Outcomes of Patients Receiving a Kidney Transplant or Remaining on the Transplant Waiting List at the Epicentre of the COVID-19 Pandemic in Europe: An Observational Comparative Study

Since the declaration of the COVID-19 pandemic, the number of kidney transplants (KT) performed worldwide has plummeted. Besides the generalised healthcare crisis, this unprecedented drop has multiple explanations such as the risk of viral transmission through the allograft, the perceived increase in SARS-CoV-2-related morbidity and mortality in immunocompromised hosts, and the virtual "safety" of dialysis while awaiting effective antiviral prophylaxis or treatment. Our institution, operating at the epicentre of the COVID-19 pandemic in Italy, has continued the KT programme without pre-set limitations. In this single-centre retrospective observational study with one-year follow-up, we assessed the outcomes of patients who had undergone KT (KTR) or remained on the transplant waiting list (TWL), before (Pre-COV) or during (COV) the pandemic. The main demographic and clinical characteristics of the patients on the TWL or receiving a KT were very similar in the two periods. The pandemic did not affect post-transplant recipient and allograft loss rates. On the contrary, there was a trend toward higher mortality among COV-TWL patients compared to Pre-COV-TWL subjects. Such a discrepancy was primarily due to SARS-CoV-2 infections. Chronic exposure to immunosuppression, incidence of delayed allograft function, and rejection rates were comparable. However, after one year, COV-KTR showed significantly higher median serum creatinine than Pre-COV-KTR. Our data confirm that KT practice could be safely maintained during the COVID-19 pandemic, with excellent patient- and allograft-related outcomes. Strict infection control strategies, aggressive follow-up monitoring, and preservation of dedicated personnel and resources are key factors for the optimisation of the results in case of future pandemics.

MO959: Covid-19 Vaccine in Kidney Transplanted Patients. is There A Clinical Relevance? An Italian Single Center Experience

BACKGROUND AND AIMS

COVID-19 is a life-threatening infection among elderly, comorbid patients or transplanted patients. In our recently published paper (Campise, M.; Alfieri, C.M.; et al. Pathogens 2021, 10, 964), we described our single Centre experience with 82 adult kidney-transplant patients (KTxp) with COVID-19 infection during the previous two pandemic outbreaks: 27 KTxp (first outbreak) and 65 (second). We observed a relatively low and possibly underestimated incidence of infection (5.1%) with a incidence of death almost four times higher than in general population (13%). The availability of COVID-19 vaccines has undoubtedly changed the outcome of the infection in both immunocompetent and immunosuppressed patients.

Aim of this second ongoing observational and descriptive study, is to evaluate if the vaccination performed extensively among our KTxp, has modified the incidence and gravity of COVID-19 infection.

METHOD

Data on KTxp with COVID-19 infection (COV+) from the 29 October 2021 to 31 December 2021 were collected. Particularly, we focused our anthropometric, clinical and therapeutic aspects. In the statistical analyses, continuous variables were expressed as median and interquartile range (25%–75%), and nominal variables were reported as percentage of cases.

RESULTS

From the 29 October 2021 to the 31 December 2021, 33 KTxp developed COVID-19 infection, 60% were male. Median age was 50[29–58] years. Transplant vintage was 57[27–163] months. Median serum creatinine was 1.30[1.0–1.9] mg/dL and body mass index was 23[21–28] kg/m². Immunosuppressive schedule included: CNI inhibitors, steroids and mycophenolate (MMF) in 97–90 and 70% of COV + respectively. In 50% of cases native vitamin D supplementation was present, whereas only 30% of cases were treated with renin-angiotensin inhibitors. Only one had insulin dependent diabetes. At the moment of nasopharyngeal swab positivity 64% of COV + had already received three doses of vaccine (Comirnaty (BNT162b2)^®) and 30% 2 doses. Only 3% of pts had received a single dose. One patient had refused vaccination for personal reasons.

Antigenic nasopharyngeal swab was performed in 70% of COV + and molecular swab in 60%. Thirty-five % of COV + were tested with both methods.

The most frequent symptoms were: fever (70%), cough (75%) and headache (40%). In the previous outbreaks dyspnea was present in 33% of cases dropping to 13% in this cohort. Smell and taste alteration were present in 25% and 28% respectively. We did not perform the COVID-19 sequence. But, on the base of the symptoms referred, we are confident that 17 patients had delta variant and remaining had omicron.

The first therapeutic approaches were the increase of the daily steroid dosage up to 25 mg (60% of cases) together with MMF temporarily withdrawing in 70% of cases and halving in 10%. Forty % of pts were also treated with monoclonal antibodies (Ronapreve ^®) upon infectious disease specialist evaluation. During the first two outbreaks, hospitalization was necessary in 45% of cases, and 13% of pts died. In the present cohort only 10% of patients required oxygen support and hospitalization. Nobody died.

CONCLUSION

Although very preliminary, our results indicate that the vaccination campaign has noticeably ameliorated the incidence, the clinical presentation and the outcome of COVID-19 in KTxp. This comforting data should further sensitize the medical community on vaccination counseling in KTxp as soon as possible. Study with higher number of patients are needed to further clarify the individual response on antibody production and sensitivity to this still life-threatening infection.

MO963: Vitamin D Status and Sars-Cov-2 Infection in A Cohort of Renal Transplanted Patients

BACKGROUND AND AIMS

Immunomodulatory and anti-inflammatory properties have been hypothesized for native vitamin D (nVD). Very little is reported about nVD and risk of Sars-CoV-2 infection (COV) in renal transplant (RTx). In a cohort of renal transplanted patients (RTxp) we retrospectively evaluated: (i) nVD status in patients with (COV+) and without (COV-) COV infection; (ii) the impact of nVD status on severity of COV.

METHOD

The study includes 61 COV + in whom nVD status was available in the year before the infection, and 122 COV- matched 1:2 for age (53[45–64]years), gender (M = 60.7%), RTx vintage (7[2–15] years), presence of diabetes (18%), arterial hypertension (85%) and cardiac symptomatic disease (3%). Renal function, 24-h proteinuria and mineral metabolism (MM) parameters were evaluated at 1, 6 and 12 months before COV whereas nVD status was considered as the mean 25-OH-VD levels at the same timepoints. Severity of COV was based on the need for hospitalization (HOSP+: 27/61, 44.3%) and death (D+: 6/61, 9.8%).

RESULTS

(i) nVD levels were significantly lower in COV + than in COV- (19[12–26] ng/mL and 23[16–30] ng/mL, respectively, P = 0.01). No differences in the other biochemical parameters were found. The COV discriminative power of nVD status was evaluated by ROC curve (AUC 0.61, 95% CI: 0.54–0.68, P = 0.01), with a value of 25-OHVD 23.9 ng/mL showing the best discriminative power (sensibility 72%, specificity 47%). (ii) nVD levels showed a trend towards lower values in HOSP + COV + than HOSP-COV+ (17[8–25] ng/mL versus 20[14–26] ng/mL) and in D + COV + than D-COV+ (13[6–23] ng/mL versus 20[13–26] ng/mL), although these differences did not reach the statistical significance (P = 0.1 and P = 0.2, respectively).

CONCLUSION

With the limitations of the retrospective nature of the study and the small sample size, our data report that:

No association was found between nVD levels in the year preceding the infection and COV severity.

MO961: Mineral Metabolism Parameters and Bone Density During The First Year of Kidney Transplantation

BACKGROUND AND AIMS

We evaluated retrospectively in a cohort of kidney-transplanted patients (KTxp), the variations of mineral metabolism (MM) parameters, femoral and vertebral bone density during the first year of kidney transplantation (KTx).

METHOD

383 KTxp (M = 232), up to the 650 transplanted in our Department (2004–2017) were studied. At 1st(T1) and 12th(T2) mth of KTx biochemical, femoral and vertebral dual-energy X-ray absorption (DEXA) data were recorded. T-score (Ts) -1 >Ts > -2.5 was considered Osteopenia (F-OPN/V-OPN) and Ts < -2.5 osteoporosis (F-OPS/V-OPS).

RESULTS

The KTxp age and dialysis vintage (DV) were 48 ± 12 years and 53 ± 25 months; 67% of KTxp had a history of hemodialysis. In 82.5% of cases, a donor deceased KTx (DD) was performed and in 40% of KTxp had a previous history of steroid therapy. During the first year of KTx 91% and 93% of KTxp received respectively calcineurin inhibitors and mycophenolate, and the steroids cumulative dose (SCD) was 2683 ± 926 mg. At T1, cholecalciferol and calcifediol were supplemented in 5% and 8% of KTxp, and AT T12 in 12% and 15% of KTxp. An increase in BMI (23 ± 3 versus 24 ± 3 kg/m2 P < 0.0001), Ca (9.82 ± 0.83 versus 9.9 ± 0.73 mg/dL, P < 0.0001), P (2.4 ± 0.96 versus 3.1 ± 0.61 mg/dL, P  < 0.0001), 25OH-D (14.4 ± 6.81 versus 18.8 ± 9.7 ng/mL, P  < 0.0001), Hb (11.0 ± 1.4 versus 12.8 ± 1.5 g/dL, P  < 0.0001), albumin (4.2 ± 0.38 versus 4.46 ± 0.35 g/dL, P  < 0.0001) was observed. Serum creatinine (1.41 ± 0.4 versus 1.37 ± 0.3 mg/dL, P = 0.03), PTH (87 ± 73 versus 79 ± 86 pg/mL, P = 0.06 and ALP (107 ± 92 versus 93 ± 58 U/L, P  < 0.0001) had a reduction.

Femoral bone mineral density (F-BMD) at T1 and F-Ts-T1 were 0.749 ± 0.17 g/cm2 and -1.55 ± 1.06. F-OPS-T1 was present in 17.5% and F-OPN-T1 in 53% of KTxp. F-BMD-T1 correlated directly with BMI-T1 (P  < 0.0001) and inversely with 25OH-D-T1 (P  < 0.004). F-Ts-T1 was inversely correlated with DV (P = 0.04), BMI-T1 (P <0.0001) and PTH-T1 (P = 0.02). KTxp with F-OPS-T1 had longer DV and lower BMI (P = 0.02). At T12, F-BMD-T12 and F-Ts-T12 were 0.77 ± 0.67 g/cm2 (P = 0.17 versus F-BMD-T1) and −1.4 ± 0.9 (P = 0.002 versus F-Ts-T1).F-OPS-T12 was present in 13.2% of patients and F-OPN-T1 in 55.2%. F-BMD-T12 correlated directly with BMI-T12 (P  < 0.04). F-Ts-T12 correlated inversely with DV (P = 0.004), Ca at T1 (P = 0.001) and T12 (P = 0.0005) and with [SCD at T12 (P = 0.02)]. Patients with F-OPS-T1 had longer DV (P = 0.004) and higher PTH at T1 and T12 (P = 0.04 and P = 0.08). F-DEXA category worsened in 3.5% of KTxp.

At T1, V-BMD-T1 and V-Ts-T1 were 0.92 ± 0.19 g/cm2 and −1.5 ± 1.58. V-OPS-T1 was present in 30% of KTxp and V-OPN-T1 in 34.5%. V-BMD-T1 correlated directly with BMI-T1 (P  < 0.0001) and Ca-T1 (P = 0.04). V-Ts-T1 was inversely correlated with DV (P = 0.04), PTH-T1 (P = 0.02), Ca-T1 (P = 0.03), ALP-T1 (P = 0.01). A direct correlation between V-Ts-T1 and BMI-T1 (P  < 0.0001) and 25OHD-T1 (P = 0.02) was present. V-OPS-T1 was more prevalent in males (P = 0.01).They had lower BMI (P  < 0.0001), albumin (P = 0.02) and higher Ca-T1 (P = 0.008) and ALP-T1 (P = 0.03). 

At T12, V-BMD-T12 and V-Ts-T12 were 0.90 ± 0.22 g/cm2 and −1.5 ± 1 .33 (both NS versus T1). V-OPS-T12 was present in 27.7% of KTxp and V-OPN-T12 in 37.2%. V-BMD-T12 correlated directly with BMI-T1 and T12 (P  < 0.0001 and P = 0.005) and inversely with Ca-T12 (P = 0.03) and SCD-T12 (P = 0.04). V-Ts-T12 was inversely correlated with DV (P = 0.004), SCD-T12 (P = 0.02) and with Ca at T1 (P = 0.001) and T12 (P = 0.0005). A direct correlation was found with BMI-T1 and T12 (P = 0.0002 and P = 0.001). V-OPS-T12 was more prevalent in DD (P = 0.001). They were older (P = 0.01), had longer DV (P = 0.01). BMI-T1 and T12 were lower in V-OPS-T12 (P = 0.002 and P = 0.03) and Ca-T12 higher (P = 0.01). SCD-T12 was higher in V-OPN-T12 and V-OPS-T12 (P = 0.05). V-DEXA category worsened in 32% of KTxp.

CONCLUSION

In the first year of KTx several modifications of MM are present. Both femoral and vertebral DEXA seem to be strongly related to the pre-KTx status, in particular, nutritional status and dialysis vintage are related to bone status at T1. Strong importance on T12 evaluation is taken by the SCD.

MO922CASUAL FACTORS AND CLINICAL IMPACT OF URINARY TRACT INFECTIONS IN RENAL TRANSPLANTED PATIENTS: AN OBSERVATIONAL RETROSPECTIVE STUDY*

Background and Aims

Urinary tract infections (UTIs) are the most common infectious disease in kidney transplanted patients (KTxps), especially during the first year of kidney transplantation (KTx). This study aims to examine the etiology of UTIs in a large cohort of KTxps, trying to identify their potential predisposing factors both during the first year and in the global follow-up (FU) of KTx. The impact of UTIs on KTx and patient’s survival in the long term will also be analyzed.

Method

In our study 585 KTxps (M 343; median age 49 years), out of the 616 KTxps transplanted in our Department between 2004 and 2016, were studied and followed up for a median time of 8 years. Clinical and biochemical data about the 1st (T1) and the 12th month (T12) of KTx were collected. Parameters related to UTIs, defined by a positive urine culture associated with urinary sediment suggestive of UTI, regardless of clinical symptoms, were considered in the global FU. A number of UTIs ≥3 was considered significant during the 1st year of KTx and in the overall FU. The reduction of the eGFR/year of FU, the loss of graft and the death of KTxps with a functioning graft were evaluated as outcome.

Results

The cohort had a slight prevalence of males (59%) and a median age of 49 years. At the time of KTx, JJ ureteral stent (JJ) was placed in 38% of KTxps, with a median stay time of 47 days. During the FU, 1700 UTIs were found in 458 KTxp, 550 UTIs during the first year of KTx. The pathogens most responsible for UTIs in the global FU were Escherichia coli (61%), Enterococcus (12%) and Klebsiella (8%).

According to the number of UTIs found during the 1st year of KTx, KTxp were categorized in: UTI1≥3 (N=139) and UTI1<3 (N=446). UTI1≥3 were more frequently female and older than UTI1<3, had more prevalence of JJ and ATG induction therapy, and had lower hemoglobin and serum albumin at both T1 and T12. The presence of JJ, belonging to the female gender and induction therapy with ATG were the factors most correlated with IVU1≥3 (OR 1.9, 5.3 and 2.1).

The studied cohort was also categorized according to the number of UTIs during the global FU in UTItot ≥3 (N=168) and UTItot<3 (N=417). UTI tot ≥3 were more frequently females, older, had a longer dialysis vintage and higher prevalence of JJ placement than UTI tot<3. Furthermore, they had significantly lower hemoglobin and serum albumin values, both at T1 and T12. The presence of JJ, the female gender and age at KTx were the factors most related to UTItot ≥3 (OR 1.8, 5.9 and 1.0).

During the FU, the median absolute reduction in eGFR was found to be -0.6[-2.0; +0.9](mL/min)/years. Despite a greater reduction in glomerular filtrate rate in UTI tot≥3 group, the graft loss and the death with functioning graft had no correlation with either UTI1≥3 (7 and 5 patients, respectively) or UTItot≥3 (12 and 8 patients, respectively).

Graft loss was observed in 51 KTxps. The number of infections/follow-up time of these KTxps was comparable to that found in those who had a still functioning transplant at the end of observation, and no statistical differences were found in survival analysis according to IVU tot≥3 category.

During the global FU, 40 KTxp died with functioning graft. Also with regard to this outcome, no significant correlations were observed with the number of UTIs/follow-up time and in the survival analysis.

Conclusion

Our data confirm that UTIs are frequent in KTxps. Some factors, such as induction therapy and JJ use, certainly have a favoring effect in UTIs development. Despite the relation observed between UTIs and eGFR reduction, UTIs had no significant impact on graft loss. Beyond prevention through the improvement of lifestyles and various behavioral aspects, the implementation of personalized immunosuppressive protocols associated with a careful management of JJ are desirable interventions in order to prevent the development of UTIs in KTxps.

Bone Effect and Safety of One-Year Denosumab Therapy in a Cohort of Renal Transplanted Patients: An Observational Monocentric Study

In 32-kidney transplanted patients (KTxps), the safety and the effects on BMD and mineral metabolism (MM) of one-year treatment with denosumab (DB) were studied. Femoral and vertebral BMD and T-score, FRAX score and vertebral fractures (sVF) before (T0) and after 12 months (T12) of treatment were measured. MM, renal parameters, hypocalcemic episodes (HpCa), urinary tract infections (UTI), major graft and KTxps outcomes were monitored. The cohort was composed mainly of females, n = 21. We had 29 KTxps on steroid therapy and 22 KTxps on vitamin D supplementation. At T0, 25 and 7 KTxps had femoral osteoporosis (F-OPS) and osteopenia (F-OPS), respectively. Twenty-three and six KTxps had vertebral osteoporosis (V-OPS) and osteopenia (V-OPS), respectively. Seventeen KTxps had sVF. At T12, T-score increased at femoral and vertebral sites (p = 0.05, p = 0.008). The prevalence of F-OPS and V-OPS reduced from 78% to 69% and from 72% to 50%, respectively. Twenty-five KTxps ameliorated FRAX score and two KTxps had novel sVF. At T12, a slight reduction of Ca was present, without HpCa. Four KTxps had UTI. No graft rejections, loss of graft or deaths were reported. Our preliminary results show a good efficacy and safety of DB in KTxps. Longer and randomized studies involving more KTxps might elucidate the possible primary role of DB in the treatment of bone disorders in KTxps.

P0569ACUTE KIDNEY INJURY AFTER LUNG TRANSPLANTATION: INCIDENCE, RISK FACTORS AND OUTCOMES IN A MONOCENTRIC RETROSPECTIVE COHORT STUDY

Background and Aims

Acute kidney Injury (AKI) occurs in more than 50% of patients after lung transplantation (LTx). Our aim was to describe the incidence, risk factors and outcomes associated with AKI after LTx in a retrospective monocentric cohort study.

Method

We studied all recipients of LTx (> 16 years of age) occurring at Ospedale Maggiore Policlinico Milano between Jan 1st 2015 and Dec 31st 2017. AKI was defined according to KDIGO classification, eGFR was calculated according to CKD (Chronic Kidney Disease) Epidemiology Collaboration formula and CKD was defined by an eGFR< 60 ml/min per 1.73 m2. Chi square, Fisher exact test, t.-test and logistic regression were used to define risk factors for AKI in the early post-surgical period and for CKD at 1 and 2 years after LTx. AKI-related survival was estimated using Kaplan Meyer model.

Results

Of 78 LTx patients enrolled in our Center, 50% of patients was affected by cystic fibrosis. Median age at transplant was 43 years (27-55); median follow- up was 31 months (20-40). Survival rate was 80.77% at 1 year, 69.23% at 2 years and 66.67% on Dec 31st 2019 (last follow-up).

AKI occurred in 42 (53.85%) patients within the first week after LTx, respectively grade I and II in 12 each (15.38%) and grade III in 18 (23.08%) patients.

Pre-transplant low albumin levels and hypertension were independently associated with AKI at univariate and multivariate (p= 0.0018 and 0.0004 respectively) analysis. Pre-transplant low albumin levels, pre-transplant ECMO-use, hypertension, ECMO-use during transplant surgery were associated with severe AKI in univariate analysis but only pre-transplant hypertension and ECMO-use during transplant surgery were independently associated in the multivariate one (p=0.0266 and 0.0463 respectively).

Survival was significantly reduced in patients affected by AKI (p=0.035); this observation became strongly significant when only mild and moderate (grade I and II) AKI was considered (p=0.0071).

CKD was diagnosed in 38.09% of patients at 1 year and 35.18% at 2 years.

While numerous risk factors were related to the occurrence of CKD at 1 and 2 years after LTx at univariate analysis, only grade III AKI remained independently associated with CKD at multivariate analysis (p= 0.0081 for 1 year-CKD, p=0.0154 for 2 year-CKD).

Conclusions

In our population, AKI after LTx occurred in about half of the patients and was predicted by history of hypertension, low albumin levels and hemodynamic instability during the surgery. Mild-moderate AKI, often clinically underestimated, was strongly associated with reduced survival. Severe forms of AKI were predictive of occurrence of CKD.

P1700CYTOMEGALOVIRUS DISEASE IN RENAL TRANSPLANTED PATIENTS: DETERMINING FACTORS AND ITS RELATION WITH GRAFT OUTCOME AND PATIENTS SURVIVAL

Background

CMV disease (CMVd) is a frequent complication in renal transplanted patients (RTxp), especially during the first year of transplantation (RTx). CMVd impacts on long term graft and patients outcomes is still debated. Our observational retrospective study aims to evaluate: 1) the prevalence of CMVd during the first year of RTx; 2) the factors related to CMVd; 3) the relationship between CMVd and early and long term graft and patients survival.

Method In 505 RTxp (age: 50[41;58]yrs – 292 males), up to the 616 transplanted in our unit between 2004 and 2016, clinical, blood and urinary parameters were recorded after 1 (T1) and 12 (T12) months of RTx. eGFR was estimated by MDRD formula. Donor (D) and Recipient (R) CMV serology was tested at the moment of RTx. CMV IgG-D+/IgG-R- RTxp (12%) and high risk patients (second or more RTx, ATG induction therapy), received prophylaxis therapy until the 3rd month of RTx. CMVd, was defined by the presence either of CMVr (CMV replication without clinical signs of CMV disease) or CMVs (CMV replication with signs of disease and/or need of antiviral therapy/reduction of immunosuppressive therapy). Median follow up (FU) was 8[5-11]yrs. The following outcomes were investigated: 1) graft: reduction of eGFR >20% between T1 and T12; reduction of eGFR >50% between T1 and end of FU (eGFRr>50%); graft loss (GL); eGFRr>50% + GL.; 2) RTxp survival at the end of FU.

Results Ninty percent of RTxp had a kidney from a deceased D; 73% and 21% received haemodialysis (HD+) and peritoneal dialysis before RTx. Dialysis vintage was 50[33-75] months. In 12% of RTxp, induction therapy included ATG. Cumulative steroids dose was 880[840-105]mg and 2272[2598-3223]mg at T1 and T12 respectively. During the first year of RTx, 45% of patients had CMVd (CMVd+). CMVd+ were older than CMV free RTxp (CMVd-). Female gender, HD+ and CMV IgG-D+/IgG-R- were more prevalent in CMVd+. In addition, at T1, CMVd+ had lower albumin, haemoglobin and higher PTH, uric acid and reactive C protein levels than CMVd- and, both at T1 and T12, received higher steroid dose. In multivariate analysis, albumin-T1 was the most significant modifiable factor in determining CMVd+ (p=0.009 OR 0.50 – IC 0.29-0.84). Albumin-T1 maintained its significance also after the addiction of CMV serology IgG-D+/IgG-R- to the model (albumin T1: p=0.008 OR 0.48 – IC 0.29-0.84; CMV serology IgG-D+/IgG-R-: p=0.01 OR 2.16 – IC 1,18 -3,95). Among CMVd, 19% and 25% had respectively CMVr and CMVs. CMVs were characterized by lower dialysis vintage and higher prevalence of CMV IgG-D+/IgG-R- than CMVr. GL and death were observed in 11% and 8% of RTxp respectively. In univariate and survival analyses, CMVd, CMVr and CMVs didn’t show any impact on the graft and patients outcomes examined.

Conclusion Our retrospective study confirms the high prevalence of CMVd during the first year of RTx, and identifies albumin at T1 as the most impacting parameter in influence CMVd insurgence. This might reflect the importance of the pre-RTx status in CMVd development after RTx. Nevertheless, CMVd seems not impact significantly on early and long term outcomes, experienced however in a small part of the cohort studied. Future studies, possibly prospective and including higher number of patients might better elucidate this issue.

P0893BONE EFFECTS AND SAFETY OF ONE YEAR DENOSUMAB THERAPY IN A COHORT OF RENAL TRANSPLANTED PATIENTS: AN OBSERVATIONAL MONOCENTRIC STUDY

Background and aims

Bone and mineral metabolism (MM) disorders are relevant problems in renal transplanted patients (RTxp). In our observational monocentric study, we evaluated the effects on femoral and lumbar bone mineral density (BMD) and on MM parameters, and the safety of one year-treatment with Denosumab (DB) in a cohort of RTxp.

Method

We recorded data about 32 RTxp treated with DB in our Center in the last year. RTxp were evaluated for BMD and T-score (Ts) before the start (T0) and after 12 months (T12) of treatment. Osteopenia was defined, at femoral (F-OPN) and lumbar (L-OPN) sites as Ts:-1>Ts>-2.5 whereas osteoporosis, in the same sites (F-OPS and L-OPS) as Ts<-2.5. X ray evaluation for spontaneous vertebral fractures (sVF) was made at T0 and, in 25 RTxp repeated at T12. MM and renal function parameters (serum creatinine, sCr and daily urinary protein excretion, ProtU) were recorded at T0 and after 1,3,6, and 12 months of therapy. The clinical indications for DB therapy, in the presence of Ca>9.0 mg/dL were the finding at T0 of: 1) F-OPS and/or V-OPS; 2) sVF. During the year of treatment, hypocalcemic (HpCa=Ca<8.0 mg/dL) episodes, infections, graft rejections and loss and RTxp survival were monitored.

Results

The cohort was composed mainly by females (n=21). The time of RTx was 144[59-232]mths. Steroid therapy was prescribed in 30 RTxp (93%), 22(68%) and in 2 (6%) RTxp were taking 25OHD and 1-25OH. Three RTxp (9%) were receiving Ca supplements. Bisphosphonate therapy was reported in 15 RTxp (46%) in the year before DB start. At T0, 25(78%) and 7 (22%) RTxp had F-OPS and F-OPN. Twenty-three (71%) and 6 (20%) RTxp had L-OPS and L-OPN. In 3 RTxp normal lumbar T-score was found. sVF were present in 17 RTxp (53%). Ca and P were 9.6±0.6 mg/dL and 3.1±0.6 mg/dL whereas PTH, ALP and 25OHD were 64±32 pg/mL, 80±37 U/L and 28±16 mg/dL. SCr and Prot-U were 1,32±0,4 mg/dL and 0,23±0,16 g/24h. At T12, F-Ts increased significantly (T0: -3.0[-3.5/-2.5] vs T12:-2.8[-3.5/-2.4) as like as V-Ts (T0: -3.0[-3.7/-1.9] vs T12:-2.8[-3.0/-1.6) both p<0.0001. A significant increase was found also in BMD: F-BMD +2.4%[-1.1%/+13%] (p<0.0001), V-BMD +2.6%[-3.4%/+12%] (p=0.009). The prevalence of F-OPS reduced from 78% to 73% (p<0.0001) and 4 RTxp ameliorated their Ts category. Prevalence of V-OPS reduced to 53% at T12 from 71% (p<0.001), and 4 RTxp ameliorated their Ts category. In 2 RTxp were found novel sVF. During the treatment no significant modifications of Ca were found, with only a slight but significant difference between T0 and T12 (T12 Ca: 9.22±1.17, p=0.01). PTH and ALP were significantly higher at T3, T6 and T12 respect T0. No differences in 25OH, sCr and ProtU were found. During the year of treatment, in 3 RTxp 25OHD supplementation was started. No one required novel Ca supplementation. DB therapy wasn’t associated to HpCa episodes. Four RTxp had infections during the time of treatment (mean time of DB treatment:114 days). They had positive pathologic anamnesis for urinary tract infections (UTI). Two of them had symptomatic UTI and 2 required hospitalization for sepsis. No biopsy proven graft rejections were observed during the time of treatment and no graft loss or RTxp death were reported.

Conclusions

The preliminary results presented in our study, limited by the monocentric, not randomized design and by the smallness of the cohort, reported a good bone efficacy of DB in RTxp, especially at lumbar level. The therapy was characterized by a good general safety. Future longer and randomized studies, involving more RTxp might elucidate the possible primary role of DB in the treatment of bone disorders in RTxp.

Impact of hepatitis C virus and direct acting antivirals on kidney recipients: a retrospective study

Hepatitis C virus (HCV) in kidney transplanted patients (KTx-p) carries a high risk for a worse outcome. This retrospective study evaluates the impact of HCV and of the new direct acting antivirals (DAAs) on patient and graft outcomes in KTx patients. Forty (6.5%) of the 616 KTx-p, who received a kidney transplantation (KTx) in our Centre had antibodies against HCV: 13 were positive for HCV RNA and received DAAs (Group A); 11 were HCV RNA positive and did not receive any treatment (Group B; n = 11); 16 were negative for HCV RNA (Group C). All Group A patients had HCV RNA negativity after 12 weeks of treatment, and 12 (92.30%) achieved a sustained virological response (SVR). Only two patients, who had proteinuria greater than 500 mg/day showed a worsening of proteinuria after antiviral therapy in Group A. Liver enzyme elevation and death were significantly more frequent in Group B than other groups. Our results support the notion that active HCV infection negatively affects kidney recipients and that DAA have a high safety and efficacy profile after KTx with no significant negative effect on allograft function, particularly in well-functioning renal grafts.

Optimizing utilization of kidneys from deceased donors over 60 years: five-year outcomes after implementation of a combined clinical and histological allocation algorithm

This 5 year observational multicentre study conducted in the Nord Italian Transplant programme area evaluated outcomes in patients receiving kidneys from donors over 60 years allocated according to a combined clinical and histological algorithm. Low-risk donors 60-69 years without risk factors were allocated to single kidney transplant (LR-SKT) based on clinical criteria. Biopsy was performed in donors over 70 years or 60-69 years with risk factors, allocated to Single (HR-SKT) or Dual kidney transplant (HR-DKT) according to the severity of histological damage. Forty HR-DKTs, 41 HR-SKTs and 234 LR-SKTs were evaluated. Baseline differences generally reflected stratification and allocation criteria. Patient and graft (death censored) survival were 90% and 92% for HR-DKT, 85% and 89% for HR-SKT, 88% and 87% for LR-SKT. The algorithm appeared user-friendly in daily practice and was safe and efficient, as demonstrated by satisfactory outcomes in all groups at 5 years. Clinical criteria performed well in low-risk donors. The excellent outcomes observed in DKTs call for fine-tuning of cut-off scores for allocation to DKT or SKT in high-risk patients.

Mycophenolate mofetil modifies kidney tubular injury and Foxp3+ regulatory T cell trafficking during recovery from experimental ischemia-reperfusion

Lymphocytes participate in the early pathogenesis of ischemia-reperfusion injury (IRI) in kidney; however, their role during repair is largely unknown. Recent data have shown that Foxp3(+) regulatory T cells (Tregs) traffic into kidney during healing from IRI and directly participate in repair. Since lymphocyte-targeting therapy is currently administered to prevent rejection during recovery from IRI in renal transplants, we hypothesized that mycophenolate mofetil (MMF) would alter Treg trafficking and kidney repair. C57BL/6J and T cell deficient mice underwent unilateral clamping of renal pedicle for 45 min, followed by reperfusion, and were sacrificed at day 10. Mice were treated with saline (C) or MMF (100mg/kg) i.p. daily starting at day 2 until sacrifice (n=5-12/group). MMF worsened kidney tubular damage compared to C at 10 days (cortex and outer medulla: p<0.05) in wild-type mice; tubular apoptotic index was increased in cortex in MMF group as well (p=0.01). MMF reduced the total number of kidney-infiltrating mononuclear cells (p<0.001 versus C) and the percentages of TCRbeta(+)CD4(+) and TCRbeta(+)CD8(+) T cells (p<0.01), but not natural killer (NK), NKT or B lymphocytes. MMF specifically reduced kidney Foxp3(+) Tregs (0.82+/-0.11% versus 1.75+/-0.17%, p<0.05). Tubular proliferative index and tissue levels of basic FGF were increased in MMF group (p<0.05), IL-10 and IL-6 were decreased (p<0.05). To evaluate if MMF effect occurred through non-lymphocytic cells, T cell deficient mice were treated with MMF. Tubular injury in T cell deficient mice was not affected by MMF treatment, though MMF-treated animals had increased VEGF and decreased PDGF-BB protein tissue levels compared to controls (p<0.05). Thus, MMF modifies the structural, epithelial proliferative and inflammatory response during healing, likely through effects on T cells and possibly Tregs. Kidney repair after IRI can be altered by agents that target lymphocytes.

B cells limit repair after ischemic acute kidney injury

There is no established modality to repair kidney damage resulting from ischemia-reperfusion injury (IRI). Early responses to IRI involve lymphocytes, but the role of B cells in tissue repair after IRI is unknown. Here, we examined B cell trafficking into postischemic mouse kidneys and compared the repair response between control (wild-type) and muMT (B cell-deficient) mice with and without adoptive transfer of B cells. B cells infiltrated postischemic kidneys and subsequently activated and differentiated to plasma cells during the repair phase. Plasma cells expressing CD126 increased and B-1 B cells trafficked into postischemic kidneys with distinct kinetics. An increase in B lymphocyte chemoattractant in the kidney preceded B cell trafficking. Postischemic kidneys of muMT mice expressed higher IL-10 and vascular endothelial growth factor and exhibited more tubular proliferation and less tubular atrophy. Adoptive transfer of B cells into muMT mice reduced tubular proliferation and increased tubular atrophy. Treatment with anti-CD126 antibody increased tubular proliferation and reduced tubular atrophy in the late repair phase. These results demonstrate that B cells may limit the repair process after kidney IRI. Targeting B cells could have therapeutic potential to improve repair after IRI.

Early exposure to germs modifies kidney damage and inflammation after experimental ischemia-reperfusion injury

Kidney ischemia-reperfusion injury (IRI) is, in part, mediated by immune and inflammatory factors. Since microbial stimuli are known to alter immune and inflammatory responses, we hypothesized that differences in perinatal microbial status would modify renal injury following IRI. We performed bilateral renal IRI on 6-wk-old germ-free and control mice and studied the effects on kidney lymphocyte trafficking, cytokines, function, and structure. Compared with control mice, normal kidneys of germ-free mice exhibited more NKT cells and lower IL-4 levels. Postischemia, more CD8 T cells trafficked into postischemic kidneys of germ-free mice compared with control mice. Renal structural injury and functional decline following IRI were more severe in germ-free mice compared with control mice. When germ-free mice were conventionalized with the addition of bacteria to their diet, the extent of renal injury after IRI became equivalent to age-matched control mice, with similar numbers and phenotypes of T cells and NKT cells, as well as cytokine expression in both normal kidneys and postischemic kidneys of conventionalized germ-free mice and age-matched control mice. Thus microbial stimuli influence the phenotype of renal lymphocytes and the expression of cytokines of normal kidneys and also modulate the outcome of IRI.

Foxp3+ regulatory T cells participate in repair of ischemic acute kidney injury

T lymphocytes modulate early ischemia-reperfusion injury in the kidney; however, their role during repair is unknown. We studied the role of TCRbeta(+)CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs), known to blunt immune responses, in repair after ischemia-reperfusion injury to the kidney. Using a murine model of ischemic acute kidney injury we found that there was a significant trafficking of Tregs into the kidneys after 3 and 10 days. Post-ischemic kidneys had increased numbers of TCRbeta(+)CD4(+) and TCRbeta(+)CD8(+) T cells with enhanced pro-inflammatory cytokine production. Treg depletion starting 1 day after ischemic injury using anti-CD25 antibodies increased renal tubular damage, reduced tubular proliferation at both time points, enhanced infiltrating T lymphocyte cytokine production at 3 days and TNF-alpha generation by TCRbeta(+)CD4(+) T cells at 10 days. In separate mice, infusion of CD4(+)CD25(+) Tregs 1 day after initial injury reduced INF-gamma production by TCRbeta(+)CD4(+) T cells at 3 days, improved repair and reduced cytokine generation at 10 days. Treg manipulation had minimal effect on neutrophil and macrophage infiltration; Treg depletion worsened mortality and serum creatinine, while Treg infusion had a late beneficial effect on serum creatinine in bilateral ischemia. Our study demonstrates that Tregs infiltrate ischemic-reperfused kidneys during the healing process promoting repair, likely through modulation of pro-inflammatory cytokine production of other T cell subsets. Treg targeting could be a novel therapeutic approach to enhance recovery from ischemic acute kidney injury.

Androgen-mediated apoptosis of kidney tubule cells: role of c-Jun amino terminal kinase

The incidence and the rate of progression of chronic kidney diseases (CKD) are for most diseases greater in men than in age-matched women. We have previously shown that testosterone (T) promotes the apoptosis of proximal tubule kidney cells. To better understand the downstream signaling process associated with T-induced apoptosis, we examined the involvement of c-Jun amino terminal kinase (JNK) in a human proximal tubule cell line (HK-2) exposed to T: JNK and its downstream effector c-Jun were rapidly phosphorylated. By blocking androgen receptor, JNK phosphorylation was reduced and 17beta-Estradiol treatment had no effect on it. Similarly, pre-treatment with the JNK inhibitor SP600125 prevented the T-induced apoptosis, the phosphorylation of c-Jun and the upregulation of the Fas/FADD pathway. These data show that the JNK/c-Jun pathway is directly regulated by androgens in vitro and highlight a potential mechanism explaining the reported gender differences in the progression of renal diseases.

The role for T cell repertoire/antigen-specific interactions in experimental kidney ischemia reperfusion injury

T cells have been implicated in the early pathogenesis of ischemia reperfusion injury (IRI) of kidney, liver, lung, and brain. It is not known whether Ag-TCR engagement followed by Ag-specific T cell activation participates in IRI. T cell-deficient nu/nu mice are moderately resistant to renal IRI, which can be reversed upon reconstitution with syngeneic T cells. In this study, we found that nu/nu mice reconstituted with DO11.10 T cells, limited in their TCR repertoire, have significantly less kidney dysfunction and tubular injury after renal IRI compared with that in nu/nu mice reconstituted with wild-type T cells having a diverse TCR repertoire. CD4(+) T cells infiltrating ischemic kidneys of nu/nu mice reconstituted with DO11.10 T cells exhibited lower IFN-gamma production than that of wild-type controls. Frequency of regulatory T cells in kidneys of these mice was similar in both DO11.10 T cells and wild-type T cell recipient groups. DO11.10 mice immunized with OVA-CFA had significantly worse kidney function at 24 h after ischemia than those immunized with CFA alone. Thus, without T cell activation, diverse TCR repertoire was important for renal IRI in naive mice. However, once T cells were activated in an Ag-specific manner through TCR in DO11.10 mice, a restricted TCR repertoire no longer limited the extent of kidney injury. Thus, both TCR repertoire-dependent and -independent factors mediate T cell functions in kidney IRI.

Mechanisms of renal ammonia production and protein turnover

Renal synthesis and excretion of ammonia are critical for efficient removal of acids from the body. Besides the rate of ammonia production, the intrarenal distribution of produced ammonia is a crucial step in the renal regulation of acid-base balance. Various acid-base disorders are associated not only with changes in ammonia production but also with its distribution between the urine and the renal veins. The final effect of ammonia production on acid-base balance largely depends on the events that determine the distribution of ammonia produced between urine and blood. Several factors, among which urine pH, urine flow, total ammonia production "per se" and renal blood flow may affect the percent of ammonia excreted into urines in humans with different acid-base disturbances. Among these factors, urine pH is the most important. An additional effect of stimulated ammoniagenesis is kidney hypertrophy. In tubule epithelial cells, the associated increase in ammonia production, rather than the acidosis per se, is responsible for favoring tubular hypertrophy. This effect is related to the inhibition of protein degradation, owing to changes in lysosomal pH and cathepsin activity, without effects on cell cycle. Both changes of PI-3 kinase pathway and the suppression of chaperone-mediated autophagy are candidate mechanism for ammonia-mediated inhibition of protein degradation in tubule cells. Available data in humans indicate that the response of kidney to metabolic acidosis includes both changes in amino acid uptake and suppression of protein degradation. The latter effect is associated with the increase in ammonia excretion and partition into the urine.

Accelerated senescence in the kidneys of patients with type 2 diabetic nephropathy

We examined the hypothesis that senescence represents a proximate mechanism by which the kidney is damaged in type 2 diabetic nephropathy (DN). As a first step, we studied whether the senescence-associated β-galactosidase (SA-β-Gal) and the cell cycle inhibitor p16INK4A are induced in renal biopsies from patients with type 2 DN. SA-β-Gal staining was approximately threefold higher ( P < 0.05) than in controls in the tubular compartment of diabetic kidneys and correlated directly with body mass index and blood glucose. P16INK4A expression was significantly increased in tubules ( P < 0.005) and in podocytes ( P = 0.04). Nuclear p16INK4A in glomeruli was associated with proteinuria ( P < 0.002), while tubular p16INK4A was directly associated with body mass index, LDL cholesterol, and HbA1c ( P < 0.001–0.05). In a parallel set of experiments, proximal tubule cells passaged under high glucose presented a limited life span and an approximately twofold increase in SA-β-Gal and p16INK4A protein. Mean telomere lengths decreased ∼20% as an effect of replicative senescence. In addition, mean telomere decreased further by ∼30% in cells cultivated under high glucose. Our results show that the kidney with type 2 diabetic nephropathy displays an accelerated senescent phenotype in defined renal cell types, mainly tubule cells and, to a lesser extent, podocytes. A similar senescent pattern was observed when proximal tubule cell cultures where incubated under high-glucose media. These changes are associated with shortening tubular telomere length in vitro. These findings indicate that diabetes may boost common pathways involving kidney cell senescence, thus reinforcing the role of the metabolic syndrome on biological aging of tissues.

Apoptosis in the kidneys of patients with type II diabetic nephropathy

The occurrence and extent of apoptosis in the kidneys of patients with diabetic nephropathy is largely unknown. We evaluated apoptosis in renal biopsies obtained from patients with early or advanced type II diabetic nephropathy. Apoptosis was about 6- and 3-fold higher, respectively, in glomeruli and tubules in kidneys of patients with early nephropathy than in the normal kidney and this was not further increased in advanced diabetic nephropathy. Glomerular apoptosis was related directly to hemoglobin A1(c) and systolic blood pressure, whereas tubular cell apoptosis correlated to diabetes duration and low-density lipoprotein-cholesterol. Fas, Fas ligand, and p38 mitogen-activated protein kinase expressions were enhanced in glomeruli and tubules; however, this did not correlate with apoptosis. In patients with proteinuria, apoptosis was associated with the subsequent loss of kidney function. When these parameters were subjected to multivariate analysis, only glomerular apoptosis retained a significant independent predictive value. Our findings suggest that apoptosis might be a clinically relevant mechanism of glomerular and tubular cell loss in proteinuric type II diabetic patients.

Very early alloantigen-independent trafficking of lymphocytes during ischemic acute kidney injury

Lymphocytes play an important role during ischemia-reperfusion injury (IRI). Lai et al. have demonstrated, for the first time, an increase in kidney lymphocytes 1 hour after IRI, a newly identified kidney lymphocyte reservoir, and have confirmed the pathogenic role of lymphocytes by manipulating the sphingosine-1-phosphate (SIP)-sphingosine-1-phosphate type 1 (S1P1) receptor pathway.

Kidney and splanchnic handling of Interleukin-6 in humans

Chronic elevation of circulating Interleukin-6 (IL-6) is observed in elderly individuals as well as in several illnesses, including chronic kidney diseases. A number of cells and tissues possess the ability to metabolize significant amounts of IL-6 in vitro. However, information on signals and mechanisms by which IL-6 is removed from blood in humans is still incomplete. To assess the individual role of splanchnic organs and kidney on IL-6 inter-organ exchange we used the IL-6 mass-balance technique across the hepato-splanchnic bed and kidney in six subjects with normal renal and liver function undergoing diagnostic venous catheterizations. Both in the hepatic and renal veins IL-6 levels were significantly lower (p=0.041 and 0.038, respectively), than in the artery. The fractional extraction of IL-6, i.e., the percentage of arterial IL-6 extracted after a single pass, was greater across the splanchnic organs (18%) than across the kidney (8%). Accordingly, IL-6 plasma clearance across splanchnic organs was greater than across the kidney and the sum of kidney and splanchnic removal accounted for as much as 63% of the estimated adipocyte IL-6 release. Our data demonstrate that, although the individual contribution to removal is different, both splanchnic organs and kidneys affect in a significant way the disposal of IL-6 in humans. According, both liver and kidney dysfunction could affect the handling of this proinflammatory cytokine and favour a chronic inflammatory response.

Peripheral tissue release of interleukin-6 in patients with chronic kidney diseases: effects of end-stage renal disease and microinflammatory state

To examine if uremia influences muscle interleukin-6 (IL-6) metabolism we studied the exchange of IL-6 across the forearm in 16 patients with chronic kidney disease (CKD) (stages 3 and 4), in 15 hemodialysis (HD)-treated end-stage renal disease (ESRD) patients (n=15), and in six healthy controls. In addition, we performed an analysis of both IL-6 protein and IL-6 mRNA expression in muscle of CKD (stage 4) patients showing evidence of inflammation and in controls. A release of IL-6 from the forearm was observed in patients with elevated IL-6 plasma levels. Arterial IL-6 was directly related to released IL-6 (r=0.69; P<0.004) in HD patients. Both IL-6 protein and IL-6 mRNA expression were increased in muscle of inflamed CKD patients vs controls (P<0.05). Although muscle net protein balance was similar in all patients, it was significantly more negative in HD patients with high than in those with low IL-6 plasma levels (P<0.05). In addition, net protein balance was related to the forearm release of IL-6 in HD patients only (r=0.47; P<0.038). These data demonstrate that IL-6 expression is upregulated in muscle, and that muscle tissue, by releasing this cytokine, may contribute to the inflammatory response in HD patients. The release of IL-6 from peripheral tissues is associated with an increase in muscle protein loss in HD patients, suggesting that muscle release of IL-6 is linked to protein catabolism in these patients. The release of IL-6 from peripheral tissues may act as a signal for the inflammatory response and contribute to functional dysregulation in uremia.

Testosterone promotes apoptotic damage in human renal tubular cells

BACKGROUND

Apoptosis is a mode of cell death that participates in the kidney physiologic remodeling processes and is thought to contribute to cell loss and kidney structural damage in chronic renal diseases. Gender is one factor which contributes to accelerated nephron loss, with progression more rapid in men than in women in diabetic and nondiabetic chronic renal diseases. Mechanisms by which androgens may cause higher rate of progression of chronic renal diseases in men are poorly explored.

METHODS

In this study, to investigate the role of androgens on apoptotic damage and its associated mechanisms, we examined the effects of testosterone (T) (0.1 nmol/L to 1 micromol/L) on apoptosis, and apoptosis-related proteins in a proximal human tubule cell line (HK-2 cells). Additional experiments were performed in primary cultures of proximal tubular epithelial cells (PTECs). Cells were grown to subconfluence in normal growth medium, and apoptotic damage was induced by serum deprivation for 24 to 48 hours. Cycloheximide, flutamide (a T-receptor antagonist), 17-beta estradiol, or caspase inhibitors were added to cultures that were successively processed for terminal deoxynucleotidyl transferase-mediated uridine triphosphate nick end-labeling (TUNEL) analysis, annexin V/propidium iodide staining, immunofluorescence, or immunoblots to identify effects and apoptotic pathways that could be modulating cell survival.

RESULTS

Both morphologic analysis by annexin V/propidium iodide staining and TUNEL showed that physiologic T levels (1 to 10 nmol/L) induced a significant increase in apoptosis both in HK-2 cells and PTECs. In both types of cell lines pretreatment with the androgen receptor antagonist flutamide prevented the T-induced apoptosis. T-induced apoptosis was enhanced by treatment with cycloheximide and prevented by 17beta-estradiol. Fas, Fas ligand (FasL), and Fas-associating death domain containing protein (FADD) were clearly up-regulated within 48 hours of T treatment in HK-2 cells. Also, T significantly increased the expression of Bax protein (P < 0.01 vs. control) (an effect which was blocked by flutamide), and decreased the expression of Bcl-2. Western blot analysis showed that caspase-3 was activated. Moreover, cleavage into an 85-kD poly(ADP-ribose) polymerase-1 (PARP-1) terminal breakdown product was detectable. The changes in cellular morphology induced by T at 48 hours were no longer observed after the addition of caspase-8, caspase-9, and caspase-3 inhibitors to the culture medium.

CONCLUSION

These results indicate that T increases the permissiveness of proximal tubule kidney cells to apoptotic effects by triggering an apoptotic pathway involving caspase activation, Fas up-regulation, and FasL expression, thus potentially interacting with mechanisms of cell loss which have been already shown to be activated in chronic renal diseases. This is consistent with a role for T in promoting renal injury in men.

Gender and the progression of chronic renal diseases: does apoptosis make the difference?

Several studies in patients with chronic kidney diseases have shown that men have a more rapid disease progression than women. Also, with ageing, men exhibit greater decrements in renal function and increased glomerular sclerosis than women. Data from meta-analysis studies indicate that women with several non-diabetic renal diseases such as membranous nephropathy, IgA nephropathy and polycystic kidney disease present a slower progression, but in diabetic renal disease this is not yet established. Thus, men appear to be at greater risk for renal injury than are women, but the underlying mechanisms are unknown. Sex hormones may mediate the effects of gender on chronic renal disease, through the interaction with the renin-angiotensin system, the modulation of nitric oxide synthesis and the downregulation of collagen degradation. New observations indicate that androgens may contribute to continuous loss of kidney cells though the stimulation of apoptotic pathways. Apoptosis is an unique type of programmed cell death which is activated in several chronic kidney diseases. Studies in vitro indicate that androgens prime a Fas/FasL dependent apoptotic pathway in kidney tubule cells. This apoptotic cell death pathway is receptor-linked and interacts with the mitochondrial pathway, which may be activated by other mechanisms, such as toxins and ischemia. Therefore, the mechanisms to cell death which are primed by androgens may interact with others occurring in several conditions leading to the loss of renal cells. These findings are consistent with a role for androgens to promote chronic renal injury in men.

Oxidative Stress Mediates Apoptotic Changes Induced by Hyperglycemia in Human Tubular Kidney Cells

Reactive oxygen species (ROS) are important mediators for several biologic responses, including apoptosis. The present study evaluated the time course of changes in intracellular ROS production and apoptosis-related proteins, as well as apoptotic changes in human tubular proximal cells (HK-2 cells) exposed to hyperglycemia. Apoptosis (annexin V binding), ROS formation (fluorescence probe dichlorofluorescin diacetate and FACScan flow cytometry), and X chromosome-linked protein (XIAP; Western blot) were studied in HK-2 cells grown in a medium containing normal (NG) or high glucose (HG) concentrations (5.5 or 30 mM, respectively) for 18 to 48 h. HG promoted an increase (65% at 18 h and 73% at 24 h; P < 0.05 versus NG) in intracellular ROS generation. At 18 h, the NF-kB binding activity (evaluated by electrophoretic mobility-shift assay) was suppressed by HG. At the same time, the expression of NF-kB-induced antiapoptotic XIAP was reduced in HG-treated cells. Apoptotic changes were observed at 48 h (34 +/- 7% in HG versus 10 +/- 3% in NG; P < 0.001). Changes in ROS production at 24 h predicted changes in the apoptotic index at 48 h (r = 0.96, P < 0.0001). These results suggest that hyperglycemia induces apoptotic changes in human tubular cells via an increase in oxidative stress and that a downregulation of antiapoptotic protein XIAP is a component of this response.

Interorgan exchange of aminothiols in humans

In the present study, we used organ balance across the kidney, splanchnic organs, and lower limb in subjects undergoing diagnostic central venous catheterizations to gain insight into the renal and extrarenal exchange of aminothiols in humans. Although Hcy was released only in low amounts from leg tissues, Cys-Gly (a peptide derived from GSH hydrolysis) was released by both the leg and splanchnic organs, whereas Cys was released by the kidney and taken up by splanchnic organs. The kidney removed approximately 90% of the Cys-Gly released into the circulation. Removal of Cys-Gly by the kidney depended on Cys-Gly arterial levels and showed a high fractional extraction ( approximately 26%), with clearance rates slightly higher than the glomerular filtration rate (GFR). Although the average kidney removal of Hcy was not statistically significant, the fractional extraction of Hcy across the kidney varied directly with renal plasma flow. Our data show that thiol metabolism in humans is a compartmentalized interorgan process involving fluxes of individual aminothiols that are parallel and of opposite sign among peripheral tissues, splanchnic organs, and kidney. Cys-Gly is released by peripheral tissue and splanchnic organs from GSH hydrolysis and is taken up by the kidney by GFR; the kidney returns Cys to the circulation to preserve substrate availability for GSH synthesis. On the other hand, Hcy is released by peripheral tissues in low amounts, and its removal by the kidney seems to depend on blood supply. These findings may help explain several alterations in aminothiol metabolism observed in patients with chronic diseases.

Taurine prevents apoptosis induced by high ambient glucose in human tubule renal cells

BACKGROUND

Hyperglycemia selectively triggers apoptosis in tubule and endothelial cells. Taurine, a conditionally essential amino acid, is abundant in several tubule segments, but its role has not been defined fully. It can serve as an osmolyte or as an endogenous antioxidant. Taurine metabolism is altered in diabetes mellitus, with extracellular and intracellular pools reduced. It is still unknown whether taurine can play a role as a protective agent in apoptosis induced by high glucose in tubular cells.

METHODS

Apoptosis (by annexin V binding and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method), cellular reactive oxygen species (ROS) formation (by fluorescent probe 2'-7' dichlorofluorescin diacetate and FACScan flow cytometry), and Bcl-2 and Bax proteins (by immunostaining) were studied in a human proximal tubular cell line (HK-2) grown in a medium with physiologic (5.5 mM) or high (30 mM) glucose concentrations for 48 hours. In separate experiments, taurine (3-24 mM) was added to the media.

RESULTS

The exposure of human tubule cells to 30 mM glucose for 48 hours resulted in a significant increase in apoptosis compared with 5.5 mM glucose (35 +/- 8% vs. 6 +/- 3%, p < 0.001). Thirty mM mannitol failed to induce the effects of high glucose. High glucose-mediated apoptosis was associated with a decrease in the expression of Bcl-2 (-87%) and a twofold increase in the expression of Bax protein. Taurine had a dose-dependent effect in preventing high-glucose-induced apoptosis (-78%, p < 0.001 at 24 mM). Moreover, with taurine, intracellular ROS decreased by 34% (p < 0.05), and changes in intracellular ROS formation induced by taurine at 24 hours predicted the variations in the apoptotic index at 48 hours (r = 0.87, p < 0.02). Other antioxidants, such as glutathione and N-acetylcysteine, also attenuated the high glucose-induced apoptosis.

CONCLUSION

These results demonstrate that taurine attenuates hyperglycemia-induced apoptosis in human tubular cells via an inhibition of oxidative stress. Taurine might act as an endogenous antioxidant in tubule cells and could exert a beneficial effect in preventing tubulointerstitial injury in diabetic nephropathy.

Apoptosis induced by serum withdrawal in human mesangial cells. Role of IGFBP-3

Apoptosis has been reported to occur both during the course of kidney development and the progression of kidney injury to scarring. Insulin-like growth factor binding protein-3 (IGFBP-3), a component of the IGF system, has been shown to induce apoptosis in cancer cell lines. However, if IGFBP-3 has similar effects in human mesangial cells (HMC) remains unknown. The purpose of this study was to examine the expression of IGFBP-3 and its possible effect on the induction of apoptosis in HMC during serum deprivation. We have observed that IGFBP-3 accumulates progressively in HMC in which serum has been withdrawn. In these cells, an increase of IGFBP-3 is observed before the production of apoptosis suggesting a link between these phenomena. Furthermore, the addition of IGFBP-3 in physiological amounts (from 100 to 400 ng/ml) to culture medium devoid of growth factors accelerates and increases the apoptotic process with a dose-dependent effect. These findings suggest that IGFBP-3 is a mediator of cell death in human mesangial cells when the availability of growth factors is curtailed. These data also suggest that IGFBP-3 could contribute to apoptotic processes observed in human disease.

[Insulin-dependent diabetes and pregnancy. A model of coordinated approach]

A historical account of the relation between diabetes and pregnancy is followed by the presentation of a personal series of 10 insulin-dependent diabetic pregnant women (3 White's class B, 2 class C, 3 class D and 2 class F/R) treated in accordance with a newly applied quarterly and fortnightly protocol. Nearly normal blood sugar (HbA1 maintained around 8% in the second and third trimester) was achieved through home blood glucose self-monitoring, in keeping with the Karen Bruni Centre's educational programme. This includes self-management of intensified insulin treatment in the form of 2-3 injections per day (Monotard MC and HM, Actrapid MC and HM), as well as the use of Novo Pen (100 U/ml Actrapid HM) for supplementary insulinisation. Average insulin initial dose: 0.51 U/Kg/day (range 0.2-0.7); final dose 0.83 U/Kg/day (range 0.6-1.2). Delivery was by caesarean section on obstetric indication: 9 at the 36th week, 1 at the 34th for trisymptomatic gestosis. There were no foetal nor neonatal death. All children were subjected to intensive neonatological care. There were 3 cases of macrosomia and 1 tetralogy of Fallot, which followed a benign course. Despite their absence of statistical value, these data show that optimised multidisciplinary treatment can be of utility in preventing neonatal morbidity and mortality in an insulin-dependent diabetic pregnancy. They also indicate that a coordinated treatment model can equally be put into effect even in a non centralised structure, provided certain facilities exist: in our case, voluntary support on the part of Karen Bruni Diabetic Association, obstetric interest in diabetology and a neonatological background for treatment of the offspring of diabetic mothers. Lastly, this series substantiate the effectiveness of the programme of self-checking and self-management of diabetes in the accomplishment of "optimised" blood glucose control and containment of costly hospitalisation at the time of delivery.

[Importance and usefulness of transcutaneous PO2 in neonatology. Experience with the healthy and sick neonate]

The authors have checked transcutaneous PO2 in newborns in the Neonatology Department of Maria Vittoria Hospital, Torino, Italy. 39 full-term newborns (healthy, Apgar score more than 7) have been monitorized during their first minutes. The results have been divided in four groups: spontaneous birth or caesarean section with fetal suffering or not. Significant differences have been shown between newborns with fetal suffering whether they were born by caesarean section or not, and between born by caesarean section with or without fetal suffering. 27 newborns with gestational age of 32 weeks or less have been monitorized all the time they were in need of oxygen therapy. 29,6% of these babies have shown, during the first week of life, at least one peak of tcPO2 more than 100 torr. The authors insist on the importance of tcPO2 monitoring during the first moments of life, on the influence of labour conditions and type of birth. In preterm neonates treated with oxygen therapy, tcPO2 is now the best method to evaluate hypoxia (leading to cerebral lesions) and hyperoxia (with risk of retinal and pulmonary damage).

[Perinatal mortality in various weight classes: evaluation of data of the Ospedale Maria Vittoria, Turin 1977-1981]

The authors have studied stillbirth, early neonatal death rate, perinatal death rate following weight classes, weight distribution in live born and death causes between 1977 and 1981. These data permit to evaluate the degree of efficiency in the obstetrical and neonatological department. Weight distribution pattern has been fairly constant and low-weight incidence similar to that found by other authors. Perinatal death rate has remained stable in time around 11,4%. Still births have increased particularly in weight classes between 1001 and 2000 g. Early newborn death rate has decreased in weight classes between 2001 and 2500 and over 4000 g. Asphyxia was the most frequent death cause in weight classes between 1501 and 2000 g and between 2501 and 4000 g. These data are similar to those found in british and swedish studies. The authors insist that every effort must be made to reduce not only perinatal death rate but also to prevent future handicaps.