Development and Validation of a Prediction Model for Future Estimated Glomerular Filtration Rate in People With Type 2 Diabetes and Chronic Kidney Disease.

Importance: Type 2 diabetes increases the risk of progressive diabetic kidney disease, but reliable prediction tools that can be used in clinical practice and aid in patients' understanding of disease progression are currently lacking. Objective: To develop and externally validate a model to predict future trajectories in estimated glomerular filtration rate (eGFR) in adults with type 2 diabetes and chronic kidney disease using data from 3 European multinational cohorts. Design, Setting, and Participants: This prognostic study used baseline and follow-up information collected between February 2010 and December 2019 from 3 prospective multinational cohort studies: PROVALID (Prospective Cohort Study in Patients with Type 2 Diabetes Mellitus for Validation of Biomarkers), GCKD (German Chronic Kidney Disease), and DIACORE (Diabetes Cohorte). A total of 4637 adult participants (aged 18-75 years) with type 2 diabetes and mildly to moderately impaired kidney function (baseline eGFR of ≥30 mL/min/1.73 m2) were included. Data were analyzed between June 30, 2021, and January 31, 2023. Main Outcomes and Measures: Thirteen variables readily available from routine clinical care visits (age, sex, body mass index; smoking status; hemoglobin A1c [mmol/mol and percentage]; hemoglobin, and serum cholesterol levels; mean arterial pressure, urinary albumin-creatinine ratio, and intake of glucose-lowering, blood-pressure lowering, or lipid-lowering medication) were selected as predictors. Repeated eGFR measurements at baseline and follow-up visits were used as the outcome. A linear mixed-effects model for repeated eGFR measurements at study entry up to the last recorded follow-up visit (up to 5 years after baseline) was fit and externally validated. Results: Among 4637 adults with type 2 diabetes and chronic kidney disease (mean [SD] age at baseline, 63.5 [9.1] years; 2680 men [57.8%]; all of White race), 3323 participants from the PROVALID and GCKD studies (mean [SD] age at baseline, 63.2 [9.3] years; 1864 men [56.1%]) were included in the model development cohort, and 1314 participants from the DIACORE study (mean [SD] age at baseline, 64.5 [8.3] years; 816 men [62.1%]) were included in the external validation cohort, with a mean (SD) follow-up of 5.0 (0.6) years. Updating the random coefficient estimates with baseline eGFR values yielded improved predictive performance, which was particularly evident in the visual inspection of the calibration curve (calibration slope at 5 years: 1.09; 95% CI, 1.04-1.15). The prediction model had good discrimination in the validation cohort, with the lowest C statistic at 5 years after baseline (0.79; 95% CI, 0.77-0.80). The model also had predictive accuracy, with an R2 ranging from 0.70 (95% CI, 0.63-0.76) at year 1 to 0.58 (95% CI, 0.53-0.63) at year 5. Conclusions and Relevance: In this prognostic study, a reliable prediction model was developed and externally validated; the robust model was well calibrated and capable of predicting kidney function decline up to 5 years after baseline. The results and prediction model are publicly available in an accompanying web-based application, which may open the way for improved prediction of individual eGFR trajectories and disease progression.

[High patient unawareness for chronic kidney disease even in later stages - but why is it more frequent in women than in men?] / Eine chronische Niereninsuffizienz, auch in höherem Stadium, ist Patienten häufig unbekannt ­ aber warum wissen Frauen noch seltener von ihrer Erkrankung als Männer?

INTRODUCTION: Chronic kidney failure (CKD) is as common as diabetes or coronary heart disease in a population aged 40 years and older. Although CKD increases the risk of secondary diseases or premature death, patients with CKD are often unaware of their disease. In a recent analysis of German data, unawareness CKD was higher in women than in men. METHODS: Baseline data from 2010 of 3,305 CKD patients from German cohort studies and registries were analyzed. Stage 1-4 CKD was defined by eGFR (estimated glomerular filtration rate) and albumin-creatinine ratio according to the KDIGO-guideline. Patient knowledge of CKD was coded according to self-report. The proportion of patients without knowledge of CKD and the sex-specific proportion difference (each with 95 % confidence interval) were calculated according to CKD stages and additional comorbidities (diabetes, hypertension, anemia, and cardiovascular disease). In addition, the prevalence ratio (PR) for not knowing about CKD was estimated for women compared to men crude and adjusted for age and other risk factors. RESULTS: Women were less likely than men to know about their CKD in all subgroups studied by age, CKD stage, and comorbidities. The proportion difference for CKD awareness increased with higher CKD stage and was 21 percentage points (7.6; 34.6) at the expense of women in CKD stage 4. Among patients with CKD stage 3b and concomitant grade 2 hypertension, 61 % of women versus 45 % of men were unaware of their disease. The PR for CKD unawareness in women compared with men in the fully adjusted model increased from 1.08 (1.00; 1.16) in CKD stage 3a to 1.75 (1.14; 2.68) in CKD stage 4. CONCLUSION: Despite the presence risk factors that necessitate monitoring of renal function, less than half of patients know they have CKD stage 3b or 4. Women are less likely to be aware of their CKD in all subgroups. Possible causes are gender-related differences in primary health care (gender bias) or in patient-doctor communication.

Long-Term Weight Change and Glycemic Control in Patients With Type 2 Diabetes Mellitus and Treated vs. Untreated Sleep-Disordered Breathing-Analysis From the DIAbetes COhoRtE.

Hypothesis: Positive airway pressure (PAP) is the standard treatment for sleep-disordered breathing (SDB), a prevalent condition in patients with type 2 diabetes mellitus (DM2). Recent studies showed that short-term PAP treatment may cause weight gain. However, long-term data for patients with DM2 are scarce. Therefore, the aim of the present analysis was to assess changes in weight and glycemic control in patients with DM2 and treated vs. untreated SDB. Methods: The DIAbetes COhoRtE (DIACORE) study is a prospective population-based cohort study in patients with DM2. At baseline, patients of the DIACORE-SDB sub-study were tested for SDB [defined as apnea-hypopnea-index (AHI) ≥ 15/h] using a two-channel ambulatory SDB-monitoring device. In this observational study, PAP treatment was initiated in a subgroup of patients with SDB (SDB PAP) within clinical routine between the baseline and first follow-up visit [median observation period of 2.3 (2.2; 2.4) years], whereas the other patients with SDB did not receive PAP (SDB untreated). At baseline and first follow-up visit, weight and HbA1c were assessed. Results: Of the 346 patients with SDB [mean age 68 years, 71% male, body-mass index (BMI) 31.9 kg/m2], 17% were in the SDB PAP and 83% in the SDB untreated group. Weight change within the observation period was similar in both groups (-0.2 and -0.9 kg; p = 0.322). The percentage of patients with severe weight gain (≥ 5 kg) within the observation period was significantly higher in the SDB PAP group compared to the SDB untreated group (15.0 vs. 5.6%; p = 0.011). Multivariable regression analysis, accounting for baseline HbA1c, insulin substitution, BMI, waist-to-hip ratio (WHR), physical activity, and AHI, showed that PAP treatment was significantly associated with a weight gain ≥ 5 kg [odds ratio (OR) = 3.497; 95% CI (1.343; 9.106); p = 0.010] and an increase in HbA1c [B = 2.410; 95% CI (0.118; 4.702); p = 0.039]. Conclusion: Median weight change was similar in patients with SDB with and without PAP treatment. However, patients with DM2 and PAP treatment have an increased risk of severe long-term weight gain and an increase in HbA1c. Clinical Trial registration: DRKS00010498.

Sleep apnoea and incident malignancy in type 2 diabetes.

BACKGROUND: Sleep apnoea and type 2 diabetes (T2D) have been linked to malignancy. The aim of the present study was to evaluate the association between sleep apnoea and incidence of malignancy in patients with T2D. METHODS: The DIACORE (DIAbetes COhoRtE) study is a prospective, population-based cohort study in T2D patients. In the sleep disordered breathing substudy, the apnoea-hypopnoea index (AHI), oxygen desaturation index (ODI) and percentage of night-time spent with a peripheral oxygen saturation of <90% (t sat90%) were assessed using a two-channel ambulatory monitoring device. Malignancy diagnoses were gathered using self-reported medical history data validated by medical records. Hazard ratios (HRs) for incident malignancy were derived by Cox regression adjusting for sex, age, body mass index, smoking status, alcohol intake, socioeconomic status and HbA1c. RESULTS: Of 1239 patients with T2D (mean age 67 years, 41% female, mean body mass index 30.9 kg·m-2), 79 (6.4%) were first-time diagnosed with a malignancy within a median follow-up period of 2.7 years (interquartile range 2.2-4.5 years). AHI, ODI and t sat90% were not associated with incident malignancy. In subgroup analysis, females showed increased cancer risk per AHI unit (adjusted HR 1.03 per AHI unit, 95% CI 1.00-1.06; p=0.028) and severe sleep apnoea (defined as AHI ≥30 events·h-1; adjusted HR 4.19, 95% CI 1.39-12.77; p=0.012). This was not seen in males, and a significant interaction was observed (interaction terms p=0.048 and p=0.033, respectively). CONCLUSION: Sleep apnoea was not associated with incident malignancy in T2D patients. However, stratified analysis revealed a significant association between sleep apnoea and incident malignancy in females, but not in males.

Meta-analysis uncovers genome-wide significant variants for rapid kidney function decline.

Rapid decline of glomerular filtration rate estimated from creatinine (eGFRcrea) is associated with severe clinical endpoints. In contrast to cross-sectionally assessed eGFRcrea, the genetic basis for rapid eGFRcrea decline is largely unknown. To help define this, we meta-analyzed 42 genome-wide association studies from the Chronic Kidney Diseases Genetics Consortium and United Kingdom Biobank to identify genetic loci for rapid eGFRcrea decline. Two definitions of eGFRcrea decline were used: 3 mL/min/1.73m2/year or more ("Rapid3"; encompassing 34,874 cases, 107,090 controls) and eGFRcrea decline 25% or more and eGFRcrea under 60 mL/min/1.73m2 at follow-up among those with eGFRcrea 60 mL/min/1.73m2 or more at baseline ("CKDi25"; encompassing 19,901 cases, 175,244 controls). Seven independent variants were identified across six loci for Rapid3 and/or CKDi25: consisting of five variants at four loci with genome-wide significance (near UMOD-PDILT (2), PRKAG2, WDR72, OR2S2) and two variants among 265 known eGFRcrea variants (near GATM, LARP4B). All these loci were novel for Rapid3 and/or CKDi25 and our bioinformatic follow-up prioritized variants and genes underneath these loci. The OR2S2 locus is novel for any eGFRcrea trait including interesting candidates. For the five genome-wide significant lead variants, we found supporting effects for annual change in blood urea nitrogen or cystatin-based eGFR, but not for GATM or LARP4B. Individuals at high compared to those at low genetic risk (8-14 vs. 0-5 adverse alleles) had a 1.20-fold increased risk of acute kidney injury (95% confidence interval 1.08-1.33). Thus, our identified loci for rapid kidney function decline may help prioritize therapeutic targets and identify mechanisms and individuals at risk for sustained deterioration of kidney function.

Periodic breathing is associated with blood pressure above the recommended target in patients with type 2 diabetes.

BACKGROUND: Due to its prognostic importance for patients with type 2 diabetes (DM2), current guidelines recommend a systolic <130 mm Hg and diastolic <80 mm Hg blood pressure target. Periodic breathing, a form of sleep-disordered breathing, acutely causes repetitive hypoxia, sympathetic nervous system activation as well as oscillations of heart rate and blood pressure. However, limited data on the association of periodic breathing and control of blood pressure (BP) in patients with DM2 are available. Thus, the aim of the present study was to assess whether there is an association between periodic breathing and increased BP above the recommended target in DM2. METHODS: Cross-sectional data of 679 patients with DM2 from the DIACORE-SDB sub-study were analysed for association of periodic breathing with BP. Sleep-disordered breathing was assessed with a 2-channel ambulatory monitoring device including validated automatic pattern recognition for periodic breathing. BP values were determined in a standardized manner with three repeated measurements at rest. RESULTS: Of the 679 analysed individuals (61% male, age 66 ± 9 years, Body Mass Index [BMI] 31.0 ± 5.4 kg/m2), 11% had periodic breathing. Patients with periodic breathing had significantly higher systolic BP values (144 ± 19 mm Hg vs. 137 ± 18 mm Hg, p = 0.003). Multivariable regression analysis revealed that periodic breathing was associated with higher systolic BP (B [95% confidence interval, CI] = 4.4 [0.1; 8.7], p = 0.043) and not meeting the recommended BP target for patients with diabetes (<130/80 mmHg) (odds ratio, OR [95%CI] = 2.1 [1.1; 4.0], p = 0.026) independent of sex, age, high density lipoproteins, renal function, coronary heart disease and antihypertensive treatment. CONCLUSION: Periodic breathing is associated with higher systolic BP in patients with DM2.

Poor risk factor control in outpatients with diabetes mellitus type 2 in Germany: The DIAbetes COhoRtE (DIACORE) study.

INTRODUCTION: Patients with diabetes mellitus type 2 (DM2) are at high risk for micro- and macrovascular disease. Here, we explore the degree of traditional risk factor control in the baseline visit of a cohort of DM2 outpatients. METHODS: DIACORE (DIAbetes COhoRtE) is a prospective cohort study of 3000 adult DM2 outpatients. Here, we present results from the baseline visit. Sociodemographic and anthropometric variables, cardiovascular risk factors, comorbidities and medication were assessed by interview and medical exams. Serum-creatinine based estimated glomerular filtration rate (eGFRcrea) and urinary albumin-creatinine ratio (UACR) were determined for classification of chronic kidney disease (CKD). The proportion of patients with adequate control of traditional risk factors (blood pressure<140/90mmHg, HbA1c<7.5%, LDL<100mg/dl) was calculated in 2892 patients with non-missing data in 9 relevant variables within each KDIGO 2012 CKD class. RESULTS: In the analyzed baseline data (n = 2892, 60.2% men), mean (standard deviation) values for age, DM2 duration and HbA1c were 65.3 (9.3) years, 10.3 (8.4) years and 6.9% (1.1) respectively. Of these 2892 patients, 18.7% had CKD stage 3 or higher, 25.7% had UACR≥30mg/g. Adequate blood pressure, HbA1c and LDL control was achieved in 55.7%, 78.5% and 34.4%, respectively. In 16.4% of patients (473), all three risk factors were below recommended targets. The proportion of adequate risk factor control was similar across KDIGO eGFRcrea classes. Adequate blood pressure and HbA1c control were significantly associated with lower UACR category without and with controlling for other risk factors (p<0.0001, p = 0.0002, respectively). CONCLUSION: In our study of patients with diabetes mellitus type 2, we observed a low level of risk factor control indicating potential for risk reduction.

Daytime napping and diabetes-associated kidney disease.

BACKGROUND: Diabetes-associated Kidney Disease (DKD) is a common comorbidity in patients with type 2 diabetes. The present study investigates whether daytime sleeping duration in patients, ill with type 2 diabetes, is associated with DKD. METHODS: A total of 733 outpatients of the cross-sectional baseline survey of the DIACORE study were analyzed with respect to their self-reported daytime sleeping duration, assessed by a standardized questionnaire. DKD was defined as eGFR <60 ml/min/1.73 m2 and/or urinary albumin-to-creatinine-ratio (UACR) > 30 mg/g. RESULTS: Mean daytime sleeping duration was 17 ± 27 min. With increasing daytime sleeping duration a statistically significant decrease in eGFR (p = 0.002) and increase in UACR (p < 0.001) were found, respectively. Prevalence of DKD was significantly higher in patients with longer daytime sleeping duration (31% in patients not napping, 40% in patients napping less than 30 min, 47% in patients napping 30-60 min, 56% in patients napping 60 min or more; p = 0.001). After accounting for known modulators (Age, sex, BMI, waist-hip-ratio, systolic and diastolic blood pressure, physical activity, diabetes duration, HbA1c, homeostasis model assessment (HOMA-Index), nighttime sleeping duration, apnea-hypopnea-index (AHI), Epworth Sleepiness Scale (ESS)), longer daytime sleeping duration was significantly associated with impaired eGFR [B (95% CI) = -0.05 (-0.09; 0.00), p = 0.044] and increased UACR [B (95% CI) = 0.01 (0.01; 0.02), p < 0.001], respectively. CONCLUSION: Increased daytime sleeping duration is significantly associated with reduced eGFR and higher UACR, independent of known modulators of DKD. The direction of this relationship remains unclear.

Excessive dietary lipid intake provokes an acquired form of lysosomal lipid storage disease in the kidney.

Obesity and dyslipidaemia are features of the metabolic syndrome and risk factors for chronic kidney disease. The cellular mechanisms connecting metabolic syndrome with chronic kidney disease onset and progression remain largely unclear. We show that proximal tubular epithelium is a target site for lipid deposition upon overnutrition with a cholesterol-rich Western-type diet. Affected proximal tubule epithelial cells displayed giant vacuoles of lysosomal or autophagosomal origin, harbouring oxidised lipoproteins and concentric membrane layer structures (multilamellar bodies), reminiscent of lysosomal storage diseases. Additionally, lipidomic analysis revealed renal deposition of cholesterol and phospholipids, including lysosomal phospholipids. Proteomic profiles of renal multilamellar bodies were distinct from those of epidermis or lung multilamellar bodies and of cytoplasmic lipid droplets. Tubular multilamellar bodies were observed in kidney biopsies of obese hypercholesterolaemic patients, and the concentration of the phospholipidosis marker di-docosahexaenoyl (22:6)-bis(monoacylglycerol) phosphate was doubled in urine from individuals with metabolic syndrome and chronic kidney disease. The enrichment of proximal tubule epithelial cells with phospholipids and multilamellar bodies was accompanied by enhanced inflammation, fibrosis, tubular damage markers, and higher urinary electrolyte content. Concomitantly to the intralysosomal lipid storage, a renal transcriptional response was initiated to enhance lysosomal degradation and lipid synthesis. In cultured proximal tubule epithelial cells, inhibition of cholesterol efflux transport or oxysterol treatment induced effects very similar to the in vivo situation, such as multilamellar body and phospholipid amassing, and induction of damage, inflammatory, fibrotic, and lipogenic molecules. The onset of phospholipidosis in proximal tubule epithelial cells is a novel pathological trait in metabolic syndrome-related chronic kidney disease, and emphasises the importance of healthy lysosomes and nutrition for kidney well-being. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Association of sleep-disordered breathing with severe chronic vascular disease in patients with type 2 diabetes.

BACKGROUND: Severe chronic vascular disease (CVD) is a major cause of co-morbidity and mortality in patients with type 2 diabetes (DM2). Sleep-disordered breathing (SDB) has been linked to CVD in the general population due to enhanced sympathetic activation, oxidative stress, endothelial dysfunction, and hypertension; however data for DM2 patients is scarce. Therefore, the aim of the present analysis to assess whether SDB is associated with CVD in patients with DM2, independent of other known associated factors. METHODS: We analyzed cross-sectional data of 679 patients with DM2 from the DIACORE-SDB sub-study for association of SDB with CVD. SDB was assessed with a validated 2-channel ambulatory monitoring device. CVD was ascertained as a previous diagnosis of peripheral artery disease (PAD), coronary artery disease (CAD), or stroke via medical records and general practitioners. RESULTS: Of the analyzed 679 patients, 228 (34%) had SDB (respiratory event index [REI] ≥15/hour); and were significantly more often affected by CVD than patients without SDB (38% vs. 23%, p < 0.01; PAD 7% vs. 2%, p = 0.01; CAD 27% vs. 18%, p = 0.01; stroke 11% vs. 6%, p = 0.07). Regression analysis accounting for known modulators of CVD, such as age, body-mass index, systolic blood pressure, duration of DM2, HbA1c, smoking status, and low-density lipoprotein showed that the REI was independently associated with CVD (OR 1.099 per 5 REI points; 95%CI = [1.024, 1.179]). CONCLUSIONS: In patients with DM2, SDB is significantly associated with CVD, independent of other known modulators of atherosclerosis.

Analysis of Luminex-based Algorithms to Define Unacceptable HLA Antibodies in CDC-crossmatch Negative Kidney Transplant Recipients.

BACKGROUND: HLA-specific antibodies detected by solid phase assays are increasingly used to define unacceptable HLA antigen mismatches (UAM) before renal transplantation. The accuracy of this approach is unclear. METHODS: Day of transplant sera from 211 complement-dependent cytotoxicity crossmatch-negative patients were retrospectively analyzed for donor-specific anti-HLA antibodies (DSA) using Luminex technology. HLA were defined as UAM if DSA had mean fluorescence intensity above (I) 3000 (patients retransplanted and those with DSA against HLA class I and II) or 5000 (all other patients), (II) 5000 for HLA-A, -B, and -DR and 10 000 for HLA DQ or (III) 10 000 (all HLA). We then studied the accuracy of these algorithms to identify patients with antibody-mediated rejection (AMR) and graft loss. UAM were also determined in 256 transplant candidates and vPRA levels calculated. RESULTS: At transplantation, 67 of 211 patients had DSA. Of these, 31 (algorithm I), 24 (II) and 17 (III) had UAM. Nine (I and II) and 8 (III) of 11 early AMR episodes and 7 (I), 6 (II) and 5 (III) of 9 graft losses occurred in UAM-positive patients during 4.9 years of follow-up. Algorithms I and II identified patients with persistently lower glomerular filtration rate even in the absence of overt AMR. Of the waiting list patients, 22-33% had UAM with median virtual panel reactive antibody of 69.2% to 79.1%. CONCLUSIONS: Algorithms I and II had comparable efficacy but were superior to Algorithm III in identifying at-risk patients at an acceptable false-positive rate. However, Luminex-defined UAM significantly restrict the donor pool of affected patients, which might prolong waiting time.

Biomarker-guided Intervention to Prevent Acute Kidney Injury After Major Surgery: The Prospective Randomized BigpAK Study.

OBJECTIVE: To determine the impact of renal biomarker-guided implementation of the Kidney Disease Improving Global Outcomes (KDIGO) care bundle on the incidence of acute kidney injury (AKI) after major noncardiac surgery in a single-center unblinded randomized clinical trial. BACKGROUND: Early optimization of volume status and discontinuation of nephrotoxic medication before the occurrence of AKI may be the crucial step to reduce preventable AKI. METHODS: The urinary biomarker-triggered KDIGO care bundle (early optimization of fluid status, maintenance of perfusion pressure, discontinuation of nephrotoxic agents) was compared to standard intensive care unit (ICU) care in 121 patients with an increased AKI risk after major abdominal surgery that was determined by urinary biomarker (inhibitor of metalloproteinase-2 × insulin-like growth factor-binding protein 7) >0.3. Incidence of overall AKI, severity of AKI, length of stay, major kidney events at discharge, and cost effectiveness were evaluated. RESULTS: The overall stages of AKI were not statistically different between the 2 groups, but in patients with inhibitor of metalloproteinase-2 × insulin-like growth factor-binding protein 7 values of 0.3 to 2.0 a subgroup analysis demonstrated a significantly reduced incidence of AKI 13/48 (27.1%) in the intervention group compared to control 24/50 (48.0%, P = 0.03). Incidence of moderate and severe AKI (P = 0.04), incidence of creatinine increase >25% of baseline value (P = 0.01), length of ICU, and hospital stay (P = 0.04) were significantly lower in the intervention group. Intervention was associated with cost reduction. There were no significant differences regarding renal replacement therapy, in-hospital mortality, or major kidney events at hospital discharge. CONCLUSIONS: Early biomarker-based prediction of imminent AKI followed by implementation of KDIGO care bundle reduced AKI severity, postoperative creatinine increase, length of ICU, and hospital stay in patients after major noncardiac surgery.

Renal allograft rejection, lymphocyte infiltration, and de novo donor-specific antibodies in a novel model of non-adherence to immunosuppressive therapy.

BACKGROUND: Non-adherence has been associated with reduced graft survival. The aim of this study was to investigate the immunological mechanisms underlying chronic renal allograft rejection using a model of non-adherence to immunosuppressive therapy. We used a MHC (major histocompatibility complex) -mismatched rat model of renal transplantation (Brown Norway to Lewis), in which rats received daily oral cyclosporine A. In analogy to non-adherence to therapy, one group received cyclosporine A on alternating days only. Rejection was histologically graded according to the Banff classification. We quantified fibrosis by trichrome staining and intra-graft infiltration of T cells, B cells, and monocytes/macrophages by immunohistochemistry. The distribution of B lymphocytes was assessed using immunofluorescence microscopy. Intra-graft chemokine, chemokine receptor, BAFF (B cell activating factor belonging to the TNF family), and immunoglobulin G transcription levels were analysed by RT-PCR. Finally, we evaluated donor-specific antibodies (DSA) and complement-dependent cytotoxicity using flow cytometry. RESULTS: After 28 days, cellular rejection occurred during non-adherence in 5/6 animals, mixed with humoral rejection in 3/6 animals. After non-adherence, the number of T lymphocytes were elevated compared to daily immunosuppression. Monocyte numbers declined over time. Accordingly, lymphocyte chemokine transcription was significantly increased in the graft, as was the transcription of BAFF, BAFF receptor, and Immunoglobulin G. Donor specific antibodies were elevated in non-adherence, but did not induce complement-dependent cytotoxicity. CONCLUSION: Cellular and humoral rejection, lymphocyte infiltration, and de novo DSA are induced in this model of non-adherence.

Infiltration of Macrophages Correlates with Severity of Allograft Rejection and Outcome in Human Kidney Transplantation.

OBJECTIVE: Despite substantial progress in recent years, graft survival beyond the first year still requires improvement. Since modern immunosuppression addresses mainly T-cell activation and proliferation, we studied macrophage infiltration into the allografts of 103 kidney transplant recipients during acute antibody and T-cell mediated rejection. Macrophage infiltration was correlated with both graft function and graft survival until month 36 after transplantation. RESULTS: Macrophage infiltration was significantly elevated in antibody-mediated and T-cell mediated rejection, but not in kidneys with established IFTA. Treatment of rejection with steroids was less successful in patients with more prominent macrophage infiltration into the allografts. Macrophage infiltration was accompanied by increased cell proliferation as well as antigen presentation. With regard to the compartmental distribution severity of T-cell-mediated rejection was correlated to the amount of CD68+ cells especially in the peritubular and perivascular compartment, whereas biopsies with ABMR showed mainly peritubular CD68 infiltration. Furthermore, severity of macrophage infiltration was a valid predictor of resulting creatinine values two weeks as well as two and three years after renal transplantation as illustrated by multivariate analysis. Additionally performed ROC curve analysis showed that magnitude of macrophage infiltration (below vs. above the median) was a valid predictor for the necessity to restart dialysis. Having additionally stratified biopsies in accordance to the magnitude of macrophage infiltration, differential CD68+ cell infiltration was reflected by striking differences in overall graft survival. CONCLUSION: The differences in acute allograft rejection have not only been reflected by different magnitudes of macrophage infiltration, but also by compartment-specific infiltration pattern and subsequent impact on resulting allograft function as well as need for dialysis initiation. There is a robust relationship between macrophage infiltration, accompanying antigen-presentation and resulting allograft function.

Comprehensive morphometric analysis of mononuclear cell infiltration during experimental renal allograft rejection.

The role of specific subtypes of infiltrating cells in acute kidney allograft rejection is still not clear and was so far not examined by different analyzing methods under standardized conditions of an experimental kidney transplantation model. Immunohistochemical staining of CD3, CD20 and CD68 was performed in rat allografts, in syngeneically transplanted rats and in control rats with a test duration of 6 and 28 days. The detailed expression and localization of infiltrating cells were analyzed manually in different kidney compartments under light microscope and by the two different morphometric software programs. Data were correlated with the corresponding kidney function as well as with histopathological classification. The information provided by the morphometric software programs on the infiltration of the specific cell types after renal transplantation was in accordance with the manual analysis. Morphometric methods were solid to analyze reliably the induction of cellular infiltrates after renal transplantation. By manual analysis we could clearly demonstrate the detailed localization of the specific cell infiltrates in the different kidney compartments. Besides infiltration of CD3 and CD68 infiltrating cells, a robust infiltration of CD20 B-cells in allogeneically transplanted rats, even at early time points after transplantation was detected. Additionally an MHC class I expression could reliable be seen in allogeneically transplanted rats. The infiltration of B-cells and the reliable antigen presentation might act as a silent subclinical trigger for subsequent chronic rejection and premature graft loss.

Toll-like receptor 4 in experimental kidney transplantation: early mediator of endogenous danger signals.

The role of toll-like receptors (TLRs) has been described in the pathogenesis of renal ischemia/reperfusion injury, but data on the expression and function of TLR4 during renal allograft damage are still scarce. We analyzed the expression of TLR4 in an experimental rat model 6 and 28 days after allogeneic kidney transplantation in comparison to control rats and rats after syngeneic transplantation. On day 6, a significant induction in TLR4 expression--restricted to the glomerular compartment--was found in acute rejecting allografts only. TLR4 expression strongly correlated with renal function, and TLR4 induction was accompanied by a significant increase in CC chemokine expression within the graft as well as in urinary CC chemokine excretion. TLR4 induction may be caused by an influx of macrophages as well as TLR4-expressing intrinsic renal cells. Fibrinogen deposition in renal allografts correlated with renal TLR4 expression and may act as a potent stimulator of chemokine release via TLR4 activation. This study provides, for the first time, data about the precise intrarenal localization and TLR4 induction after experimental kidney transplantation. It supports the hypothesis that local TLR4 activation by endogenous ligands may be one pathological link from unspecific primary allograft damage to subsequent chemokine release, infiltration and activation of immune cells leading to deterioration of renal function and induction of renal fibrosis.

Traditional and nontraditional cardiovascular risk factors and estimated risk for coronary artery disease in renal transplant recipients: a single-center experience.

BACKGROUND/AIMS: The prevalence of cardiovascular disease in renal transplant recipients is markedly higher than in the general population due to the high prevalence of traditional cardiovascular risk factors, renal transplant function impairment and treatment with immunosuppressive drugs that affect blood pressure, cholesterol and blood glucose levels. METHODS: Cross-sectional analysis using our renal transplant clinic cohort investigating (1) the cardiovascular risk factors present in this cohort, and (2) estimating their impact on the risk of coronary artery disease (CAD) by using the Framingham algorithm. RESULTS: Control of modifiable cardiovascular risk factors in 231 renal transplant recipients is suboptimal, i.e. 47.2% of patients are hypertensive, 10.3% actively smoke, 39.4% have serum cholesterol concentrations >200 mg/dl, and 19.7% have diabetes mellitus. Blood pressure, age, hyperlipidemia, smoking and diabetes modulate the estimated CAD risk in males and females. Furthermore, a short time period (less than 1 year) since transplantation and increased serum creatinine levels negatively influenced the CAD risk in this patient population. CONCLUSION: According to current guidelines, the control of modifiable cardiovascular risk factors in renal transplant recipients is suboptimal. The decreasing CAD risk over time after transplantation may be due to the reduction of immunosuppressive drugs with time and survival bias.

Kidney injury molecule-1 and N-acetyl-ß-D-glucosaminidase in chronic heart failure: possible biomarkers of cardiorenal syndrome.

AIMS: Patients with chronic heart failure are often characterized by impaired renal function, also referred to as cardiorenal syndrome (CRS). The aim of this study was to assess whether novel markers of kidney injury are elevated in chronic heart failure and CRS. METHODS AND RESULTS: The new renal biomarkers kidney injury molecule-1 (KIM-1), N-acetyl-ß-d-glucosaminidase (NAG) and neutrophil gelatinase-associated lipocalin (NGAL) were assessed from urine samples of 173 individuals. Patients with chronic heart failure (n= 150) were characterized by decreased ejection fraction (32 ± 9% vs. controls 62 ± 4%, P < 0.001) and increased plasma N-terminal pro-brain natriuretic peptide (median 1460 pg/mL, interquartile range (IQR) 630-3000 pg/mL vs. controls 56, IQR 25-64l pg/mL, P < 0.001). Urinary analysis showed that KIM-1 was significantly elevated in heart failure patients compared with healthy controls (1100, IQR 620-1920 vs. 550, IQR 320-740 ng/g urinary creatinine, P < 0.001). Further, KIM-1 increased significantly with decreasing left ventricular function (r = -0.37, P < 0.001) and severity of New York Heart Association (NYHA)-class (r = 0.5, P < 0.001). N-acetyl-ß-d-glucosaminidase showed a weaker response but correlated significantly with left ventricular dysfunction (r = -0.18, P= 0.015) and more severe clinical condition (r = 0.22, P= 0.04). In contrast, NGAL showed no significant correlation. Kidney injury molecule-1 and NAG were also predictors of all-cause mortality and the composite of all-cause mortality and rehospitalization for heart failure (all P < 0.05). CONCLUSIONS: Kidney injury molecule-1 and NAG are elevated in symptomatic heart failure. This finding may be present in patients with apparently normal kidney function and indicates tubular injury in chronic heart failure. Kidney injury molecule-1 and NAG are potential markers of CRS with additional prognostic value.

Hypertonic stress promotes the upregulation and phosphorylation of zonula occludens 1.

Tight junction molecules form a barrier between adjacent cells and mediate the cells' ability to develop membranes that constitute boundaries of different compartments within the body. Membranes with selective ion and water passage are important for the electrolyte and water homeostasis in the kidney. Due to their role in the urinary concentration process, renal medullary cells are exposed to hyperosmotic stress. Therefore, we were interested in the question of how mouse inner medullary collecting duct cells (mIMCD3) manage to maintain their cell-cell contacts, despite hypertonicity-induced cell shrinkage. Employing mRNA expression analysis, we found that the zonula occludens type 1 (Zo-1), multi-PDZ domain protein 1 (MUPP1) and cortactin mRNA levels were upregulated in a tonicity-dependent manner. Using Western blot analysis, immunoprecipitation and immunofluorescence, we show that the Zo-1 protein is upregulated, phosphorylated and linked to the actin cytoskeleton in response to hypertonic stress. After cell exposure to hypertonicity, rearrangement of the actin cytoskeleton resulted in a stronger colocalization of actin fibres with Zo-1. Urea, which generates hyperosmolality, but no transcellular gradient, did not induce changes in Zo-1 protein expression or actin rearrangement. This data indicates that Zo-1 is a response protein to inner medullary tonicity and that extracellular stressors can promote Zo-1 protein expression, tyrosine phosphorylation and cytoskeleton association.

Impact of Toll-like receptor 2 expression in renal allograft rejection.

BACKGROUND: An important role of TLR2 has been shown in various experimental models of renal ischaemia/reperfusion injury. To study the expression of TLR2 in renal allograft rejection systematically, we established an experimental rat transplantation model. METHODS: TLR2 expression was analysed in 99 human renal allograft biopsies, and in rat allografts at Day 6 and 28 after experimental renal transplantation. To discriminate whether regulation of TLR2 was following immunological processes after allogeneic transplantation or was a consequence from ischaemia/reperfusion injury, control animals subjected to syngeneic transplantation or to ischaemia/reperfusion damage were also investigated. RESULTS: TLR2 mRNA was significantly elevated in rat allografts with acute rejection on Day 6 and decreased spontaneously towards Day 28. TLR2 induction correlated with renal function and TLR2 excretion in the urine of transplanted rats. TLR2 staining was also significantly increased in human allografts with acute rejection. TLR2 protein could be localized in tubular epithelial cells and vascular endothelial cells, and in CD68- and CD4-positive infiltrating cells. CONCLUSIONS: TLR2 is markedly up-regulated in both experimental and human acute renal allograft rejection. Our data suggest a role for TLR2 during allogen-dependent graft damage after renal transplantation.