WCN25-541 THE ASSOCIATIONS OF DIFFERENT STATINS WITH AIM ON KIDNEY INJURY

Coronavirus Disease 2019: Coronaviruses and Kidney Injury.

Five field experiments were conducted in Ontario to determine the tolerance of dry beans to pyraflufen-ethyl (6.7 and 13.4 g ai ha-1), 2,4-D ester (520.3 and 1040.6 g ai ha-1) and pyraflufen-ethyl/2,4-D ester (527 and 1054 g ai ha-1) applied preplant. Pyraflufen-ethyl at 6.7 and 13.4 g ai ha-1 caused < 2% injury in azuki, kidney, small red, and white bean. 2,4-D ester at 520.3 and 1040.6 g ai ha-1 caused up to 4 and 6% injury in azuki bean; up to 5 and 12% injury in kidney bean; up to 7 and 12% injury in small red bean; and up to 5 and 8% injury in white bean, respectively. Pyraflufen-ethyl/2,4-D ester at 527 and 1054 g ai ha-1 caused up to 4 and 6% injury in azuki bean; 5 and 11% injury in kidney bean; 7 and 13% injury in small red bean; and 5 and 10% injury in white bean, respectively. Pyraflufen-ethyl (6.7 and 13.4 g ai ha-1), 2,4-D ester (520.3 and 1040.6 g ai ha-1) or their combination applied preplant caused no adverse effect on dry bean stand, aboveground dry biomass, height, seed moisture content, or yield except for 2,4-D (2X rate) and pyraflufen-ethyl/2,4-D ester (2X rate) which reduced dry bean aboveground biomass as much as 32% and plant height up to 28%. This study concludes that pyraflufen-ethyl (6.7 g ai ha-1), 2,4-D ester (520.3 g ai ha-1), and pyraflufen-ethyl/2,4-D ester (527 g ai ha-1) applied preplant is safe to use for weed management in azuki, kidney, small red, and white bean. However, care must be taken to avoid spray overlaps with 2,4-D ester and pyraflufen-ethyl/2,4-D ester to avoid unacceptable dry bean injury.

To ascertain whether systemic administration of mitochondria-rich fraction isolated from mesenchymal stromal cells would reduce lung, kidney, and liver injury in experimental sepsis. Animal study. Laboratory investigation. Sixty C57BL/6 male mice. Sepsis was induced by cecal ligation and puncture; sham-operated animals were used as control. At 24 hours after surgery, cecal ligation and puncture and Sham animals were further randomized to receive saline or mitochondria-rich fraction isolated from mesenchymal stromal cells (3 × 106) IV. At 48 hours, survival, peritoneal bacterial load, lung, kidney, and liver injury were analyzed. Furthermore, the effects of mitochondria on oxygen consumption rate and reactive oxygen species production of lung epithelial and endothelial cells were evaluated in vitro. In vitro exposure of lung epithelial and endothelial cells from cecal ligation and puncture animals to mitochondria-rich fraction isolated from mesenchymal stromal cells restored oxygen consumption rate and reduced total reactive oxygen species production. Infusion of exogenous mitochondria-rich fraction from mesenchymal stromal cells (mitotherapy) reduced peritoneal bacterial load, improved lung mechanics and histology, and decreased the expression of interleukin-1β, keratinocyte chemoattractant, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in lung tissue, while increasing keratinocyte growth factor expression and survival rate in cecal ligation and puncture-induced sepsis. Mitotherapy also reduced kidney and liver injury, plasma creatinine levels, and messenger RNA expressions of interleukin-18 in kidney, interleukin-6, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in liver, while increasing nuclear factor erythroid 2-related factor-2 and superoxide dismutase-2 in kidney and interleukin-10 in liver. Mitotherapy decreased lung, liver, and kidney injury and increased survival rate in cecal ligation and puncture-induced sepsis.

Fructose induces insulin resistance with kidney inflammation and injury. MicroRNAs are emerged as key regulators of insulin signaling. Morin has insulin-mimetic effect with the improvement of insulin resistance and kidney injury. This study investigated the protective mechanisms of morin against fructose-induced kidney injury, with particular focus on miR-330 expression change, inflammatory response, and insulin signaling impairment. miR-330, sphingosine kinase 1 (SphK1)/sphingosine-1-phosphate (S1P)/S1P receptor (S1PR)1/3 signaling, nuclear factor-κB (NF-κB)/NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome, and insulin signaling were detected in kidney cortex of fructose-fed rats and fructose-exposed HK-2 cells, respectively. Whether miR-330 mediated inflammatory response to affect insulin signaling was examined using SphK1 inhibitor, S1PR1/3 short interfering RNA, or miR-330 mimic/inhibitor, respectively. Fructose was found to downregulate miR-330 expression to increase SphK1/S1P/S1PR1/3 signaling, and then activate NF-κB/NLRP3 inflammasome to produce IL-1β, causing insulin signaling impairment. Moreover, morin upregulated miR-330 and partly attenuated inflammatory response and insulin signaling impairment to alleviate kidney injury. These findings suggest that morin protects against fructose-induced kidney insulin signaling impairment by upregulating miR-330 to reduce inflammatory response. Morin may be a potential therapeutic agent for the treatment of kidney injury associated with fructose-induced inflammation and insulin signaling impairment.

The kidney performs a multitude of essential functions to maintain homeostasis. In clinical medicine, glomerular filtration rate (GFR) provides the best index of overall kidney function, and proteinuria adds additional information on renal and nonrenal prognosis. Several novel biomarkers of kidney injury and function are under investigation. Plasma creatinine concentration is the most widely used measure for estimation of GFR. Plasma cystatin C and β-trace protein may eventually prove to be superior to creatinine. GFR may be measured directly by use of exogenous filtration markers, although their role is primarily limited to the research setting. Real-time, noninvasive measurement of GFR by using fluorescently labeled markers may be available in the future. Novel biomarkers of tubular injury such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, liver-type fatty acid binding protein, N-acetyl-β-(D)-glucosaminidase, and interleukin-18 may enable the early detection of acute kidney injury before or in the absence of a change in GFR. A variety of methods are available to assist clinicians in the assessment of kidney function and injury. Ongoing investigation will help determine the utility of several new markers and clarify their role in the care of patients with and at risk for kidney disease.

Inflammatory bowel disease is associated with multiple extraintestinal disorders, including hepato-nephrological disruptions. The aim of this study was to evaluate the hepato-nephroprotective effect of Salvia officinalis leaf decoction extract (SLDE) on acetic acid (AA)-induced colitis accompanied with liver and kidney injuries. Wistar albinos rats were pretreated with SLDE (50, 100, and 200 mg kg-1, b.w., p.o.) during 10 days and intoxicated for 24 h by acute rectal administration of AA (3%, v/v, 5 mL kg-1, b.w.). Our results showed that S. officinalis treatment protected against AA-induced liver and kidney injuries by plasma transaminase activities and preservation of the hepatic and renal tissue structures. The level of high-density lipoprotein-cholesterol was also reverted back to near normalcy by treatment. Lipid peroxidation was decreased significantly by officinal sage supplementation. Treatment with SLDE increased enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and nonenzymatic (-SH groups and reduced glutathione) antioxidants in liver and kidney tissues. Also, SLDE treatment significantly protected against inflammation markers and reversed all intracellular mediator perturbations. This study suggests that the S. officinalis has a beneficial effect in controlling kidney and liver injuries by reducing lipid peroxidation and increasing antioxidant enzyme activities and nonenzymatic contents, which reduce the risk of developing extraintestinal complications.

Background and Aims Receptor-interacting protein kinase 3 (RIPK3) is traditionally involved in necroptosis, a regulated necrosis pathway which has been observed in diseases associated to cell death and inflammation. However, RIPK3 has been also associated to inflammatory responses independent of necroptosis. In previous studies we demonstrated that RIPK3 deficiency does not prevent renal injury but protects from inflammation in folic acid-induced AKI (FA-AKI), suggesting a proinflammatory role independently of cell death. In the present work, we aim to explore the role of RIPK3 in kidney injury and inflammation induced by a cytokine storm. Method Lipopolysaccharide (LPS) was used to induce cytokine storm-AKI in mice. For this, female 12- to 14-week-old wild type (WT), RIPK3-KO, MLKL-KO or NRLP3-KO C57BL/6J mice received a single intraperitoneal (i.p) injection of LPS 5 mg/kg or vehicle and were sacrificed 1h, 4h and 24 hours later. To generate chimera mice, WT and Ripk3-KO receptor mice were irradiated to deplete the autologous bone marrow (BM). BM was extracted from the femur and tibia of donor WT or Ripk3-KO mice, and 107 cells were transferred to irradiated receptor mice by intravenous injection. After 1 month, LPS-AKI was induced. Plasma was collected to assess kidney function. Kidneys were collected for RNA, protein studies, and histologic studies. Additionally, a WT group received 1.65 mg/kg of the necroptosis inhibitor Necrostatin-1 (Nec1) i.p. prior to LPS to evaluate the impact of necroptosis pathway. Liver, lungs and heart were also collected to assess the systemic inflammatory response. Additionally, cultured murine immortalized tubular MCT cells, and primary tubular cells, bone marrow dendritic cells (BMDC) and bone marrow derived macrophages (BMDM) isolated from WT and Ripk3-KO mice were studied. Cells were stimulated with 100 ng/ml LPS for 6h and RNA was studied. To analyze the impact of the inflammatory response on tubular cells, supernatants from LPS-stimulated BMDM and BMDC were collected and used to stimulate MCT cells. RNA expression was studied by RT-PCR and protein expression by Western Blotting. Results The kidney expression of RIPK3 mRNA and protein was upregulated in cytokine storm-AKI in mice, while Ripk3 deficiency improved survival and renal function, with less expression of proinflammatory cytokines and inflammatory infiltrate. Necroptosis did not seem to be implicated in cytokine storm-AKI, since neither Nec1 nor genetic MLKL ablation offered protection on renal function. Systemic inflammation in non-kidney organs was also milder with Ripk3 deficiency. In addition, inflammasome-related proteins were upregulated in cytokine storm-AKI, and this was reduced in Ripk3-KO mice. However, Nlrp3-deficient mice developed kidney injury and inflammation after LPS injection. Next, we explored the role of RIPK3 in BM-derived cells in cytokine storm-AKI by generating chimera mice. In this context, WT mice with Ripk3 deficient BM exhibited less inflammation and better renal function. This supports that RIPK3 from BM cells mediates kidney inflammation and injury during cytokine storm-AKI. In cultured cells, LPS induced RIPK3 expression in BMDMs but not in tubular cells, and RIPK3 mediated IL-6 expression in BMDMs but not in tubular cells. Moreover, IL-6 and conditioned media from LPS-exposed WT macrophages promoted proinflammatory responses in cultured tubular cells, that was partially ameliorated for RIPK3-KO LPS-macrophage conditioned medium. Conclusion In conclusion, RIPK3 mediates kidney injury and systemic inflammation induced by a cytokine storm independently of the necroptosis pathway. These results identify RIPK3 as a therapeutic target for renal inflammatory diseases.

Diabetes mellitus and hypertension are major risk factors for chronic kidney injury, together accounting for >70% of end-stage renal disease. In this study, we assessed interactions of hypertension and diabetes mellitus in causing kidney dysfunction and injury and the role of endoplasmic reticulum (ER) stress. Hypertension was induced by aorta constriction (AC) between the renal arteries in 6-month-old male Goto-Kakizaki (GK) type 2 diabetic and control Wistar rats. Fasting plasma glucose averaged 162±11 and 87±2 mg/dL in GK and Wistar rats, respectively. AC produced hypertension in the right kidney (above AC) and near normal blood pressure in the left kidney (below AC), with both kidneys exposed to the same levels of glucose, circulating hormones, and neural influences. After 8 weeks of AC, blood pressure above the AC (and in the right kidney) increased from 109±1 to 152±5 mm Hg in GK rats and from 106±4 to 141±5 mm Hg in Wistar rats. The diabetic-hypertensive right kidneys in GK-AC rats had much greater increases in albumin excretion and histological injury compared with left kidneys (diabetes mellitus only) of GK rats or right kidneys (hypertension only) of Wistar-AC rats. Marked increases in ER stress and oxidative stress indicators were observed in diabetic-hypertensive kidneys of GK-AC rats. Inhibition of ER stress with tauroursodeoxycholic acid for 6 weeks reduced blood pressure (135±4 versus 151±4 mm Hg), albumin excretion, ER and oxidative stress, and glomerular injury, while increasing glomerular filtration rate in hypertensive-diabetic kidneys. These results suggest that diabetes mellitus and hypertension interact synergistically to promote kidney dysfunction and injury via ER stress.

Meprin metalloproteinases have been implicated in the pathophysiology of IR‐induced kidney injury. Existing in vitro data show that meprins could modulate interleukin‐6 (IL‐6)‐mediated inflammation via proteolytic processing of IL‐6 and its receptor. However, it is not known whether meprin β cleaves IL‐6 in vivo, and how inactivation of IL‐6 modulates downstream mediators of the IL‐6 signaling pathway in kidney tissue. The goal of the current study was to determine how meprin β expression affects IL‐6 and its correlation to kidney injury and cellular apoptosis/survival in mice kidneys subjected to IR. We used the unilateral IR as a model of renal inflammation in wild‐type (WT) and meprin β knockout (βKO) male mice, with the contralateral kidneys serving as controls. The mice were sacrificed at 24 h post‐IR, and kidney tissue processed for evaluation by RT‐PCR, western blot, and immunohistochemistry (IHC). IHC staining for kidney injury molecule 1 (KIM‐1) was used to assess kidney injury. Statistical analysis utilized 2‐way ANOVA. Real‐time PCR data showed a significant increase (P ≤ 0.0001) in mRNA levels for IL‐6, Caspase3, and BCL‐2 in both WT and βKO mice subjected to IR when compared to counterpart control kidneys. Western blot data showed that protein levels for IL‐6, P‐STAT3β, Caspase3, and BCL‐2 significantly increased in βKO kidneys (P ≤ 0.0001) but not in WT counterparts at 24 h post‐IR, suggesting meprin β‐mediated decreases in IL‐6, Caspase3 and BCL‐2. Interestingly, immunohistochemical staining of kidney sections for IL‐6, P‐JAK2 and P‐STAT3, Caspase3 and BCL‐2 showed significant increases only in select kidney tubules for both genotypes. In the renal corpuscles, P‐JAK2 levels significantly increased only in the βKO (P ≤ 0.0001) and not in WT kidneys at 24h post‐IR. In contrast, BCL‐2 expression in the renal corpuscle was significantly higher in WT kidneys subjected to IR compared to control kidneys (P ≤ 0.0001) but not in βKO mice. To assess the correlations in localization of IL‐6 expression and the kidney injury and cellular apoptosis in kidney tubules, we used immunofluorescence counterstaining of IL‐6 with either kidney injury biomarker, KIM‐1, or cellular apoptosis biomarker, Caspase 3. Our data showed that IL‐6 expression was positively associated with both KIM‐1 and Caspase 3, and thus kidney injury and cellular apoptosis in several tubules in both genotypes subjected to IR. Data from immunofluorescence counterstaining of kidney tissues also showed that the levels of IL‐6, Caspase3 and BCL‐2 were higher in meprin β‐expressing proximal tubules (PTs), at 24 h post‐IR when compared to the distal kidney tubules (DTs), which lack meprins. High levels of IL‐6, Caspase3 and BCL‐2 were also detected at 24 h post‐IR in the lumen of PTs and DTs from WT and βKO kidneys, suggesting increased release into filtrate and subsequently into urine. However, P‐JAK2 and P‐STAT3 expression were high in PTs of both genotypes with accumulation in the lumen of PTs in βKO kidneys only at 24 h post‐IR. In conclusion, data showed that Meprin β expression modulates IR‐induced kidney injury and cellular apoptosis/survival in part through IL6‐ mediated JAK/STAT signaling.

Nicorandil, an ATP-sensitive potassium (K(ATP) ) channel opener and nitric oxide donor, is used in the treatment of angina and acute heart failure. Here we investigated the effects of two K(ATP) channel openers, nicorandil and cromakalim on ischaemia reperfusion (I-R) injury in the kidney. Right nephrectomy was performed in 8-week-old male Sprague-Dawley rats and they were then divided into six groups: control group; I-R, including 30 min of left renal ischaemia followed by 24 h of reperfusion; I-R groups plus nicorandil 3 or 10 mg·kg⁻¹ i.p.; and I-R groups plus cromakalim 100 or 300 µg·kg⁻¹ i.p. After reperfusion, renal function was estimated by serum creatinine (SCr), urinary albumin:creatinine ratio (ACR) and urinary β2-microglobulin (β2-MG). Levels of K(ATP) channel subtypes were investigated by Western blot. Kidney sections were stained for 4-hydroxy-2-nonenal and 8-hydroxy-2'-deoxyguanosine. Renal I-R induced significant increases in SCr, ACR and β2-MG levels compared with the control animals. Treatment with K(ATP) channel openers reduced urinary β2-MG levels, raised by I-R. Both K(IR) 6.1 and K(IR) 6.2 channels were expressed. Expression of K(IR) 6.2 channels in the I-R group was lower than in the control group, which was restored to normal by treatment with K(ATP) channel openers. Histologically, severe acute tubular damage was observed in the I-R kidney and this damage was ameliorated by K(ATP) channel openers, dose-dependently. ATP-sensitive potassium channel openers protected against proximal tubule damage after I-R injury. Nicorandil could represent a powerful additional component in the treatment of patients undergoing partial nephrectomy or renal transplantation.

Renovascular disease (RVD) produces chronic underperfusion of the renal parenchyma and progressive ischemic injury. Metabolic abnormalities often accompany renal ischemia, and are linked to poorer renal outcomes. However, the mechanisms of injury in kidneys exposed to the ischemic and metabolic components of RVD are incompletely understood. We hypothesized that coexisting renal artery stenosis (RAS) and metabolic syndrome (MetS) would exacerbate mitochondrial damage, aggravating poststenotic kidney injury in swine. Domestic pigs were studied after 16 weeks of either standard diet (Lean) or high-fat/high-fructose (MetS) with or without superimposed RAS (n = 6 each). Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were assessed in vivo with multidetector-CT, and renal tubular mitochondrial structure, homeostasis and function and renal injury ex vivo. Both RAS groups achieved significant stenosis. Single-kidney RBF and GFR were higher in MetS compared with Lean, but decreased in Lean+RAS and MetS+RAS vs. their respective controls. MetS and RAS further induced changes in mitochondrial structure, dynamics, and function, and their interaction (diet × ischemia) decreased matrix density, mitophagy, and ATP production, and lead to greater renal fibrosis. Coexisting RAS and MetS synergistically aggravate mitochondrial structural damage and dysfunction, which may contribute to structural injury and dysfunction in the poststenotic kidney. These observations suggest that mitochondrial damage precedes loss of renal function in experimental RVD, and position mitochondria as novel therapeutic targets in these patients.

G protein-coupled receptor (GPCR) kinase 2 (GRK2) is an integrative node in many signalling network cascades. An emerging study indicates that GRK2 can interact with GPCRs and non-GPCR substrates in both kinase-dependent and -independent modes. Alterations in the functional levels of GRK2 have been found in a variety of renal diseases, such as hypertension-related kidney injury, sepsis-associated acute kidney injury (S-AKI), cardiorenal syndrome (CRS), acute kidney injury (AKI), age-related kidney injury or hyperglycemia-related kidney injury. Abnormal GRK2 expression contribute to the development of renal diseases, making them promising molecular targets for treating renal diseases. Blocking the prostaglandin E2 (PGE2)-EP1-Gaq-Ca2+ signal pathway in glomerular mesangial cells (GMCs) by internalizing prostaglandin E2 receptor 1 (EP1) with GRK2 may be a potential treatment for diabetic nephropathy (DN). In addition, GRK2 inhibition may have therapeutic effects in a variety of renal diseases, such as SLE-related kidney injury, DN, age-related kidney injury, hypertension-related kidney injury, and CRS. However, there is still a long way to go for the large-scale application of GRK2 inhibition in the field of renal diseases. In this review, we discuss recent updates in understanding the role of GRK2 in kidney dysfunction. Furthermore, we explore the potential of GRK2 as a possible therapeutic target for renal pathologies. We believe it will shed light on the future development of small-molecule inhibitors of GRK, as well as the clinical applications in renal diseases.

Activation of the renin-angiotensin-aldosterone system (RAAS) drives blood pressure (BP) responses and kidney injury in humans and rodent models. Previously, we reported activation of dipeptidyl peptidase 4 (DPP4) by RAAS which may play an important role in BP responses and kidney injury. Classically, either angiotensin II (Ang II) or deoxycorticosterone (DOCA)-salt administration to mice, raises their BP over a period of hours to days. Recently, the two have been combined to elicit more robust kidney injury and proteinuria. Although there are not many head to head comparison studies, it is known through historical association that different strains of mice have different baseline BPs and vary in their response to vasoconstrictor agents for BP peaks as well as associated kidney injury. In this regard, the C57Bl/6J and C57Bl/6N mice are genetically very similar although they differ with respect to their responses to circadian rhythm on salt sensitivity to BP. Therefore, we hypothesized that J versus N strain will have differential BP responses to Ang II/DOCA and kidney injury susceptibility. C57Bl/6 J and N mice ( DPP4 +/+ and DPP4 -/- ) were subjected to Ang II/DOCA salt infusion for 2 weeks (Ang II 1000ng/kg/min via miniosmotic pumps, DOCA 50mg pellet, 0.9% saline in drinking water) and compared to mice receiving saline only (osmotic pumps). BP was measured by Millar catheter. Kidney injury was quantified via albuminuria and histology. While the Ang II/DOCA treated J strain had mean BP (MBP) of 135mmHg, the Ang II/DOCA treated N strain had MBP of 125mmHg. There was no effect of DPP4 gene deletion on BP in either strain. The J strain treated with Ang II/DOCA salt had higher albuminuria when compared to the N strain (180ug/ml vs. 60ug/ml). DPP4 -/- mice on the J strain receiving Ang II/DOCA had a relative improvement in albuminuria (120ug/ml vs. 180ug/ml). Surprisingly, the DPP4 -/- mice on the N strain had higher albuminuria when compared to the DPP4 +/+ mice receiving Ang II/DOCA (143ug/ml vs. 60ug/ml). Taken together, our results suggest that mice strain plays an important role in BP and kidney injury responses to Ang II/DOCA and DPP4 gene deletion. These results highlight the importance of selecting patient populations carefully to maximize the benefit of DPP4 inhibitors.

BackgroundPolymyxins have been revived as a last-line therapeutic option for multi-drug resistant bacteria and continue to account for a significant proportion of global antibiotic usage. However, kidney injury is often a treatment limiting event with kidney failure rates ranging from 5 to 13%. The mechanisms underlying polymyxin-induced nephrotoxicity are currently unclear. Researches of polymyxin-associated acute kidney injury (AKI) models need to be more standardized, which is crucial for obtaining consistent and robust mechanistic results.MethodsIn this study, male C57BL/6 mice received different doses of polymyxin B (PB) and polymyxin E (PE, also known as colistin) by different routes once daily (QD), twice daily (BID), and thrice daily (TID) for 3 days. We continuously monitored the glomerular filtration rate (GFR) and the AKI biomarkers, including serum creatinine (Scr), blood urea nitrogen (BUN), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1). We also performed histopathological examinations to assess the extent of kidney injury.ResultsMice receiving PB (35 mg/kg/day subcutaneously) once daily exhibited a significant decrease in GFR and a notable increase in KIM-1 two hours after the first dose. Changes in GFR and KIM-1 at 24, 48 and 72 h were consistent and demonstrated the occurrence of kidney injury. Histopathological assessments showed a positive correlation between the severity of kidney injury and the changes in GFR and KIM-1 (Spearman’s rho = 0.3167, P = 0.0264). The other groups of mice injected with PB and PE did not show significant changes in GFR and AKI biomarkers compared to the control group.ConclusionThe group receiving PB (35 mg/kg/day subcutaneously) once daily consistently developed AKI at 2 h after the first dose. Establishing an early and stable AKI model facilitates researches into the mechanisms of early-stage kidney injury. In addition, our results indicated that PE had less toxicity than PB and mice receiving the same dose of PB in the QD group exhibited more severe kidney injury than the BID and TID groups.

Invited Commentary