[Influence of standard treatment on changes in the structural and functional properties of circulation red blood cells in obstructive and non-obstructive acute pyelonephritis].

AIM: To determine the effect of standard treatment on changes in the structural and functional properties of erythrocytes in obstructive and non-obstructive acute pyelonephritis. MATERIALS AND METHODS: The structural and functional properties of erythrocytes and their intracellular metabolism in 78 patients with a diagnosis of primary non-obstructive and secondary obstructive acute pyelonephritis, randomized by age, gender, and the minimum number of concomitant diseases were investigated. RESULTS AND DISCUSSION: In acute non-obstructive pyelonephritis, changes of the content of proteins in circulating erythrocytes responsible for the structure formation and stabilization of the plasma membrane (-spectrin, anion transport protein, pallidin, protein 4.1), intracellular metabolism (anion transport protein, glutathione-S-transferase), membrane flexibility and shape (actin, tropomyosin) are insignificant, alike from acute obstructive pyelonephritis. In addition, processes of lipid peroxidation inside red blood cells are intensified, and oxidative stress develops with a decrease in the sorption capacity of erythrocytes, as well as the content and ratio of lipid fractions in the plasma membrane, which form the basis of the lipid components and play the main role in the sequencing of protein macromolecules and the normal metabolism of red blood cells. CONCLUSION: In acute obstructive pyelonephritis, changes in the content and ratio of proteins and lipids in the erythrocyte membrane lead to functional rearrangements that are not corrected by standard treatment.

Regulation of renal aquaporin water channels in acute pyelonephritis.

Acute pyelonephritis (APN) is most frequently caused by uropathogenic Escherichia coli (UPEC), which ascends from the bladder to the kidneys during a urinary tract infection. Patients with APN have been reported to have reduced renal concentration capacity under challenged conditions, polyuria, and increased aquaporin-2 (AQP2) excretion in the urine. We have recently shown increased AQP2 accumulation in the plasma membrane in cell cultures exposed to E. coli lysates and in the apical plasma membrane of inner medullary collecting ducts in a 5-day APN mouse model. This study aimed to investigate if AQP2 expression in host cells increases UPEC infection efficiency and to identify specific bacterial components that mediate AQP2 plasma membrane insertion. As the transepithelial water permeability in the collecting duct is codetermined by AQP3 and AQP4, we also investigated whether AQP3 and AQP4 localization is altered in the APN mouse model. We show that AQP2 expression does not increase UPEC infection efficiency and that AQP2 was targeted to the plasma membrane in AQP2-expressing cells in response to the two pathogen-associated molecular patterns (PAMPs), lipopolysaccharide and peptidoglycan. In contrast to AQP2, the subcellular localizations of AQP1, AQP3, and AQP4 were unaffected both in lysate-incubated cell cultures and in the APN mouse model. Our finding demonstrated that cellular exposure to lipopolysaccharide and peptidoglycan can trigger the insertion of AQP2 in the plasma membrane revealing a new regulatory pathway for AQP2 plasma membrane translocation, which may potentially be exploited in intervention strategies.NEW & NOTEWORTHY Acute pyelonephritis (APN) is associated with reduced renal concentration capacity and increased aquaporin-2 (AQP2) excretion. Uropathogenic Escherichia coli (UPEC) mediates changes in the subcellular localization of AQP2 and we show that in vitro, these changes could be elicited by two pathogen-associated molecular patterns (PAMPs), namely, lipopolysaccharide and peptidoglycan. UPEC infection was unaltered by AQP2 expression and the other renal AQPs (AQP1, AQP3, and AQP4) were unaltered in APN.

Acute pyelonephritis: Increased plasma membrane targeting of renal aquaporin-2.

AIM: Aquaporin-2 (AQP2) shuttling between intracellular vesicles and the apical plasma membrane is pivotal in arginine vasopressin-mediated urine concentration and is dysregulated in multiple diseases associated with water balance disorders. Children and adults with acute pyelonephritis have a urinary concentration defect and studies in children revealed increased AQP2 excretion in the urine. This study aimed to analyse AQP2 trafficking in response to acute pyelonephritis. METHODS: Immunofluorescence analysis was used to evaluate subcellular localization of AQP2 and AQP2-S256A (mimicking non-phosphorylated AQP2 on serine 256) in cells stimulated with bacterial lysates and of AQP2 and pS256-AQP2 in a mouse model at day 5 of acute pyelonephritis. Western blotting was used to evaluate AQP2 levels and AQP2 phosphorylation on S256 upon incubation with bacterial lysates. Time-lapse imaging was used to measure intracellular cAMP levels in response to incubation with bacterial lysates. RESULTS: In cell cultures, lysates from both uropathogenic and nonpathogenic bacteria-mediated AQP2 plasma membrane targeting and increased AQP2 phosphorylation on serine 256 (pS256) without increasing cAMP levels. Both bacterial lysates induced plasma membrane targeting of AQP2-S256A. Immunofluorescence analysis of renal sections from mice after 5 days of acute pyelonephritis revealed apical plasma membrane targeting of AQP2 and pS256-AQP2 in inner medullary collecting ducts. CONCLUSION: Uropathogenic bacteria induce AQP2 plasma membrane targeting in vitro and in vivo. cAMP levels were not elevated by the bacterial lysates and AQP2 plasma membrane targeting could occur without S256 phosphorylation. This may explain increased AQP2 excretion in the urine during acute pyelonephritis.

The bacteria and the host: a story of purinergic signaling in urinary tract infections.

The local environment forces a selection of bacteria that might invade the urinary tract, allowing only the most virulent to access the kidney. Quite similar to the diet in setting the stage for the gut microbiome, renal function determines the conditions for bacteria-host interaction in the urinary tract. In the kidney, the term local environment or microenvironment is completely justified because the environment literally changes within a few micrometers. The precise composition of the urine is a function of the epithelium lining the microdomain, and the microenvironment in the kidney shows more variation in the content of nutrients, ion composition, osmolality, and pH than any other site of bacteria-host interaction. This review will cover some of the aspects of bacterial-host interaction in this unique setting and how uropathogenic bacteria can alter the condition for bacteria-host interaction. There will be a particular focus on the recent findings regarding how bacteria specifically trigger host paracrine signaling, via release of extracellular ATP and activation of P2 purinergic receptors. These finding will be discussed from the perspective of severe urinary tract infections, including pyelonephritis and urosepsis.

Preadmission kidney function and risk of acute kidney injury in patients hospitalized with acute pyelonephritis: A Danish population-based cohort study.

BACKGROUND AND OBJECTIVES: Only few smaller studies have examined if impaired kidney function increases the risk of acute kidney injury in patients with acute pyelonephritis. Therefore, we estimated 30-day risk of acute kidney injury by preadmission kidney function in patients with acute pyelonephritis. Furthermore, we examined if impaired kidney function was a risk factor for development of acute kidney injury in pyelonephritis patients. METHODS: This cohort study included patients with a first-time hospitalization with pyelonephritis from 2000 to 2017. Preadmission kidney function (estimated glomerular filtration rate (eGFR) <30, 30-44, 45-59, 60-89, and ≥90 ml/min/1.73 m2) and acute kidney injury within 30 days after admission were assessed using laboratory data on serum creatinine. The absolute 30-days risk of acute kidney injury was assessed treating death as a competing risk. The impact of eGFR on the odds of acute kidney injury was compared by odds ratios (ORs) with 95% confidence intervals estimated using logistic regression adjusted for potential confounding factors. RESULTS: Among 8,760 patients with available data on preadmission kidney function, 25.8% had a preadmission eGFR <60. The 30-day risk of acute kidney injury was 16% among patients with preadmission eGFR ≥90 and increased to 22%, 33%, 42%, and 47% for patients with preadmission eGFR of 60-89, 45-59, 30-44, and <30 respectively. Compared with eGFR≥90, the adjusted ORs for the subgroups with eGFR 60-89, 45-59, 30-45, and <30 were 0.95, 1.32, 1.78, and 2.19 respectively. CONCLUSION: Acute kidney injury is a common complication in patients hospitalized with acute pyelonephritis. Preadmission impaired kidney function is a strong risk factor for development of acute kidney injury in pyelonephritis patients and more attention should be raised in prevention of pyelonephritis in patients with a low kidney function.

Consistent alteration of chain length-specific ceramides in human and mouse fibrotic kidneys.

BACKGROUND: Several studies revealed alterations of single sphingolipid species, such as chain length-specific ceramides, in plasma and serum of patients with kidney diseases. Here, we investigated whether such alterations occur in kidney tissue from patients and mice suffering from renal fibrosis, the common endpoint of chronic kidney diseases. METHODS: Human fibrotic kidney samples were collected from nephrectomy specimens with hydronephrosis and/or pyelonephritis. Healthy parts from tumor nephrectomies served as nonfibrotic controls. Mouse fibrotic kidney samples were collected from male C57BL/6J mice treated with an adenine-rich diet for 14 days or were subjected to 7 days of unilateral ureteral obstruction (UUO). Kidneys of untreated mice and contralateral kidneys (UUO) served as respective controls. Sphingolipid levels were detected by LC-MS/MS. Fibrotic markers were analyzed by TaqMan® analysis and immunohistology. RESULTS: Very long-chain ceramides Cer d18:1/24:0 and Cer d18:1/24:1 were significantly downregulated in both fibrotic human kidney cortex and fibrotic murine kidney compared to respective control samples. These effects correlate with upregulation of COL1α1, COL3α1 and αSMA expression in fibrotic human kidney cortex and fibrotic mouse kidney. CONCLUSION: We have shown that very long-chain ceramides Cer d18:1/24:0 and Cer d18:1/24:1 are consistently downregulated in fibrotic kidney samples from human and mouse. Our findings support the use of in vivo murine models as appropriate translational means to understand the involvement of ceramides in human kidney diseases. In addition, our study raises interesting questions about the possible manipulation of ceramide metabolism to prevent progression of fibrosis and the use of ceramides as potential biomarkers of chronic kidney disease.

Neutrophil-Macrophage Imbalance Drives the Development of Renal Scarring during Experimental Pyelonephritis.

BACKGROUND: In children, the acute pyelonephritis that can result from urinary tract infections (UTIs), which commonly ascend from the bladder to the kidney, is a growing concern because it poses a risk of renal scarring and irreversible loss of kidney function. To date, the cellular mechanisms underlying acute pyelonephritis-driven renal scarring remain unknown. METHODS: We used a preclinical model of uropathogenic Escherichia coli-induced acute pyelonephritis to determine the contribution of neutrophils and monocytes to resolution of the condition and the subsequent development of kidney fibrosis. We used cell-specific monoclonal antibodies to eliminate neutrophils, monocytes, or both. Bacterial ascent and the cell dynamics of phagocytic cells were assessed by biophotonic imaging and flow cytometry, respectively. We used quantitative RT-PCR and histopathologic analyses to evaluate inflammation and renal scarring. RESULTS: We found that neutrophils are critical to control bacterial ascent, which is in line with previous studies suggesting a protective role for neutrophils during a UTI, whereas monocyte-derived macrophages orchestrate a strong, but ineffective, inflammatory response against uropathogenic, E. coli-induced, acute pyelonephritis. Experimental neutropenia during acute pyelonephritis resulted in a compensatory increase in the number of monocytes and heightened macrophage-dependent inflammation in the kidney. Exacerbated macrophage-mediated inflammatory responses promoted renal scarring and compromised renal function, as indicated by elevated serum creatinine, BUN, and potassium. CONCLUSIONS: These findings reveal a previously unappreciated outcome for neutrophil-macrophage imbalance in promoting host susceptibility to acute pyelonephritis and the development of permanent renal damage. This suggests targeting dysregulated macrophage responses might be a therapeutic tool to prevent renal scarring during acute pyelonephritis.

Lipopolysaccharide directly inhibits bicarbonate absorption by the renal outer medullary collecting duct.

Acidosis is associated with E. coli induced pyelonephritis but whether bacterial cell wall constituents inhibit HCO3 transport in the outer medullary collecting duct from the inner stripe (OMCDi) is not known. We examined the effect of lipopolysaccharide (LPS), on HCO3 absorption in isolated perfused rabbit OMCDi. LPS caused a ~ 40% decrease in HCO3 absorption, providing a mechanism for E. coli pyelonephritis-induced acidosis. Monophosphoryl lipid A (MPLA), a detoxified TLR4 agonist, and Wortmannin, a phosphoinositide 3-kinase inhibitor, prevented the LPS-mediated decrease, demonstrating the role of TLR4-PI3-kinase signaling and providing proof-of-concept for therapeutic interventions aimed at ameliorating OMCDi dysfunction and pyelonephritis-induced acidosis.

Metabolic acidosis exacerbates pyelonephritis in mice prone to vesicoureteral reflux.

Acute pyelonephritis is a common, serious bacterial infection in children. The prevalence of acute pyelonephritis is due at least in part to vesicoureteral reflux (VUR). Although an association between abnormalities in electrolyte and acid-base balance and pyelonephritis is common in young children, the impact of metabolic acidosis (MA) on progression of acute pyelonephritis is not fully understood. In this study, the effect of MA on pyelonephritis was studied in C3H mouse strains prone to VUR. MA induced by ammonium chloride supplementation in food specifically impaired clearance of urinary tract infection with uropathogenic Escherichia. coli (UPEC-UTI) in innate immune competent C3H strains (HeOuJ, HeN), whereas kidney UPEC burden in Tlr-4-deficient HeJ mice was unaffected. Antibody-mediated depletion of myeloid cells (monocytes, neutrophil) markedly increased UPEC burden in the bladder and kidney confirming the pivotal role of neutrophils and tissue-resident macrophages in clearance of UPEC-UTI. MA concurrent with UPEC-UTI markedly increased expression of cytokine (TNFα, IL-1ß, IL-6) and chemokine (CXCL 1, 2, and 5) mRNA in isolated kidney CD cells and kidney neutrophil infiltrates were increased four- to fivefold compared to normal, UPEC-infected mice. Thus, MA intensified pyelonephritis and increased the risk of kidney injury by impairing clearance of UPEC-UTI and potentiating renal inflammation characterized by an elevated kidney neutrophil infiltrate.

Exploring the Therapeutic Efficacy of Zingerone Nanoparticles in Treating Biofilm-Associated Pyelonephritis Caused by Pseudomonas aeruginosa in the Murine Model.

Biofilms of Pseudomonas aeruginosa can cause complicated urinary tract infections especially in people with indwelling catheters which may result in pyelonephritis. Microorganisms in biofilm demonstrate high resistance to both antibiotics and host protection mechanisms, often resulting in chronic and difficult-to-treat infections. This study is aimed to assess in vivo and ex vivo efficacy of Zingerone nanoparticles (Z-NPs) against P. aeruginosa biofilm-associated murine acute pyelonephritis. In the present study, Zingerone and chitosan acted synergistically in the form of Z-NPs and found to be nontoxic to the kidney cell lines as depicted in MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay demonstrating their cytocompatibility. In vivo experiments indicated that Z-NPs (100 mg/kg) treatment reduced P. aeruginosa pathogenicity and enhanced the clearance of bacterial count from the renal and bladder tissue. Z-NPs improved the disease outcome by lowering the levels of various inflammatory markers, and histopathological examination revealed better recovery in renal and bladder tissue. Besides, ex vivo efficacy also confirmed that Z-NPs enhanced serum bactericidal effect along with increased phagocytic uptake and intracellular killing of P. aeruginosa as confirmed by fluorescent microscopy. To the best of our knowledge, this is the first study to provide evidence that Z-NPs are effective therapeutic agents for combating P. aeruginosa associated pyelonephritis.

Androgen-Influenced Polarization of Activin A-Producing Macrophages Accompanies Post-pyelonephritic Renal Scarring.

Ascending bacterial pyelonephritis, a form of urinary tract infection (UTI) that can result in hospitalization, sepsis, and other complications, occurs in ~250,000 US patients annually; uropathogenic Escherichia coli (UPEC) cause a large majority of these infections. Although UTIs are primarily a disease of women, acute pyelonephritis in males is associated with increased mortality and morbidity, including renal scarring, and end-stage renal disease. Preclinical models of UTI have only recently allowed investigation of sex and sex-hormone effects on pathogenesis. We previously demonstrated that renal scarring after experimental UPEC pyelonephritis is augmented by androgen exposure; testosterone exposure increases both the severity of pyelonephritis and the degree of renal scarring in both male and female mice. Activin A is an important driver of scarring in non-infectious renal injury, as well as a mediator of macrophage polarization. In this work, we investigated how androgen exposure influences immune cell recruitment to the UPEC-infected kidney and how cell-specific activin A production affects post-pyelonephritic scar formation. Compared with vehicle-treated females, androgenized mice exhibited reduced bacterial clearance from the kidney, despite robust myeloid cell recruitment that continued to increase as infection progressed. Infected kidneys from androgenized mice harbored more alternatively activated (M2) macrophages than vehicle-treated mice, reflecting an earlier shift from a pro-inflammatory (M1) phenotype. Androgen exposure also led to a sharp increase in activin A-producing myeloid cells in the infected kidney, as well as decreased levels of follistatin (which normally antagonizes activin action). As a result, infection in androgenized mice featured prolonged polarization of macrophages toward a pro-fibrotic M2a phenotype, accompanied by an increase in M2a-associated cytokines. These data indicate that androgen enhancement of UTI severity and resulting scar formation is related to augmented local activin A production and corresponding promotion of M2a macrophage polarization.

Real-Time DMSA-SPECT/US Fusion Imaging Revealing Nonscarring Loss of Function After Pyelonephritis.

Using real-time SPECT/US fusion imaging, the localization of an uptake defect in DMSA scan could be identified unambiguously after being uncertain in ultrasound alone. Thereby, a localized functional loss, due to history of pyelonephritis, without scarring, but reduced cortical thickness could be verified. DMSA-SPECT/US primarily demonstrates its utility in depiction of renal pathologies and may be a descriptive tool in equivocal constellation of findings.

TGFß1 orchestrates renal fibrosis following Escherichia coli pyelonephritis.

Renal scarring after pyelonephritis is linked to long-term health risks for hypertension and chronic kidney disease. Androgen exposure increases susceptibility to, and severity of, uropathogenic Escherichia coli (UPEC) pyelonephritis and resultant scarring in both male and female mice, while anti-androgen therapy is protective against severe urinary tract infection (UTI) in these models. This work employed androgenized female C57BL/6 mice to elucidate the molecular mechanisms of post-infectious renal fibrosis and to determine how these pathways are altered by the presence of androgens. We found that elevated circulating testosterone levels primed the kidney for fibrosis by increasing local production of TGFß1 before the initiation of UTI, altering the ratio of transcription factors Smad2 and Smad3 and increasing the presence of mesenchymal stem cell (MSC)-like cells and Gli1 + activated myofibroblasts, the cells primarily responsible for deposition of scar components. Increased production of TGFß1 and aberrations in Smad2:Smad3 were maintained throughout the course of infection in the presence of androgen, correlating with renal scarring that was not observed in non-androgenized female mice. Pharmacologic inhibition of TGFß1 signaling blunted myofibroblast activation. We conclude that renal fibrosis after pyelonephritis is exacerbated by the presence of androgens and involves activation of the TGFß1 signaling cascade, leading to increases in cortical populations of MSC-like cells and the Gli1 + activated myofibroblasts that are responsible for scarring.

Staphylococcus Aureus Osteomyelitis as an Inducer of Tolerance to Escherichia Coli Pyelonephritis: an Experimental Study.

The high incidence of osteomyelitis in vulnerable populations like those with multiple injuries or elderly undergoing joint arthroplasties generates the question what may be their responses to subsequent infection by high virulent isolates. Rabbits were subject to two operations at three week intervals; sham osteomyelitis and sham pyelonephritis (group S); sham osteomyelitis and Escherichia coli pyelonephritis (group P); and Staphylococcus aureus osteomyelitis and E. coli pyelonephritis (group OP). Survival was recorded; cytokine stimulation of circulating mononuclear cells (PBMCs) and tissue myeloperoxidase (MPO) activity and bacterial growth were monitored. In some experiments, dalbavancin treatment was given before pyelonephritis. Healthy PBMCs were pre-treated with bone homogenate, S. aureus or both. Mortality of groups S, P and OP after induction of pyelonephritis was 0%, 50% and 8.3% respectively. Tumour necrosis factor-alpha (TNFα) production by PBMCs was significantly lower in the OP group at 48 hours. E. coli bacterial load was similar in groups P and OP at death or sacrifice whereas the MPO activity of group OP was decreased. Production of TNFα was further decreased among dalbavancin treated rabbits; in these rabbits tissue MPO was increased. TNFα production decreased when healthy PBMCs pre-treated with bone homogenate, S. aureus (HKSA) or both were stimulated with E. coli (HKEC); production was further decreased in the presence of anti-TLR4 and anti-TLR9. It is concluded that staphylococcal osteomyelitis modulated the innate immune responses of the host leading to protection from death by highly virulent E. coli. Tolerance to TLR ligands is the most likely mechanism of action.

Using single-cell technologies to map the human immune system - implications for nephrology.

Advances in single-cell technologies are transforming our understanding of cellular identity. For instance, the application of single-cell RNA sequencing and mass cytometry technologies to the study of immune cell populations in blood, secondary lymphoid organs and the renal tract is helping researchers to map the complex immune landscape within the kidney, define cell ontogeny and understand the relationship of kidney-resident immune cells with their circulating counterparts. These studies also provide insights into the interactions of immune cell populations with neighbouring epithelial and endothelial cells in health, and across a range of kidney diseases and cancer. These data have translational potential and will aid the identification of drug targets and enable better prediction of off-target effects. The application of single-cell technologies to clinical renal biopsy samples, or even cells within urine, will improve diagnostic accuracy and assist with personalized prognostication for patients with various kidney diseases. A comparison of immune cell types in peripheral blood and secondary lymphoid organs in healthy individuals and in patients with systemic autoimmune diseases that affect the kidney will also help to unravel the mechanisms that underpin the breakdown in self-tolerance and propagation of autoimmune responses. Together, these immune cell atlases have the potential to transform nephrology.

Alpha-hemolysin of uropathogenic Escherichia coli induces GM-CSF-mediated acute kidney injury.

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs), inducing acute pyelonephritis and may result in permanent renal scarring and failure. Alpha-hemolysin (HlyA), a key UPEC toxin, causes serious tissue damage; however, the mechanism through which HlyA induces kidney injury remains unclear. In the present study, granulocyte-macrophage colony-stimulating factor (GM-CSF) secreted by renal epithelial cells was upregulated by HlyA in vitro and in vivo, which induced M1 macrophage accumulation in kidney, and ADAM10 was found involved in HlyA-induced GM-CSF. Macrophage elimination or GM-CSF neutralization protected against acute kidney injury in mice, and increased GM-CSF was detected in urine of patients infected by hlyA-positive UPEC. In addition, HlyA was found to promote UPEC invasion into renal epithelial cells by interacting with Nectin-2 in vitro. However, HlyA did not affect bacterial titers during acute kidney infections, and HlyA-induced invasion did not contribute to GM-CSF upregulation in vitro, which indicate that HlyA-induced GM-CSF is independent of bacteria invasion. The role of GM-CSF in HlyA-mediated kidney injury may lead to novel strategies to treat acute pyelonephritis.

Comparative Pharmacokinetics of Gallic Acid, Protocatechuic Acid, and Quercitrin in Normal and Pyelonephritis Rats after Oral Administration of a Polygonum capitatum Extract.

Polygonum capitatum Buch.-Ham. ex D. Don is traditionally used by Hmong for the treatment of urinary tract infections and pyelonephritis. Information regarding the pharmacokinetic behavior of the extract in the condition of pyelonephritis is lacking. In the present study, we aimed to compare the pharmacokinetic properties of gallic acid (GA), protocatechuic acid (PCA), and quercitrin (QR)-the main bioactive constituents in the herb-in normal and pyelonephritis rats. The plasma samples were collected at various time points after administration of a single dose of Polygonum capitatum extract. The plasma level of GA, PCA, and QR at the designed time points was determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and drug concentration versus time plots were constructed to estimate the pharmacokinetic parameters. The AUC(0-t), AUC(0-∞), MRT(0-t), and CL of GA, PCA, and QR in pyelonephritis rats was significantly different from those of the normal rats. The results indicated that the three constituents have higher rate of uptake and slower rate of elimination in the rats with pyelonephritis, suggesting altered rate and extent of drug metabolism.

Lack of P2X7 Receptors Protects against Renal Fibrosis after Pyelonephritis with α-Hemolysin-Producing Escherichia coli.

Severe urinary tract infections are commonly caused by sub-strains of Escherichia coli secreting the pore-forming virulence factor α-hemolysin (HlyA). Repeated or severe cases of pyelonephritis can cause renal scarring that subsequently can lead to progressive failure. We have previously demonstrated that HlyA releases cellular ATP directly through its membrane pore and that acute HlyA-induced cell damage is completely prevented by blocking ATP signaling. Local ATP signaling and P2X7 receptor activation play a key role in the development of tissue fibrosis. This study investigated the effect of P2X7 receptors on infection-induced renal scarring in a murine model of pyelonephritis. Pyelonephritis was induced by injecting 100 million HlyA-producing, uropathogenic E. coli into the urinary bladder of BALB/cJ mice. A similar degree of pyelonephritis and mortality was confirmed at day 5 after infection in P2X7+/+ and P2X7-/- mice. Fibrosis was first observed 2 weeks after infection, and the data clearly demonstrated that P2X7-/- mice and mice exposed to the P2X7 antagonist, brillian blue G, show markedly less renal fibrosis 14 days after infection compared with controls (P < 0.001). Immunohistochemistry revealed comparable early neutrophil infiltration in the renal cortex from P2X7+/+ and P2X7-/- mice. Interestingly, lack of P2X7 receptors resulted in diminished macrophage infiltration and reduced neutrophil clearance in the cortex of P2X7-/- mice. Hence, this study suggests the P2X7 receptor to be an appealing antifibrotic target after renal infections.

INTENSITY OF THE ANTIOXIDANT PROTECTION SYSTEM AND OXIDATIVE STRESS FACTORS IN PATIENTS WITH NON-ALCOHOLIC STEATOHEPATITIS DEPENDING ON THE FORM OF CHRONIC KIDNEY DISEASE.

The article presents a theoretical generalization of the research results the intensity of the antioxidant protection system and oxidative stress factors in patients with non-alcoholic steatohepatitis depending on the form of chronic kidney disease. The objective of the article - determining the pathogenetic role of the processes of antioxidant protection system in the development and interconnection mechanisms of non-alcoholic steatohepatitis (NASH) and obesity depending on the form and stage of chronic kidney disease (CKD). 177 patients were examined for this purpose, including: 35 patients with NASH with concomitant obesity of І-ІІ degree (1st group), 36 patients with NASH with accompanying obesity of І-ІІ degree and CKD І-ІІ stage: Chronic bilateral pyelonephritis in the phase of exacerbation (2A group), 35 patients with NASH on the background of obesity I-II st. with CKD of the 3rd stage: Chronic bilateral peyelonephritis, exacerbation (2B group), 37 patients with NASH with obesity I-II stage and gouty nephropathy (group 3), 34 patients with NASH, which developed on the background of obesity I-II stages that developed from asymptomatic hyperuricemia (AHU) (group 4). The control group consisted of 30 practically healthy persons (PHP). For the comorbidity of NASH from CKD of the I-III stages. In the form of chronic pyelonephritis, the intensity of oxidative stress increases: the accumulation of intermediate (isolated double bonds, diene conjugates) and terminal (malonic aldehyde, ketodienes and conjugated triines) products of lipids peroxide oxidation, oxidation proteins modification (aldehyde and ketone dinitrophenyl hydrazones of the main and neutral) against the background of the disintegration of the activity of antiradical protection factors (reduction of content in erythrocytes of recovered glutathione, activity of superoxide dismutase, the growth of catalase activity, glutathion-dependent enzymes). Due to the comorbidity of non-alcoholic steatohepatitis with gouty nephropathy and in conditions of asymptomatic hyperuricemia, the degree of oxidative stress is significantly lower due to the strong antioxidant properties of uric acid, but the degree of endotoxicosis predominates in steatohepatitis without kidney damage. The uncontrolled intensification of the processes of free radical oxidation of lipids and proteins in patients with non-alcoholic steatohepatitis that developed on the background of obesity and CKD I-III stages, determines the degree of pathological process activity in the liver and the degree of endotoxicosis.

C5aR1 promotes acute pyelonephritis induced by uropathogenic E. coli.

C5a receptor 1 (C5aR1) is a G protein-coupled receptor for C5a and also an N-linked glycosylated protein. In addition to myeloid cells, C5aR1 is expressed on epithelial cells. In this study, we examined the role of C5aR1 in bacterial adhesion/colonization of renal tubular epithelium and addressed the underlying mechanisms of this role. We show that acute kidney infection was significantly reduced in mice with genetic deletion or through pharmacologic inhibition of C5aR1 following bladder inoculation with uropathogenic E. coli (UPEC). This was associated with reduced expression of terminal α-mannosyl residues (Man; a ligand for type 1 fimbriae of E. coli) on the luminal surface of renal tubular epithelium and reduction of early UPEC colonization in these mice. Confocal microscopy demonstrated that UPEC bind to Man on the luminal surface of renal tubular epithelium. In vitro analyses showed that C5a stimulation enhances Man expression in renal tubular epithelial cells and subsequent bacterial adhesion, which, at least in part, is dependent on TNF-α driven by C5aR1-mediated intracellular signaling. Our findings demonstrate a previously unknown pathogenic role for C5aR1 in acute pyelonephritis, proposing a potentially novel mechanism by which C5a/C5aR1 signaling mediates upregulation of carbohydrate ligands on renal tubules to facilitate UPEC adhesion.