L-651,392, a potent leukotriene inhibitor, controls inflammatory process in Escherichia coli pyelonephritis

Preventive Effect of L-Carnitine on Scar Formation During Acute Pyelonephritis: A Randomized Placebo-Controlled Trial

BACKGROUND

Urinary tract infection and pyelonephritis are clinical problems that frequently occur in children. Several factors are responsible for renal tissue injury, morbidity, and renal scarring after pyelonephritis. The aim of this study was to evaluate the preventive effect of L-carnitine on renal scarring in acute pyelonephritis.

METHODS

A randomized double-blind clinical trial was conducted on 65 children aged 6 months to 10 years. Patients were randomized into 2 groups to receive 7-day treatment with only antibiotics without L-carnitine (control group; n = 32) and 7-day treatment with L-carnitine (case group; n = 33) during the acute phase of infection. Technetium-99m-labeled dimercaptosuccinic acid (DMSA) scintigraphy was performed for all children during the acute phase (in 2-7 days of hospitalization) and late phase. P-value less than 0.05 was statistically significant.

RESULTS

We recruited 65 participants in the study: 32 children in control group and 33 children in case group. Three children in the control group and 2 children in the case group refused to perform the second DMSA scan. Overall, data analysis at the end of the study was done on 60 patients. Age distribution of girl patients with upper urinary infection was 6.5% in girl children aged between 6 months and 12 months, 41.1% aged between 1 and 5 years, 33.3% aged between 5 and 10 years, respectively. There was no significant difference between 2 groups in age and sex. There was no significant difference between 2 groups in systolic blood pressure, diastolic blood pressure, the lab data including urine white blood cells and serum erythrocyte sedimentation rate, and antibiogram profiles. Voiding dysfunction was detected in 10% of the participants. The baseline DMSA was not significantly difference in 2 groups, but worsening of kidney lesions was significantly higher in control group after 6 months (P = 0.012).

CONCLUSION

Our study showed that L-carnitine significantly decreased renal scarring because of acute pyelonephritis.

Mouse model for pyelonephritis

This unit describes a simple way to induce pyelonephritis in female mice using uropathogenic Escherichia coli (UPEC). Methods for culturing and preparing working stocks of UPEC are provided. Protocols to measure the bacterial load in the murine kidney following the establishment of pyelonephritis by determining the bacterial colony forming units (CFU) are also included. This assay can be performed with kidney homogenates if the bacterial load is the sole read-out or if cellular intactness is not required for subsequent assays, or from kidney single cell suspensions prepared by enzymatic digestion. A support protocol describes methods for isolating cells for flow cytometry, ex vivo culture, and other assays.

Montelukast ameliorates kidney function and urinary bladder sensitivity in experimentally induced renal dysfunction in rats

Effect of montelukast on the renal dysfunction induced by cisplatin was investigated. A single dose of cisplatin (7 mg/kg, i.p.) induced nephrotoxicity, which was manifested by increasing the sensitivity of isolated urinary bladder rings to acetylcholine (ACh) together with a significant elevation of serum creatinine, blood urea nitrogen, and lactate dehydrogenase. On the other hand, serum albumin was significantly decreased. Moreover, renal dysfunction was further confirmed by a significant increase in lipid peroxides that were measured as malondialdehyde (MDA) in kidney tissue homogenate. Kidney reduced glutathione (GSH) content and superoxide dismutase (SOD) activity were measured, which were decreased and increased, respectively. Administration of montelukast (10 mg/kg/day, p.o.) 5 days before and 5 days after cisplatin injection significantly ameliorated the renotoxic effects of cisplatin, as judged by a significant reduction in the responses of isolated bladder rings to ACh. The deleterious changes induced by cisplatin treatment in kidney function parameters and oxidative stress markers were significantly mitigated by montelukast treatment.

CONCLUSION

Montelukast may be a beneficial remedy for cisplatin-induced renal dysfunction.

The role of dexamethasone on decreasing urinary cytokines in children with acute pyelonephritis

Cytokines play a major role in renal scar formation following febrile urinary tract infection (UTI). We investigated the role of dexamethasone combined with antibiotics in diminishing urinary interleukin-6 (UIL-6) and UIL-8 concentrations during the acute phase of pyelonephritis compared with standard antibiotic therapy. UIL-6 and UIL-8 concentrations were determined by enzyme immunoassay in 34 children with pyelonephritis who were treated with ceftriaxone plus dexamethasone (case group) and in 20 patients with the same diagnosis treated with ceftriaxone alone (control group). Urine samples were obtained at the time of presentation prior to drug administration and at follow-up 72 h after initiation of medication. Creatinine concentrations were also determined, and cytokine/creatinine ratios were calculated to standardize samples. Differences between cytokine/creatinine ratios in initial and follow-up urine samples were significant in the case group (P < 0.001) but not for controls. In addition, combined antibiotic and dexamethasone significantly decreased UIL-6 and UIL-8 concentrations compared with antibiotic alone (P < 0.05). We conclude that dexamethasone combined with antibiotics significantly decreases UIL-6 and UIL-8 levels in patients with acute pyelonephritis. This suggests that the clinical use of corticosteroids may prevent scar formation following febrile UTI.

Oxidative renal damage in pyelonephritic rats is ameliorated by montelukast, a selective leukotriene CysLT1 receptor antagonist

Urinary tract infections may induce severe inflammation, transient impairment in renal function and scar formation, ranging in severity from acute symptomatic pyelonephritis to chronic pyelonephritis, which have a potential to lead to renal failure and death. The present study aimed to investigate the possible protective effect of montelukast, a selective antagonist of cysteinyl leukotriene receptor 1 (leukotriene CysLT1), against Escherichia coli-induced oxidative injury and scarring in renal tissue. Wistar rats were injected 0.1 ml of E. coli (ATCC 25922 10(10) cfu/ml) or saline into left renal medullae. Six rats were assigned as the sham group and were given 0.1 ml 0.9% NaCl. Pyelonephritic rats were treated with either saline or montelukast immediately after surgery and at daily intervals. Twenty-four hours or one week after E. coli injection, rats were decapitated and the kidney samples were taken for histological examination or determination of renal malondialdehyde, glutathione (GSH) levels, myeloperoxidase (MPO) activity, and collagen contents. Formation of reactive oxygen species in renal tissue samples was monitored by using chemiluminescence technique with luminol and lucigenin probes. Creatinine, blood urea nitrogen and lactate dehydrogenase (LDH) activity were measured in the serum samples. E. coli inoculation caused significant increases in malondialdehyde level, MPO activity, chemiluminescence levels and collagen content, while GSH level was decreased in the renal tissues (p<0.05-0.001). On the other hand, serum TNF-alpha, LDH, blood urea nitrogen and serum creatinine levels were elevated in the pyelonephritic rats as compared to control group. Leukotriene CysLT1 receptor antagonist montelukast reversed all these biochemical indices, as well as histopathological alterations, that were induced by acute pyelonephritis. It seems likely that montelukast protects kidney tissue by inhibiting neutrophil infiltration, balancing oxidant-antioxidant status, and regulating the generation of inflammatory mediators suggesting a future role for leukotriene CysLT1 receptor antagonists in the treatment of pyelonephritis.

Imaging Techniques for the Study of Escherichia coli and Salmonella Infections

Infectious diseases are among the leading causes of mortality worldwide, and numerous bacterial species are included in the vast array of causative agents. This review describes microscopy-based techniques that can be used to study interactions between bacteria and infected host cells, bacterial gene expression in the infected animal, and bacteria-induced cell signaling in eukaryotic cells. As infectious model systems, urinary tract infections caused by uropathogenic Escherichia coli (UPEC) and a mouse model of typhoid fever caused by Salmonella enterica serovar Typhimurium are used. To study the interaction mechanism between bacteria and eukaryotic cells, one commonly uses cell lines, primary cells, and animal models. Within the host, bacteria can be located in various organs where they are exposed to different cell types, ranging from epithelial cells at the mucosal linings to phagocytic white blood cells. In each site, bacteria are exposed to specific sets of innate immune defense mechanisms, and to survive these threats, bacteria must rapidly adapt their gene expression profile to maximize their chance of survival in any situation. The rapid development of fluorescent reporter proteins and advances in microscopy-based techniques have provided new and promising approaches not only to locate bacteria in tissues, but also to analyze expression of virulence factors in individual bacteria and host cells during the progression of disease. These techniques enable, for the first time, studies of the complex microenvironments within infected organs and will reveal the alterations of bacterial physiology that occur during bacterial growth within a host.

Nephrektomie bei akuter unkomplizierter Pyelonephritis

BACKGROUND

Which complications can develop from uncomplicated pyelonephritis that may require nephrectomy?

METHODS

From January 1999 to June 2003 we carried out nephrectomy in ten cases due to abscess formation after acute, uncomplicated pyelonephritis. The medical files were evaluated retrospectively.

RESULTS

Nine women and one man were involved. The mean age was 36.2 years. Leading symptoms: flank pain, fever and chills. The mean symptom duration before admission was 14.6 days. Urinary tract infections were caused by Escherichia coli (six), E. coli and Enterococcus (once) and Klebsiella pneumoniae (once). Two cultures were sterile. Indications for nephrectomy were urosepsis (7 cases), anuria (once), increasing abscess formation under antibiotic therapy (once), drastic deterioration of general condition (once).

CONCLUSIONS

Uncomplicated pyelonephritis is easy to treat under outpatient conditions with adequate oral antibiotic therapy. Close control must be ensured and clear recovery of symptoms should occur within 48 h. In the case of long duration of symptoms (>6-7 days) or lack of improvement of symptoms under calculated therapy in the first 2 days, inpatient therapy should be initiated because of the high risk of infectious complications. According to our experience, the following patient group is especially at risk: female, symptom duration of at least approximately 1 week, pre-treatment and transfer from another departments.

Role of TGF-beta1 in renal parenchymal scarring following childhood urinary tract infection

BACKGROUND

Significant variability exists in the outcome of renal parenchymal inflammation following urinary tract infection (UTI) in childhood as some children experience renal parenchymal scarring (RPS) while others do not scar. Since TGF-beta1 is pro-fibrotic, we examined the role of this cytokine in RPS following UTI.

METHODS

Five polymorphisms of the TGF-beta1 gene were investigated as well as the relationship between these polymorphisms and TGF-beta1 production by peripheral blood mononuclear cells (PBMC) in vitro. DNA was isolated from 91 children shown to have developed RPS, 43 children with no evidence of scarring (NS) following UTI, and 171 healthy controls. Genotyping was performed by restriction fragment length polymorphism (RFLP). PBMC were isolated from a subgroup of 24 patients from the total population. Cells were stimulated with LPS + PMA + PHA and then TGF-beta1 production was determined by ELISA.

RESULTS

Comparing the NS with the RPS group, there was an increase in the -800 GA genotypes (18.6 vs. 7.4%, P=0.05; chi2) and the Leu10-->Pro CT (62.8 vs. 41.5%, P=0.021), and a decrease in the -509 TT genotype (0.0 vs. 8.5%, P=0.049). PBMC TGF-beta1 production was higher in those patients with the -800 GG compared to those with a GA genotype stimulation index [stimulated/unstimulated TGF-beta1 levels were 1.54 interquartile range (IQR) 1.42 to 1.75 vs. 1.19, IQR 0.94 to 1.51, P=0.031].

CONCLUSIONS

There is an association between the TGF-beta1 -800 GA, -509 TT and Leu10-->Pro CT genotypes and the presence or absence of RPS. The low TGF-beta1 producer status of the -800 GA genotype may protect against the development of a pro-fibrotic pathology.

Treatment of pyelonephritis in adults

Although prescribing an antibiotic for the treatment of pyelonephritis seems to be a relatively easy task, a close look at the available data is disturbing. Optimal therapies for the different clinical syndromes of pyelonephritis have not yet been defined. The high failure rate suggests that in pyelonephritis (bacteria protected in the medulla) as well as in bacterial endocarditis (bacteria sequestered in vegetations) and in infections in neutropenic patients (host defenses not necessarily operating in conjunction with antibiotics), it may be necessary to maintain bactericidal levels at the site of infection (infected medulla) to achieve cure. Pharmacodynamic studies suggest that TMP/SMX, quinolones, and aminoglycosides, which penetrate well the infected renal parenchyma and are not impaired by the local inflammatory process, should, with the exception of pyelonephritis in pregnancy, be preferred to beta-lactams as first-choice agents for the therapy of gram-negative pyelonephritis.