Impact of hyperparathyroidism on allograft histology and function after kidney transplantation: Rethinking its causal role in graft dysfunction

INTRODUCTION

The causal relationship between hyperparathyroidism and kidney graft dysfunction remains inconclusive. Applying Bradford-Hill's temporality and consistency causation principles, we assessed the effect of parathyroid hormone (iPTH) on graft histology and eGFR trajectory on kidney transplant recipients (KTRs) with normal time-zero graft biopsies.

METHODS

Retrospective cohort study evaluating the effect of hyperparathyroidism on interstitial fibrosis and tubular atrophy (IF/TA) development in 1232 graft biopsies. Pre-transplant hyperparathyroidism was categorized by KDIGO or KDOQI criteria, and post-transplant hyperparathyroidism by iPTH >1× and >2× the URL 1 year after transplantation.

RESULTS

We included 325 KTRs (56% female, age 38 ± 13 years, follow-up 4.2 years [IQR: 2.7-5.8]). Based on pre-transplant iPTH levels, 26% and 66% exceeded the KDIGO and KDOQI targets, respectively. There were no significant differences in the development of >25% IF/TA between KTRs with pre-transplant iPTH levels above and within target range according to KDIGO (53% vs. 62%, P = .16, HR.94 [95% CI:.67-1.32]) and KDOQI (60% vs. 60%, P = 1.0, HR 1.19 [95% CI:.88-1.60]) criteria. Similarly, there were no differences when using 1 year post-transplant iPTH cut-offs > 88 pg/mL (58% vs. 64%, P = .33) and > 176 pg/mL (55% vs. 62%, P = .19). After adjusting for confounders, no significant differences were observed in eGFR trajectories among the iPTH strata.

CONCLUSION

In young KTRs who received a healthy graft, no association was found between increased pre- and post-transplant iPTH levels and graft dysfunction, as assessed histologically and through eGFR trajectory. The concept of hyperparathyroidism as a risk factor for graft dysfunction in recipients at low risk requires reevaluation.

Long-term effects of hypercalcemia in kidney transplant recipients with persistent hyperparathyroidism

BACKGROUND

Hypercalcemia is highly prevalent in kidney transplant recipients with hyperparathyroidism. However, its long-term impact on graft function is uncertain.

METHODS

We conducted a prospective cohort study investigating adverse graft outcomes associated with persistent hypercalcemia (free calcium > 5.2 mg/dL in ≥ 80% of measures) and inappropriately elevated intact parathyroid hormone (> 30 pg/mL) in kidney transplant recipients. Asymptomatic mild hypercalcemia was monitored unless complications developed.

RESULTS

We included 385 kidney transplant recipients. During a 4-year (range 1-9) median follow-up time, 62% of kidney transplant recipients presented persistent hypercalcemia. Compared to kidney transplant recipients without hypercalcemia, there were no significant differences in graft dysfunction (10% vs. 12%, p = 0.61), symptomatic urolithiasis (5% vs. 3%, p = 0.43), biopsy-proven calcium deposits (6% vs. 5%, p = 1.0), fractures (6% vs. 4%, p = 0.64), and a composite outcome of urolithiasis, calcium deposits, fractures, and parathyroidectomy indication (16% vs. 13%, p = 0.55). In a subset of 76 kidney transplant recipients, subjects with persistent hypercalcemia had higher urinary calcium (median 84 [43-170] vs. 38 [24-64] mg/day, p = 0.03) and intact fibroblast growth factor 23 (median 36 [24-54] vs. 27 [19-40] pg/mL, p = 0.04), and lower 25-hydroxyvitamin D levels (11.3 ± 1.2 vs. 16.3 ± 1.4 ng/mL, p < 0.001). In multivariate analysis, pretransplant intact parathyroid hormone < 300 pg/mL was associated with a reduced risk of post-transplant hypercalcemia (OR 0.51, 95% CI 0.32-0.80).

CONCLUSIONS

Long-term persistent mild hypercalcemia (tertiary hyperparathyroidism) was frequent in kidney transplant recipients in our series. This condition presented with lower phosphate and 25-hydroxyvitamin D, and higher urinary calcium and intact fibroblast growth factor 23 levels compared to kidney transplant recipients without hypercalcemia, resembling a mild form of primary hyperparathyroidism. Despite these metabolic derangements, the risk of adverse graft outcomes was low.

Antibodies for β2-Microglobulin and the Heavy Chains of HLA-E, HLA-F, and HLA-G Reflect the HLA-Variants on Activated Immune Cells and Phases of Disease Progression in Rheumatoid Arthritis Patients under Treatment

Rheumatoid arthritis (RA) is a progressive, inflammatory, autoimmune, symmetrical polyarticular arthritis. It is characterized by synovial infiltration and activation of several types of immune cells, culminating in their apoptosis and antibody generation against “altered” autoantigens. β2-microglobulin (β2m)-associated heavy chains (HCs) of HLA antigens, also known as closed conformers (Face-1), undergo “alteration” during activation of immune cells, resulting in β2m-free structural variants, including monomeric open conformers (Face-2) that are capable of dimerizing as either homodimers (Face-3) or as heterodimers (Face-4). β2m-free HCs uncover the cryptic epitopes that can elicit antibodies (Abs). We report here the levels of IgM and IgG Abs against both β2m and HCs of HLA-E, HLA-F, and HLA-G in 74 RA patients receiving immunosuppressive drugs. Anti-β2m IgM was present in 20 of 74 patients, whereas anti-β2m IgG was found in only 8 patients. Abs against β2m would be expected if Abs were generated against β2m-associated HLA HCs. The majority of patients were devoid of either anti-β2m IgM or IgG but had Abs against HCs of different HLA-Ib molecules. The paucity of anti-β2m Abs in this cohort of patients suggests that Abs were developed against β2m-free HLA HCs, such as Face-2, Face-3, and Face-4. While 63 of 68 patients had IgG Abs against anti-HLA-F HCs, 36 and 50 patients showed IgG Ab reactivity against HLA-E and anti-HLA-G HCs, respectively. Evidently, anti-HLA-F HC Abs are the most predominant anti-HLA-Ib HC IgG Abs in RA patients. The incidence and intensity of Abs against HLA-E, HLA-F, and HLA-G in the normal control group were much higher than those observed in RA patients. Evidently, the lower level of Abs in RA patients points to the impact of the immunosuppressive drugs on these patients. These results underscore the need for further studies to unravel the nature of HLA-F variants on activated immune cells and synoviocytes of RA patients.

Renal arterial resistive index, monocyte chemotactic protein 1 and neutrophil gelatinase-associated lipocalin, for predicting acute kidney injury in critically ill cancer patients

PURPOSE

We evaluated the renal arterial resistive index (RRI), urine monocyte chemotactic protein 1 (uMCP-1), and urine neutrophil gelatinase-associated lipocalin (uNGAL) to predict acute kidney injury (AKI) in critically ill cancer patients.

METHODS

In this prospective study, we included patients without AKI. We compared the area under the curve (AUC) of RRI, uMCP-1, and uNGAL to predict any stage of AKI and stage-3 AKI with the DeLong method, and we established cutoff points with the Youden index.

RESULTS

We included 64 patients, and 43 (67.2%) developed AKI. The AUC to predict AKI were: 0.714 (95% CI 0.587-0.820) for the RRI, 0.656 (95% CI 0.526-0.770) for uMCP-1, and 0.677 (95% CI 0.549-0.789) for uNGAL. The AUC to predict stage-3 AKI were: 0.740 (95% CI 0.615-0.842) for the RRI, 0.757 (95% CI 0.633-0.855) for uMCP-1, and 0.817 (95% CI 0.701-0.903) for uNGAL, without statistical differences among them. For stage 3 AKI prediction, the sensitivity and specificity were: 56.3% and 87.5% for a RRI > 0.705; 70% and 79.2% for an uMCP-1 > 2169 ng/mL; and 87.5% and 70.8% for a uNGAL > 200 ng/mL. The RRI was significantly correlated to age (r = 0.280), estimated glomerular filtration rate (r = - 0.259), mean arterial pressure (r = - 0.357), and serum lactate (r = 0.276).

CONCLUSION

The RRI, uMCP-1, and uNGAL have a similar ability to predict AKI. The RRI is more specific, while urine biomarkers are more sensitive to predict stage 3 AKI. The RRI correlates with hemodynamic variables. The novel uMCP-1 could be a useful biomarker that needs to be extensively studied.

A.L.L. Y.O.U. N.E.E.D. I.S. L.O.V.E. Manual on health self-management and patient-reported outcomes among low-income young adult Mexicans on chronic dialysis: Feasibility study

PURPOSE

We evaluated disease knowledge/self-management skills among low-income Mexican young adults maintained on dialysis and to test the effectiveness of the A.L.L. Y.O.U. N.E.E.D. I.S. L.O.V.E (AYNIL) Manual - Spanish Version on patient-reported outcomes. This is a low literacy teaching tool designed with patients and educators' input.

DESIGN AND METHODS

A quasi-experimental study was conducted in 17 chronic dialysis patients at Mexico City's Hospital General de México, Dr. Eduardo Liceaga. Ages 18-30-year-old completed disease knowledge/self-management and quality of life measures before the intervention and 6 weeks later.

RESULTS

Significant increases were observed on disease knowledge/self-management scores in the STARx questionnaire from 47 (IQ: 40,51) to 50 (IQ: 48,54) p = 0.04. The UNC-TRxANSITION Index increased significantly from 4.8 (IQ: 3.9,5.7) to 7.7 (IQ: 7.5,8.2) p ≤0.001. Significant increases in scores were detected in the "Burden of kidney disease" (p = 0.008), "Effects of kidney disease" " (p = 0.03) and " Dialysis staff encouragement" (p = 0.027) based on the KDQoL survey.

CONCLUSIONS

In this vulnerable population, the Spanish version of the A.L.L. Y.O.U. N.E.E.D. I.S. L.O.V.E. - AYNIL Manual improved CKD/ESRD disease knowledge/self-management skills and HRQoL. This study highlighted the need for low-literacy educational tools to improve patient-reported outcomes.

PRACTICE IMPLICATIONS

Young adults with CKD/ESRD can benefit from patient-centered educational interventions to enhance their autonomy and the development of self-management behaviors that improve patient-reported outcomes and potential complications of the disease. Special attention is needed in low-income patients with low rates of adherence to treatments and poor self-management skills.

Incidence of cervical intraepithelial lesions and human papilloma virus infection in female renal transplant recipients

BACKGROUND

Female renal transplant recipients (RTR) are at high risk of human papillomavirus (HPV)-related anogenital premalignancies and cancer. The aim of this study was to estimate the incidence of cervical intraepithelial lesions (IL) and HPV infection, and their associated factors, in Mexican RTR.

METHODS

This is a prospective cohort study conducted between January 2011 and December 2017. Demographic, clinical, and gynecological data were collected using a previously designed questionnaire. Gynecological examination, cervical cytology, and detection of high- and low-risk HPV DNA were undertaken prior to and after the renal transplant (RT). Colposcopically guided biopsies were obtained from patients who presented high grade squamous intraepithelial lesions (HSIL) during the follow-up period. Diagnoses were established according to the Bethesda system.

RESULTS

Among 130 RTR, 62 were eligible for our study. The overall incidence of IL was 17.7% (95% CI, 8% to 27%), (11/62 patients), at 25.6 ± 10.7 months post-RT. Nine out of the eleven affected patients had low-grade squamous intraepithelial lesions (81.8%) and only two had HSIL (18.2%). The incidence of HPV infection, determined in a subgroup of 30 RTR, was 53.3% (95% CI, 35% to 71%), (16 out of 30 patients), at 18.3 ± 8.9 months post-RT. High-risk HPV genotypes were present in 62.5% of HPV positive cases (10/16). In 11 patients (36.6%), HPV infection was not associated to IL.

CONCLUSIONS

HPV infection and cervical IL are common in the early posttransplant period. Our findings support the need of screening for cervical cancer to detect precancerous changes in RTR and the need of strengthening the knowledge of medical personnel on this issue.

Evaluation of cerebral dysfunction in patients with chronic kidney disease using neuropsychometric and neurophysiological tests

Background

Uremic encephalopathy is defined as cerebral dysfunction due to toxin accumulation in patients with chronic kidney disease (CKD). This condition is characterized by subtle to florid symptoms, and its clinical course is always progressive when untreated but partially reversible with renal replacement therapy. While no test exists to measure subclinical uremic encephalopathy, two tests have been validated to measure minimal hepatic encephalopathy: the critical flicker frequency (CFF) test and the psychometric hepatic encephalopathy score (PHES).

Objective

To use CFF and PHES to measure the prevalence of cerebral dysfunction in individuals with CKD.

Methods

This cross-sectional study included a total of 69 patients with stage-5 CKD. Cutoff points for minimal encephalopathy were established using existing clinical guidelines: ≤39 Hz for CFF and < −4 for PHES. All participants were also screened for cognitive function and depression.

Results

Eighteen cases (26.1%) of cerebral dysfunction linked to uremic encephalopathy were detected with CFF, while twelve (17.4%) were detected by PHES; only six cases (8.7%) were diagnosed by both methods. Half of the cases (50%) had diabetes, and 61% were on hemodialysis. Cognitive function scores did not differ significantly between those receiving dialysis, hemodialysis, or no renal replacement therapy.

Conclusions

It is essential to identify cerebral dysfunction when uremic encephalopathy is in early subclinical stages to reduce preventable events as traffic and work accidents.

TRPV4: A Physio and Pathophysiologically Significant Ion Channel

Transient Receptor Potential (TRP) channels are a family of ion channels whose members are distributed among all kinds of animals, from invertebrates to vertebrates. The importance of these molecules is exemplified by the variety of physiological roles they play. Perhaps, the most extensively studied member of this family is the TRPV1 ion channel; nonetheless, the activity of TRPV4 has been associated to several physio and pathophysiological processes, and its dysfunction can lead to severe consequences. Several lines of evidence derived from animal models and even clinical trials in humans highlight TRPV4 as a therapeutic target and as a protein that will receive even more attention in the near future, as will be reviewed here.

Angiotensin II receptor agonist antibodies are associated with microvascular damage in lupus nephritis

Angiotensin II type 1 receptor agonist antibodies (AT1R-AAs) have been associated with hypertension, atherosclerosis and vascular inflammation in human diseases. The aim of the study was to evaluate the prevalence of AT1R-AAs in active lupus nephritis (LN) patients and their association with vascular damage. One hundred and seven active LN patients underwent a complete clinical examination, measurement of AT1R-AAs, ambulatory blood pressure monitoring, carotid intima-media thickness measurement and morphometric analysis of subintimal fibrosis and medial hyperplasia of the vessels in the kidney tissue. Plasma AT1R-AAs were positive in 58 (54.2%) patients. The Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, complement C3 and C4 levels and titers of anti-dsDNA antibodies were higher in the group with positive AT1R-AAs compared with those with negative AT1R-AAs. The AT1R-AA titers correlated with anti-dsDNA antibody titers and with complement C3 and C4 serum levels. In the kidney biopsy, the percentage of subintimal fibrosis and the area of medial hyperplasia were greater in the AT1R-AA-positive patients. No differences in arterial pressure, carotid intima-media thickness and response to therapy were detected. In conclusion, AT1R-AAs are prevalent in active LN patients and are associated with histologic features of microvascular damage.

Spironolactone reduces oxidative stress in living donor kidney transplantation: a randomized controlled trial

Mineralocorticoid receptor antagonism prevents acute kidney injury induced by ischemia-reperfusion in rodent and pig preclinical models. In a pilot study, we showed that spironolactone (25 mg) reduced oxidative stress after 5 days of kidney transplant (KT). In the present study, we investigated the effects of higher doses (50 and 100 mg) of spironolactone on kidney function, tubular injury markers, and oxidative stress in living donor KT recipients. We included KT recipients aged 18 yr or older who received immunosuppression therapy with IL-2 receptor antagonist, mycophenolate mofetil, corticosteroids, and tacrolimus with negative cross-match, and compatible blood group. Patients were randomized to receive placebo ( n = 27), spironolactone (50 mg, n = 25), or spironolactone (100 mg, n = 25). Treatment was given from 3 days before and up to 5 days after KT. Serum creatinine, K+, urine neutrophil gelatinase-associated lipocalin-2, heat shock protein 72, and 8-hydroxy-2-deoxyguanosine levels were assessed. As expected, kidney function was improved after KT. Serum K+ remained in the normal range along the study. There was no significant effect of spironolactone on urinary neutrophil gelatinase-associated lipocalin-2 levels, whereas the increase in urinary heat shock protein 72 levels tended to be less intense in the 100 mg spironolactone-treated group ( P = 0.054). In the placebo-treated group, urinary 8-hydroxylated-guanosine levels increased on days 3 and 5 after transplantation. This effect was prevented in patients that received spironolactone. In conclusion, spironolactone reduces the acute increase in urinary oxidative stress in living donor KT recipients.

Is delayed graft function associated with ureteral stenosis in the kidney transplant recipient? A case-control study

INTRODUCTION

Ureteral stricture (US) in the kidney transplant recipient is a rare complication that can lead to morbidity and graft loss. Risk factor recognition is crucial in the prevention and management of this entity. Delayed graft function (DGF), as defined by the need for dialysis in the first week after transplantation, has been proposed as a risk factor in previous studies. Our objective is to determine the impact of DGF in US development in kidney transplant patients.

METHODS

We designed a matched case-control study. US cases in kidney transplant recipients were identified in the 2008-2017 period. We defined US as the rise in serum creatinine associated with findings suggesting obstruction in ultrasound, scintigraphy, or retrograde pyelogram; any other cause of graft dysfunction was excluded. Controls were defined as kidney transplant recipients from the same population and period without US, matched in a 1:2 fashion by age, sex, and donor type.

RESULTS

From 532 kidney transplant patients, 31 cases and 62 controls were included. Cumulative US incidence was 58 per 1000 cases. When calculating for odds ratio (OR), post-operative urinoma (OR 3.2; 95% confidence interval [CI] 2.36-4.37) and ureteral duplication (OR 3.29; 95% CI 2.40-4.51) were associated with an increased risk for US, while DGF was not found to be statistically significant as a risk factor (OR 3.3; 95% CI 0.96-11.52). No statistically significant differences were found between groups in other pre- and post-transplant-related factors CONCLUSIONS:: DGF was not associated with US in our cohort; however, ureteral duplication and postoperative urinoma were associated with an increased risk of graft ureteral stenosis development.

Long-term survival of kidney grafts in lupus nephritis: a Mexican cohort

Kidney transplant for patients with lupus nephritis (LN) has satisfactory outcomes in studies with short-term or mid-term follow up. Nevertheless, information about long-term outcomes is scarce. We performed a retrospective matched-pair cohort study in 74 LN recipients compared with 148 non-LN controls matched by age, sex, immunosuppressive treatment, human leukocyte antigen (HLA) matches, and transplant period in order to evaluate long-term outcomes of kidney transplant in LN recipients. Matched pairs were predominantly females (83%), median age at transplant surgery of 32 years (interquartile range 23–38 years), and 66% received a graft from a living related donor. Among LN recipients, 5-, 10-, 15-, and 20-year graft survival was 81%, 79%, 57% and 51%, respectively, and it was similar to that observed in controls (89%, 78%, 64%, and 56%, respectively). Graft loss (27% vs. 21%, p = 0.24) and overall survival ( p = 0.15) were not different between LN recipients and controls. Also, there was no difference in episodes of immunological rejection, thrombosis, or infection. Only six LN recipients had biopsy-proven lupus recurrence and three of them had graft loss. In a cohort with a long follow up of kidney transplant recipients, LN recipients had similar long-term graft survival and overall outcomes compared with non-lupus recipients when predictors are matched between groups.

Prognostic significance of renal vascular pathology in lupus nephritis

We performed a retrospective cohort analysis to define the prognostic significance of vascular lesions documented in renal biopsies of lupus nephritis patients. A total of 429 patients were segregated into five groups: (1) no vascular lesions (NVL), (2) arterial sclerosis (AS), (3) non-inflammatory necrotizing vasculitis (NNV), (4) thrombotic microangiopathy (TMA), and (5) true renal vasculitis (TRV). Renal outcomes were analyzed by Cox regression models, and correlations between vascular lesions and activity/chronicity scores were determined by Spearman's coefficients. A total of 200 (46.6%) had NVL, 189 (44.0%) AS, six NNV (1.4%), 23 (5.4%) TMA, and 11 (2.6%) TRV. Patients with NVL were younger, with higher renal function; patients with TMA and TRV had lower renal function and higher arterial pressure at baseline. Antiphospholipid syndrome and positive lupus anticoagulant were more frequently observed in the TMA group. Five-year renal survival was 83% for NVL, 63% for AS, 67% for NNV, 31% for TMA, and 33% for TRV. NNV and TRV were significantly correlated with activity scores, while AS and chronic TMA were correlated with chronicity scores. Renal vascular lesions are associated with renal outcomes but do not behave as independent factors. The addition of vascular lesions to currently used scores should be further explored.

Renal flare prediction and prognosis in lupus nephritis Hispanic patients

We performed a retrospective cohort analysis focusing on lupus nephritis renal flare incidence and outcome predictors. One hundred and eighteen patients with biopsy-proven lupus nephritis were segregated by induction/maintenance regimes. The primary outcome was the proportion of patients experiencing renal flare. Secondary assessment included doubling of serum creatinine and development of end-stage renal disease. After a median follow-up of 31 months (interquartile range 21–46) from the date of response to induction therapy, 47 patients (39.8%) developed a renal flare. Azathioprine-maintained patients had a higher risk of renal flare compared with mycophenolate mofetil-maintained patients (hazard ratio 2.53, 95% confidence interval 1.39–4.59, p < 0.01). Age (hazard ratio 0.96, 0.92–0.99, p = 0.03), serum creatinine at presentation (hazard ratio 1.76, 1.13–2.76, p = 0.01), complete remission after induction therapy (hazard ratio 0.28, 0.14–0.56, p < 0.001) and azathioprine maintenance therapy (hazard ratio 4.78, 2.16–10.6, p < 0.001) were associated with renal flare on multivariate analysis. Ten patients progressed to end-stage renal disease (8.5%) by a median 32.5 months. Age (hazard ratio 0.88, 0.77–0.99, p = 0.05), complete remission after induction therapy (hazard ratio 0.08, 0.01–0.94, p = 0.04) and severe nephritic flare (hazard ratio 13.6, 1.72–107.7, p = 0.01) were associated with end-stage renal disease development. Azathioprine maintenance therapy is associated with a higher incidence of relapse in the Mexican-mestizo population. Younger age and nephritic flares predict development of end-stage renal disease.

Comparison of Lupus Nephritis Induction Treatments in a Hispanic Population: A Single-center Cohort Analysis

OBJECTIVE

To evaluate response rates in an adult lupus nephritis (LN) cohort in Mexico City, Mexico.

METHODS

We analyzed 165 patients with biopsy-proven LN histological International Society of Nephrology/Renal Pathology Society classes III, IV, or V, distributed by treatment drug in 3 groups: mycophenolate mofetil (MMF; dosage > 2 g/day per 6 mos, n = 63), intravenous cyclophosphamide (IVC; 0.7 g/m(2) body surface area monthly per 6 pulses, n = 66), or azathioprine (AZA; dosage > 1.5 mg/kg/day per 6 mos, n = 36). Median followup was 31 ± 18 months. The primary endpoint was the proportion of patients achieving complete renal response (CR). Secondary endpoints included the proportion of patients achieving renal response (complete or partial), renal flare-free survival, doubling of serum creatinine, and progression to endstage renal disease (ESRD).

RESULTS

MMF induction was superior to IVC (HR 2.00, 95% CI 1.23-3.25, p = 0.005) and AZA (HR 2.12, 95% CI 1.23-3.66, p = 0.007) in the primary endpoint. Censored CR rates at 6, 12, 24, and 36 months were 32.6%, 56.1%, 76.6%, and 94.1% for MMF; 24.2%, 34.4%, 57.9%, and 62.1% for IVC; and 8.4%, 39.8%, 49.7%, and 49.7% for AZA. MMF was also superior in renal response to treatment and renal flare-free survival outcomes. There were no differences between groups in doubling of serum creatinine or progression to ESRD. The induction treatment with MMF (HR 2.04, 95% CI 1.25-3.33, p = 0.005) and absence of vascular lesions on renal biopsy (HR 2.05, 95% CI 1.25-3.37, p = 0.004) were associated with CR, whereas proteinuria at the time of presentation was negatively associated with CR (HR 0.91, 95% CI 0.84-0.98, p = 0.013).

CONCLUSION

MMF induction therapy is superior to IVC and AZA in patients with LN of Mexican-mestizo race.

[Incidence of acute rejection in patients with renal graft dysfunction]

INTRODUCTION

Acute rejection has been identified as the main cause of renal graft dysfunction during the first year after transplantation; it is associated with chronic structural and functional damage, which causes loss of graft and decrease in patient survival.

MATERIAL AND METHODS

We performed a retrospective and descriptive research consisting in a review of the final reports of biopsies performed due to renal graft dysfunction during the postransplant period. Patients included were transplanted at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ) from January 2007 to December 2011.

RESULTS

A total number of 223 patients underwent renal transplantation during the period considered for this study purpose, 222 biopsies were performed due to renal graft dysfunction in 118 patients (52.9%). 74.5% of patients developed graft dysfunction in the first year after transplantation. The main histopathological findings reported were immunologic events in both living donor (LDRTR) and deceased donor renal transplant recipients (DDRTR), borderline changes were the most common diagnosis. The median time to detect immune events as cause of dysfunction was shorter for DDRTR and they tend to occur in the first 4 months after transplantation.

CONCLUSION

We observed an incidence of 11.8% for acute rejection in the first year after transplantation for LDRTR and 17.4% for DDRTR. Further studies are needed to determine the causes of immunological events and their implications in the evolution of renal graft and patient's survival.

Probability of deceased donor kidney transplantation based on % PRA

Sensitization to HLA antigens creates an obstacle for the accessibility and success of kidney transplantation (KT). Highly sensitized patients have longer waiting times and some may never receive a KT.

AIM

To determine the probability of patients on the deceased donor (DD) waiting list to receive a KT based on the panel reactive antibody percentage (% PRA) in our center.

METHODS

The DD waiting list from our institution was analyzed from 01/05 to 08/12 documenting the clinical variables from donor and potential recipients (ABO blood group), lymphocyte cross-match [CxM (CDC-AHG)] results, highest % PRA determination, and time on the waiting list. The patients were classified into 4 groups based on the % PRA: 0%, 1-19%, 20-79% and 80-100%. The data was analyzed using odds ratio and logistic regression (significant p<0.05).

RESULTS

58 DD (F:M 34:24, ABO group O=35, A=13, B=10) and 179 potential recipients were analyzed (F:M 98:81, ABO group O=127, A=33, B=19, participating 4.2 ± 3.8 times with different donors to receive KT). The mean PRA for the whole group was 22 ± 32%, median [md] 0 (0-98). A total of 100 patients received KT (mean waiting time 2.2 ± 1.7 years, 12 days-7 years) and their mean % PRA was 11.6 ± 24, md 0 (0-94) vs. 31.4 ± 37 md 8.5 (0-98) in those who have not received a KT. An association between the % PRA group and KT (p<0.003) was observed. The probability of receiving KT with a 0% PRA vs. >0% was higher (OR 2.12, 1.17-3.84). There was no difference between the 0% vs. 1-19% group (OR 1); differences were observed between 0% vs. 20-79% (OR 2.5, 1.18-5.3) and 0% vs. 80-100% (OR 5, 1.67-14.9). For every percent increase in the PRA above 20%, the risk of not receiving a KT increased by 5% (1-9, p<0.01).

CONCLUSIONS

The probability of receiving a DD kidney transplant is inversely related to the % PRA although a higher risk for not receiving a KT becomes evident with a PRA >20%.

Mineralocorticoid receptor blockade reduced oxidative stress in renal transplant recipients: a double-blind, randomized pilot study

BACKGROUND

Previous experimental studies from our laboratory have demonstrated that aldosterone plays a central role in renal ischemic processes. This study was designed to evaluate the effect of mineralocorticoid receptor blockade in renal transplant recipients from living donors.

METHODS

20 adult kidney transplant recipients from living donors were included in a double-blind, randomized, placebo-controlled clinical pilot study that compared spironolactone and placebo. Placebo or spironolactone (25 mg) was administered 1 day before and 3 days posttransplantation. Renal function and urinary kidney injury molecule-1, interleukin-18, and heat shock protein 72 as well as urinary hydrogen peroxide (H2O2) levels were quantified.

RESULTS

No significant differences were seen between the groups studied regarding age, gender, indication for kidney transplantation, residual renal function, renal replacement therapy, or warm and cold ischemia periods. In contrast, spironolactone administration significantly reduced the oxidative stress assessed by the urinary H2O2 excretion, in spite of no differences in renal function or reduction in tubular injury biomarkers.

CONCLUSIONS

The findings of this exploratory study strongly suggest that aldosterone promotes oxidative stress and that the administration of spironolactone reduces the production of urinary H2O2 as a result of lesser formation of surrogate reactive oxygen species secondary to the ischemia-reperfusion phenomenon.

Infiltrating cellular pattern in kidney graft biopsies translates into forkhead box protein 3 up-regulation and p16INK4α senescence protein down-regulation in patients treated with belatacept compared to cyclosporin A

Renal allograft survival is related directly to cell senescence. In the transplantation scenario many cellular events - participating as immunological and non-immunological factors - could contribute to accelerate this biological process, responsible for the ultimate fate of the graft. Mechanisms concerned in tolerance versus rejection are paramount in this outcome. For this reason, immunosuppressive treatment constitutes an extremely important decision to prevent organ dysfunction and, finally, graft loss. This study was conducted to document the proportion of CD4(+) /interleukin (IL)-17A(+) -, CD16(+) /indoleamine 2, 3-dioxygenase (IDO(+) )-, forkhead box protein P3 (FoxP3(+))-expressing cells, senescent cells (p16(INK) (4α)) and the percentage of interstitial fibrosis (IF) in graft biopsies of kidney transplant recipients participating in the BENEFIT (Bristol-Myers Squibb IM103008) study. CD4(+) /IL-17A(+) , CD16(+) /IDO(+), FoxP3(+) and p16(INK) (4α+) cells were evaluated by immunohistochemistry, and the percentage of IF by morphometry on graft biopsies obtained at time 0 (pre-implantation) and at 12 months post-transplant. Senescent cells and CD4(+) /IL-17A(+) cells were increased among graft biopsies in subjects receiving cyclosporin A (CsA) compared to those under belatacept treatment. Meanwhile, CD16(+) /IDO(+) and FoxP3(+) -expressing cells were lower in biopsies from CsA treatment compared to patients treated with Belatacept. Histological morphometric analyses disclosed more IF in 12-month CsA-treated patients in comparison to pre-implantation biopsy findings. Summing up, renal biopsies from patients receiving belatacept showed greater amounts of FoxP3(+) cells and lower amounts of CD4(+) /IL-17A(+) and senescent cells compared to patients under CsA treatment. Along with these findings, an increase in IF in annual CsA-treated-patients biopsies compared to pre-implantation and belatacept-treated patients were observed.

Immune response after rabies vaccine in a kidney transplant recipient

A 48-year-old male kidney-transplant recipient was bitten by a rabid dog. His immunosuppressive treatment consisted of cyclosporine 60 mg b.i.d., mycophenolate mofetil (MMF) 250 mg t.i.d., and prednisone 5 mg. After wound care, he received 5 doses of purified vero cell rabies vaccine on days 0, 3, 7, 14, and 28, and human rabies immunoglobulin, according to international guidelines. Adequate levels of rabies virus neutralizing antibodies were observed after the administration of the third vaccine dose. However, a decrease of antibody titer was detected by day 28. Immunosuppressive medication was minimized, withdrawing MMF and reducing the dose of cyclosporine. Booster doses of the same vaccine were administered on days 38, 41, 45, 52, and 66. Adequate neutralizing antibody response was recovered during the ensuing 12 months, under reduced immunosuppression. Nineteen months after the incident, the patient remains with good graft function and is asymptomatic for rabies. It remains to be determined whether the attained immune response was either the result of the booster vaccinations or the reduction of immunosuppression alone. Nevertheless, such an outcome would have been possible only with the combined management strategy implemented.

[Kidney transplantation: consecutive one thousand transplants at National Institute of Medical Sciences and Nutrition Salvador Zubirán in Mexico City]

INTRODUCTION

The National Institute of Medical Sciences and Nutrition Salvador Zubiran (INCMNSZ) is a specialty hospital for adults and a teaching hospital, which performed the first kidney transplant in 1967; in 1971 it began the formal program of renal transplantation. Recently, it was performed the kidney transplant number 1000, so this article presents the information of these thousand kidney transplants, with special emphasis on survival.

MATERIAL AND METHODS

Retrospective cohort study which included 1000 consecutive transplants performed at the INCMNSZ between 1967 and June 2011. It describes the general characteristics of kidney transplant recipients, transplant-related variables, initial immunosuppression and complications. Descriptive statistics were used. The survival analysis was performed using the Kaplan-Meier method. It shows the patient survival, graft survival censored for death with functional graft and total graft survival (uncensored).

RESULTS

Patient survival at 1, 3, 5, 10, 15, and 20 years was 94.9, 89.6, 86.8, 76.9, 66.1, and 62.2%, respectively. Graft survival censored for death with functional graft at 1, 3, 5, 10, 15, and 20 years was 93.1, 87.1, 83.5, 73.9, 62.7, and 52.5% respectively. Risk factors associated with poorer graft survival were younger age of the recipient, transplant during the first period (1967-1983), and a HLA mismatch.

CONCLUSION

Patient and graft survival have improved over time through the use of better immunosuppression and use of induction therapy. Identification of risk factors affecting graft survival, allows each center to set their strategies to improve the patient's outcome.

Parameters of Doppler ultrasound at five days posttransplantation as predictors of histology and renal function at one year

INTRODUCTION

In our center, a Doppler ultrasound (DU) is performed at 5 days after transplantation. The normal upper limit of flow velocity (FV) in the renal artery is 200-250 cm/s. The resistance index (RI) is considered elevated when >0.8. Elevation of the RI can be shown in all the forms of graft dysfunction.

OBJECTIVE

The objective of this study was to evaluate the capacity of the DU to predict the prognosis of graft function and histological damage at 1 year.

METHODS

We examined a retrospective cohort of patients undergoing renal transplantation between January 2004 and May 2007. The renal function was evaluated with serum creatinine measurements and glomerular filtration rate (GFR) estimates by the quadratic Modification of Diet in Renal Disease study equation. The biopsy specimen was evaluated according to the Banff 1997 classification.

RESULTS

The overall average age was 35 years, and 58% of the subjects were men. Eight cases (25.8%) showed abnormal DU. The Delta among those with normal DU was -0.94 versus 0.27 +/- 0.39 with abnormal DU (P < .005). There was no significance as far as the biopsy at 1 year.

CONCLUSIONS

Renal DU allows physicians to suspect complications at the first posttransplantation year. It shows a tendency to elevated blood pressure, as well as increased deterioration of renal function over the first year.

[Clinical and laboratorial predictors related to progression to chronic kidney disease in patients with autosomal dominant polycystic kidney disease]

OBJECTIVE

To determine clinical and laboratorial factors related to progression to chronic kidney disease in patients with autosomal dominant polycystic kidney disease (ADPKD).

MATERIAL AND METHODS

Retrolective cohort. We reviewed the files of patients with diagnosis of ADPKD between 1980 and 2008. We collected demographic, clinical and laboratory data. The primary endpoint was the development of advanced kidney disease (GFR estimated < 15 mL/min with MDRD, renal replacement therapy or kidney transplantation). The Cox proportional hazards model was used to investigate the effect of clinical and laboratorial covariates on the progression to advanced kidney disease.

RESULTS

Advanced chronic kidney disease developed in 37.4% (n = 34) of the patients with median survival renal of 57 years (IC95% 50.3-63.8). Variables associated with progression to advanced chronic kidney disease in the multivariate analysis were the levels of serum creatinine (HR = 1.59 IC95% 0.99-2.55 p = 0.05) and dyslipidemia (HR = 3.40; IC95% 1.23-9.39; p = 0.01).

CONCLUSIONS

Progression to advanced chronic renal failure was common in our population and the predicting factors for progression were the levels of serum creatinine and dyslipidemia.

Anti-major histocompatibility complex class I-related chain A antibodies in organ transplantation

Candidate trigger antigens for alloreactive responses have been appearing continuously in the organ transplant scenario. Major histocompatibility complex class I-related chain A (MICA) is a polymorphic gene family, located near the HLA-B locus on chromosome 6, that encode a 62-kd cell surface glycoprotein. Endothelial cells, in addition to many cell lines, express MICA, whereas resting lymphocytes do not, making this polymorphic molecule a target for both cellular and humoral immune responses. Major histocompatibility complex class I-related chain A antigens are able to elicit the synthesis of alloantibodies in transplant recipients. These antibodies have been found in association with irreversible allograft rejection, an increased frequency of acute rejection episodes, and a significantly lower deceased donor graft survival, as well as in the eluates from rejected grafts. This review summarizes currently available information on MICA in the transplant setting. Undoubtedly, the questions that have surfaced surpass in excess the currently available answers.

Prevalence of HLA Antibodies and Its Impact on Graft Function in a Group of Kidney Transplant Recipients: A Cross-Sectional Study

HLA alloantibodies (Abs) are associated with chronic rejection and poorer graft survival. The current study was designed to document the prevalence of HLA Abs in a group of kidney transplant recipients (KTR) and its impact on graft function.

PATIENTS AND METHODS

283 KTR transplanted between January 1990 and December 2003 who had a functional graft were invited to participate. 198 KTR were enrolled. HLA class I and II Abs were measured by Luminex-One Lambda. Graft function was assessed by DeltaCr and GFR calculated by the Levey formula.

RESULTS

Median post-kidney transplant (post-KT) follow-up was 51.4 (4.3 to 176.3) months. Forty-four (22.2%) KTR were found to have class I and/or class II Abs. Eleven had both class I and II Abs, ten were positive only for class I, and 23 for class II. Overall, no significant difference was seen in renal function. The DeltaCr for Ab positive and Ab negative were -0.24+/-0.84 and -0.17+/-0.60 mg/dL (P=0.54), respectively. The GFR for Ab positive and Ab negative were 64.4+/-26 and 60.2+/-20 mL/min (P=0.25), respectively. No statistically significant difference was found between HLA Abs and number of HLA mismatches, gender, blood transfusions, pre-KT pregnancies, DGF, history of acute rejection, and chronic allograft nephropathy. Adjusting analysis by transplant year showed no significant difference.

CONCLUSION

The prevalence of HLA antibodies was similar to previous reports. In this cross-sectional study, the presence of HLA antibodies was not related to a negative impact on renal function.

Effect of rapamycin on cytokine profile in kidney transplant recipients treated with triple drug therapy

The aim of this study was to explore differences in the cytokine profile among de novo kidney transplant recipients treated with either Rapamycin (Rapa) + cyclosporine (CsA) + prednisone (P) or CsA + azathioprine (Aza) + P.

PATIENTS AND METHODS

Among the 13 adult kidney transplant recipients studied, seven received Rapa + CsA + P while the remaining six received CsA + Aza + P with their living donors serving as controls (n = 13). Spontaneous production of IL-2, IFNgamma, IL-10, and TGF-beta were measured by ELISA in supernatants from 24-hour cultured unstimulated peripheral blood mononuclear cell (PBMC) at time zero (the day before the transplant), and at 3 and 6 months posttransplant. Cytokines were also measured 1 month after CsA withdrawal in the Rapa + CsA + P group.

RESULTS

From time zero to the end of the study, IL-2, IFNgamma, and IL-10 were present at low or undetectable levels in all three groups. TGF-beta tended to increase in supernatants from patients under Rapa + CsA + P at 6 months posttransplant and at 1 month after CsA withdrawal without correlation to Rapa blood levels. TGF-beta remained stable throughout the study period for patients included in the CsA + Aza + P group. There was no difference in this cytokine level between these study groups at any given time.

CONCLUSIONS

This study showed no differences in the spontaneous cytokine profiles evaluated in patients treated with both therapeutic schemes.

[Pontine myelinolysis after a hypoglycemic episode]

A case of central pontine myelinolysis following hypoglycemia is reported. The case was a 26- year-old female. Diabetes mellitus was found when she was 8 years old and she has hypertension and renal failure. She suffered a severe hypoglycemia at an unknown time. After the episode she developed a vegetative state. A magnetic resonance scan showed features consistent with the presence of central pontine myelinolysis.