Reduced pulsatility induces periarteritis in kidney: role of the local renin-angiotensin system

J Thorac Cardiovasc Surg. 2008 Jul;136(1):150-8. doi: 10.1016/j.jtcvs.2007.12.023. Epub 2008 May 19.

Abstract

Objective: The need for pulsatility in the circulation during long-term mechanical support has been a subject of debate. We compared histologic changes in calf renal arteries subjected to various degrees of pulsatile circulation in vivo. We addressed the hypothesis that the local renin-angiotensin system may be implicated in these histologic changes.

Methods and results: Sixteen calves were implanted with devices giving differing degrees of pulsatile circulation: 6 had a continuous flow left ventricular assist device (LVAD); 6 had a continuous flow right ventricular assist device (RVAD); and 4 had a pulsatile total artificial heart (TAH). Six other calves were histologic and immunohistochemical controls. In the LVAD group, the pulsatility index was significantly lower (0.28 +/- 0.07 LVAD vs 0.56 +/- 0.08 RVAD, vs 0.53 +/- 0.10 TAH; P < 0.01), and we observed severe periarteritis in all cases in the LVAD group. The number of angiotensin II type 1 receptor-positive cells and angiotensin converting enzyme-positive cells in periarterial areas was significantly higher in the LVAD group (angiotensin II type 1 receptor: 350 +/- 139 LVAD vs 8 +/- 6 RVAD, vs 3 +/- 2 TAH, vs 3 +/- 2 control; P < .001; angiotensin-converting enzyme: 325 +/- 59 LVAD vs 6 +/- 4 RVAD, vs 6 +/- 5 TAH, vs 3 +/- 1 control; P < .001).

Conclusions: The reduced pulsatility produced by a continuous flow LVAD implantation induced severe periarteritis in the kidneys. The local renin-angiotensin system was up-regulated in the inflammatory cells only in the continuous flow LVAD group.

MeSH terms

  • Angiotensin II / biosynthesis
  • Animals
  • Arteritis / pathology
  • Arteritis / physiopathology*
  • Cattle
  • Hemodynamics
  • Immunohistochemistry
  • Kidney / blood supply*
  • Kidney / metabolism
  • Male
  • Nephritis / pathology
  • Nephritis / physiopathology*
  • Peptidyl-Dipeptidase A / metabolism
  • Pulsatile Flow
  • Receptors, Angiotensin / metabolism
  • Renal Artery / pathology*
  • Renal Artery / physiopathology*
  • Renin-Angiotensin System*

Substances

  • Receptors, Angiotensin
  • Angiotensin II
  • Peptidyl-Dipeptidase A