Effects of delayed rapamycin treatment on renal fibrosis and inflammation in experimental ischemia reperfusion injury

Transplant Proc. 2009 Dec;41(10):4065-71. doi: 10.1016/j.transproceed.2009.08.083.

Abstract

Ischemia reperfusion injury (IRI) has long-term sequelae on kidney allograft function. Early initiation of rapamycin can retard surgical wound healing and recovery from IRI. In contrast, rapamycin may paradoxically retard long-term fibrotic effects of kidney IRI. We, therefore, hypothesized that delayed initiation of rapamycin after kidney ischemia, started after the initial week of wound healing, would decrease the long-term inflammation and fibrosis caused by IRI. C57BL/6 male mice were subjected to either 45 or 60 minutes of unilateral kidney ischemia or a sham operation. Mice were given rapamycin (subcutaneous, 1.5 mg/kg/d) or vehicle starting at 1 week after IRI surgery for 3 weeks. Urine albumin excretion, kidney histology, and kidney cytokine proteins were examined at 4 weeks after surgery. The 3-week treatment course of rapamycin significantly reduced body weight gain in all 3 groups and reduced postischemic kidney weight in both the 45- and 60-minute ischemia groups, but unexpectedly increased urine albumin excretion in all rapamycin-treated sham or IRI mice compared with vehicle-treated mice. Rapamycin treatment showed minimal effects on postischemic kidney fibrosis with variable effects on various cytokine/chemokine protein expressions, namely, decreasing interleukin (IL)-1alpha, IL-6, tumor necrosis factor (TNF)-alpha, and regulated on activation normal T cell expressed and secreted (RANTES) while increasing IL-4, keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP-1alpha), and IL-10 in the ischemic kidney. These data demonstrated that rapamycin reduced mouse body weight and ischemic kidney weight, while increasing urinary albumin excretion. Delayed initiation of rapamycin after IRI had a minimal effect on renal fibrosis and mixed effects on proinflammatory mediator production. These data do not support delayed initiation of rapamycin after IRI to attenuate IRI-induced progressive fibrosis and inflammation, and They raise further caution regarding rapamycin and albuminuria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albuminuria
  • Animals
  • Body Weight / drug effects
  • Cytokines / metabolism
  • Fibrosis / drug therapy*
  • Fibrosis / immunology
  • Immunosuppressive Agents / administration & dosage
  • Immunosuppressive Agents / blood
  • Immunosuppressive Agents / therapeutic use
  • Injections, Subcutaneous
  • Kidney / anatomy & histology
  • Kidney / immunology
  • Kidney / pathology
  • Kidney Diseases / drug therapy*
  • Kidney Diseases / immunology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Organ Size / drug effects
  • Reperfusion Injury / drug therapy*
  • Sirolimus / administration & dosage
  • Sirolimus / blood
  • Sirolimus / therapeutic use*
  • Weight Gain

Substances

  • Cytokines
  • Immunosuppressive Agents
  • Sirolimus