Prevention of tissue injury in an ascending mouse model of chronic pyelonephritis—role of free radical scavengers

Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

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.

Therapeutic effects of 5,2'-dibromo-2,4',5'-trihydroxydiphenylmethanone (LM49) in an experimental rat model of acute pyelonephritis by immunomodulation and anti-inflammation

Antibiotics are still the primary therapy for acute pyelonephritis (APN); rarely, natural polyphenols are also used. LM49 is a novel marine bromophenol derivative displaying strong anti-inflammatory effects. We investigated the therapeutic efficacy of LM49 in an experimental rat model of APN. The model was established by injecting 0.5 mL Escherichia coli (ATCC 25922, 10⁸ CFU/mL) into the urinary bladders of Sprague Dawley rats. This model showed increased kidney viscera indices and renal bacterial growth scores, as well as pathological changes in kidneys. We also performed a broth microdilution antimicrobial susceptibility test of the E. coli strain. Both norfloxacin and LM49 treatment reduced kidney viscera indices and decreased microbial counts in urine cultures and kidney homogenates in APN rats. However, in vitro experiments showed that LM49 did not directly inhibit bacteria. Rather, LM49 treatment inhibited inflammatory cell infiltration or abscess and improved tissue lesions in the renal medullary junction, renal pelvis, and calyx, and high-dose LM49 treatment inhibited the production of inflammatory interleukin-1β (IL-1β) and interleukin-6 (IL-6) in serum. CD4⁺ T cells were higher in the LM49 groups treated with high, medium, and low doses than in the model group, whereas only high-dose LM49 treatment increased the number of CD8⁺ T cells, as compared with that in the model group. However, LM49 treatment did not influence hematological parameters. Our results show that LM49 therapeutic effects in an APN animal model may be achieved by regulating immune responses and inhibiting inflammatory mediators, suggesting it as a candidate APN treatment.

Use of antioxidants in urinary tract infection

Pyelonephritis is an inflammatory process, and oxidative stress plays a major role in it. Anti-inflammatory or antioxidant therapy given concomitantly with antibiotics should lower the risk of postpyelonephritic scarring. As the lack of review studies in the use of antioxidants in urinary tract infections was detected, this study was designed. We conducted a review of available articles in PubMed and Google Scholar with a simple review, using keywords of “antioxidant” and “pyelonephritis” with all their possible synonyms and combinations. Only interventional studies were collected. There were neither limitations on time, nor the location of the study, type of subjects, administration rout of the antioxidant drug, and the antioxidant drug used. After studying the abstracts or in some cases the full text of articles, they were categorized based on the type of antioxidant, type and number of subjects, rout of administration, dosing, duration of treatment, year of publication of the paper, and the results. A total of 66 articles published from 1991 to 2015 were found by studying just the title of the papers. Studying the abstracts reduced this number to 51 studies. Antioxidants used for this condition were Vitamins A, E, and C, cytoflavin, caffeic acid phenethyl ester, ebselen, allopurinol, melatonin, N-acetylcysteine, oleuropein, montelukast, oxytocin, ozon, dapsone, pentoxifyllin, tadalafil, bilirubin, cranberry, meloxicam, L-carnitine, colchicine, perfluoran, methylprednisolone, and dexamethasone. Studies show that antioxidants are capable of reducing oxidative stress and can be used effectively along with antibiotics to reduce the scar formation.

Oxidative status parameters in children with urinary tract infection

Introduction:

Urinary tract infection (UTI) is one of the most common bacterial infectious diseases in children. The aim of this study was to determine the total prooxidant and antioxidant capacity of children with UTI, as well as changes of oxidative status parameters according to acute inflammation persistence and acute kidney injury (AKI) development.

Materials and methods:

The patients enrolled in the study comprised 50 Caucasian children (median age was 6 months) with UTI. Total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), inflammation marker C-reactive protein (CRP) and renal function parameters urea and creatinine were analyzed in patient’s serums.

Results:

According to duration of inflammation during UTI, TAS values were significantly higher (0.99 vs. 0.58 mmol/L, P = 0.017) and OSI values were significantly lower (0.032 vs. 0.041 AU, P = 0.037) in the subjects with longer duration of inflammation than in the subjects with shorter duration of inflammation. We did not find significant difference in basal values of oxidative status parameters according to AKI development.

Conclusions:

OSI values could detect the simultaneous change of TAS and TOS due to change in the oxidative-antioxidant balance during the recovery of children with UTI. TAS and OSI as markers of oxidative stress during UTI are sensitive to accompanying inflammatory condition. Further investigations are needed to evaluate whether TAS, TOS and OSI could be used to monitor disease severity in children with UTI.

Evaluation of the effects of ozone therapy on Escherichia coli-induced cytitis in rat

OBJECTIVES

The aim of the study was to investigate the effect of ozone on oxidative/nitrosative stress and bladder injury caused by Escherichia coli in rat bladder.

METHODS

Twenty-one Wistar-Albino-type female rats included in the study were divided into three groups of equal number: (1) sham operation (control), (2) E. coli-only (EC), (3) EC + ozone. After ozone therapy for 3 days, urine and tissue samples were obtained for biochemical, microbiological, and histopathological analysis.

RESULTS

Tissue malondialdehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO) level were increased, whereas superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity was decreased in the EC group. MDA, MPO, and NO levels were decreased, whereas SOD, GPx activity was increased in the ozone-treated group. Also, there was no bacterial translocation in this group.

CONCLUSION

The results of the present study suggest that ozone may be used as an agent to protect the bladder from oxidative/nitrosative stress occurring in cystitis.

Anti-inflammatory and antioxidant activity of thymoquinone in a rat model of acute bacterial prostatitis

Prostatitis plays a major role in morbidity and mortality related to prostate diseases. The aim of this study was to detect whether thymoquinone (TQ) could ameliorate oxidative damage and the proliferative response induced by Escherichia coli ( E. coli) in rats. A total of 42 adult male Wistar rats were used. The rats were randomly divided into seven groups (three treatment groups, three infected groups and one control group). Control group received saline and was killed 24 h after saline administration. Infected rats were killed after 24, 48 and 72 h following direct injection of E. coli into the prostate. Treatment groups were administered with 10 mg/kg dose of TQ intraperitoneally following E. coli injection and after 24 and 48 h following E. coli injection. The rats were killed at 24, 48 and 72 h after the first drug administration. Each group was compared with each other and with the control group. In addition, infected groups were compared with treatment groups. Our findings show that the treatment with TQ has a protective effect against bacterial prostatitis-induced tissue injury. Increase in malondialdehyde levels and histological damage caused by E. coli were improved markedly with TQ treatment. TQ treatment particularly increased the activity of glutathione peroxidase and decreased the activities of catalase and superoxide dismutase. These observations might be attributed, at least in part, to the antioxidant effect of TQ and suggest that it could be a clinically valuable agent in the prevention of acute prostatitis caused by E. coli.

Ozone therapy prevents renal inflammation and fibrosis in a rat model of acute pyelonephritis

INTRODUCTION

Not only bacterial characteristics but also oxidative/nitrosative stress could play a significant role in renal parenchymal inflammatory processes in acute pyelonephritis (APN). This study was conducted to evaluate the effect of ozone therapy (OT), as an immunomodulator and antioxidant, on the renal function, morphology and biochemical parameters of oxidative stress in an experimental model of APN in rats.

MATERIALS AND METHODS

Forty rats were divided equally into five groups as control, APN, APN + Antibiotic, APN + OT, and APN + Antibiotic + OT. APN was induced by 0.1 ml of freshly prepared Escherichia coli (ATCC 25922) solution containing 10(10) colony-forming unit/ml into the kidney. A control group was administered 0.1 ml of 0.9 % NaCl solution. Treatment was begun 72 h after bacterial inoculation. Control and APN groups were given 0.9% NaCl solution, APN + Antibiotic and APN + OT were given either antibiotic (ciprofloxacine 150 mg/kg intramuscular/twice daily) or OT. APN + Antibiotic + OT group was given both antibiotic and OT for five consecutive days. At the end of the seventh day, animals were killed via decapitation and trunk blood was collected. Both kidneys were harvested and one half of each kidney were immediately stored for antioxidant enzyme activity, tissue lipid peroxidation and protein carbonyl content. The remainder was fixed for histopathologic examination.

RESULTS

E. coli-induced APN increased the renal glomerular and tubular dysfunction, oxidative stress parameters and antioxidant enzyme activities. Either antibiotherapy or OT markedly ameliorated renal dysfunction, the antioxidant status of the kidneys and histopathological injuries subjected to E. coli-induced APN. Interestingly, the combination of antibiotherapy and OT was much more effective than either of the treatment modalities alone.

CONCLUSION

The combination of antibiotherapy and OT markedly ameliorated renal dysfunction and improved antioxidant status and histopathologic modalities in rats subjected to E. coli-induced APN than either antibiotherapy or OT treatment alone. Therefore, OT may be considered as an adjuvant therapy to classical antibiotherapy to prevent renal inflammation and fibrosis in APN.

Evaluation of Effectiveness of Vitamins C and E on Prevention of Renal Scar due to Pyelonephritis in Rat

Aim was evaluation of the effects of cosupplementation of, vitamins E and C, in preventing renal scarring in acute pyelonephritis. Animals and Treatments. Sixty rats were used, bacteria was injected through kidney. The rats were arranged randomly in 3 groups of 20 rats each. Rats in groups 1 and 2 were given once-daily intraperitoneal injections of gentamicin for ten consecutive days, beginning on the third day after inoculation. In group 2, vitamins E and C cotreatment and in group 3, vitamins E and C cotreatment without gentamicin injection were started. Three rats in each group were killed 24 hours after the inoculation (for infection and inflammation document) and forty-eight hours after the antibiotic injection (for efficacy of treatment). After eight weeks, the rest of rats were killed, and kidneys evaluated for percent of scaring. Result. There was also significant difference of degree of scar formation (1.4 and 3.4% versus 8.6%, P = .001). The group which received gentamicin only had moderate to severe scaring, but the two groups which received vitamin C and vitamin E showed no or mild renal scaring. Conclusion. The study showed that administration of antioxidants can protect scaring due to pyelonephritis with or without antibiotic administration.

Renal tissue damage after experimental pyelonephritis: role of antioxidants and selective cyclooxygenase-2 inhibitors

OBJECTIVES

To investigate the involvement of oxidative stress in the pathogenesis of acute pyelonephritis, and to evaluate the impact of meloxicam and/or L-carnitine in addition to conventional antibiotic treatment.

METHODS

A total of 48 Wistar rats were divided into 4 groups according to their treatment, which was started 1 day after inoculation of all rats with Escherichia coli (ATCC 25 922, 10(10) cfu/mL). Group 1 received only antibiotic treatment with ceftriaxone (50 mg/kg, IM). Groups 2 and 3 received L-carnitine (500 mg/kg, IM) and meloxicam (3 mg/kg, IM) in addition to conventional treatment, respectively. Group 4 received combination therapy (L-carnitine and meloxicam) in addition to the first group. Rats were killed 3 and 7 days after E. coli inoculation and underwent nephrectomy. Histologic determination of tubular atrophy, acute and chronic inflammation, interstitial fibrosis and biochemical determination of superoxide dismutase and catalase activity, total thiol content, total antioxidant capacity, and malondialdehyde and protein hydroperoxide levels were measured.

RESULTS

Interstitial fibrosis (P = .06), chronic inflammation (P = .536), and tubular atrophy (P = 0.094) decreased in group 4 compared with the other groups, but there was a statistically significant decrease only in acute inflammation (P = .015). In addition, if the day of nephrectomy is considered, there was again a significant decrease in acute inflammation on day 7 compared with day 3 in groups 2, 3, and 4 (P = .002). Catalase significantly increased in group 2 (P = .029), group 3 (P = .02), and group 4 (P = .014), and decreased in group 1 (P = .012) in day 7.

CONCLUSIONS

L-carnitine and meloxicam alleviated oxidative stress, probably by decreasing lipid peroxidation and enforcing antioxidant defense system. Acute renal inflammatory injury can be prevented much more effectively by combination therapy rather than by conventional therapy alone.

The effects of methylene blue on renal scarring due to pyelonephritis in rats

The aim of this study was to evaluate the efficiency of methylene blue (MB) in preventing renal scar formation after the induction of pyelonephritis (PNP) in a rat model with delayed antimicrobial therapy. An inoculum of the K-12 strain of Escherichia coli was injected into both kidneys. Control groups received isotonic saline instead of bacterial solution. Four equal groups were then formed: the PNP group was untreated and the PNP ciprofloxacin (CIP) treated group was treated only with CIP intraperitoneally (i.p.) starting on the third day following bacterial inoculation. In the PNP (MB)-treated group, MB was given i.p., and in the PNP MB + CIP-treated group, MB + CIP were administered i.p.. In the sixth week following bacterial inoculation, all rats were sacrificed, and both kidneys of the rats in all groups were examined biochemically and histopathologically for renal scarring. Renal scar was significant in the groups treated with MB alone or MB + CIP combination compared with untreated or antibiotic only groups. Delayed treatment with antibiotics had no effect on scarring. These results suggest that the addition of MB to the delayed antibiotic therapy might be beneficial in preventing PNP-induced oxidative renal tissue damage.

Caffeic acid phenethyl ester suppresses oxidative stress in Escherichia coli-induced pyelonephritis in rats

Although oxidative damage is known to be involved in inflammatory-mediated tissue destruction, modulation of oxygen free radical production represents a new approach to the treatment of inflammatory diseases. Caffeic acid phenethyl ester (CAPE), an active component of propolis from honeybee hives, has antioxidant, anti-inflammatory and antibacterial properties. For that reason, we aimed to investigate the efficiency of CAPE administration in preventing oxidative damage in pyelonephritis (PYN) caused by Escherichia coli. In this study, 35 Wistar rats were grouped as follows: control, PYN 24 h, PYN 48 h, PYN 72 h, CAPE 24 h, CAPE 48 h and CAPE 72 h. E. coli (1 x 10(9) c.f.u.) were inoculated into the rats in both PYN and CAPE groups via urethral catheterization. Ten microM/kg-body weight CAPE was injected to the rats in all CAPE groups 24 h before E. coli infection, and injections were repeated at 24-h intervals. Rats were sacrificed 24 h, 48 h and 72 h after infection in both PYN and CAPE groups. Malondialdehyde (MDA) and nitric oxide (NO) levels were significantly increased in kidneys of PYN groups. The activities of the antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and xanthine oxidase (XO) were also elevated by E. coli. However, CAPE administration reduced MDA and NO levels, as well as XO activity, although it increased SOD and GSH-Px activities. Histopathological examination showed that CAPE reduced the inflammation grade induced by E. coli. In conclusion, CAPE administrations decrease the oxidative damage occurring in PYN and therefore could be used for medical management of bacterial nephropathy.

Urinary tract infections-microbial virulence determinants and reactive oxygen species

The human urinary tract is able to combat with the microbial invasion under normal circumstances. To cause urinary tract infection the organism has to evade the host defense mechanisms by possessing distinct properties which contribute to the virulence of the organism hence called virulence determinants Ninety percent of uncomplicated urinary tract infections are caused by Escherichia coli, hence the knowledge of the virulence determinants of this organism can be extrapolated to other uropathogenic organism as well. Virulence determinants of uropathogenic E. coli include adhesins, siderophore production, polysaccharide coating, hemolysin production, outer membrane proteins etc. The intestinal E. coli, which are the reservoir of E. coli for causing UTI, lack these virulence determinants. On the other hand these virulence determinants enable the organism to colonize and invade the urinary tract. In addition these are important in acquiring the nutrients in other wise nutrient deficient environment. Further, they also help the organisms in triggering an inflammatory response and hence bringing about pathological changes which leads to symptomatic UTI. Severity of symptomatic infections and tissue damage during the infective process depends upon the magnitude of the inflammatory response triggered by the uropathogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells; hence role of antioxidants as an adjunct to antibiotics in the treatment of infective process needs to be evaluated further.