biopsies from 101 nonrenal transplant recipients (bone marrow 14, liver 41, lung 30, heart 20). Biopsy indications were protracted acute renal failure (9%), creatinine increases (83%), heavy proteinuria (22%), or renal insufficiency before re-transplantation (9%). Histological findings other than nonspecific chronic changes, hypertension-related damage, and signs of chronic CNI toxicity included primary glomerular disease (17%), mostly after liver transplantation (21%) or after bone marrow transplantation (29%), and thrombotic microangiopathy (TMA) namely (10%). TMA had the most serious impact on the clinical course. Besides severe hypertension, one TMA patient died of cerebral hemorrhage, 5 had hemolytic-uremic syndrome, and 6 rapidly developed end-stage renal failure. TMA patients had the shortest kidney survival post-biopsy and, together with patients with acute tubular injury, the shortest kidney and patient survival since transplantation. Nine TMA patients had received CNI, 3 of them concomitantly received an mTOR-inhibitor. CNI toxicity is implicated in most patients with renal failure after transplant of other organs and may play a role in the development of TMA, the most serious complication. However, decreased renal function should not be routinely ascribed to CNI.

Estimation of glomerular filtration rate in liver-transplanted children: comparison of simplified procedures using 51Cr-EDTA and endogenous markers with Sapirstein's method as a reference standard

This study evaluated simple procedures for GFR determination in 48 liver-transplanted children. After injection of (51)Cr-EDTA, blood samples were obtained up to four h, and activity retention in the body was measured for 60 min with scintillation probes. As a reference, GFR was calculated according to Sapirstein. Simplified calculations were performed according to Brochner-Mortensen, Russel, Devaux and Oberhausen. Additionally, GFR was determined using plasma creatinine and cystatin C according to Schwartz and Filler, respectively. The reference revealed mildly reduced GFR (62 +/- 20 mL/min/1.73 m(2)). Russel's method provided the highest degree of correlation (r(2) = 0.95), the smallest bias in GFR determination (-2%), and only one false exclusion plus one false diagnosis of chronic kidney disease. Oberhausen's method with blood sampling at one h post-injection performed slightly worse (r(2) = 0.67, bias: 3%). All other methods resulted in significantly different GFR estimates compared to the reference. Nevertheless, notably, the second narrowest 95% limits of agreement (-31% to 45%) was observed using cystatin C. In conclusion, this data implies to prefer Russel's method as a simplified procedure, and if patients cannot be available long enough (four h) for measurements, Oberhausen's method instead. If radiotracer methods are not available at all or for screening GFR, cystatin C appears to be the procedure of choice.

Nonimmune complications after transplantation

As posttransplant longevity has increased, nonimmune complications related to the transplant and posttransplant course have emerged as important factors in defining long-term outcomes. The incidence of, and risk factors for these complications may vary by transplanted organ based on immunosuppressive protocols and preexisting risk factors. This article discusses the relevant nonimmune complications associated with posttransplant care, with a focus on risk factors and management strategies.

Renal dysfunction in cystic fibrosis: is there cause for concern?

Most people associate cystic fibrosis (CF) with lung disease. Although this is the major cause of morbidity and mortality, CF is in fact a multi-organ disease. Patients with CF are living longer. Accompanying their increased life expectancy are complications not previously encountered. One of the less obvious concerns is that of renal dysfunction associated with long-term exposure to aminoglycosides as well as renally toxic immunosuppressants in lung transplant recipients. This article reviews what is known about the extent of the problem, summarizes what the current practices of measuring and monitoring renal function in patients with CF, and makes suggestions for alternative approaches. In particular, the potential role of cystatin C will be discussed.

Chronic kidney disease in children following lung and heart-lung transplantation

CKD is a major co-morbidity in pediatric lung transplant recipients. We report the prevalence of renal impairment post-lung transplant at a single center, using a modified, age-adjusted eGFR for the best approximation of true GFR, and investigated associations and possible predictors of decline in renal function post-transplant. Renal function was assessed by eGFR pre-transplant, three and 12 months post-transplant, and at last follow-up. Decline in renal function was analyzed as percentage fall in eGFR in two phases (0-3 and 3-12). Furthermore, we investigated impact of gender, age, pre-transplant diagnosis and renal function, transplant type, early post-transplant dialysis, and tacrolimus trough levels on decline in eGFR using multivariate analysis. Over a five-yr period, 30 transplants were performed. Mean eGFR pretransplant was 117 mL/min/1.73 m(2) (s.d. 35) with mean decline in eGFR during the first three months post-transplant of 33% (s.d. 31, p < 0.001). Thereafter, mean decline in eGFR was 8% (s.d. 18, p = 0.02). None of the factors assessed were significantly associated with decline in eGFR post-transplant. In conclusion, many children have decline in renal function following lung transplantation, particularly early post-transplant. Unlike in adults, we were unable to detect any predictors of renal impairment in pediatric lung transplant recipients.

Renal histopathological lesions after lung transplantation in patients with cystic fibrosis

We have analyzed the evolution of renal status beyond the perioperative period in patients with cystic fibrosis (CF) undergoing lung transplantation and presented histological analysis of 15 patients biopsied for an episode of accelerated renal function loss (RFL). Episodes of accelerated RFL after the perioperative period occurred in 32.5% of patients and significantly raised the risk of end-stage renal disease (ESRD) (p < 0.001). The histologic lesions associated with these episodes differed according to the time of onset. Early onset (10 cases) was associated with tubulointerstitial lesions in the form of oxalate nephropathy (50%) and/or a pigmented tubulopathy (80%). This latter was correlated with treatment with antiviral agents (p = 0.002) and aminoside and glycopeptide antibiotics (p = 0.03) administered in the month preceding biopsy. Lesions in late episodes of accelerated RFL (5 cases) were principally vascular: arteriosclerosis and arteriolosclerosis (p = 0.007, p = 0.00002), correlated with diabetic glomerulosclerosis or focal segmental glomerulosclerosis in the absence of prominent diabetic changes. Specific calcineurin-inhibitor nephrotoxicity was present in 93.3% of biopsies associated with thrombotic microangiopathy in 46.7% of cases. The identification of specific etiologies of progressive kidney disease in patients with CF after lung transplantation should permit more effective post-transplant care of these patients.

Renal function impacts outcomes after intestinal transplantation

BACKGROUND

Although renal dysfunction (RD) has been commonly associated with poor outcome after other solid organ transplants, it has not been studied in detail after intestinal transplantation (ITx). Here we provide a detailed analysis of renal function after ITx, and identify predictors of post-ITx RD.

METHODS

A retrospective analysis of patients undergoing ITx from 1991 to 2006 was performed. For each patient, the estimated glomerular filtration rate (eGFR) was compared with the normal GFR for age and gender to obtain the percent of normal eGFR. Chi-square analysis and log-rank tests were used to identify categorical variables associated with RD (eGFR <75% of normal) and to determine if RD was predictive of post-ITx survival.

RESULTS

Sixty-eight transplantations were performed in 62 patients. Overall patient survival at 1 and 5 years was 78% and 56%, respectively. Renal dysfunction was observed in 16% of patients post-ITx. The most frequent predictors of post-ITx RD were preoperative eGFR less than 75% of normal, pre-ITx location in the intensive care unit, and high-dose tacrolimus immunotherapy. An eGFR less than 75% of normal at days 7, 28, and 365 was predictive of poor patient survival (P<0.05).

CONCLUSIONS

This study provides the first detailed analysis of renal function after ITx. We identified specific risk factors for the development of RD in the first year post-ITx and found a significant association of RD with decreased long-term survival. Given the strong correlation of RD with poor outcome, preserving renal function may be key to improving long-term outcomes in ITx recipients.

Renal disease in recipients of nonrenal solid organ transplantation

Worldwide, more than 250,000 individuals who have received a liver, heart, lung, or intestinal transplant are living longer. Twenty percent to 25% of these recipients experience perioperative acute renal failure, with 10% to 15% requiring renal replacement therapy. Chronic kidney disease (CKD) is also highly prevalent, affecting 30% to 50% of the nonrenal organ transplant population with an annual end-stage renal disease risk of 1.5% to 2.0%. Both acute renal failure and CKD contribute to increased morbidity and premature mortality. The dominant causative factor for renal disorders seen in nonrenal transplant recipients are the calcineurin inhibitors (CNI) and rapamycin analogues, which singly or in combination lead to a variety of nephrotoxic injury. However, 25% to 30% of nonrenal transplant recipients with CKD have other conditions such as hypertension, focal segmental glomerulosclerosis, diabetes mellitus, and hepatitis C infection as the principal underlying cause. Management strategies for renal disease in the nonrenal transplant recipients include the following: (1) delayed introduction of CNI after graft implantation, (2) withdrawal or minimization of long-term CNI therapy, (3) timely use of an appropriate dialysis modality, and (4) expeditious introduction of supportive measures such as anemia management, phosphate binding therapy, and dietary modification. Compared with maintenance dialysis, kidney transplantation reduces long-term mortality by 60% to 70% in nonrenal transplant recipients with end-stage renal disease.

Successful lung transplantation for adolescents at a hospital for adults

OBJECTIVE

To describe the results of lung transplantation (LTx) in adolescents at a hospital for adults.

DESIGN AND SETTING

Prospective cohort study set in an LTx unit at an adult tertiary referral hospital from 1991 to 2006.

PATIENTS

37 consecutive adolescent lung transplant recipients including 13 males and 24 females (mean age, 16.7+/-2.0 [SD] years; range 12-19 years) who received heart-lung (six patients) or bilateral LTx (31 patients) for cystic fibrosis (29), congenital heart disease (four), acute respiratory failure (two), or another disorder (two). Two patients were transplanted after invasive ventilation, five after non-invasive ventilation and two after extracorporeal membrane oxygenation.

MAIN OUTCOME MEASURES

Overall survival compared with an adult cohort; survival free of bronchiolitis obliterans syndrome (BOS); overall and BOS-free survival in those transplanted before and after January 2000.

RESULTS

Mean waiting time was 273 days (range, 5-964 days; median, 163 days), mean donor age was 28 years (range, 9-53 years). Median inpatient stay was 11 days (range, 7-94 days). Mean follow-up was 1540+/-1357 days (range, 35-5163 days). The 5-year survival rate for the 16 patients transplanted before January 2000 was 38%, versus 74% for the 21 transplanted since January 2000 (P=0.05; Mantel-Cox). Overall, 18 of 35 evaluable patients developed BOS. Only BOS was associated with an increased mortality risk (P<0.01).

CONCLUSION

LTx may be performed successfully in adolescents at a hospital for adults.

Homologous peptide of connective tissue growth factor ameliorates epithelial to mesenchymal transition of tubular epithelial cells

The hallmark of failing renal transplants is tubular atrophy and interstitial fibrosis. The cytokine connective tissue growth factor (CTGF or CCN2) plays an important role in epithelial-mesenchymal transition (EMT) of tubular epithelial cells (TECs). A unique domain within CTGF (IRTPKISKPIKFELSG) which binds to its potential receptor integrin alpha v beta3 has been identified. This study was carried out to further characterize a synthetic hexadeca-peptide (P2) homologous to this domain and to determine its effect on CTGF-mediated solid phase cell adhesion, EMT induction and fibrogenesis in rat renal NRK-52E cells. Results showed that both P2 and recombinant CTGF bound to NRK-52E cells. Unlike CTGF, P2 had little effect on EMT induction including cytoskeleton remodeling and expression of alpha-smooth muscle actin (alpha-SMA) and E-cadherin, nor did it have effect on fibrogenic induction including alternation of extracellular matrix (ECM) proteins, collagen type I and IV at gene and protein levels. All data showed that P2 bound preferably on the surface of NRK-52E cells and inhibited the effect of CTGF on EMT induction and cell fibrogenesis, probably by occupying the binding sites of CTGF within its potential receptors. Therefore, P2 may be used as a potential anti-fibrotic agent.

Heart and lung transplantation in children

During the past two decades, several advances have resulted in marked improvement in medium-term survival for infants and children undergoing heart transplantation. Unfortunately, progress has been less dramatic in the field of lung and heart-lung transplantation, where there is little evidence of improved outcomes. The procedures remain palliative and all transplant recipients are at risk for the adverse effects of non-specific immunosuppression, including infections, lymphoproliferative disorders, and non-lymphoid malignancies. In addition, current immunosuppressive agents have narrow therapeutic windows and exhibit a wide array of organ toxicities, posing special challenges for the young patient who must endure life-long immunosuppression. New immunosuppressive regimens have lowered the rates of acute rejection but appear to have had relatively little impact on the incidence of chronic rejection, the principal cause of late graft loss. The ultimate goal is to induce a state of donor-specific tolerance, wherein the recipient will accept the allograft indefinitely without the need for long-term immunosuppression. This quest is currently being realised in animal models of solid organ transplantation, and offers great hope for children undergoing heart and lung transplantation in the future.