Reduced Microvascular Density in Omental Biopsies of Children with Chronic Kidney Disease

PLoS One. 2016 Nov 15;11(11):e0166050. doi: 10.1371/journal.pone.0166050. eCollection 2016.

Abstract

Background: Endothelial dysfunction is an early manifestation of cardiovascular disease (CVD) and consistently observed in patients with chronic kidney disease (CKD). We hypothesized that CKD is associated with systemic damage to the microcirculation, preceding macrovascular pathology. To assess the degree of "uremic microangiopathy", we have measured microvascular density in biopsies of the omentum of children with CKD.

Patients and methods: Omental tissue was collected from 32 healthy children (0-18 years) undergoing elective abdominal surgery and from 23 age-matched cases with stage 5 CKD at the time of catheter insertion for initiation of peritoneal dialysis. Biopsies were analyzed by independent observers using either a manual or an automated imaging system for the assessment of microvascular density. Quantitative immunohistochemistry was performed for markers of autophagy and apoptosis, and for the abundance of the angiogenesis-regulating proteins VEGF-A, VEGF-R2, Angpt1 and Angpt2.

Results: Microvascular density was significantly reduced in uremic children compared to healthy controls, both by manual imaging with a digital microscope (median surface area 0.61% vs. 0.95%, p<0.0021 and by automated quantification (total microvascular surface area 0.89% vs. 1.17% p = 0.01). Density measured by manual imaging was significantly associated with age, height, weight and body surface area in CKD patients and healthy controls. In multivariate analysis, age and serum creatinine level were the only independent, significant predictors of microvascular density (r2 = 0.73). There was no immunohistochemical evidence for apoptosis or autophagy. Quantitative staining showed similar expression levels of the angiogenesis regulators VEGF-A, VEGF-receptor 2 and Angpt1 (p = 0.11), but Angpt2 was significantly lower in CKD children (p = 0.01).

Conclusions: Microvascular density is profoundly reduced in omental biopsies of children with stage 5 CKD and associated with diminished Angpt2 signaling. Microvascular rarefaction could be an early systemic manifestation of CKD-induced cardiovascular disease.

MeSH terms

  • Adolescent
  • Angiopoietin-1 / blood*
  • Angiopoietin-2 / blood*
  • Apoptosis / genetics
  • Autophagy / genetics
  • Biomarkers / blood
  • Biopsy
  • Cardiovascular Diseases / blood*
  • Cardiovascular Diseases / genetics
  • Cardiovascular Diseases / pathology
  • Child
  • Child, Preschool
  • Female
  • Gene Expression Regulation
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Microcirculation / genetics
  • Microvessels / pathology
  • Peritoneal Dialysis
  • Renal Insufficiency, Chronic / blood*
  • Renal Insufficiency, Chronic / genetics
  • Renal Insufficiency, Chronic / pathology
  • Vascular Endothelial Growth Factor A / blood*
  • Vascular Endothelial Growth Factor Receptor-2 / blood*

Substances

  • ANGPT1 protein, human
  • ANGPT2 protein, human
  • Angiopoietin-1
  • Angiopoietin-2
  • Biomarkers
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • KDR protein, human
  • Vascular Endothelial Growth Factor Receptor-2

Grants and funding

BS was funded by the Medical Faculty of Heidelberg, and MB by the European Training and Research in PD consortium, EuTriPD (FP7, 287813). Christian Freise was supported by the Else-Kröner-Fresenius Stiftung (2011-A19). Further support was received from ERA-EDTA, and the KfH Foundation for Preventive Medicine.