[Drug-related disorders of water and electrolyte metabolism]. / Volumen- und Elektrolytstörungen bei medikamentöser Therapie.

Pharmacologic treatment may lead to diverse disturbances of water and electrolyte metabolism as adverse drug events. Diuretics are particularly likely to cause these complications typically including volume depletion, metabolic alkalosis, hyponatremia, and hypokalemia. Salt and water retention with edema formation is most frequently elicited by antihypertensives, steroid hormones, and nonsteroidal anti-inflammatory drugs. Drug-induced disorders of Na+ concentration may usually be attributed to altered antidiuretic hormone (ADH) effects, either as diabetes insipidus or as the syndrome of inappropriate ADH secretion. With hyper- and hypokalemia, redistribution between intra- and extracellular fluid as well as renal excretion play a role. Strategies to prevent these adverse drug reactions include careful consideration of risk factors and clinical and laboratory controls in the course of treatment.

Acquired thrombotic thrombocytopenic purpura as the presenting symptom of systemic lupus erythematosus. Successful treatment with plasma exchange and immunosuppression--report of two cases.

Thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening syndrome characterized by platelet aggregation causing occlusive microangiopathy. It has been described as a complication in systemic lupus erythematosus (SLE). Recent research indicated that genetic or autoantibody-induced deficiency of the metalloprotease ADAMTS13 plays a key role in the pathogenesis of TTP. Here we report two uncommon cases of TTP as the first presenting symptom of SLE. Both patients were treated with combined plasma exchange and immunosuppressive therapy, and recovered completely. Although TTP and SLE have several clinical findings in common, and both disorders may coexist more frequently than we currently assume, features of one disease should not mislead to reject the alternative disorder.

Chloroquine-induced phospholipidosis of the kidney mimicking Fabry's disease: case report and review of the literature.

A 46-year-old female patient with Sjögren's syndrome, hypertension, and stable chronic renal insufficiency (creatinine [CR], 1.9 to 2.1 mg/dL) had a progressive worsening of renal function (CR, 5.0 mg/dL) after 11 months of chloroquine therapy (155 mg/day; cumulative dose of approximately 51 g). Light microscopy revealed nonspecific angionephrosclerosis. Electron microscopy showed accumulations of lamellated myelinoid material and occasionally also of curvilinear bodies, especially in the glomerular podocytes and to a lesser extent in vascular myothelial and endothelial cells. In the tubular system, mainly protein droplets were stored. Activity of alpha-galactosidase A was normal in isolated leukocytes (56 nmol/mg; range, 33.2 to 109 nmol/mg), ruling out Fabry's disease. Clinical, morphological, and biochemical findings were consistent with chloroquine-associated deterioration of renal function that improved considerably after discontinuation of chloroquine treatment. Adverse effects of chloroquine may aggravate preexisting renal disease. Electron microscopy is a worthwhile tool for establishing the correct diagnosis.

Identification of new regulatory sequences far upstream of the mouse monocyte chemoattractant protein-1 gene.

We systematically searched for sequences influencing the expression of the mouse monocyte chemoattractant protein-1 (MCP-1) gene (Scya2) by mapping DNase I hypersensitive sites (HS) in the chromatin of mesangial cells in a 40-kb interval around the gene. We found nine HS located between -24 kb and +12.7 kb. Three HS coincided with previously known regulatory sequences (HS-2.4, HS-1.0, and HS-0.2). We tested two of the previously unknown HS located far upstream of Scya2 (HS-19.4 and HS-16.3) in transfection experiments using luciferase reporter constructs and mouse mesangial cells as recipients. In transient transfections, both HS had a moderate effect on basal promoter activity as well as promoter activity stimulated by tumor necrosis factor-alpha. In stable transfection experiments, we found much higher activity. A DNA fragment containing HS-19.4 and HS-16.3 caused a considerable increase in the number of stably integrated luciferase copies. We determined the nucleotide sequence of the 5' flanking region to -28.6 kb. Computer-assisted sequence analysis did not yield evidence of an additional gene. These HS are located within the 5' flanking region of a gene cluster consisting of Scya2 (MCP-1), Scya7 (MCP-3), Scya11 (eotaxin), Scya12 (MCP-5), and Scya8 (MCP-2). This report represents the first comprehensive chromatin analysis of the mouse MCP-1 locus leading to the identification of a complex regulatory region located far upstream of Scya2.

[Nephrologic emergency or bland course? Why glomerulonephritis should be checked out]. / Nephrologischer Notfall oder blander Verlauf? Warum Sie einer Glomerulonephritis auf den Grund gehen sollten.

Glomerulonephritis frequently takes an asymptomatic course, and may lead on to chronic renal insufficiency. If clinical signs of glomerulonephritis are present, the syndrome must be characterized by means of a comprehensive diagnostic work-up. The definitive diagnosis can be established only on the basis of a renal biopsy, which also permits an assessment of the prognosis. In this review, the basic pathogenetic principles are described in brief. Taking the most important forms of glomerulonephritis--IgA nephropathy, membranous glomerulonephritis and rapidly progressive glomerulonephritis--as examples, the general therapeutic options and a number of specific treatment strategies are discussed. New facts relating to the mechanisms of glomerular damage will in future make possible the use of targeted therapeutic interventions.

Transcriptional regulation of the interleukin-6 gene in mesangial cells.

Cytokine secretion by mesangial cells (MC) plays a major role in the pathogenesis of glomerulonephritis. To define signaling events that occur during the activation of MC, the cell-specific transcriptional regulation of the interleukin-6 (IL-6) gene was studied. Stimulation with lipopolysaccharide and IL-1beta resulted in the full induction of IL-6 expression only if the cells were coincubated with cAMP agonists; this effect was attenuated by protein kinase A inhibitors. In reporter gene experiments, the IL-6 promoter showed a stimulation pattern comparable to that of the endogenous gene. Elimination of individual transcription factor binding sites provided evidence for functional roles for four cis-acting elements, i.e., activator protein-1, cAMP response element-binding protein (CREB), nuclear factor for IL-6 expression (NF-IL6), and nuclear factor-kappaB (NF-kappaB). Electrophoretic mobility shift assays using nuclear extracts from MC revealed that the DNA-binding activities of activator protein-1 and NF-KB were inducible, whereas no change could be observed for CREB and NF-IL6. The presence of several transcription factor proteins, including JunB, JunD, c-Fos, Fra-1, CREB-1, activating transcription factor-2, NF-KB p50, p52, and p65, and CAAT/enhancer-binding protein-delta, was demonstrated by supershift analysis. Of particular interest was the novel finding of the participation of NF-kappaB p65 in the NF-IL6 complex. In summary, a signal transduction pathway in MC that requires protein kinase A activation in addition to a second signal provided by lipopolysaccharide or IL-1beta was identified.

Characterization of nephropathy induced by immunization with high molecular weight dextran.

BACKGROUND: Injection of DEAE dextran into Lewis rats can produce proteinuria and has been reported as a model of IgA nephropathy. METHODS: Cationic diethyl aminoethyl (DEAE) dextran of molecular weight 500 kDa was injected into male Lewis rats. After a pre-immunization period of 3 weeks, the animals were divided into two groups: group 1 (n = 14) received daily i.v, injections of 3.5 mg of antigen, group 2 (n = 14) was injected with 1.5 mg three times per week for a total period of 6 weeks. I.v. treatment was initiated with gradually increasing doses of DEAE dextran in both groups for 1 week, after which the maintenance dose was reached. RESULTS: We observed the appearance of proteinuria in a nephrotic range after 5 weeks of i.v. injections in group 1 (urinary excretion: 332 +/- 83 mg/24 h, controls: 53 +/- 14 mg/24 h). In group 2, the proteinuria was almost equal to protein excretion of healthy rats of the same weight (67 +/- 20 mg/24 h). The serum and urine creatinine were normal. By light microscopy of kidney biopsies, the presence of focal and segmental proliferation of mesangial cells after 6 weeks of i.v. injections was identified. Immunohistochemistry revealed no deposition of IgA, IgM, IgG, or C3. Using anti-ED1 antibodies, there was no evidence of interstitial infiltration of monocytes/macrophages after 6 weeks of i.v. injections. Staining for proliferating cell nuclear antigen (PCNA) did not show the presence of proliferating cells either in glomeruli or in the interstitium. Staining with FITC-WGA lectin revealed focal and segmental loss of the negative charge in the capillary wall. By electron microscopy there was deposition of dextran in the basal membrane and segmental and focal damage of the podocyte foot processes. As the chemokine RANTES may be involved in glomerular injury, we examined the kidneys of proteinuric and non-proteinuric rats for the presence of RANTES. By indirect immunofluorescence only the proteinuric rats showed RANTES deposition in the mesangium. CONCLUSIONS: Injection of rats with DEAE dextran leads to dose-dependent proteinuria without deposition of immune complexes but with podocyte damage. This is associated with local expression of the chemokine RANTES which may play a role in proteinuria of glomerular disease.

Molecular biology of cytokines.

The development of the technological armamentarium of molecular biology has revolutionized biomedical research in general and nephrologic investigation in particular. In addition to the recent identification of several genes involved in normal kidney function and pathologic conditions, our knowledge regarding the role of cytokines in primary renal diseases, transplant rejection, and dialysis effects has expanded greatly. In particular, molecular biologic methodology has provided insight into the mechanisms controlling cytokine gene regulation, which occurs primarily at the transcriptional level and is mediated by DNA-binding proteins interacting with specific recognition motifs in genetic promoter and enhancer elements. Interleukin-6 (IL-6) is discussed as an example because it is a secretory product of mesangial cells and participates in the cytokine network that determines glomerular and interstitial inflammation. In our analysis of IL-6 gene regulation employing reporter gene and electrophoretic mobility shift assays, we have found that bacterial lipopolysaccharide and cyclic adenosine monophosphate synergistically induce IL-6 expression in macrophages through at least four transcription factors, including AP-1, cAMP-responsive element-binding protein (CREB), NF-IL6, and NF-kappa B. One of the most exciting areas of future research will focus on transcription factor activation in experimental and clinical disease states. Novel therapeutic approaches targeting transcriptional regulation are currently being explored.

Induction of IL-8 expression in T cells uses the CD28 costimulatory pathway.

IL-8, a potent chemotactic factor for neutrophil granulocytes and lymphocytes, is a proinflammatory cytokine secreted by a variety of cell types, including T cells. Stimulation of the CD28 cell surface molecule delivers costimulatory signals essential for lymphokine production in activated T cells via a conserved sequence element found in the promoter of several lymphokine genes. Anti-CD28-stimulated T cells produced significant amounts of IL-8; additionally, costimulation with anti-CD3 and anti-CD28 Abs resulted in a synergistic induction of IL-8 secretion. Sequence homology, single nucleotide mutations, and anti-CD28 Ab stimulation studies established that the NF-kappa B-like sequence in the promoter of the IL-8 gene functioned as a CD28 response element. Furthermore, cyclosporin A, but not rapamycin, blocked the synergistic induction of IL-8 expression achieved with anti-CD3 and anti-CD28 costimulation. The involvement of a CD28 response element in the induction of IL-8 expression in activated T cells may provide new insights into the pathogenesis and persistence of immune disorders characterized by increased levels of IL-8, such as psoriasis and rheumatoid arthritis.

Multiple regulatory elements in the interleukin-6 gene mediate induction by prostaglandins, cyclic AMP, and lipopolysaccharide.

Induction of interleukin-6 (IL-6) gene expression is mediated by numerous agents involving all major signal transduction pathways. We have compared the effects of prostaglandins and their second messenger cyclic AMP (cAMP) with the effect of lipopolysaccharide (LPS) on IL-6 gene expression. We demonstrate that secretion of IL-6 is induced by cAMP in murine monocytic PU5-1.8 cells, even though to a lesser extent than by LPS. Nevertheless, cAMP and prostaglandins of the E series in the presence of theophylline induce transcription of the IL-6 promoter more strongly than LPS, suggesting distinctive effects of cAMP and LPS on posttranscriptional events. Mutations within four regulatory elements, namely, the multiple response element (MRE), AP-1, NF-IL6, and NF-kappa B sites, significantly reduce, but do not completely abrogate, inducibility by cAMP and prostaglandin E1, whereas alterations of four additional sites have no effects. LPS-induced promoter activity, however, is almost completely abolished by mutations in the NF-kappa B site, suggesting that a single regulatory element is crucial for inducibility by LPS. Stimulation by cAMP is correlated with the binding of inducible factors to the AP-1, NF-IL6, and NF-kappa B elements, whereas factors binding to the MRE are constitutively expressed. Recombinant cAMP response element-binding protein binds to the MRE, indicating a potential role for this factor in the cAMP response. Our results suggest that cAMP and prostaglandins act through multiple, partially redundant regulatory elements to induce IL-6 expression in monocytic cells. Nuclear events that overlap partially with the LPS response but also exhibit distinctive features are involved.

ERP, a new member of the ets transcription factor/oncoprotein family: cloning, characterization, and differential expression during B-lymphocyte development.

The ets gene family encodes a group of proteins which function as transcription factors under physiological conditions and, if aberrantly expressed, can cause cellular transformation. We have recently identified two regulatory elements in the murine immunoglobulin heavy-chain (IgH) enhancer, pi and microB, which exhibit striking similarity to binding sites for ets-related proteins. To identify ets-related transcriptional regulators expressed in pre-B lymphocytes that may interact with either the pi or the microB site, we have used a PCR approach with degenerate oligonucleotides encoding conserved sequences in all members of the ets family. We have cloned the gene for a new ets-related transcription factor, ERP (ets-related protein), from the murine pre-B cell line BASC 6C2 and from mouse lung tissue. The ERP protein contains a region of high homology with the ETS DNA-binding domain common to all members of the ets transcription factor/oncoprotein family. Three additional smaller regions show homology to the ELK-1 and SAP-1 genes, a subgroup of the ets gene family that interacts with the serum response factor. Full-length ERP expresses only negligible DNA-binding activity by itself. Removal of the carboxy terminus enables ERP to interact with a variety of ets-binding sites including the E74 site, the IgH enhancer pi site, and the lck promoter ets site, suggesting a carboxy-terminal negative regulatory domain. At least three ERP-related transcripts are expressed in a variety of tissues. However, within the B-cell lineage, ERP is highly expressed primarily at early stages of B-lymphocyte development, and expression declines drastically upon B-cell maturation, correlating with the enhancer activity of the IgH pi site. These data suggest that ERP might play a role in B-cell development and in IgH gene regulation.