The relationship between renal volume and histology in obese and nonobese kidney donors

Obesity is a risk factor for progression to kidney transplant waitlisting after liver transplantation

BACKGROUND

Non-alcoholic steatohepatitis has emerged as a leading cause of cirrhosis, and obesity-associated comorbidities, including renal disease, have increased in prevalence. Obesity predisposes the kidney to hyperfiltration injury, potentially impairing acute kidney injury recovery. Identification of patients at risk for renal dysfunction is impeded by poor performance of renal function estimating equations among cirrhotics. To better understand obesity among cirrhotics and renal disease progression, we examined likelihood of kidney transplantation (KT) waitlisting after liver transplant alone (LTA) by obesity class.

METHODS

68 607 LTA recipients were identified in SRTR (2005-2018). Fine and Gray competing risks models were used to analyze likelihood of KT waitlisting.

RESULTS

27.4% of recipients were obese (BMI ≥ 30 kg/m² ) and were 10% more likely to require KT waitlisting (aHR: 1.10, 95%CI: 1.01-1.20). Risk was highest among recipients with Classes II and III obesity (BMI: ≥35 kg/m² ) (aHR: 1.37, 95%CI: 1.17-1.56). Moreover, recipients with Classes II and III obesity were 57% more likely to require KT waitlisting within one year post-LTA (aHR: 1.57, 95%CI: 1.18-2.10) compared to non-obese recipients.

DISCUSSION

These findings suggest obesity was a risk factor for renal recovery failure and/or renal disease progression post-LTA and may confound identification of renal dysfunction and/or prediction of renal recovery among cirrhotics.

Effect of unilateral nephrectomy on urinary angiotensinogen levels in living kidney donors: 1 year follow-up study

Background:

Urinary angiotensinogen (uAGT) has recently been proposed as a marker of kidney injury and activated intrarenal renin–angiotensin system. We investigated the effects of living donor nephrectomy on uAGT levels, blood pressure, estimated glomerular filtration rate, proteinuria and compensatory hypertrophy in the remaining kidney of living kidney donors.

Methods:

Twenty living kidney donors were included in the study and followed for 1 year. uAGT levels were measured with enzyme-linked immunosorbent assay preoperatively and postoperatively at the 15th day, 1, 6 and 12 months.

Results:

Four donors were excluded from the study due to lack of data. The mean baseline estimated glomerular filtration rate was 98 ± 15 ml/min/1.73 m². Serum creatinine, uAGT/creatinine, uAGT/protein levels were higher and estimated glomerular filtration rate was lower than baseline values at all time periods. Urinary protein/creatinine levels increased after donor nephrectomy, but after 6 months they returned to baseline values. Renal volume increased after nephrectomy, but these changes did not show any correlation with uAGT/creatinine, uAGT/protein, estimated glomerular filtration rate or systolic/diastolic blood pressures. uAGT/creatinine at 6 months and urinary protein/creatinine ratio at 12 months showed a positive correlation (P=0.008, r=0.639).

Conclusion:

After donor nephrectomy, increasing uAGT levels can be the result of activation of the intrarenal renin–angiotensin system affecting the compensatory changes in the remaining kidney. The long-term effects of increased uAGT levels on the remaining kidney should be examined more closely in future studies.

Simple renal cysts in the solitary kidney: Are they innocent in adult patients?

In patients with a solitary kidney; residual renal volume is an important prognostic factor for kidney survival. At present, the impact of renal cysts on solitary kidney survival is not clear. The aim of this study is to examine the association of cysts on progression of renal failure in patients with a solitary kidney.

METHODS

This study included sixtyfive solitary kidney patients. The remaining kidneys after indication nephrectomy (IN) were evaluated with urinary system ultrasound. The primary outcome of the study is the progression of kidney failure during follow-up which was defined as: 25% decrease in glomerular filtration rate (GFR) and / or the need for renal replacement therapy (RRT).

RESULTS

The mean age of the patients was 55 ± 14 years and mean follow-up was 53 ± 27 months. Renal cysts were present in 30.7% of patients. 33.8 percent of patients had kidney disease progression and 10.7 % required RRT. Those with progressive disease were older (61 ± 13, 52 ± 14; P = 0.011), had lower baseline GFR (30 ± 11, 39 ± 18; P = 0.035), higher proteiuria (2.84 ± 0.58, 2.47 ± 0.57; P = 0.031) and frequently harboring cysts in the solitary kidney (52.3%, 20.4%; P = 0.006). Progression to kidney failure and RRT requirement in cases with or without renal cysts was (60% vs. 22%; P = 0.004) and (20% vs. 6.6%; P = 0.123), respectively. Acquired cysts in solitary kidney was independently associated with progression to kidney failure and RRT respectively (Exp(B) 3.173; P = 0.01 and Exp(B) 12.35; P = 0.04).

CONCLUSION

Simple renal cysts in solitary kidney patients with impaired renal function is associated with poor renal outcome. Large-scale studies are needed to clarify this issue.

Relationship between diurnal blood pressure and renal histopathological changes in white coat hypertension

BACKGROUND

Multiple epidemiological studies have clearly demonstrated the macrovascular risks associated with white coat hypertension (WCH) or sustained hypertension (SH). In patients with WCH, there is no literature available on renal histopathological changes and that on blood pressure pattern and native kidney outcome is scant. We aimed to clarify the relationship between blood pressure variables and pathological features of kidney biopsies in living kidney donors with WCH.

METHODS

This cross-sectional study included living kidney donors with WCH (n = 10) and SH (n = 10), and 20 healthy kidney donors with similar demographic features (control group). Kidney allograft biopsy samples were obtained during transplantation and chronic glomerular, vascular and tubulointertitial changes were semiquantitatively scored according to the Banff classification.

RESULTS

The mean age of the 20 hypertensive subjects (Group 1) and controls (Group 2) was 59.3 ± 8.5 versus 59.6 ± 7.6 years and almost half were female. There was no difference in renal function parameters between the groups; however, kidney histopathology in Group 1 was worse than Group 2 with a chronicity index of 2.80 ± 1.67 versus 1.75 ± 1.16 (p = 0.02). There was no difference between histopathological scores of patients with WCH or SH (chronicity index: 2.60 ± 1.43 vs. 2.70 ± 1.70, p = 0.88). Night-to-day mean arterial pressure (MAP) ratio was significantly associated with chronicity index in patients with WCH. Moreover, WCH patients with non-dipper hypertensive pattern had a worse chronicity index.

CONCLUSIONS

Significant histopathological alterations in the kidney were observed in patients with WCH and SH, and were accentuated in WCH patients with non-dipper blood pressure pattern.