Acute kidney injury

Suppression of allograft rejection is central to successful organ transplantation; thus, immunosuppressive agents are crucial for successful allograft function. Immunosuppressive drugs are used for induction (intense immunosuppression in the initial days after transplantation), maintenance, and reversal of established rejection. This review considers the use of immunosuppressive drugs in organ transplantation, focusing on renal transplantation.

https://www.nejm.org/doi/pdf/10.1056/NEJMra033540

Immunosuppressive Drugs for Kidney Transplantation

Hemorrhagic Complications of Anticoagulant Treatment

The use of the calcineurin inhibitors cyclosporine and tacrolimus led to major advances in the field of transplantation, with excellent short-term outcome. However, the chronic nephrotoxicity of these drugs is the Achilles' heel of current immunosuppressive regimens. In this review, the authors summarize the clinical features and histologic appearance of both acute and chronic calcineurin inhibitor nephrotoxicity in renal and nonrenal transplantation, together with the pitfalls in its diagnosis. The authors also review the available literature on the physiologic and molecular mechanisms underlying acute and chronic calcineurin inhibitor nephrotoxicity, and demonstrate that its development is related to both reversible alterations and irreversible damage to all compartments of the kidneys, including glomeruli, arterioles, and tubulo-interstitium. The main question--whether nephrotoxicity is secondary to the actions of cyclosporine and tacrolimus on the calcineurin-NFAT pathway--remains largely unanswered. The authors critically review the current evidence relating systemic blood levels of cyclosporine and tacrolimus to calcineurin inhibitor nephrotoxicity, and summarize the data suggesting that local exposure to cyclosporine or tacrolimus could be more important than systemic exposure. Finally, other local susceptibility factors for calcineurin inhibitor nephrotoxicity are reviewed, including variability in P-glycoprotein and CYP3A4/5 expression or activity, older kidney age, salt depletion, the use of nonsteroidal anti-inflammatory drugs, and genetic polymorphisms in genes like TGF-beta and ACE. Better insight into the mechanisms underlying calcineurin inhibitor nephrotoxicity might pave the way toward more targeted therapy or prevention of calcineurin inhibitor nephrotoxicity.

Calcineurin Inhibitor Nephrotoxicity

Background Despite the use of antiplatelet agents, usually aspirin, in patients who have had an ischemic stroke, there is still a substantial rate of recurrence. Therefore, we investigated whether warfarin, which is effective and superior to aspirin in the prevention of cardiogenic embolism, would also prove superior in the prevention of recurrent ischemic stroke in patients with a prior noncardioembolic ischemic stroke. Methods In a multicenter, double-blind, randomized trial, we compared the effect of warfarin (at a dose adjusted to produce an international normalized ratio of 1.4 to 2.8) and that of aspirin (325 mg per day) on the combined primary end point of recurrent ischemic stroke or death from any cause within two years. Results The two randomized study groups were similar with respect to base-line risk factors. In the intention-to-treat analysis, no significant differences were found between the treatment groups in any of the outcomes measured. The primary end point of death or recurrent ischemi...

https://www.nejm.org/doi/pdf/10.1056/NEJMoa011258

A comparison of warfarin and aspirin for the prevention of recurrent ischemic stroke.

Placebo-controlled study of mycophenolate mofetil combined with cyclosporine and corticosteroids for prevention of acute rejection

In a prospective study, 139 serial blood samples from 15 transplant recipients were assessed for the presence of cytomegalovirus (CMV) by virus isolation (CMV viremia) and by direct staining of CMV antigens (CMV Ag) in blood leukocytes (CMV antigenemia). CMV was isolated from 23 samples, whereas CMV Ag was detected in 44 specimens. All positive samples were from a total of nine patients who were diagnosed as having active CMV infections. In seven patients, active CMV infections were diagnosed by virus isolation from blood and urine and by a significant rise of CMV-specific antibodies. In these patients, 21 of the 23 blood samples which were positive for CMV by cell culture were also positive by direct CMV Ag detection. Moreover, CMV Ag were detected in 23 of the 116 culture-negative samples. Twenty of these samples were from the acute phase of infection in the same seven patients. The remaining three CMV Ag-positive specimens were from the other two patients, from whom CMV was not isolated but who had serological evidence of concomitant active CMV infections. These results suggest that direct detection of CMV Ag in peripheral blood leukocytes is as specific as and more sensitive than current isolation techniques. Furthermore, by its sensitivity and inherent rapidity the antigen detection test proved to be the earliest diagnostic marker of active CMV infection in eight of the nine patients. Finally, it was shown that monoclonal antibodies to CMV immediate early antigens are a prerequisite for demonstration of CMV antigenemia.

Comparison between viremia and antigenemia for detection of cytomegalovirus in blood.

Background. Renal allograft thrombosis is a serious complication of kidney transplantation that ultimately leads to graft loss. Its association with acute and hyperacute rejection is well documented; however, in a large proportion of patients the precise cause remains obscure. The exact incidence and the associated risk factors for those episodes of graft thrombosis lacking evidence of rejection have not yet been clearly established. Methods. All reported episodes of graft thrombosis in 558 consecutive cadaveric kidney transplants performed in a single centre were examined to identify those without histopathological evidence of rejection, i.e. primary renal graft thrombosis. Univariate and multivariate types of analysis were applied to study the possibly related risk factors and any associated morbid event(s) of those episodes. Recipients without reported episodes of primary renal graft thrombosis (/j=493) represented the control group for the 34 identified cases. Results. The calculated incidence of primary renal graft thrombosis was 6% (1.9% arterial, 3.4% venous and 0.7% both), comprising 45% of early (90 days) and 37% of 1-year graft losses in our centre. The multivariate analysis identified five independent risk factors for primary renal graft thrombosis: donor's right kidney P< 0.007, past history of venous thrombosis (renal or extrarenal) P=0.000, and diabetic nephropathy P = 0.000 of the recipient, technical surgical problems P = 0.000, and recipient's haemodynamic status peri and early postoperatively P< 0.001. Primary renal graft thrombosis was related to the presentation with delayed graft function (DGF) P< 0.0005 and was significantly associated with extrarenal thromboembolic manifestations P<0.0005. There was no association between primary renal graft thrombosis and recipient's age, sex, number of previous transplants, type of dialysis, pretransplant treatment with erythropoietin, antiplatelet agents, or oral anticoagulants, donor's age, sex, number of graft vessels,

Primary renal graft thrombosis

Improved primary renal allograft survival on cyclosporin limited to women with previous pregnancies.

The effect of a daily supplementation of 6 g fish oil (30% C20:5 omega-3 (EPA) and 20% C22:6 omega-3 for three months on renal function variables was investigated in a placebo-controlled (6 g corn oil, 50% C18:2 omega-6) prospective, randomized, double-blind study in stable cyclosporine-treated renal transplant recipients, at least nine months after grafting. Ten patients ingested placebo capsules and eleven patients fish oil. When measuring glomerular filtration rate and effective renal plasma flow (ERPF) before (baseline [BL]) and after 3 months of oil ingestion nothing changed in the placebo-treated group: GFR-BL = 64.5 GFR-3 months = 60 ml/min/1.73m2 (NS; median, Wilcoxon test) ERPF BL = 229.5 and ERPF-3 months = 242.5 ml/min/1.73m2 (NS). In the fish oil-treated group GFR rose by 20.3% from GFR-BL = 56 to GFR-3 months = 68 ml/min/1.73m2 and ERPF by 16.4% from ERPF-BL 218 to ERPF-3 months = 245 ml/min/1.73m2, (P less than 0.01). In the placebo-treated group mean arterial pressure and calculated total renal vascular resistance (TRVR) did not change: MAP-BL = 106 mmHg and MAP-3 months = 109 mmHg, TRVR being 20856 dyne.sec/cm5 and 19862 dyne/sec/cm5, respectively (NS). In the fish oil-treated group MAP and TRVR fell by 8.6% and 21.1%, respectively: MAP-BL = 106 mmHg and MAP-3 months = 98 mmHg (P less than 0.01), TRVR-BL = 21952 dyne/sec/cm5 and TRVR-3 months = 17087 dyne/sec/cm5 (P less than 0.01). According to these results fish oil supplementation has considerable effects on renal function and blood pressure in stable CsA-treated renal transplant recipients.

Adam Tegzess

Papers

Placebo-controlled study of mycophenolate mofetil combined with cyclosporine and corticosteroids for prevention of acute rejection

Comparison between viremia and antigenemia for detection of cytomegalovirus in blood.

Primary renal graft thrombosis

Improved primary renal allograft survival on cyclosporin limited to women with previous pregnancies.

The effects of dietary supplementation with fish oil on renal function in cyclosporine-treated renal transplant recipients.