Histopathologic Evaluation of Pretransplant Biopsy as a Factor Influencing Graft Function After Kidney Transplantation: A 1-Year Observation

Correlation of acute tubular injury in reperfusion biopsy with renal transplant outcomes

Acute tubular injury (ATI) is common at reperfusion, but its relationship to graft outcomes is unclear. Prior studies lack standardization of morphological assessments and included elements of acute and chronic tubular injury. This study aimed to evaluate the impact of ATI on graft outcomes. Reperfusion biopsies from 2004 to 2009 were retrospectively reviewed. ATI was assessed by a new standardized scoring system. We also assessed chronic injury (CI) by the Banff criteria. Outcomes evaluated included glomerular filtration rate (GFR) at 1 and 5 years and delayed graft function (DGF), acute rejection (AR), graft and patient survival. ATI did not correlate with DGF, AR, graft or overall survival. Mild-moderate ATI was not predictive of GFR post-transplant. Moderate-severe CI was associated with lower GFR at 5 years with a mean difference of -7.14 mL/min/1.73 m(2) (P=.04) and overall survival (HR 2.44, P=.01). Other predictors of graft function included donor age, DGF, and AR. Histologic criteria of ATI at implantation in the absence of donor demographics or clinical information do not provide sufficient predictability in outcomes after transplantation. On the other hand, histologic assessment of CI correlates with GFR and overall survival.

The prognostic value of frozen section preimplantation graft biopsy in the outcome of renal transplantation

INTRODUCTION

Preimplantation biopsy provides a window on the state of the renal allograft. In this study, the prognostic value of frozen section preimplantation graft biopsy was estimated and compared to regularly processed formalin-fixed biopsy.

MATERIALS AND METHODS

Seventy-four renal allograft recipients were studied. The degree of glomerulosclerosis, acute tubular necrosis, interstitial fibrosis, arteriosclerosis, and arteriolosclerosis was rapidly estimated in frozen sections and correlated to the renal function in the immediate posttransplantation period and 3 months thereafter. The histological changes were also examined in paraffin-embedded sections.

RESULTS

The histological changes observed in rapidly processed frozen sections were comparable to those observed on regularly processed sections and their differences did not reach statistical significance. Glomerulosclerosis and arteriolosclerosis were underestimated, whereas acute tubular necrosis and interstitial fibrosis were overestimated, in the frozen sections compared to permanent ones, but those differences were not statistically significant. Immediate graft function was observed in 45 patients (61%). Delayed graft function was more frequently observed among recipients with donor age above 60 years (57% vs. 32%). Serum creatinine 3 months after transplantation was above 2 mg/dL in 33 recipients (44.5%) and was positively correlated to the degree of tubular necrosis (p = 0.04) and donor age (p = 0.03). Donor age was correlated to the degree of arteriolosclerosis (p < 0.01).

CONCLUSIONS

Frozen section preimplantation biopsy gives reliable information for the situation of the graft that is related to the outcome of renal transplantation.

Correlation between proteinuria level and renal morphology with special reference to electron microscopy in kidney donors

The aims of this study were to evaluate whether there is a correlation between protein level in urine and renal morphology in kidney transplant donors, as well as to detect the role of electron microscopy. For this purpose, kidney biopsies of 10 donors with urine protein levels were evaluated. Seven patients were female and three were male. Two had physiologic proteinuria (< 150 mg/24h), four had non-significant proteinuria (150-300 mg/24h), and three had significant (> 300 mg/24h) proteinuria. Serum creatinine levels were in normal ranges in all patients except for one who had a slight increase (1.76 mg/dL). Seven cases were reported to have normal or nonspecific light microscopic findings. Two of those seven cases had physiologic proteinuria, three had non-significant proteinuria, and two had significant proteinuria. One case had IgA nephropathy with significant proteinuria. One donor had early stage focal segmental glomerulosclerosis with non-significant proteinuria, and one donor had focal interstitial fibrosis with normal urine protein level. There was no statistically significant difference between score means of ultrastructural morphology of the six patients with same patients' light microscopic results and score means of light microscopic results with urine protein levels of all patients. However, there was a significant difference between score means of ultrastructural morphology with urine protein levels of those six patients. In conclusion, urine protein levels and light microscopic findings did not always reflect the detailed morphology alone and together. Therefore, combining with electron microscopic examination could be more beneficial in relieving problems occurring in long-term prognoses.

Can machine perfusion decrease the likelihood of discard among biopsied kidneys?

Many factors, such as donor risk factors and renal function, have been shown to be associated with an increased likelihood of discard after recovering kidneys from deceased donors. When these factors are insufficient for assessment, renal biopsy is often performed at the time of harvest to assess suitability. Our aims were to identify factors that predict the discard of a biopsied kidney and to assess the impact of machine perfusion (MP) on kidney discard. We biopsied 678 kidneys from deceased donors aged >or=40 years from 2001 to 2006. We used a logistic regression model to estimate the adjusted odds ratios for kidney discard. Thirty-nine percent (n = 261) of biopsied kidneys were discarded. Kidneys with glomerulosclerosis (GS) > 20% had the highest likelihood of discard. Other significant predictors of discard included extreme donor age, final resistance (>40), atherosclerosis, interstitial fibrosis, arteriolosclerosis, and terminal serum creatinine value (SCr) > 1.5 mg/dL. MP kidneys (n = 69) were less likely to be discarded than cold storage (CS) kidneys after adjusting for other factors (adjusted odds ratio = .13, P < .001). In conclusion, abnormal biopsy findings were associated with the highest likelihood of discard. MP was used in only 10% of the cases; however, the use of MP was associated with a decreased likelihood of discard among biopsied kidneys.

Review of nonimmunological causes for deteriorated graft function and graft loss after transplantation

Various factors determine the graft- and patient survival after transplantation. HLA-matching and immunological factors are of importance for the short- and long-term survival. Apart from these obvious determinants, nonimmunological factors play an important role in defining the baseline organ quality as well as the recipients' status. The influence of these parameters on graft- and patient survival is still underestimated and is a topic of debate. On account of the increasing acceptance of marginal-donor organs these events are of increasing importance for graft survival and long-term function. We review nonimmunological causes for deteriorated graft function and graft loss after solid organ transplantation.