Quantitative digital histochemistry with methenamine silver staining in renal allograft biopsies excluding pure chronic allograft nephropathy cases.

Deterioration of renal function is correlated with irreversible damage in chronic diseases. Recently we described a digital quantitative histochemistry method, relying on periodic acid methenamine silver (PAMS) staining to determine the chronic renal lesions. This index was strongly correlated with progressive deterioration of renal function in grafts with chronic allograft nephropathy (CAN). Herein the method has been applied to a cohort of renal allografts which were biopsied for various reasons, we sought to highlight its value to quantify chronic graft damage. Forty-four renal allograft biopsies from 37 patients with elevated serum creatinine values (SCr) underwent light microscopic image analysis (Mediscope, Dokuz Eylül University, Clinical Engineering Department, Izmir, Turkey) of the PAMS-stained area percentage (SAP). SCr was recorded at four intervals to overcome acute effects: the under SCr value before (SCr1) and after a biopsy within 3 months (SCr3), SCr at the time of the biopsy (SCr2), and the latest value (SCr4). The PAMS-SAP scores were strongly associated with increased interstitial fibrosis and tubular atrophy Banff scores (Kruskal-Wallis test, P = .006 and P = .003, respectively). There was a moderate positive correlation between PAMS and SCr3 (Pearson correlation test, P = .04, r = .312), and a strong positive correlation between time from transplantation to biopsy (Pearson correlation test, P << .000, r = .532). The present results show that PAMS-SAP seems to be of value to quantify renal scarring in allograft biopsies, reflecting four compartments. The strong correlation with time is noteworthy especially as a probable reflection of aging of the renal allograft.

Association of corticosteroids and factor V, prothrombin, and MTHFR gene mutations with avascular osteonecrosis in renal allograft recipients.

The mechanism of posttransplantation avascular osteonecrosis (AVN) is controversial. Besides an increased bone marrow pressure due to reduced blood supply, enhanced coagulation has been considered. We investigated the associations of factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations as well as cumulative corticosteroid doses with AVN in renal allograft recipients. The records of 39 volunteer patients and 11 patients in whom osteonecrosis was previously identified were reviewed for cumulative corticosteroid dosages during the first year. All patients were screened for factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations by direct sequencing of genomic DNA. The cumulative corticosteroid dosages at 3, 6, and 12 months in the osteonecrotic group (5033.5 +/- 1565.3, 7164.9 +/- 2063.1, 8835.1 +/- 2216.8 mg) were significantly higher than in the control group (3629 +/- 1504.1, 4784.5 +/- 1568.7, 6322.4 +/- 1686.6 mg; P = .013, P = .001, P = .001, respectively). No significant difference in factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations was observed between the osteonecrotic and control groups (P > .05). In conclusion, an association between the first year (3, 6, and 12 month) cumulative corticosteroid dosages and AVN was demonstrated in renal transplant recipients. However, no correlation was determined between factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations and osteonecrosis.

Methenamine silver staining quantitative digital histochemistry in chronic allograft nephropathy.

Renal function and final outcome of renal allografts have been correlated with irreversible damage. This study describes a quantitative histochemical method relying on periodic acid methenamine silver (PAMS) staining of all renal compartments. Among 60 renal allograft biopsies from 43 patients, 15 biopsies showing pure chronic allograft nephropathy were selected to determine PAMS-stained area percentage (SAP), using image analysis with quantitative histochemistry. Of the 15 cases, 9 (60%) were grade I and 6 (40%) were grade II chronic allograft nephropathy (CAN). The mean serum creatinine (sCr) value was 1.86 +/- 0.47 for allograft biopsies. The mean (+/-SD) SAP for the implantation biopsies was 10.58 +/- 1.87%, and for allograft biopsies 25.26 +/- 9.67 (P <<.000). The serum creatinine (sCr) values for grade I versus II CAN were 1.63 +/- 0.24 versus 2.20 +/- 0.54 mg/dL, respectively (P=.019), and SAP values were 18.97 +/- 0.24 versus 34.7 +/- 5.89 (P=.003). There was a strong positive correlation between sCr values and SAP (P=.005; r=0.64). These findings show the PAMS approach to be a useful alternative method for reflecting damage in more than one compartment of the renal tissue. Also, the method can discriminated implantation and allograft biopsies as well as grade I and II CAN cases. The series is small for a multivariate analysis of the value of SAP measurements in PAMS-stained sections as a prognosticator, but the data support its use.