Kidney Week

Abstract: SA-PO911

CKD of Unknown Etiology (CKDu): Histopathology of the Disease in Patients from Nicaragua

Session Information

• Pathology and Lab Medicine - 2
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1800 Pathology and Lab Medicine

Authors

• Mikhailov, Alexei V., Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, North Carolina, United States

Alexei V. Mikhailov, MD, PhD

• Carstens, Michael H., Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, North Carolina, United States

Michael H. Carstens, MD

• Mandayam, Sreedhar A., The University of Texas MD Anderson Cancer Center, Houston, Texas, United States

Sreedhar A. Mandayam, MD, FASN, MBA, MPH

• Workeneh, Biruh, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States

Biruh Workeneh, MD, FASN

• Garcia Salazar, Nelson Benito, Mauricio Abdalah Hospital Departamental, Chinandega, Nicaragua

Nelson Benito Garcia Salazar

Background

Chronic kidney disease of uncertain origin (CKDu) is an endemic disease mainly affecting young male agricultural workers in tropical countries. CKDu displays an inexorable course with rapid deterioration of renal function. Since kidney biopsies are unavailable in endemic countries, our knowledge about the CKDu etiology is limited.

Methods

Patients with CKDu stages 3A-3B were identified by nephrologists in several Nicaraguan agricultural communities. All underwent clinical study, including ultrasonography. 2-3 cores were obtained for each patient via ultrasound-guided percutaneous renal biopsy. Light, electron microscopy, and immunofluorescence studies on pronase-treated paraffin-embedded material were performed.

Results

21 patients were selected for this study, age 21 to 59 years (mean 41 y.o.), serum creatinine at biopsy 1.9±0.3 mg/dL, eGFR 40±9 mL/min/1.75m², resistance index 0.67±0.08, renal volume 131±51 cm³. The major findings were global glomerulosclerosis affecting 30-88% of glomeruli in 80% of patients and glomerular capillary deflation. Perihilar FSGS was found in 1 biopsy. Tubules displayed fixation artifacts; chronic changes seen in 80% of patients were those of mild to rarely severe focal or diffuse interstitial fibrosis and tubular atrophy associated with mononuclear infiltration. 5 patient biopsies showed mild or moderate arteriosclerosis. Low-intensity segmental IgM deposition was noted in 50% of biopsies on the glomerular capillary walls or in the mesangium. Electron microscopy showed wrinkling of the glomerular capillary walls in 50% of biopsies. One biopsy showed thin glomerular basement membranes (GBMs), and another one- GBM remodeling; podocyte foot process effacement was segmental and rare. Toxic lysosomal inclusions were only rarely observed in the tubular epithelium by light and electron microscopy.

Conclusion

The most common pathological changes in Nicaraguan patients clinically diagnosed with CKDu were those of marked glomerulosclerosis and chronic tubulointerstitial lesions with associated inflammation. The concomitant pathology included arteriosclerosis, perihilar FSGS, and thin basement membrane disease. Our current research explores the treatment of CKDu with intraarterial injection of autologous stromal vascular fraction.

Funding

• Private Foundation Support