Effects of melatonin on suppression of renal scarring in experimental model of pyelonephritis

Investigation of the Effects of N-acetylcysteine and Selenium on Vesicoureteral Reflux Nephropathy: An Experimental Study

INTRODUCTION

This study aimed to investigate the effects of N-acetylcysteine (NAC) and selenium (Se) on vesicoureteral reflux (VUR) nephropathy.

METHODS

A total of 44 rabbits in 7 groups, namely group 1 (Control), group 2 (VUR + sterile urine), group 3 (VUR + sterile urine + NAC), group 4 (VUR + sterile urine + Se), group 5 (VUR + infected urine), group 6 (VUR + infected urine + NAC) and group 7 (VUR + infected urine + Se), were used. 99mTc Dimercaptosuccinic acid renal scan (DMSA), cystogram and urine culture were performed both at the beginning and end of the study. Left VUR was created surgically, and E. coli was inoculated in infected urine groups. NAC and Se were administered daily for 21 days. Malondialdehyde (MDA) measurement, inflammatory response scores (IRSs), and cicatrization response scores (CRSs) in renal tissues were evaluated.

RESULTS

VUR did not reduce left renal uptake values in neither group 2 nor group 5. MDA levels of the left kidney were significantly higher in group 5 compared to group 1 (p = 0.001). There was no significant difference in MDA levels between group 5 and group 6, and between group 5 and group 7. Left kidney IRSs were found to be higher in all other groups except group 2 compared to the control group (p < 0.001). Left kidney CRSs were significantly higher in group 5 compared to group 2 (p = 0.026), group 6 (p < 0.001) and group 7 (p = 0.006).

CONCLUSION

A decrease in renal functions was not observed in VUR, even if there was infection. When CRSs were evaluated, NAC and Se had protective effects in terms of scar formation in VUR nephropathy.

TYPE OF STUDY

Experimental animal study.

LEVELS OF EVIDENCE

N/A.

Effect of melatonin on oxidative stress indicators in animal models of fibrosis: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Imbalance of oxidative stress has been detected in a range of fibrotic diseases. Melatonin as an indoleamine hormone plays an important role in regulating the circadian rhythm of human, while in recent years, its antioxidant effect has also attracted increasing attention. This study aimed to perform a systematic review and meta-analysis to comprehensively evaluate the antioxidant effect of melatonin in animal models of fibrosis.

METHODS

The PubMed, Cochrane Library, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang database, China Science and Technology Journal Database (VIP), and SinoMed databases were searched from inception to March 1st, 2022 to retrieve eligible studies that evaluated the effect of melatonin supplementation on the levels of malondialdehyde (MDA), lipid peroxidation (LPO), nitric oxide (NO), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and catalase (CAT) in animal models of fibrosis.

RESULTS

A total of 64 studies were included in this meta-analysis. The results showed that melatonin supplementation significantly reduced the levels of oxidative indicators including MDA (P < 0.00001), LPO (P < 0.00001) and NO (P < 0.0001), and elevated the levels of antioxidant indicators including GSH (P < 0.00001), GPx (P < 0.00001) and SOD (P < 0.00001) in fibrotic diseases.

CONCLUSIONS

Our research findings showed that melatonin supplementation could significantly reduce the levels of oxidative indicators including MDA, LPO and NO and elevate the levels of antioxidant indicators including GSH, GPx and SOD so as to correct oxidative stress in animal models of fibrosis. However, no significant changes were observed in CAT level. More clinical studies are needed to further confirm the beneficial role of melatonin in fibrotic diseases.

Investigation of the Optimum Preparation of Peach Gum Polysaccharides and the In Vivo and In Vitro Therapeutic Effects on Acute Pyelonephritis

BACKGROUND

Acute pyelonephritis (APN), known as stranguria in traditional Chinese medicine, is commonly treated with antibiotics. However, the rise in antibiotic resistance and the high rates of recurrence of APN make its treatment complicated, thus the development of alternative therapies is critical. Peach gum has long been recognized by traditional Chinese medicine as a food with medicinal value of relieving stranguria, but whether and how its primary constituent peach gum polysaccharides (PGPs) contribute to the diuretic function is still not clear.

PURPOSE

The aim of this study was to investigate the optimum extraction process of PGPs and to evaluate its therapeutic effect on APN rats and to discover the underlying mechanism.

METHODS

In this study, surface design optimization was adopted to optimize the preparation of PGPs and HPLC and FT-IR spectra were used to evaluate the quality of PGPs; APN model rat was established by the Escherichia coli urinary tract infection method; the therapeutic effect and mechanism of PGPs on APN were determined by the visceral index, biochemical indicators, pathological section of the APN rat, and diuretic activity on mice and antibacterial activity in vitro.

RESULTS

Compared with an untreated APN group, the results showed that treatment with PGPs increased the APN-induced attenuation of secretory immunoglobulin A (sIgA) and creatinine clearance and decreased the APN-induced enhancement of the number of white blood cell (WBC), neutrophil counts (NC), bacteria load of the kidneys, kidney index, serum creatinine, urine volume, blood urea nitrogen (BUN), and interleukin-2 (IL-2) levels. The mechanism underlying these effects was further elucidated through in vitro experiments of the antibacterial and antiadhesion effects of PGPs.

CONCLUSION

Due to the good therapeutic effects and advantages of PGPs, it could be considered as an alternative medicine to treat APN.

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.

Melatonin: the dawning of a treatment for fibrosis?

Fibrosis is a common occurrence following organ injury and failure. To date, there is no effective treatment for this condition. Melatonin targets numerous molecular pathways, a consequence of its antioxidant and anti-inflammatory actions that reduce excessive fibrosis. Herein, we review the multiple protective effects of melatonin against fibrosis. There exist four major phases of the fibrogenic response including primary injury to the organ, activation of effector cells, the elaboration of extracellular matrix (ECM) and dynamic deposition. Melatonin regulates each of these phases. Additionally, melatonin reduces fibrosis levels in numerous organs. Melatonin exhibits its anti-fibrosis effects in heart, liver, lung, kidney, and other organs. In addition, adhesions which occur following surgical procedures are also inhibited by melatonin. The information reviewed here should be significant to understanding the protective role of melatonin against fibrosis, contribute to the design of further experimental studies related to melatonin and the fibrotic response and shed light on a potential treatment for fibrosis.

Could pyelonephritic scarring be prevented by anti-inflammatory treatment? An experimental model of acute pyelonephritis

Objectives. This study aimed to demonstrate if the addition of anti-inflammatory treatment to antibiotic therapy shows any superiority to the treatment with antibiotic only. Methods. Forty-nine Wistar rats were divided into 7 groups. Pyelonephritis was performed by E. coli injection to upper pole of kidneys except control group. Group 2 was not treated. Ceftriaxone, ketoprofen, “ceftriaxone + ketoprofen,” methylprednisolone, and “ceftriaxone + methylprednisolone” were given in the groups. The technetium-99m-dimercaptosuccinic acid scintigraphies were performed in 3rd day to detect pyelonephritis and 10th week to detect renal scarring. All kidneys were also histopathologically evaluated. Results. When 3rd day and 10th week scintigraphies were compared, initial 2.00 ± 0.30 point pyelonephritis score resulted in 0.71 ± 0.36 renal scar score in “ceftriaxone + ketoprofen” group (P = 0.039). Initial 2.00 ± 0.43 point pyelonephritis score resulted in 0.86 ± 0.26 renal scar score in “ceftriaxone + methylprednisolone” group (P = 0.041). Renal scar score was declined in “ceftriaxone + ketoprofen” group and “ceftriaxone + methylprednisolone” group compared with no-treatment group on 10th week of the study (P = 0.026, P = 0.044). On histopathological evaluation, it was seen that renal scar prevalence and expansion declined significantly in “ceftriaxone + ketoprofen and ceftriaxone + methylprednisolone” (P = 0.011, P = 0.023). Conclusion. It was evidenced that ceftriaxone treatment in combination with ketoprofen or methylprednisolone declined scar formation in scintigraphic and histopathologic examinations of the kidneys.

Protective effect of mitochondria-targeted antioxidants in an acute bacterial infection

Acute pyelonephritis is a potentially life-threatening infection of the upper urinary tract. Inflammatory response and the accompanying oxidative stress can contribute to kidney tissue damage, resulting in infection-induced intoxication that can become fatal in the absence of antibiotic therapy. Here, we show that pyelonephritis was associated with oxidative stress and renal cell death. Oxidative stress observed in pyelonephritic kidney was accompanied by a reduced level of mitochondrial B-cell lymphoma 2 (Bcl-2). Importantly, renal cell death and animal mortality were both alleviated by mitochondria-targeted antioxidant 10(6'-plastoquinonyl) decylrhodamine 19 (SkQR1). These findings suggest that pyelonephritis can be treated by reducing mitochondrial reactive oxygen species and thus by protecting mitochondrial integrity and lowering kidney damage.

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.

The effect of vitamin A on renal damage following acute pyelonephritis in children

Animal studies suggest that administration of vitamin A to rats with experimental urinary tract infection decreases the frequency of renal scars (Kavukçu et al., BJU Int 83(9):1055-1059, 1999). The aim of this study was to determine the effect of vitamin A on the rate of permanent renal damage in children with acute pyelonephritis. Fifty children, median age of 24 months (range 2-144), with first-time pyelonephritis verified by an uptake defect on acute dimercaptosuccinic acid (DMSA) scan were included in the study and randomly allocated to the case or control groups. All were given intravenous ceftriaxone for 10 days followed by oral cephalexin for 3 months. Cases in addition were given a single intramuscular dose of vitamin A, 25,000 U for infants below 1 year of age and 50,000 U for older children. At the repeat DMSA scan after 3 months, five of 25 cases (20%) and 17 of 25 controls (68%) had abnormal findings (p = 0.001). In conclusion, administration of vitamin A was associated with a significantly lower rate of permanent renal damage.

Matrix metalloproteinases in health and disease: regulation by melatonin

Matrix metalloproteinases (MMPs) are part of a superfamily of metal-requiring proteases that play important roles in tissue remodeling by breaking down proteins in the extracellular matrix that provides structural support for cells. The intricate balance in protease/anti-protease stoichiometry is a contributing factor in a number of diseases. Melatonin possesses multifunctional bioactivities including antioxidative, anti-inflammatory, endocrinologic and behavioral effects. As melatonin affects the redox status of tissues, the association of reactive oxygen species (ROS) with tissue injury under different circumstances may be mitigated by melatonin. Redox signaling is expanding into all areas of basic and clinical sciences, and this timely review focuses on the topic of regulation of MMP activities by melatonin. This is a rapidly growing field. Accumulating evidence indicates that oxidative stress plays an important role in regulating the activities of MMPs that are involved in various cellular processes such as cellular proliferation, angiogenesis, apoptosis, invasion and metastasis. This review offers sections on MMPs, melatonin, major physiological and pathophysiological conditions in the context to MMPs, followed by redox signaling mechanisms that are known to influence the cellular processes. Finally, we discuss the emerging molecular mechanisms relevant to regulatory actions of melatonin on the activities of MMPs. The possibility that melatonin might have therapeutic significance via regulation of MMPs may be a novel approach in the treatment of some diseases.

Protective effect of melatonin against formaldehyde-induced kidney damage in rats

This study was undertaken to investigate the protective effects of melatonin against formaldehyde-induced renal damage in rats. For this purpose, 21 male Wistar rats were divided into three groups. The animals in Group I were used as a control, whereas the rats in group II were injected every other day with formaldehyde. The rats in group III received melatonin daily while exposed to formaldehyde. At the end of the 14-day experimental period, all rats were killed by decapitation, and the kidneys were removed. Some of the renal tissue specimens were used for determination of superoxide dismutase, glutatione peroxidase enzyme activities, and malondialdehyde levels. The remaining kidney tissue specimens were used for light microscopic evaluation. The renal tissue activities of superoxide dismutase and glutatione peroxidase were significantly decreased, and malondialdehyde levels were significantly increased in rats treated with formaldehyde compared with those of the control animals. In the light microscopic evaluation of this group, degenerative glomerules, vacuolization and dilatation of distal tubules, and vascular congestion were detected. However, an increase was observed in activities of superoxide dismutase and glutatione peroxidase enzymes, and a decrease of malondialdehyde levels in animals treated with formaldehyde plus melatonin was observed. Furthermore, the histopathological changes caused by formaldehyde were disappeared except for minimal tubular dilatation in this group. In conclusion, the biochemical and histological findings of our study suggest that melatonin administration prevents formaldehyde-induced oxidative renal damage in rats.

Vitamin E administration at the onset of fever prevents renal scarring in acute pyelonephritis

We evaluated the protective effects of antioxidant at the onset of fever on renal damage in a rat model of acute pyelonephritis. Twenty rats were allocated to four groups. In groups 1 to 3, the animals were given direct inoculation of Escherichia coli into the right kidney, and group four served as control. All rats in groups 1 to 3 were given once-daily intraperitoneal injections of ceftriaxon for five consecutive days, beginning on the third day after inoculation. The animals' body temperatures were monitored; as soon as body temperature reaches 38 degrees C, the rats in group 2 were given allopurinol co-treatment, whereas, in group 3, vitamin E co-treatment was started at fever onset. Both kidneys were excised 6 weeks later, for the evaluation of histopathologic changes, apoptotic damage, and concentrations of transforming growth factor-beta (TGF-beta). Only minimal changes were found in control samples. Pathologic scores of inflammation and fibrosis in group 1 were higher than in the vitamin E and allopurinol groups (P < 0.05). Apoptosis index was also decreased in groups 2 and 3, compared to group 1 (P < 0.05). There was no significant difference in average TGF-beta levels between study groups. These findings suggest that administration of vitamin E or allopurinol following the onset of fever can reduce renal damage in pyelonephritis.

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.

Evidence supporting the use of melatonin in short gestation infants

Pineal melatonin regulates circadian rhythms and influences sleep. Melatonin also has protective actions against tissue damage from free-radicals and other toxins. Evidence is presented that this indoleamine is involved in pre- and postnatal brain (and ocular) development and intrauterine growth. In the absence of maternal melatonin, short gestation infants have a prolonged period of melatonin deficiency. Melatonin supplementation, which has a benign safety profile, may help reduce complications in the neonatal period that are associated with short gestation. We believe that this treatment might result in a wide range of health benefits, improved quality of life and reduced healthcare costs.