Introduction: Diabetic nephropathy (DN) is a long-term complication that occurs in ∼40% of diabetes patients and is a leading cause of end-stage renal disease. In a newly established mouse model of progressive DN, we investigated the effects of hypertension on kidney injury.
Methods: Female db/db mice were uninephrectomized (UNx) at 8 weeks of age and injected i.v. with a Renin adeno-associated virus (AAV) construct at different doses to induce hypertension, while a LacZAAV construct was used as negative control. Sham-operated db/+ mice served as healthy controls. Blood pressure and glomerular filtration rate (GFR) was measured at 22 weeks of age, while urine albumin to creatinine ratio (ACR) was measured before termination and kidney tissue sampling 24 weeks of age.
Results: GFR measurements indicated hyperfiltration in all AAV-injected UNx db/db mice compared to db/+ mice, while ReninAAV tended to dose-dependently decrease GFR compared to LacZAAV in UNx db/db mice. Urine ACR was worsened by ReninAAV-induced hypertension compared to LacZAAV controls. 3D kidney imaging demonstrated increased glomerular volume in LacZAAV UNx db/db mice compared to db/+ mice with no further effect in ReninAAV groups. Automized AI-based glomerulosclerosis scoring showed ReninAAV dose-dependent increases in glomerulosclerosis compared to LacZAAV controls. RNA sequencing revealed upregulated gene expression markers of kidney fibrogenesis (Col1a1, Col4, Fn1) and tubular injury (Ngal and Kim-1), as well as downregulation of proximal tubular markers (Megalin, Aqp1) in ReninAAV UNx db/db mice compared to LacZAAV controls.
Conclusion: ReninAAV-induced hypertension in female UNx db/db mice aggravates albuminuria and glomerulosclerosis paralleled by increased expression of genes associated with tubular injury renal fibrosis, thus confirming that ReninAAV UNx db/db mice is a reliable model of DN with features of late stage human disease.
M.V. Østergaard: None. I.R. Sørensen: None. A.A. Pedersen: None. T. Secher: Employee; Self; Gubra. Employee; Spouse/Partner; Novo Nordisk A/S. Stock/Shareholder; Self; Gubra. Stock/Shareholder; Spouse/Partner; Novo Nordisk A/S. F.E. Sembach: Employee; Self; Gubra. M.R. Madsen: None. K. Fosgerau: None. L.N. Fink: Employee; Self; Gubra. Stock/Shareholder; Self; Novo Nordisk A/S. N. Vrang: Board Member; Self; Gubra. Employee; Self; Gubra. Stock/Shareholder; Self; Gubra.