This observation is in line with a previous study in which no differences were found in phagocytic ability, reactive oxygen species production, and cell surface adhesion and transmigration markers in granulocytes between control and antibiotic-treated mice

This observation is in line with a previous study in which no differences were found in phagocytic ability, reactive oxygen species production, and cell surface adhesion and transmigration markers in granulocytes between control and antibiotic-treated mice. 13These data imply that the reduced granulocyte content in our antibiotic-treated mice was not due to impaired granulocyte functions but due to alterations preceding granulocyte influx. I/R injury by reducing maturation status of F4/80+renal resident macrophages and BM monocytes. Therefore , dampening the inflammatory response by focusing on microbiota-derived mediators might be a promising therapy against I/R injury. Keywords: ischemia-reperfusion, macrophages, immunology AKI is a major clinical problem that affects 5% of hospitalized patients and has a mortality rate of 50%80% in GLPG0187 these patients. 1Ischemia-reperfusion (I/R) injury is a major cause of AKI which can occur during shock, sepsis, and renal transplantation. GLPG0187 2Ischemia-induced damage leads to apoptosis and necrosis of renal tubular cells, followed by release of damage-associated molecular patterns which are sensed by pathogen recognition receptors present on tubular epithelial cells (TECs) and renal resident leukocytes. 36Activated TECs and resident leukocytes release cytokines/chemokines to attract inflammatory cells from blood circulation to the injured kidney to clear cell debris and promote repair. three or more, 7However, when the powerful inflammatory response is exaggerated it can also amplify renal damage. three or more, 8Thus, inflammation can possess profound but disparate roles in the pathogenesis of AKI. In the past few years, intestinal microbiotarelated research has been rapidly expanding, providing important insights into the involvement of the microbiome in GLPG0187 modulating systemic immunity and thereby affecting the outcome of several inflammatory diseases. 918For instance, antibiotic-treated mice have impaired innate and adaptive immune responses after exposure to lung infection caused by either influenza virus orStreptococcus pneumoniae. 9, 14, 16Mice lacking intestinal microbiota develop less severe symptoms in autoimmune models of arthritis and experimental autoimmune encephalomyelitis. 17, 18 In regard to renal diseases, a few studies demonstrated an improved uremic state after gut microbiotadirected interventions in CKD and ESRD. 1921However, the effect of the microbiome on the disease process of AKI remains unknown, as does a possible mechanism by which microbiota can influence the kidney. We therefore investigated the role of microbiota in I/R injuryinduced AKI by depleting gut microbiota with broad-spectrum antibiotic treatment in wild-type mice. We found that microbiota are essential for priming F4/80+ renal resident macrophages and bone marrow (BM) monocytes. Consequently, renal resident macrophages from commensal-depleted mice are less responsive to ischemic injury, resulting in protection against renal I/R injury. == Results == == Depletion of Intestinal Microbiota Protects against Renal I/R Injury == After depletion of microbiota, we found a striking and profound protection against renal I/R injury because assessed by scoring the percentage of necrotic tubules and renal expression of neutrophil gelatinase-associated lipocalin (NGAL) 24 hours after I/R injury (Figure 1, A and B). Renal function was significantly preserved in antibiotic-treated mice as indicated by reduce plasma creatinine and urea levels compared with control mice (Figure 1, C and D). Lactate dehydrogenase (LDH), Aspartate transminase (ASAT), and Alanine transminase (ALAT) plasma levels are known to increase upon Rabbit polyclonal to TLE4 renal I/R injury indicating general tissue injury. 22Conversely, in antibiotic-treated mice LDH, ASAT, and ALAT levels remain steady after I/R injury (Figure 1, EG). One day after GLPG0187 I/R injury the inflammatory milieu is predominantly characterized by a vast influx of granulocytes, 4, 6, 7, 23which can play a detrimental role in the postischemic kidney. 24We discovered significantly reduce influx of granulocytes in antibiotic-treated mice upon I/R injury (Figure 1H). In antibiotic-treated mice renal structural integrity was better managed as shown by significantly less TEC apoptosis and more TEC proliferation (Figure 1, I and J). Taken with each other, these data clearly show that depletion of the microbiota protects mice against renal I/R injury. == Physique 1 . == Depletion of gut microbiota protects against renal I/R injury. (A) Renal damage was evaluated by scoring the percentage of necrotic tubules in Periodic acidSchiff-diastasestained areas (original magnification, 400) and by measuring NGAL mRNA levels in total kidney homogenates from control (white bars) and antibiotic-treated mice (black bars) (B). Renal function was quantified by plasma creatinine (C) and urea (D) levels. Plasma levels of general organ damage and liver markers LDH (E), ALAT (F), and ASAT (G) were decided. Influx of granulocytes was assessed by scoring Ly6G+cells in the corticomedullary region from the kidney (H) (original magnification, 400). The amount of.