RESUMEN
BACKGROUND: Adipose stromal cells (ASC) are a form of mesenchymal stromal cells that elicit effects primarily via secreted factors, which may have advantages for the treatment of injury or disease. Several previous studies have demonstrated a protective role for MSC/ASC on mitigating acute kidney injury but whether ASC derived factors could hasten recovery from established injury has not been evaluated. METHODS: We generated a concentrated secretome (CS) of human ASC under well-defined conditions and evaluated its ability to improve the recovery of renal function in a preclinical model of acute kidney injury (AKI) in rats. 24 h following bilateral ischemia/reperfusion (I/R), rats were randomized following determination of plasma creatinine into groups receiving vehicle -control or ASC-CS treatment by subcutaneous injection (2 mg protein/kg) and monitored for evaluation of renal function, structure and inflammation. RESULTS: Renal function, assessed by plasma creatinine levels, recovered faster in ASC-CS treated rats vs vehicle. The most prominent difference between the ASC-CS treated vs vehicle was observed in rats with the most severe degree of initial injury (Pcr > 3.0 mg/dl 24 h post I/R), whereas rats with less severe injury (Pcr < 2.9 mg/dl) recovered quickly regardless of treatment. The quicker recovery of ASC-treated rats with severe injury was associated with less tissue damage, inflammation, and lower plasma angiopoietin 2. In vitro, ASC-CS attenuated the activation of the Th17 phenotype in lymphocytes isolated from injured kidneys. CONCLUSIONS: Taken together, these data suggest that ASC-CS represents a potent therapeutic option to improve established AKI.
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Lesión Renal Aguda , Inflamación , Lesión Renal Aguda/terapia , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/patología , Animales , Ratas , Humanos , Inflamación/patología , Inflamación/metabolismo , Masculino , Secretoma/metabolismo , Tejido Adiposo/citología , Tejido Adiposo/metabolismo , Ratas Sprague-Dawley , Inyecciones Subcutáneas , Riñón/metabolismo , Riñón/patología , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/citología , Daño por Reperfusión/metabolismo , Daño por Reperfusión/terapia , Células del Estroma/metabolismoRESUMEN
Renal reserve capacity may be compromised following recovery from acute kidney injury (AKI) and could be used to identify impaired renal function in the face of restored glomerular filtration rate (GFR) or plasma creatinine. To investigate the loss of hemodynamic renal reserve responses following recovery in a model of AKI, rats were subjected to left unilateral renal ischemia-reperfusion (I/R) injury and contralateral nephrectomy and allowed to recover for 5 wk. Some rats were treated 24 h post-I/R by hydrodynamic isotonic fluid delivery (AKI-HIFD) of saline through the renal vein, previously shown to improve recovery and inflammation relative to control rats that received saline through the vena cava (AKI-VC). At 5 wk after surgery, plasma creatinine and GFR recovered to levels observed in uninephrectomized sham controls. Baseline renal blood flow (RBF) was not different between AKI or sham groups, but infusion of l-arginine (7.5 mg/kg/min) significantly increased RBF in sham controls, whereas the RBF response to l-arginine was significantly reduced in AKI-VC rats relative to sham rats (22.6 ± 2.2% vs. 13.8 ± 1.8%, P < 0.05). RBF responses were partially protected in AKI-HIFD rats relative to AKI-VC rats (17.0 ± 2.2%) and were not significantly different from sham rats. Capillary rarefaction observed in AKI-VC rats was significantly protected in AKI-HIFD rats. There was also a significant increase in T helper 17 cell infiltration and interstitial fibrosis in AKI-VC rats versus sham rats, which was not present in AKI-HIFD rats. These data suggest that recovery from AKI results in impaired hemodynamic reserve and that associated CKD progression may be mitigated by HIFD in the early post-AKI period.NEW & NOTEWORTHY Despite the apparent recovery of renal filtration function following acute kidney injury (AKI) in rats, the renal hemodynamic reserve response is significantly attenuated, suggesting that clinical evaluation of this parameter may provide information on the potential development of chronic kidney disease. Treatments such as hydrodynamic isotonic fluid delivery, or other treatments in the early post-AKI period, could minimize chronic inflammation or loss of microvessels with the potential to promote a more favorable outcome on long-term function.
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Lesión Renal Aguda , Insuficiencia Renal Crónica , Daño por Reperfusión , Ratas , Animales , Hidrodinámica , Creatinina , Ratas Sprague-Dawley , Riñón , Lesión Renal Aguda/terapia , Hemodinámica/fisiología , Inflamación , Arginina , Modelos Animales de EnfermedadAsunto(s)
Lesión Renal Aguda , Células Madre Mesenquimatosas , Humanos , Neutrófilos , Riñón , Lesión Renal Aguda/genéticaRESUMEN
BACKGROUND: Interleukin-17 (IL-17) antagonism in rats reduces the severity and progression of AKI. IL-17-producing circulating T helper-17 (TH17) cells is increased in critically ill patients with AKI indicating that this pathway is also activated in humans. We aim to compare serum IL-17A levels in critically ill patients with versus without AKI and to examine their relationship with mortality and major adverse kidney events (MAKE). METHODS: Multicenter, prospective study of ICU patients with AKI stage 2 or 3 and without AKI. Samples were collected at 24-48 h after AKI diagnosis or ICU admission (in those without AKI) [timepoint 1, T1] and 5-7 days later [timepoint 2, T2]. MAKE was defined as the composite of death, dependence on kidney replacement therapy or a reduction in eGFR of ≥ 30% from baseline up to 90 days following hospital discharge. RESULTS: A total of 299 patients were evaluated. Patients in the highest IL-17A tertile (versus lower tertiles) at T1 had higher acuity of illness and comorbidity scores. Patients with AKI had higher levels of IL-17A than those without AKI: T1 1918.6 fg/ml (692.0-5860.9) versus 623.1 fg/ml (331.7-1503.4), p < 0.001; T2 2167.7 fg/ml (839.9-4618.9) versus 1193.5 fg/ml (523.8-2198.7), p = 0.006. Every onefold higher serum IL-17A at T1 was independently associated with increased risk of hospital mortality (aOR 1.35, 95% CI: 1.06-1.73) and MAKE (aOR 1.26, 95% CI: 1.02-1.55). The highest tertile of IL-17A (vs. the lowest tertile) was also independently associated with higher risk of MAKE (aOR 3.03, 95% CI: 1.34-6.87). There was no effect modification of these associations by AKI status. IL-17A levels remained significantly elevated at T2 in patients that died or developed MAKE. CONCLUSIONS: Serum IL-17A levels measured by the time of AKI diagnosis or ICU admission were differentially elevated in critically ill patients with AKI when compared to those without AKI and were independently associated with hospital mortality and MAKE.
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Lesión Renal Aguda , Interleucina-17 , Lesión Renal Aguda/terapia , Animales , Enfermedad Crítica/terapia , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Estudios Prospectivos , RatasRESUMEN
This review focuses on the potential mediation in the acute kidney injury (AKI)-to-chronic kidney disease (CKD) transition by lymphocytes. We highlight evidence that lymphocytes, particularly Th17 cells, modulate the severity of both acute injury and chronic kidney disease. Th17 cells are strongly influenced by the activity of the store-operated Ca2+channel Orai1, which is upregulated on lymphocytes in animal models of AKI. Inhibition of this channel attenuates both acute and chronic kidney injury in rodent models. In addition, Oria1+ cells are increased in peripheral blood of patients with AKI. Similarly, peripheral blood cells manifest an early and sustained increase in Orai1 expression in a rat model of ischemia/reperfusion, suggesting that blood cell Orai1 may represent a marker informing potential Th17 activity in the setting of AKI or the AKI-to-CKD transition.
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Lesión Renal Aguda , Proteína ORAI1 , Insuficiencia Renal Crónica , Daño por Reperfusión , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/terapia , Animales , Humanos , Riñón/metabolismo , Proteína ORAI1/metabolismo , Ratas , Insuficiencia Renal Crónica/metabolismo , Daño por Reperfusión/metabolismoRESUMEN
Estradiol (E2) inhibits fluid intake in several species, which may help to defend fluid homeostasis by preventing excessive extracellular fluid volume. Although this phenomenon is well established using the rat model, it has only been studied directly in young adults. Because aging influences the neuronal sensitivity to E2 and the fluid intake effects of E2 are mediated in the brain, we tested the hypothesis that aging influences the fluid intake effects of E2 in female rats. To do so, we examined water and NaCl intake in addition to the pressor effect after central angiotensin II treatment in young (3-4 months), middle-aged (10-12 months), and old (16-18 months) ovariectomized rats treated with estradiol benzoate (EB). As expected, EB treatment reduced water and NaCl intake in young rats. EB treatment, however, did not reduce water intake in old rats, nor did it reduce NaCl intake in middle-aged or old rats. The ability of EB to reduce blood pressure was, in contrast, observed in all three age groups. Next, we also measured the gene expression of estrogen receptors (ERs) and the angiotensin type 1 receptor (AT1R) in the areas of the brain that control fluid balance. ERß, G protein estrogen receptor (GPER), and AT1R were reduced in the paraventricular nucleus of the hypothalamus in middle-aged and old rats, compared to young rats. These results suggest the estrogenic control of fluid intake is modified by age. Older animals lost the fluid intake effects of E2, which correlated with decreased ER and AT1R expression in the hypothalamus.
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Envejecimiento/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Ingestión de Líquidos/efectos de los fármacos , Estradiol/análogos & derivados , Frecuencia Cardíaca/efectos de los fármacos , Envejecimiento/fisiología , Animales , Presión Sanguínea/fisiología , Ingestión de Líquidos/fisiología , Estradiol/administración & dosificación , Femenino , Frecuencia Cardíaca/fisiología , Ovariectomía/efectos adversos , Ovariectomía/tendencias , Ratas , Ratas Sprague-Dawley , Receptor de Angiotensina Tipo 1/fisiología , Receptores de Estrógenos/fisiologíaRESUMEN
To investigate T helper type 17 (Th17) cells in the setting of acute kidney injury, the gene encoding the master regulator of Th17 cell differentiation, that is, RAR-related orphan receptor-γ (RORγT), was mutated in Lewis rats using CRISPR/Cas9 technology. In response to 40 min of bilateral renal ischemia-reperfusion (I/R), RAR-related orphan receptor C (Rorc)-/- rats were resistant to injury relative to wild-type Rorc+/+ rats. This protection was associated with inhibition of IL-17 expression and reduced infiltration of CD4+ cells, CD8+ cells, B cells, and macrophages. To evaluate the effect of Th17 cells on repair, ischemia was increased to 50 min in Rorc-/- rats. This maneuver equalized the initial level of injury in Rorc-/- and Rorc+/+ rats 1 to 2 days post-I/R based on serum creatinine values. However, Rorc-/- rats, but not Rorc+/+ rats, failed to successfully recover renal function and had high mortality by 4 days post-I/R. Histological assessment of kidney tubules showed evidence of repair by day 4 post-I/R in Rorc+/+ rats but persistent necrosis and elevated cell proliferation in Rorc-/- rats. Adoptive transfer of CD4+ cells from the spleen of Rorc+/+ rats or supplementation of exogenous rIL-17 by an osmotic minipump improved renal function and survival of Rorc-/- rats following 50 min of I/R. This was associated with a relative decrease in the number of M1-type macrophages and a relative increase in the percentage of T regulatory cells. Taken together, these data suggest that Th17 cells have both a deleterious and a beneficial role in kidney injury and recovery, contributing to early postischemic injury and inflammation but also possibly being critical in the resolution of inflammation during kidney repair.
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Riñón/metabolismo , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Daño por Reperfusión/metabolismo , Linfocitos T Reguladores/metabolismo , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/patología , Animales , Inflamación/metabolismo , Isquemia/metabolismo , Mutación/genética , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Ratas , Ratas Endogámicas Lew , Recuperación de la Función , Daño por Reperfusión/patología , Células Th17RESUMEN
Ischemic preconditioning confers organ-wide protection against subsequent ischemic stress. A substantial body of evidence underscores the importance of mitochondria adaptation as a critical component of cell protection from ischemia. To identify changes in mitochondria protein expression in response to ischemic preconditioning, we isolated mitochondria from ischemic preconditioned kidneys and sham-treated kidneys as a basis for comparison. The proteomic screen identified highly upregulated proteins, including NADP+-dependent isocitrate dehydrogenase 2 (IDH2), and we confirmed the ability of this protein to confer cellular protection from injury in murine S3 proximal tubule cells subjected to hypoxia. To further evaluate the role of IDH2 in cell protection, we performed detailed analysis of the effects of Idh2 gene delivery on kidney susceptibility to ischemia-reperfusion injury. Gene delivery of IDH2 before injury attenuated the injury-induced rise in serum creatinine (P<0.05) observed in controls and increased the mitochondria membrane potential (P<0.05), maximal respiratory capacity (P<0.05), and intracellular ATP levels (P<0.05) above those in controls. This communication shows that gene delivery of Idh2 can confer organ-wide protection against subsequent ischemia-reperfusion injury and mimics ischemic preconditioning.
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Precondicionamiento Isquémico , Isocitrato Deshidrogenasa/genética , Riñón/irrigación sanguínea , Adenosina Trifosfato/metabolismo , Animales , Hipoxia de la Célula , Células Cultivadas , Creatinina/sangre , Vectores Genéticos/administración & dosificación , Inyecciones Intravenosas , Isocitrato Deshidrogenasa/fisiología , Túbulos Renales Proximales/citología , Masculino , Potencial de la Membrana Mitocondrial , Ratones , Mitocondrias/metabolismo , Fosforilación Oxidativa , Consumo de Oxígeno , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes de Fusión/metabolismo , Recurrencia , Transfección , Regulación hacia ArribaRESUMEN
Acute kidney injury (AKI) is associated with high mortality rates and predisposes development of chronic kidney disease (CKD). Distant organ damage, particularly in the lung, may contribute to mortality in AKI patients. Animal models of AKI demonstrate an increase in pulmonary infiltration of lymphocytes and reveal an acute compromise of lung function, but the chronic effects of AKI on pulmonary inflammation are unknown. We hypothesized that in response to renal ischemia/reperfusion (I/R), there is a persistent systemic increase in Th17 cells with potential effects on pulmonary structure and function. Renal I/R injury was performed on rats, and CKD progression was hastened by unilateral nephrectomy and exposure to 4.0% sodium diet between 35 and 63 days post-I/R. Th17 cells in peripheral blood showed a progressive increase up to 63 days after recovery from I/R injury. Infiltration of leukocytes including Th17 cells was also elevated in bronchiolar lavage (BAL) fluid 7 days after I/R and remained elevated for up to 63 days. Lung histology demonstrated an increase in alveolar cellularity and a significant increase in picrosirius red staining. Suppression of lymphocytes with mycophenolate mofetil (MMF) or an IL-17 antagonist significantly reduced Th17 cell infiltration and fibrosis in lung. In addition, tracheal smooth muscle contraction to acetylcholine was significantly enhanced 63-days after I/R relative to sham-operated controls. These data suggest that AKI is associated with a persistent increase in circulating and lung Th17 cells which may promote pulmonary fibrosis and the potential alteration in airway contractility.
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Lesión Renal Aguda/inmunología , Pulmón/inmunología , Neumonía/inmunología , Fibrosis Pulmonar/inmunología , Insuficiencia Renal Crónica/inmunología , Células Th17/inmunología , Lesión Renal Aguda/complicaciones , Lesión Renal Aguda/patología , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Inmunosupresores/farmacología , Pulmón/efectos de los fármacos , Pulmón/patología , Pulmón/fisiopatología , Masculino , Contracción Muscular , Músculo Liso/inmunología , Músculo Liso/patología , Músculo Liso/fisiopatología , Fenotipo , Neumonía/etiología , Neumonía/patología , Neumonía/fisiopatología , Fibrosis Pulmonar/etiología , Fibrosis Pulmonar/patología , Fibrosis Pulmonar/fisiopatología , Ratas Desnudas , Ratas Sprague-Dawley , Ratas Transgénicas , Insuficiencia Renal Crónica/etiología , Insuficiencia Renal Crónica/patología , Factores de Riesgo , Sodio en la Dieta/toxicidad , Células Th17/efectos de los fármacos , Factores de Tiempo , Tráquea/inmunología , Tráquea/patología , Tráquea/fisiopatologíaRESUMEN
Damage to endothelial cells contributes to acute kidney injury (AKI) by causing impaired perfusion, while the permanent loss of the capillary network following AKI has been suggested to promote chronic kidney disease. Therefore, strategies to protect renal vasculature may impact both short-term recovery and long-term functional preservation post-AKI. Human adipose stromal cells (hASCs) possess pro-angiogenic and anti-inflammatory properties and therefore have been tested as a therapeutic agent to treat ischaemic conditions. This study evaluated hASC potential to facilitate recovery from AKI with specific attention to capillary preservation and inflammation. Male Sprague Dawley rats were subjected to bilateral ischaemia/reperfusion and allowed to recover for either two or seven days. At the time of reperfusion, hASCs or vehicle was injected into the suprarenal abdominal aorta. hASC-treated rats had significantly greater survival compared to vehicle-treated rats (88.7% versus 69.3%). hASC treatment showed hastened recovery as demonstrated by lower creatinine levels at 48 hrs, while tubular damage was significantly reduced at 48 hrs. hASC treatment resulted in a significant decrease in total T cell and Th17 cell infiltration into injured kidneys at 2 days post-AKI, but an increase in accumulation of regulatory T cells. By day 7, hASC-treated rats showed significantly attenuated capillary rarefaction in the cortex (15% versus 5%) and outer medulla (36% versus 18%) compared to vehicle-treated rats as well as reduced accumulation of interstitial alpha-smooth muscle actin-positive myofibroblasts. These results suggest for the first time that hASCs improve recovery from I/R-induced injury by mechanisms that contribute to decrease in inflammation and preservation of peritubular capillaries.
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Lesión Renal Aguda/terapia , Inflamación/terapia , Daño por Reperfusión/terapia , Células del Estroma/trasplante , Lesión Renal Aguda/inmunología , Lesión Renal Aguda/fisiopatología , Adipocitos/inmunología , Adipocitos/trasplante , Tejido Adiposo/inmunología , Tejido Adiposo/trasplante , Animales , Modelos Animales de Enfermedad , Humanos , Inflamación/fisiopatología , Riñón/inmunología , Riñón/patología , Rarefacción Microvascular/inmunología , Rarefacción Microvascular/fisiopatología , Rarefacción Microvascular/terapia , Ratas , Daño por Reperfusión/inmunología , Daño por Reperfusión/fisiopatología , Células del Estroma/inmunología , Linfocitos T Reguladores/inmunología , Células Th17/inmunologíaRESUMEN
Damage to endothelial cells contributes to acute kidney injury (AKI) by leading to impaired perfusion. Endothelial colony-forming cells (ECFC) are endothelial precursor cells with high proliferative capacity, pro-angiogenic activity, and in vivo vessel forming potential. We hypothesized that ECFC may ameliorate the degree of AKI and/or promote repair of the renal vasculature following ischemia-reperfusion (I/R). Rat pulmonary microvascular endothelial cells (PMVEC) with high proliferative potential were compared with pulmonary artery endothelial cells (PAEC) with low proliferative potential in rats subjected to renal I/R. PMVEC administration reduced renal injury and hastened recovery as indicated by serum creatinine and tubular injury scores, while PAEC did not. Vehicle-treated control animals showed consistent reductions in renal medullary blood flow (MBF) within 2 h of reperfusion, while PMVEC protected against loss in MBF as measured by laser Doppler. Interestingly, PMVEC mediated protection occurred in the absence of homing to the kidney. Conditioned medium (CM) from human cultured cord blood ECFC also conveyed beneficial effects against I/R injury and loss of MBF. Moreover, ECFC-CM significantly reduced the expression of ICAM-1 and decreased the number of differentiated lymphocytes typically recruited into the kidney following renal ischemia. Taken together, these data suggest that ECFC secrete factors that preserve renal function post ischemia, in part, by preserving microvascular function.
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Lesión Renal Aguda/cirugía , Proliferación Celular , Células Progenitoras Endoteliales/trasplante , Endotelio Vascular/trasplante , Riñón/irrigación sanguínea , Neovascularización Fisiológica , Daño por Reperfusión/cirugía , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/patología , Lesión Renal Aguda/fisiopatología , Animales , Velocidad del Flujo Sanguíneo , Comunicación Celular , Células Cultivadas , Quimiotaxis de Leucocito , Medios de Cultivo Condicionados/metabolismo , Modelos Animales de Enfermedad , Células Progenitoras Endoteliales/metabolismo , Células Progenitoras Endoteliales/patología , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Endotelio Vascular/fisiopatología , Sangre Fetal/citología , Humanos , Molécula 1 de Adhesión Intercelular/metabolismo , Riñón/metabolismo , Riñón/patología , Masculino , Fenotipo , Ratas Sprague-Dawley , Circulación Renal , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Daño por Reperfusión/fisiopatología , Transducción de Señal , Factores de TiempoRESUMEN
Highly aerobic organs like the kidney are innately susceptible to ischemia-reperfusion (I/R) injury, which can originate from sources including myocardial infarction, renal trauma, and transplant. Therapy is mainly supportive and depends on the cause(s) of damage. In the absence of hypervolemia, intravenous fluid delivery is frequently the first course of treatment but does not reverse established AKI. Evidence suggests that disrupting leukocyte adhesion may prevent the impairment of renal microvascular perfusion and the heightened inflammatory response that exacerbate ischemic renal injury. We investigated the therapeutic potential of hydrodynamic isotonic fluid delivery (HIFD) to the left renal vein 24 hours after inducing moderate-to-severe unilateral IRI in rats. HIFD significantly increased hydrostatic pressure within the renal vein. When conducted after established AKI, 24 hours after I/R injury, HIFD produced substantial and statistically significant decreases in serum creatinine levels compared with levels in animals given an equivalent volume of saline via peripheral infusion (P<0.05). Intravital confocal microscopy performed immediately after HIFD showed improved microvascular perfusion. Notably, HIFD also resulted in immediate enhancement of parenchymal labeling with the fluorescent dye Hoechst 33342. HIFD also associated with a significant reduction in the accumulation of renal leukocytes, including proinflammatory T cells. Additionally, HIFD significantly reduced peritubular capillary erythrocyte congestion and improved histologic scores of tubular injury 4 days after IRI. Taken together, these results indicate that HIFD performed after establishment of AKI rapidly restores microvascular perfusion and small molecule accessibility, with improvement in overall renal function.
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Fluidoterapia/métodos , Hidrodinámica , Soluciones Isotónicas/administración & dosificación , Riñón/irrigación sanguínea , Daño por Reperfusión/terapia , Animales , Masculino , Ratas , Ratas Sprague-Dawley , Índice de Severidad de la EnfermedadRESUMEN
T cells have been implicated in the pathogenesis of acute kidney injury (AKI) and its progression to chronic kidney disease (CKD). Previous studies suggest that Th17 cells participate during the AKI-to-CKD transition, and inhibition of T cell activity by mycophenolate mofetil (MMF) or losartan attenuates the development of fibrosis following AKI. We hypothesized that T cell-deficient rats may have reduced levels of IL-17 cytokine leading to decreased fibrosis following AKI. Renal ischemis-reperfusion (I/R) was performed on T cell-deficient athymic rats (Foxn1rnu-/rnu-) and control euthymic rats (Foxn1rnu-/+), and CKD progression was hastened by unilateral nephrectomy at day 33 and subsequent exposure to 4.0% sodium diet. Renal fibrosis developed in euthymic rats and was reduced by MMF treatment. Athymic rats exhibited a similar degree of fibrosis, but this was unaffected by MMF treatment. FACS analysis demonstrated that the number of IL-17+ cells was similar between postischemic athymic vs. euthymic rats. The source of IL-17 production in euthymic rats was predominately from conventional T cells (CD3+/CD161-). In the absence of conventional T cells in athymic rats, a compensatory pathway involving natural killer cells (CD3-/CD161+) was the primary source of IL-17. Blockade of IL-17 activity using IL-17Rc receptor significantly decreased fibrosis and neutrophil recruitment in both euthymic and athymic rats compared with vehicle-treated controls. Taken together, these data suggest that IL-17 secretion participates in the pathogenesis of AKI-induced fibrosis possibly via the recruitment of neutrophils and that the source of IL-17 may be from either conventional T cells or NK cells.
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Lesión Renal Aguda/inmunología , Interleucina-17/inmunología , Riñón/inmunología , Células Asesinas Naturales/inmunología , Infiltración Neutrófila , Neutrófilos/inmunología , Insuficiencia Renal Crónica/inmunología , Daño por Reperfusión/inmunología , Lesión Renal Aguda/genética , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/patología , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Fibrosis , Factores de Transcripción Forkhead/genética , Genotipo , Interleucina-17/metabolismo , Riñón/metabolismo , Riñón/patología , Células Asesinas Naturales/metabolismo , Activación de Linfocitos , Masculino , Neutrófilos/metabolismo , Fenotipo , Ratas Desnudas , Ratas Transgénicas , Insuficiencia Renal Crónica/genética , Insuficiencia Renal Crónica/metabolismo , Insuficiencia Renal Crónica/patología , Daño por Reperfusión/genética , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Transducción de Señal , Factores de TiempoRESUMEN
Student populations are diverse such that different types of learners struggle with traditional didactic instruction. Problem-based learning has existed for several decades, but there is still controversy regarding the optimal mode of instruction to ensure success at all levels of students' past achievement. The present study addressed this problem by dividing students into the following three instructional groups for an upper-level course in animal physiology: traditional lecture-style instruction (LI), guided problem-based instruction (GPBI), and open problem-based instruction (OPBI). Student performance was measured by three summative assessments consisting of 50% multiple-choice questions and 50% short-answer questions as well as a final overall course assessment. The present study also examined how students of different academic achievement histories performed under each instructional method. When student achievement levels were not considered, the effects of instructional methods on student outcomes were modest; OPBI students performed moderately better on short-answer exam questions than both LI and GPBI groups. High-achieving students showed no difference in performance for any of the instructional methods on any metric examined. In students with low-achieving academic histories, OPBI students largely outperformed LI students on all metrics (short-answer exam: P < 0.05, d = 1.865; multiple-choice question exam: P < 0.05, d = 1.166; and final score: P < 0.05, d = 1.265). They also outperformed GPBI students on short-answer exam questions (P < 0.05, d = 1.109) but not multiple-choice exam questions (P = 0.071, d = 0.716) or final course outcome (P = 0.328, d = 0.513). These findings strongly suggest that typically low-achieving students perform at a higher level under OPBI as long as the proper support systems (formative assessment and scaffolding) are provided to encourage student success.
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Comprensión , Educación Profesional/métodos , Fisiología/educación , Aprendizaje Basado en Problemas , Estudiantes del Área de la Salud/psicología , Enseñanza/métodos , Curriculum , Evaluación Educacional , Escolaridad , HumanosRESUMEN
Mitochondrial (Mt) dysfunction contributes to the pathophysiology of renal function and promotes cardiovascular disease such as hypertension. We hypothesize that renal Mt-genes derived from female spontaneously hypertensive rats (SHR) that exhibit hypertension have reduced expression specific to kidney cortex. After breeding a female Okamoto-Aoki SHR (SAP = 188mmHg) with Brown Norway (BN) males (SAP = 100 and 104 mmHg), hypertensive female progeny were backcrossed with founder BN for 5 consecutive generations in order to maintain the SHR mitochondrial genome in offspring that contain over increasing BN nuclear genome. Mt-protein coding genes (13 total) and nuclear transcription factors mediating Mt-gene transcription were evaluated in kidney, heart and liver of normotensive (NT: n = 20) vs. hypertensive (HT: n = 20) BN/SHR-mtSHR using quantitative real-time PCR. Kidney cortex, but not liver or heart Mt-gene expression was decreased ~2-5 fold in 12 of 13 protein encoding genes of HT BN/SHR-mtSHR. Kidney cortex but not liver mRNA expression of the nuclear transcription factors Tfam, NRF1, NRF2 and Pgc1α were also decreased in HT BN/SHR-mtSHR. Kidney cortical tissue of HT BN/SHR-mtSHR exhibited lower cytochrome oxidase histochemical staining, indicating a reduction in renal oxidative phosphorylation but not in liver or heart. These results support the hypothesis that renal cortex of rats with SHR mitochondrial genome has specifically altered renal expression of genes encoding mitochondrial proteins. This kidney-specific coordinated reduction of mitochondrial and nuclear oxidative metabolism genes may be associated with heritable hypertension in SHR.
Asunto(s)
Genes Mitocondriales , Hipertensión/fisiopatología , Riñón/metabolismo , Proteínas Nucleares/genética , Fosforilación Oxidativa , Animales , Presión Sanguínea , Western Blotting , Femenino , Riñón/química , Masculino , Especificidad de Órganos , Fenotipo , ARN Mensajero/genética , Ratas , Ratas Endogámicas BN , Ratas Endogámicas SHR , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Exposure of rats to elevated dietary salt following recovery from acute kidney injury (AKI) accelerates the transition to chronic kidney disease (CKD), and is dependent on lymphocyte activity. Here we tested whether high salt diet triggers lymphocyte activation in postischemic kidneys to worsen renal inflammation and fibrosis. Male Sprague-Dawley rats on a 0.4% salt diet were subjected to left unilateral ischemia-reperfusion and allowed to recover for 5 weeks. This resulted in a mild elevation of CD4(+) T cells relative to sham animals. Contralateral unilateral nephrectomy and elevated dietary salt (4%) for 4 extra weeks hastened CKD and interstitial fibrosis. Activated T cells were increased in the kidney threefold after 4 weeks of elevated dietary salt exposure relative to post-AKI rats before salt feeding. The T cell subset was largely positive for IL-17, indicative of Th-17 cells. Because angiotensin II activity may influence lymphocyte activation, injured rats were given the AT1R antagonist, losartan, along with high salt diet. This significantly reduced the number of renal Th-17 cells to levels of sham rats, and significantly reduced the salt-induced increase in fibrosis to about half. In vitro studies in AKI-primed CD4(+) T cells indicated that angiotensin II and extracellular sodium enhanced, and losartan inhibited, IL-17 expression. Thus, dietary salt modulates immune cell activity in postischemic recovering kidneys because of the activity of local RAS, suggesting the participation of these cells in CKD progression post-AKI.
Asunto(s)
Lesión Renal Aguda/tratamiento farmacológico , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Riñón/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Insuficiencia Renal Crónica/prevención & control , Sistema Renina-Angiotensina/efectos de los fármacos , Cloruro de Sodio Dietético , Células Th17/efectos de los fármacos , Lesión Renal Aguda/inmunología , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/patología , Angiotensina II/farmacología , Animales , Células Cultivadas , Citoprotección , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Fibrosis , Riñón/inmunología , Riñón/metabolismo , Riñón/patología , Losartán/farmacología , Masculino , Nefrectomía , Ratas Sprague-Dawley , Insuficiencia Renal Crónica/inmunología , Insuficiencia Renal Crónica/metabolismo , Insuficiencia Renal Crónica/patología , Células Th17/inmunología , Células Th17/metabolismo , Factores de TiempoRESUMEN
Angiotensin II (AII) has been linked as a causal factor in several experimental models of hypertension (HT) including Okamoto spontaneously hypertensive rats (SHR). The transmission and expression of AII type 1 receptors (AT1r) in SHR and the development of genetic HT remain unknown. It is hypothesized that tissue-specific expression of renin-angiotensin system (RAS) genes derived from SHR are linked to HT in offspring of SHR crossed with Brown Norway (BN) rats. Hypertensive female progeny of BN/SHR matings was backcrossed with founder BN males to generate the F1 and five backcross generations (BN/SHR-mt(SHR)). Progeny were phenotyped according to normotension (NT: systolic arterial pressure [SAP] ≤ 124 mmHg), borderline hypertension (BHT: 124 ≤ SAP < 145 mmHg), and HT (SAP ≥ 145 mmHg). Six generations produced more HT (n = 88; 46%) than NT (n = 21; 11%) offspring. The mRNA expression of the RAS was evaluated in NT (n = 20) and HT (n = 20) BN/SHR-mt(SHR) across several generations. Quantitative real-time polymerase chain reaction analysis of kidney tissue showed increased expression of AII, type 1 receptors (Agtr1a) (â¼2.5-fold) in HT versus NT rats, while other members of both the renal and systemic RAS pathway were not different. Western blot analysis from kidney homogenates showed that AT1r protein levels were higher (P < 0.05) in backcross generation 3 (BC3) HT versus NT rats. Evaluation of SAP as a function of AT1r expression by linear regression indicated positive correlation (P < 0.05) in kidney of BC3 BN/SHR-mt(SHR) rats. Thus, elevated kidney AT1r expression may be involved in the development of HT in BN/SHR-mt(SHR) rats.