scholarly journals Microvascular disease precedes the decline in renal function in the streptozotocin-induced diabetic rat

2012 ◽  
Vol 302 (3) ◽  
pp. F308-F315 ◽  
Author(s):  
Christine Maric-Bilkan ◽  
Elizabeth R. Flynn ◽  
Alejandro R. Chade
Keyword(s):  
Renal Function ◽  
Renal Injury ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Microvascular Disease ◽  
Renal Tissue ◽  
Diabetic Rat ◽  
Sprague Dawley ◽  
Micro Computed Tomography ◽  
Diabetic Kidney

Diabetic nephropathy is a progressive and generalized vasculopathic condition associated with abnormal angiogenesis. We aim to determine whether changes in renal microvascular (MV) density correlate with and play a role in the progressive deterioration of renal function in diabetes. We hypothesize that MV changes represent the early steps of renal injury that worsen as diabetes progresses, initiating a vicious circle that leads to irreversible renal injury. Male nondiabetic (ND) or streptozotocin-induced diabetic (D) Sprague-Dawley rats were followed for 4 or 12 wk. Renal blood flow and glomerular filtration rate (GFR) were measured by PAH and 125I-[iothalamate], respectively. Renal MV density was quantified ex vivo using three-dimensional micro computed tomography and JG-12 immunoreactivity. Vascular endothelial growth factor (VEGF) levels (ELISA) and expression of VEGF receptors and factors involved in MV remodeling were quantified in renal tissue by Western blotting. Finally, renal morphology was investigated by histology. Four weeks of diabetes was associated with increased GFR, accompanied by a 34% reduction in renal MV density and augmented renal VEGF levels. However, at 12 wk, while GFR remained similarly elevated, reduction of MV density was more pronounced (75%) and associated with increased MV remodeling, renal fibrosis, but unchanged renal VEGF compared with ND at 12 wk. The damage, loss, and subsequent remodeling of the renal MV architecture in the diabetic kidney may represent the initiating events of progressive renal injury. This study suggests a novel concept of MV disease as an early instigator of diabetic kidney disease that may precede and likely promote the decline in renal function.

scholarly journals Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease

2011 ◽  
Vol 301 (1) ◽  
pp. F218-F225 ◽  
Author(s):  
Silvia Kelsen ◽  
John E. Hall ◽  
Alejandro R. Chade
Keyword(s):  
Growth Factor ◽  
Renal Injury ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Renal Tissue ◽  
Renal Hemodynamics ◽  
Microvascular Density ◽  
Receptor Blockade ◽  
Renovascular Disease

Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg−1·day−1) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD.

Multiscale imaging of the rat brain using an integrated diceCT and histology workflow

2021 ◽  
Author(s):  
Paul M. Gignac ◽  
Haley D. O’Brien ◽  
Jimena Sanchez ◽  
Dolores Vazquez Sanroman
Keyword(s):  
Computed Tomography ◽  
Low Cost ◽  
Three Dimensional ◽  
Adolescent Male ◽  
Cresyl Violet ◽  
Sprague Dawley ◽  
Biomedical Sciences ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Neural Tissues

Abstract Advancements in tissue visualization techniques have spurred significant gains in the biomedical sciences by enabling researchers to integrate their datasets across anatomical scales. Of particular import are techniques that enable the interpolation of multiple hierarchical scales in samples taken from the same individuals. This study demonstrates that two-dimensional histology techniques can be employed on neural tissues following three-dimensional diffusible iodine-based contrast-enhanced computed tomography (diceCT) without causing tissue degradation. This represents the first step toward a multiscale pipeline for brain visualization. We studied brains from adolescent male Sprague-Dawley rats, comparing experimental (diceCT-stained then de-stained) to control (without diceCT) brains to evaluate neural tissues for immunolabeling integrity, compare somata sizes, and distinguish neurons from glial cells within the telencephalon and diencephalon. We hypothesized that if experimental and control samples do not differ significantly in quantitative metrics, brain tissues are robust to the chemical, temperature, and radiation environments required for these multiple, successive imaging protocols. Visualizations for experimental brains were first captured via micro-computed tomography scanning of isolated, iodine-infused specimens. Samples were then cleared of iodine, serially sectioned, and prepared again using immunofluorescent, fluorescent, and cresyl violet labeling, followed by imaging with confocal and light microscopy, respectively. Our results show that many neural targets are resilient to diceCT imaging and compatible with downstream histological staining as part of a low-cost, multiscale brain imaging pipeline.

scholarly journals Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney

2012 ◽  
Vol 303 (4) ◽  
pp. F576-F583 ◽  
Author(s):  
Silvia Kelsen ◽  
Xiaochen He ◽  
Alejandro R. Chade
Keyword(s):  
Oxidative Stress ◽  
Renal Injury ◽  
Ex Vivo ◽  
Early Stage ◽  
Renal Perfusion ◽  
Redox Status ◽  
Renal Tissue ◽  
Tissue Sections ◽  
And Function

Renal artery stenosis (RAS), the main cause of chronic renovascular disease (RVD), is associated with significant oxidative stress. Chronic RVD induces renal injury partly by promoting renal microvascular (MV) damage and blunting MV repair in the stenotic kidney. We tested the hypothesis that superoxide anion plays a pivotal role in MV dysfunction, reduction of MV density, and progression of renal injury in the stenotic kidney. RAS was induced in 14 domestic pigs and observed for 6 wk. Seven RAS pigs were chronically treated with the superoxide dismutase mimetic tempol (RAS+T) to reduce oxidative stress. Single-kidney hemodynamics and function were quantified in vivo using multidetector computer tomography (CT) and renal MV density was quantified ex vivo using micro-CT. Expression of angiogenic, inflammatory, and apoptotic factors was measured in renal tissue, and renal apoptosis and fibrosis were quantified in tissue sections. The degree of RAS and blood pressure were similarly increased in RAS and RAS+T. Renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in the stenotic kidney (280.1 ± 36.8 and 34.2 ± 3.1 ml/min, P < 0.05 vs. control). RAS+T kidneys showed preserved GFR (58.5 ± 6.3 ml/min, P = not significant vs. control) but a similar decreases in RBF (293.6 ± 85.2 ml/min) and further decreases in MV density compared with RAS. These changes were accompanied by blunted angiogenic signaling and increased apoptosis and fibrosis in the stenotic kidney of RAS+T compared with RAS. The current study shows that tempol administration provided limited protection to the stenotic kidney. Despite preserved GFR, renal perfusion was not improved by tempol, and MV density was further reduced compared with untreated RAS, associated with increased renal apoptosis and fibrosis. These results suggest that a tight balance of the renal redox status is necessary for a normal MV repair response to injury, at least at the early stage of RVD, and raise caution regarding antioxidant strategies in RAS.

The Effect of Mesenchymal Stem Cells as a Cell Therapy in Renal Ischemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4756-4756
Author(s):  
Dae Sik Hong ◽  
Seongkyu Park ◽  
Jong-Ho Won ◽  
Chan Kyu Kim ◽  
Sang Chul Lee ◽  
...  
Keyword(s):  
Stem Cells ◽  
Renal Failure ◽  
Mesenchymal Stem Cells ◽  
Renal Function ◽  
Y Chromosome ◽  
Renal Injury ◽  
Female Rats ◽  
Sprague Dawley ◽  
Creatinine Concentration ◽  
Histologic Evaluation

Abstract Introduction: The most commonly used therapeutic targets in nephrology are the reduction of injury, the delay of progression, or renal replacement therapy. Many animal and human studies demonstrated the role of stem cells in repair and regenerations of kidney. Mesenchymal stem cells (MSCs) have shown to improve outcome of acute renal injury models. It is controversial whether MSCs can reduce injury following a toxic/ischemic event and delay renal failure in chronic kidney disease. We evaluated the hypothesis that the treatment with MSCs could improve renal function and attenuate injury in chronic renal failure (CRF). Materials and methods: Sprague-Dawley female rats (8 weeks old, 182.2 ± 7.2g) were underwent modified 5/6 nephrectomy. Rats in the MSC group received an injection of MSCs (1 × 106 cells) via tail vein 1 day after nephrectomy. Blood and urine samples were collected after 7 days and every month thereafter. The kidneys of rats were removed for histologic evaluation after 24-hr urine collection and blood sampling. The Y-chromosome stain using fluorescent in situ hybridization was performed to verify the presence of male MSCs in the kidney of female recipients. Results: No significant differences in blood urea nitrogen and creatinine concentration were observed between MSC group and untreated CRF group. However, the weight gain and creatinine clearance in the MSC group were greater than those of the CRF group. Proteinuria in the MSC group was less after 4 months. Y chromosome was detected in the kidney of MSC group. Although no significances were observed between two groups, the histologic analysis suggests that MSCs have positive effect against glomerulosclerosis. Conclusions: These results suggest that MSCs help preserve renal function and attenuate renal injury in CRF.

The role of nitric oxide in iron-induced rat renal injury

2004 ◽  
Vol 23 (11) ◽  
pp. 533-536 ◽  
Author(s):  
M Kadkhodaee ◽  
A Gol
Keyword(s):  
Nitric Oxide ◽  
Renal Function ◽  
Vitamin E ◽  
Renal Injury ◽  
Tissue Injury ◽  
Renal Tissue ◽  
No Synthase ◽  
Plasma Vitamin ◽  
Anti Oxidant ◽  
Plasma Vitamin E

Iron overload and enhanced hydroxyl radical (•OH) formation have been implicated as the causative factors of oxidative stress in different organs. Both pro-oxidant and anti-oxidant properties have been reported for nitric oxide (NO) in iron-mediated tissue injury. To determine the contribution of NO to iron-induced renal injury, eight groups of rats (eight in each group) were studied as follows: control (normal saline), L-Arg (L-arginine as a substrate of NO synthase, 400 mg/kg), L-NAME (an inhibitor of NO synthase, 8 mg/kg), Fe (iron dextran, 600 mg/kg), DFO (deferroxamine as a chelator of iron, 150 mg/kg), Fe+L-Arg, Fe+L-NAME, DFO+L-Arg. Twenty-four hours after the injections, blood samples were taken and kidneys removed for biochemical analysis. Plasma creatinine and urea were used to stimulate renal function. Renal tissue and plasma vitamin E levels, the most important endogenous fat soluble antioxidant, were measured by HPLC and UV detection. In this study, renal function was markedly reduced in the Fe group compared to controls (creatinine, 1.02± 0.05 mg/dL versus 0.78±0.04 P <0.05; urea, 49.59±1.69 mg/dL versus 40.75±0.86, P <0.01). Vitamin E levels were significantly lower in the Fe group compared to controls (plasma P <0.01; renal tissue P <0.05). Administration of L-Arg to Fe-treated groups prevented these reductions. L-NAME increased iron-induced toxicity significantly, demonstrated by further reduction in the vitamin E levels and renal function compared to the Fe group alone. We concluded that NO plays an important role in protecting the kidney from iron-induced nephrotoxicity. NO synthase blockade enhances iron-mediated renal toxicity in this model.

scholarly journals Study on Association of Pentraxin 3 and Diabetic Nephropathy in a Rat Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xuehai Chen ◽  
Jiao Luo ◽  
Minmin Wu ◽  
Zhuo Pan ◽  
Yue Xie ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Islet Transplantation ◽  
Renal Injury ◽  
Microvascular Disease ◽  
Renal Tissue ◽  
Diabetic Rats ◽  
Diabetic Patients ◽  
Tubular Injury ◽  
Clinical Progression ◽  
Renal Tubular

Diabetic nephropathy (DN) is a serious microvascular complication of diabetes. Compared with other therapies for diabetic patients, islet transplantation can effectively prevent and reverse diabetes-induced microvascular disease, such as diabetic retinopathy and nephropathy. PTX3 is the only long pentraxin that can be detected in renal tissue. In this study, we investigated the expression of PTX3 when early DN was reversed after islet transplantation.Methods. Diabetes was induced in rats by injecting streptozotocin (STZ). Twelve weeks later, the diabetic rats were divided into 2 groups: the islet transplantation group (IT) and the diabetic nephropathy group (DN). Renal injury, renal function, and the expression of PTX3 in the plasma and the kidneys were assessed with urinalysis, immunohistochemical staining, and Western blot, respectively.Results. The expression of PTX3 in the kidney was significantly decreased in the DN group but increased in the IT group because of the reversal of DN.Conclusions. Our data showed that the level of PTX3 in renal tissue is closely related to renal injury in DN. This may be used to quantify the extent of renal injury in DN, provide a potential early indicator of renal tubular injury in early DN patients, and assess DN clinical progression.

scholarly journals Optimized murine lung preparation for detailed structural evaluation via micro-computed tomography

2012 ◽  
Vol 112 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Dragoş M. Vasilescu ◽  
Lars Knudsen ◽  
Matthias Ochs ◽  
Ewald R. Weibel ◽  
Eric A. Hoffman
Keyword(s):  
In Vivo Imaging ◽  
Airway Pressure ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Imaging Method ◽  
Small Airways ◽  
Micro Computed Tomography ◽  
Vascular Perfusion ◽  
Murine Lung

Utilizing micro-X-ray CT (μCT) imaging, we sought to generate an atlas of in vivo and intact/ex vivo lungs from normal murine strains. In vivo imaging allows visualization of parenchymal density and small airways (15–28 μm/voxel). Ex vivo imaging of the intact lung via μCT allows for improved understanding of the three-dimensional lung architecture at the alveolar level with voxel dimensions of 1–2 μm. μCT requires that air spaces remain air-filled to detect alveolar architecture while in vivo structural geometry of the lungs is maintained. To achieve these requirements, a fixation and imaging methodology that permits nondestructive whole lung ex vivo μCT imaging has been implemented and tested. After in vivo imaging, lungs from supine anesthetized C57Bl/6 mice, at 15, 20, and 25 cmH2O airway pressure, were fixed in situ via vascular perfusion using a two-stage flushing system while held at 20 cmH2O airway pressure. Extracted fixed lungs were air-dried. Whole lung volume was acquired at 1, 7, 21, and >70 days after the lungs were dried and served as validation for fixation stability. No significant shrinkage was observed: +8.95% change from in vivo to fixed lung ( P = 0.12), −1.47% change from day 1 to day 7 ( P = 0.07), −2.51% change from day 1 to day 21 ( P = 0.05), and −4.90% change from day 1 to day 70 and thereafter ( P = 0.04). μCT evaluation showed well-fixed alveoli and capillary beds correlating with histological analysis. A fixation and imaging method has been established for μCT imaging of the murine lung that allows for ex vivo morphometric analysis, representative of the in vivo lung.

scholarly journals Macrophage Trafficking as Key Mediator of Adenine-Induced Kidney Injury

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Matheus Correa-Costa ◽  
Tárcio Teodoro Braga ◽  
Raphael José Ferreira Felizardo ◽  
Vinícius Andrade-Oliveira ◽  
Katia Regina Perez ◽  
...  
Keyword(s):  
Renal Function ◽  
Renal Dysfunction ◽  
Experimental Model ◽  
Interstitial Nephritis ◽  
Renal Injury ◽  
Kidney Injury ◽  
Renal Tissue ◽  
Special Role ◽  
Clodronate Liposome

Macrophages play a special role in the onset of several diseases, including acute and chronic kidney injuries. In this sense, tubule interstitial nephritis (TIN) represents an underestimated insult, which can be triggered by different stimuli and, in the absence of a proper regulation, can lead to fibrosis deposition. Based on this perception, we evaluated the participation of macrophage recruitment in the development of TIN. Initially, we provided adenine-enriched food to WT and searched for macrophage presence and action in the kidney. Also, a group of animals were depleted of macrophages with the clodronate liposome while receiving adenine-enriched diet. We collected blood and renal tissue from these animals and renal function, inflammation, and fibrosis were evaluated. We observed higher expression of chemokines in the kidneys of adenine-fed mice and a substantial protection when macrophages were depleted. Then, we specifically investigated the role of some key chemokines, CCR5 and CCL3, in this TIN experimental model. Interestingly, CCR5 KO and CCL3 KO animals showed less renal dysfunction and a decreased proinflammatory profile. Furthermore, in those animals, there was less profibrotic signaling. In conclusion, we can suggest that macrophage infiltration is important for the onset of renal injury in the adenine-induced TIN.

scholarly journals Inhibition of estradiol synthesis attenuates renal injury in male streptozotocin-induced diabetic rats

2011 ◽  
Vol 301 (3) ◽  
pp. F634-F640 ◽  
Author(s):  
Michaele B. Manigrasso ◽  
R. Taylor Sawyer ◽  
David C. Marbury ◽  
Elizabeth R. Flynn ◽  
Christine Maric
Keyword(s):  
Protein Expression ◽  
Aromatase Inhibitor ◽  
Renal Injury ◽  
Transforming Growth Factor ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Plasma Testosterone ◽  
Collagen Type Iv ◽  
Sprague Dawley ◽  
Estradiol Synthesis

We previously showed that the male streptozotocin (STZ)-induced diabetic rat exhibits decreased circulating testosterone and increased estradiol levels. While supplementation with dihydrotestosterone is partially renoprotective, the aim of the present study was to examine whether inhibition of estradiol synthesis, by blocking the aromatization of testosterone to estradiol using an aromatase inhibitor, can also prevent diabetes-associated renal injury. The study was performed on male Sprague-Dawley nondiabetic, STZ-induced diabetic, and STZ-induced diabetic rats treated with 0.15 mg/kg of anastrozole, an aromatase inhibitor (Da) for 12 wk. Treatment with anastrozole reduced diabetes-associated increases in plasma estradiol by 39% and increased plasma testosterone levels by 187%. Anastrozole treatment also attenuated urine albumin excretion by 42%, glomerulosclerosis by 30%, tubulointerstitial fibrosis by 32%, along with a decrease in the density of renal cortical CD68-positive cells by 50%, and protein expression of transforming growth factor-β by 20%, collagen type IV by 29%, tumor necrosis factor-α by 28%, and interleukin-6 by 25%. Anastrozole also increased podocin protein expression by 18%. We conclude that blocking estradiol synthesis in male STZ-induced diabetic rats is renoprotective.

scholarly journals Caspase-1 Inhibitor Reduces Pyroptosis in Kidney Injury Induced by Brain Death

2021 ◽  
Author(s):  
Weifeng Liu ◽  
Dongjing Yang ◽  
Jihua Shi ◽  
Peihao Wen ◽  
Jiakai Zhang ◽  
...  
Keyword(s):  
Renal Function ◽  
Brain Death ◽  
Renal Injury ◽  
Kidney Injury ◽  
Sprague Dawley ◽  
Protein Levels ◽  
Caspase 1 ◽  
Underlying Mechanisms

Abstract Brain death (BD) induces an organ-level inflammatory response, and BD donor kidneys show inferior survival and recovery rates. However, the underlying mechanisms have not been fully elucidated. Here, we investigated the role of caspase-1-mediated pyroptosis in BD-induced kidney injury in rats. A BD model was established in Sprague-Dawley rats. The rats were intravenously injected with a caspase-1 inhibitor (Z-YVAD-FMK) 1 h before BD, and sham-operated rats served as controls. After 0, 1, 2, 4, and 6 h of BD, renal function, renal injury, and renal expression of NLRP3, caspase-1, caspase-11, gasdermin D (GSDMD), IL-1β, and IL-18 were assessed using quantitative reverse transcriptase-polymerase chain reaction, western blotting, and immunohistochemistry. Blood urea nitrogen and serum creatinine levels were measured. Additionally, renal tubular epithelial cells (NRK-52E) were subjected to 3 h of hypoxia followed by 6 h of reoxygenation and incubated with Z-YVAD-FMK before hypoxia and reoxygenation. Caspase-11 was knocked-down using small interfering RNA technology. Cell viability and levels of pyroptosis-associated proteins were assessed thereafter. NLRP3, caspase-1, GSDMD, IL-1β, and IL-18 expression levels were upregulated in BD rats. Treatment with Z-YVAD-FMK reduced mRNA and protein levels, improved renal function, and alleviated renal injury. Z-YVAD-FMK effectively reduced pyroptosis in BD rats; however, it did not affect caspase-11 expression in vivo or in vitro. Thus, it could be considered as a therapeutic target for BD-induced kidney injury.

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