Drug-associated glomerulopathies

Adult Zebrafish Model for Screening Drug-Induced Kidney Injury

Drug-induced kidney injury is a serious safety issue in drug development. In this study, we evaluated the usefulness of adult zebrafish as a small in vivo system for detecting drug-induced kidney injury. We first investigated the effects of typical nephrotoxicants, gentamicin and doxorubicin, on adult zebrafish. We found that gentamicin induced renal tubular necrosis with increased lysosome and myeloid bodies, and doxorubicin caused foot process fusion of glomerular podocytes. These findings were similar to those seen in mammals, suggesting a common pathogenesis. Second, to further evaluate the performance of the model in detecting drug-induced kidney injury, adult zebrafish were treated with 28 nephrotoxicants or 14 nonnephrotoxicants for up to 4 days, euthanized 24 h after the final treatment, and examined histopathologically. Sixteen of the 28 nephrotoxicants and none of the 14 nonnephrotoxicants caused drug-induced kidney injury in zebrafish (sensitivity, 57%; specificity, 100%; positive predictive value, 100%; negative predictive value, 54%). Finally, we explored genomic biomarker candidates using kidneys isolated from gentamicin- and cisplatin-treated zebrafish using microarray analysis and identified 3 candidate genes, egr1, atf3, and fos based on increased expression levels and biological implications. The expression of these genes was upregulated dose dependently in cisplatin-treated groups and was > 25-fold higher in gentamicin-treated than in the control group. In conclusion, these results suggest that the adult zebrafish has (1) similar nephrotoxic response to those of mammals, (2) considerable feasibility as an experimental model for toxicity studies, and (3) applicability to pathological examination and genomic biomarker evaluation in drug-induced kidney injury.

Systemic effects induced by intralesional injection of ω-conotoxin MVIIC after spinal cord injury in rats

Background

Calcium channel blockers such as conotoxins have shown a great potential to reduce brain and spinal cord injury. MVIIC neuroprotective effects analyzed in in vitro models of brain and spinal cord ischemia suggest a potential role of this toxin in preventing injury after spinal cord trauma. However, previous clinical studies with MVIIC demonstrated that clinical side effects might limit the usefulness of this drug and there is no research on its systemic effects. Therefore, the present study aimed to investigate the potential toxic effects of MVIIC on organs and to evaluate clinical and blood profiles of rats submitted to spinal cord injury and treated with this marine toxin. Rats were treated with placebo or MVIIC (at doses of 15, 30, 60 or 120 pmol) intralesionally following spinal cord injury. Seven days after the toxin administration, kidney, brain, lung, heart, liver, adrenal, muscles, pancreas, spleen, stomach, and intestine were histopathologically investigated. In addition, blood samples collected from the rats were tested for any hematologic or biochemical changes.

Results

The clinical, hematologic and biochemical evaluation revealed no significant abnormalities in all groups, even in high doses. There was no significant alteration in organs, except for degenerative changes in kidneys at a dose of 120 pmol.

Conclusions

These findings suggest that MVIIC at 15, 30 and 60 pmol are safe for intralesional administration after spinal cord injury and could be further investigated in relation to its neuroprotective effects. However, 120 pmol doses of MVIIC may provoke adverse effects on kidney tissue.

Nephrotic syndrome associated with gemcitabine use in a patient with ovarian cancer

Background:

Here we present a patient who developed nephrotic syndrome associated with gemcitabine use.

Case Report:

Gemcitabine therapy was initiated following tumor recurrence in a patient with ovarian cancer, who was previously treated twice with carboplatin and paclitaxel. Radiological findings waned and tumor marker concentrations decreased after gemcitabine treatment. However, edema and ascites development was observed on the fifth treatment cycle. Laboratory results revealed increased blood urea nitrogen and creatinine levels, decreased serum albumin concentrations, and increased 24-hour urinary protein excretion. Renal biopsy findings were compatible with membranous glomerulonephritis. Gemcitabine administration was stopped and the cyclophosphamide and steroid therapy were initiated. The symptoms and findings disappeared after the cessation of gemcitabine and immunosuppressive treatment.

Conclusions:

Gemcitabine treatment may be associated with proteinuria to the extent of nephrotic syndrome.

Drug-induced glomerulopathies

Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules. Glomerular lesions are usually responsible for proteinuria and the nephrotic syndrome. This also holds true for the drug-induced glomerulopathies, of which membranous glomerulo-nephritis is the most frequent type of lesion encountered. Apart from this, several cases of different glomerular changes such as focal segmental glomerulosclerosis and crescentic glomerulonephritis have also been reported. The drug-induced glomerulopathies are probably immune mediated. This is, for instance, reflected in the fact that patients with drug-induced nephritic syndrome frequently have the HLA-B8 and DR3 antigens. In depth information is provided for the previously mentioned disorders.

Heroin-associated nephropathy

Since the first reports in the late 1960s and early 1970s there have been numerous studies describing the clinical and pathological features of renal diseases associated with chronic parenteral abuse of heroin, cocaine, morphine, amphetamine, and other narcotic and hallucinogenic drugs, including several adulterants. The past 35 years have witnessed an explosive growth in illicit drug use in many parts of the world. Meanwhile, drug addict nephropathy constitutes an important cause of end-stage renal disease. The term heroin-associated nephropathy' includes different morphological findings following chronic drug abuse. Up to now it still remains ambiguous as to whether or not heroin/morphine itself, adulterants, other diseases like hepatitis B and C infection, or HIV, lead to a spectrum of morphologically described heroin-associated' findings in the kidneys. As a measure of prevention it appears that the purity of heroin plays an important role.

Angiotensin-converting enzyme inhibitor captopril prevents activation-induced apoptosis by interfering with T cell activation signals

Captopril is an orally active inhibitor of angiotensin-converting enzyme (ACE) which is widely used as an anti-hypertensive agent. In addition to its ability to reduce blood pressure, captopril has a number of other biological activities. Recently the drug was shown to inhibit Fas-induced apoptosis in human activated peripheral T cells and human lung epithelial cells. In this study, we investigated whether captopril blocks activation-induced apoptosis in murine T cell hybridomas, and found that captopril inhibited IL-2 synthesis and apoptotic cell death upon activation with anti-CD3 antibody. In addition, captopril inhibited an inducible caspase-3-like activity during activation-induced apoptosis. On the other hand, captopril did not interfere with Fas signalling, since anti-Fas antibody-induced apoptosis in Fas+ Jurkat cells was unaffected by the drug. Furthermore, we examined whether captopril blocks activation-induced apoptosis by interfering with expression of Fas, Fas ligand (FasL), or both on T cell hybridomas. FasL expression on activated T cells was significantly inhibited by captopril, whereas up-expression of Fas was partially inhibited, as assessed by cell surface staining. Taking all data together, we conclude that captopril prevents activation-induced apoptosis in T cell hybridomas by interfering with T cell activation signals. Captopril has been reported to induce systemic lupus erythematosus syndrome, and our findings may be useful for elucidating the mechanism of captopril-induced autoimmunity.

Adverse reactions and interactions of cyclosporin

Cyclosporin is a potent, widely used specific immunosuppressive agent which affects T-helper cells, and has little myelotoxicity. Its pharmacokinetics are complex and many of its actions remain poorly understood. Numerous side effects have been reported, affecting most organs. Most troublesome have been renal injury, systemic hypertension and vascular changes. Oral use is more effective than intramuscular and safer than the intravenous route. Interactions with other drugs include those which affect hepatic metabolism and those which reduce clearance. Aminoglycosides, macrolide antibiotics, imidazole derivatives, calcium channel blockers, sulphonamides and steroids are included in such interactions. Other metabolic effects of cyclosporin are more subtle and include hyperchloraemic alkalosis, changes in serum potassium and magnesium and effects on testosterone and prolactin levels. Acute poisoning with cyclosporin has been reported, again without myelosuppression. Cyclosporin is an important agent with multisystem toxicity, which requires precise monitoring of drug concentrations, liver and renal function, haemoglobin levels and plasma electrolytes. Cyclosporin pharmacodynamics and interactions with other drugs need to be carefully considered if lower rates of toxicity are to be achieved.

Immunogenetically controlled autoimmune reactions induced by mercury, gold and D-penicillamine in laboratory animals: a review from the vantage point of premarketing safety studies

Mercury and gold salts as well as d-penicillamine can cause glomerulonephritis by an autoimmune mechanism in man. The susceptibility to this effect of these chemicals is controlled by the genes of the major histocompatibility complex (MHC). The presence of certain alleles confers sensitivity. The role of MHC-linked genes has been demonstrated also in the rat and mouse in the development of autoimmunity induced by these chemicals. While Brown Norway rats and ASW mice were sensitive, several other strains were resistant. Also an interaction of MHC with background genes has been shown in determination of the response to HgCl2. In conventional toxicity studies, use of a single inbred strain of laboratory animals obviously handicaps the detection of a reaction of this nature.

Mercuric chloride-, gold sodium thiomalate-, and D-penicillamine-induced antinuclear antibodies in mice

Inducibility of antinuclear antibodies (ANA) by mercuric chloride (HgCl2) was studied in various strains of mice. High response to the treatment was observed in strains A.SW (H-2s), A.CA (H-2f), A.TH (H-2t2), B10.S (H-2s), DBA/1J (H-2q), and P/J (H-2p); strains A.BY (H-2b), B10.M (H-2f), and C3H/HeSnJ (H-2k) showed a low response, while strains A/WySn (H-2a), A/J (H-2a), A.TL (H-2tl), BALB/cJ (H-2d), C57BL/10SnJ (H-2b), B10.A (H-2a), and PL/J (H-2u) did not produce any detectable ANA. Thus, the H-2a haplotype determines resistance to the treatment regardless of the genetic background; the H-2s determines susceptibility, while the H-2b and H-2f are intermediate haplotypes whose effect depends on the interaction with the background genes. Our results with intra-H-2 recombinant strains indicate that the I region of the H-2 complex is the major genetic factor controlling this response. The function of the I region is to control cellular cooperation in the immune response that finally results in production of antibodies specific for a particular antigen. Therefore, we postulated that the I region controls the antibody response to a nuclear antigen released as a result of HgCl2 toxicity in mice. A genetic study of an A.SW X C57BL/10 cross confirmed this observation, showing that resistance to ANA induction by HgCl2 in this strain combination is determined by interaction of a semidominant H-2-linked gene and one or more unlinked genes. The two drugs tested, gold sodium thiomalate and D-penicillamine, also induced ANA in A.SW mice, while other strains tested resisted this treatment.