Introduction and objectives
The preservation of postoperative renal function is one of the important goals in partial nephrectomy (PN). Some previous studies reported that metabolic diseases such as hypertension or dyslipidemia were associated with the deterioration of renal function in long-term periods after PN. However, these mechanism by metabolic parameters remained unclear. On the other hands, renal histopathological findings including glomeruli and renal tubules were reported to reflect the tissue damage by metabolic diseases or long-term prognosis of renal function. In this study, we compared between the renal histopathological findings of preserved kidney after PN and the long-term deterioration of renal function, and determined predictive factors of the deterioration of renal function.
Methods
The subjects were 33 patients (19 males and 14 females; mean age 63.0±14.0 years) who underwent robot-assisted PN (RAPN) in our institution. For renal histopathological evaluation, we used the normal area around the renal cell tumor in the resected specimens. We performed simple and multiple regression analyses between renal histopathological findings including glomerular lesions such as diffuse lesions, exudative lesions, nodular lesions, mesangiolysis, and glomerular hypertrophy, or interstitial lesions such as arteriole vitrification, periglomerular fibrosis, interstitial fibrosis/tubule atrophy, and stromal cell infiltration and postoperative estimated glomerular filtration rate (eGFR) at 6 months after RAPN.
Results
Simple and multiple regression analyses showed that both glomelular lesions such as exudative lesions (p=0.03, β=-0.38), nodular lesions (p<0.01, β=-0.46), and mesangiolysis (p=0.01, β=-0.42) and interstitial lesions such as arteriole vitrification (p=0.04, β=-0.35), periglomerular fibrosis (p=0.02, β=-0.40), and stromal cell infiltration (p=0.01, β=-0.42) were significantly associated with a decrease in eGFR before RAPN. In addition, glomerular hypertrophy (p < 0.01, β=0.861) was also significantly associated with a decrease in eGFR at 6 months after RAPN. In particular, glomerular hypertrophy (p < 0.01) was significantly associated with BMI.
Conclusions
Renal histopathological findings in the normal area around the renal cell tumor in resected specimens are useful to assess renal function in the patients who underwent PN. Our results suggest that glomerular hypertrophy might be a useful predictive factor of long-term deterioration of renal function after RAPN. Glomerular hypertrophy was reported to reflect not only the histopathological finding of obesity-related glomerulopathy but also the swelling of vascular endothelial cells by ischemia. Patients affected by both obesity-related glomerulopathy and ischemia by PN might contribute to long-term postoperative renal deterioration.
Source of Funding
No