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Protocol biopsies performed in stable renal allografts show different degrees of acute and chronic lesions. Histologic findings in protocol biopsies have been related to graft outcome. We evaluated histologic lesions observed in protocol biopsies performed in patients under different immunosuppression therapies. From June 1988 a protocol biopsy was performed at approximately 4 months in patients who fulfilled the following criteria: serum creatinine <300 μmol/L; stable renal function; and proteinuria <1 g/d. Histologic lesions were graded according to 1997 Banff criteria. For the present study we considered the following groups according to immunosuppressive schedule: (i) induction therapy with polyclonal or monoclonal antilymphocytic antibodies associated with cyclosporine and prednisone (n = 201); (ii) cyclosporine, mycophenolate mofetil, and prednisone (n = 127); and (iii) tacrolimus, mycophenolate mofetil, and prednisone (n = 51). On protocol biopsy patients treated with tacrolimus displayed a lower acute score (0.61 ± 1.01 vs 1.24 ± 1.23 in group I, 1.28 ± 1.41 in group II; P < .0001) and a higher proportion of normal biopsies (57.1% vs 41.9% in group I, 45.1% in group II; P = .016). A similar proportion of chronic lesions (chronic score of group I: 1.30 ± 1.56; group II: 1.34 ± 1.80; group III: 1.51 ± 0.95; P = NS) was observed in the three groups. Protocol biopsies displayed fewer acute lesions in patients treated with tacrolimus. This result suggests that the efficacy of new immunosuppression schedules can be evaluated using the protocol biopsy as a surrogate marker of graft outcome. [Copyright &y& Elsevier]

Abstract: Introduction: Epidemiological studies have shown that demographic, clinical, and histological donor characteristics influence renal function after transplantation, but whether these variables are independent predictors has not been established. The aim of this study was to evaluate the relative contribution of different donor variables on glomerular filtration rates (GFRs) at 3 months. Patients and methods: We analyzed single renal transplants performed at our center from January 2000 to July 2004. Donor variables included age, gender, weight and height, cause of death, duration of brain death, serum creatinine at admission and preprocurement, history of arterial hypertension or diabetes mellitus, and smoking habit. Donor chronic damage score was calculated in preimplantation biopsies as was the addition of interstitial fibrosis, fibrous intimal thickening, and glomerulosclerosis (<10% = 0, >10% = 1). Donor and recipient GFRs were calculated according to the Cockroft-Gault formula. Results: We analyzed 202 transplants obtained from 113 deceased donors. A renal biopsy was available in 111 transplants. Recipient GFR at 3 months correlated negatively with donor age (R = −0.32, P < .01) and donor chronic damage score (R = 0.32, P < .01). GFR was lower among recipients of female versus male donors (50 ± 15 vs 60 ± 20 mL/min; P < .01). Donor cerebrovascular accident death (53 ± 19 vs 63 ± 19 mL/min; P < .01) and hypertension (48 ± 16 vs 59 ± 20 mL/min; P < .01) were also associated with lower GFR at 3 months. There was a positive correlation between GFR at admission, GFR preprocurement, and GFR at 3 months (R = 0.32 and R = 0.18 respectively; P < .01). Stepwise regression analysis included chronic damage score, GFR at admission, and donor gender but not donor age as independent predictors of GFR at 3 months (R = 0.50; P < .01). Conclusion: Donor structural and functional parameters are independent predictors of renal function at 3 months. [Copyright &y& Elsevier]

After transplantation, glomerular volumes increases and large glomerular volume at 4 months is associated with better renal function. The aim is to characterize glomerular adaptation after the fourth month in two serial protocol biopsies and its relationship with subclinical rejection and chronic allograft nephropathy (CAN). Mean glomerular volume (Vg) was estimated according to the Weibel and Gomez method in a 4-month and 1-year serial protocol biopsies in 61 stable grafts. Glomerular enlargement (δVg) was calculated as the Vg difference between both biopsies. Banff schema was used to evaluate renal biopsies. Vg increased from 4.4±2.4 to 5.7±2.6 × 106 μm3 (P<0.001). Mean δVg was 1.0 × 106 μm3. Patients with δVg<1 were considered as patients with impaired glomerular enlargement (n=29). Impaired glomerular enlargement was associated with increased acute index score in the 4-month (1.83±1.56 vs 1.06±1.48; P<0.05) and 1-year protocol biopsies (1.52±1.59 vs 0.62±1.07; P<0.05). Impaired glomerular enlargement was also associated with increased progression of chronic lesions between the 4-month and 1-year biopsy in the glomerular (0.17±0.38 vs 0.55±0.63; P<0.01), tubular (0.38±0.56 vs 0.83±0.85; P<0.01), and interstitial compartment (0.41±0.57 vs 0.90±0.86; P<0.01). The proportion of sclerotic glomeruli between both biopsies increased in patients with impaired glomerular enlargement (1.5±3.9 to 5.3±10.1, P<0.05) while it did not modify in patients with glomerular enlargement (2.1±7.3 vs 2.6±4.5; P=NS). During the first year, glomeruli enlarge but this adaptation mechanism is impaired in patients with subclinical rejection. Moreover, impaired glomerular enlargement is associated with progression of CAN.Kidney International (2006) 70, 557–561. doi:10.1038/sj.ki.5001582; published online 21 June 2006 [ABSTRACT FROM AUTHOR]