Rat Model Of Chronic Kidney Disease Research Articles

Bupi Yishen formula may prevent kidney fibrosis by modulating fatty acid metabolism in renal tubules

BackgroundBupi Yishen formula (BYF), a traditional Chinese herbal mixture, has demonstrated better effectiveness than Losartan in preserving renal function and preventing composite severe adverse outcomes in patients with advanced chronic kidney disease (CKD) in a recent randomized controlled trial. Prior studies have shown that BYF exerts anti-inflammatory and anti-fibrotic effects in the kidneys of CKD models, but the underlying mechanisms have not been fully elucidated. PurposeThe aim of this study was to investigate the protective effects of BYF administration on profibrotic phenotypic changes in the kidney and to elucidate its fundamental mechanisms of action. MethodsAdenine and 5/6 nephrectomy rat models were administered with two doses of BYF extract (15 or 30 g/kg/d) by intragastric administration, and Losartan treatment was used as a positive control group. The relationship between BYF renoprotection and restoration of fatty acid dysregulation was examined using the two fibrosis models and TGFb1-induced human tubular HK2 cells. Transcriptomic profiles of the fibrotic kidneys obtained from adenine-induced CKD rats were used to identify the key mechanisms that are affected by BYF intervention. Human relevance and clinical implications were established by re-analysis of the microarray databases of CKD patients and immunostaining on human biopsy specimens. ResultsBYF effectively prevented kidney histological damage and ameliorated renal malfunction in the adenine rat model of CKD. BYF robustly attenuated the significant increase in profibrotic and proapoptotic markers in fibrotic kidneys of adenine-induced CKD rats. Transcriptomic analyses of the fibrotic kidneys of the adenine rats identified fatty acid metabolism as the key dysregulated pathway affected by BYF prevention. BYF significantly reversed defective fatty acid oxidation (FAO) and the intracellular lipids accumulation in the fibrotic kidneys induced by 5/6 nephrectomy. Furthermore, BYF prevented dysfunctional fatty acid metabolism, which were associated with the significant improvement of TGFb1-induced profibrotic changes in HK2 human proximal tubular cells. Furthermore, analyses of kidney microarray databases and biopsy specimens of CKD patients suggested that FAO defect is common in CKD in humans. ConclusionOur exploratory study found that BYF may exert protective effects on renal fibrosis by regulating the fatty acid metabolism of renal tubular cells, which may be a key mechanism for preventing kidney fibrosis in CKD.

Altered Lung Heat Shock Protein-70 Expression and Severity of Sepsis-Induced Acute Lung Injury in a Chronic Kidney Disease Rat Model

Enhanced heat shock protein-70 (HSP-70) expression in the lungs is associated with attenuated acute lung injury (ALI) in a sepsis model. Chronic kidney disease (CKD) significantly contributes to the poor prognosis of patients with sepsis. This study examined the relationship between sepsis-induced ALI severity and altered lung HSP-70 expression in CKD. Experimental rats underwent a sham operation (control group) or 5/6 nephrectomy (CKD group). Sepsis was induced with cecal ligation and puncture (CLP). Laboratory tests and lung harvest were performed in the control group (without CLP and after 3, 12, 24, and 72 h of CLP) and in the CKD group (without CLP and after 72 h of CLP). ALI was the most severe after 12 h of sepsis. The mean lung injury score at 72 h after sepsis was significantly higher in the CKD group than in the control group (4.38 versus 3.30, p < 0.01). Nonetheless, enhanced lung HSP-70 expression was not observed in the CKD group. This study shows that altered lung HSP-70 expression is associated with the worsening of sepsis-induced ALI in patients with CKD. Enhancing lung HSP-70 is a novel treatment target for patients with CKD and sepsis-induced ALI.

TNFR2 as a Potential Biomarker for Early Detection and Progression of CKD

The inflammatory pathway driven by TNF-α, through its receptors TNFR1 and TNFR2, is a common feature in the pathogenesis of chronic kidney disease (CKD), regardless of the initial disease cause. Evidence correlates the chronic inflammatory status with decreased renal function. Our aim was to evaluate the potential of TNF receptors as biomarkers for CKD diagnosis and staging, as well as their association with the progression of renal lesions, in rat models of early and moderate CKD. We analyzed the circulating levels of inflammatory molecules-tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1) and 2 (TNFR2) and tissue inhibitor of metalloproteinase-1 (TIMP-1)-and studied their associations with TNFR1 and TNFR2 renal expression, glomerular and tubulointerstitial lesions, and with biomarkers of renal (dys)function. An increase in all inflammatory markers was observed in moderate CKD, as compared to controls, but only circulating levels of both TNFR1 and TNFR2 were significantly increased in the early disease; TNFR2 serum levels were negatively correlated with eGFR. However, only TNFR2 renal expression increased with CKD severity and showed correlations with the score of mild and advanced tubular lesions. Our findings suggest that renal TNFR2 plays a role in CKD development, and has potential to be used as a biomarker for the early detection and progression of the disease. Still, the potential value of this biomarker in disease progression warrants further investigation.

Magnesium Improves Cardiac Function in Experimental Uremia by Altering Cardiac Elastin Protein Content.

Cardiovascular complications are accompanied by life-threatening complications and represent the major cause of death in patients with chronic kidney disease (CKD). Magnesium is important for the physiology of cardiac function, and its deficiency is common in CKD. In the present study, we investigated the impact of oral magnesium carbonate supplementation on cardiac function in an experimental model of CKD induced in Wistar rats by an adenine diet. Echocardiographic analyses revealed restoration of impaired left ventricular cardiac function in animals with CKD. Cardiac histology and real-time PCR confirmed a high amount of elastin protein and increased collagen III expression in CKD rats supplemented with dietary magnesium as compared with CKD controls. Both structural proteins are crucial in maintaining cardiac health and physiology. Aortic calcium content increased in CKD as compared with tissue from control animals. Magnesium supplementation numerically lowered the increases in aortic calcium content as it remained statistically unchanged, compared with controls. In summary, the present study provides evidence for an improvement in cardiovascular function and aortic wall integrity in a rat model of CKD by magnesium, as evidenced by echocardiography and histology.

PRE-084 ameliorated kidney injury by reducing endoplasmic reticulum stress in the rat model of adenine-induced chronic kidney disease.

Endoplasmic reticulum (ER) stress plays an important role in the development of chronic kidney disease (CKD). Sigma-1 receptors (σ1Rs) are novel chaperone proteins that regulate ER stress. However, effect of σ1R activation on renal ER stress is yet unexplored. So, in the present study we investigated the effects of PRE-084, aσ1R agonist on renal injury and ER stress in the rat model of CKD. CKD group rats were fed adenine for 28 days and CKD treatment group rats were additionally administered PRE-084 intraperitoneally at 1, 3 and 10mg/kg body weight dose from Day 22-28. ER stress markers were evaluated using molecular biology techniques such as immunohistochemistry and Western blot. Marked kidney injury was observed in CKD rats as revealed by biochemical and histological findings. Expression of ER stress proteins such as phosphorylated protein kinase R-like ER kinase (p-PERK), cleaved activating transcription factor-6 (ATF-6f), phosphorylated inositol requiring enzyme1α (p-IRE1α) and caspase-12 were higher in CKD rats. Nevertheless, CKD rats treated with PRE-084 particularly at 10mg/kg dose showed considerably lesser kidney injury along with higher expression of σ1R and marked reduction of all the ER stress proteins studied. Results reveal that PRE-084 likely ameliorated the adenine-induced kidney injury by lowering ER stress through increased σ1R expression.

Inhibition of the Semaphorin 4D-Plexin-B1 axis prevents calcification in vascular smooth muscle cells

Vascular calcification is common in cardiovascular diseases including atherosclerosis, and is associated with an increased risk of pathological events and mortality. Some semaphorin family members play an important role in atherosclerosis. In the present study, we show that Semaphorin 4D/Sema4D and its Plexin-B1 receptor were significantly upregulated in calcified aorta of a rat chronic kidney disease model. Significantly higher Sema4D and Plexin-B1 expression was also observed during inorganic phosphate-induced calcification of vascular smooth muscle cells. Knockdown of Sema4D or Plexin-B1 genes attenuated both the phosphate-induced osteogenic phenotype of vascular smooth muscle cells, through regulation of SMAD1/5 signaling, as well as apoptosis of vascular smooth muscle cells, through modulation of the Gas6/Axl/Akt survival pathway. Taken together, our results offer new insights on the role of Sema4D and Plexin-B1 as potential therapeutic targets against vascular calcification. [BMB Reports 2023; 56(3): 160-165].

Upacicalcet, a positive allosteric modulator of the calcium-sensing receptor, prevents vascular calcification and bone disorder in a rat adenine-induced secondary hyperparathyroidism model.

Secondary hyperparathyroidism (SHPT) is a major comorbidity of chronic kidney disease (CKD). Chronic elevation of PTH levels is associated with cortical bone deterioration and increase in the risk of fractures in CKD patients. Here, we evaluated the effect of repeated administration of upacicalcet, a novel positive allosteric modulator of the calcium-sensing receptor, in a rat model of adenine-induced renal failure, by determining serum levels of intact PTH (iPTH), calcium, phosphorus, creatinine, and urea nitrogen. Furthermore, parathyroid hyperplasia (parathyroid gland weight and Ki-67-positive cell density), ectopic calcification (calcium content in the thoracic aorta, kidney and heart and positive von Kossa staining in the thoracic aorta), and bone morphometry parameters (cortical porosity and fibrosis volume) were evaluated. Rats treated with either 0.2mg/kg or 1mg/kg upacicalcet exhibited significantly lower serum iPTH levels than CKD-control rats, as early as 7days after the first dose. Repeated administration of upacicalcet reduced serum iPTH levels and inhibited parathyroid hyperplasia in rats with adenine-induced severe renal failure. Moreover, it suppressed ectopic calcification and cortical pore formation. In contrast, serum calcium and phosphorus levels were not significantly affected, suggesting a low risk of hypocalcemia, which often occurs with SHPT treatment. In conclusion, repeated administration of upacicalcet decreased serum iPTH levels and suppressed parathyroid hyperplasia in the adenine-induced CKD rat model of SHPT. Furthermore, ectopic calcification and cortical pore formation were suppressed without significant changes in blood mineral parameters. Upacicalcet safely inhibited the progression of SHPT in an adenine-induced CKD rat model.

Dietary Resveratrol Butyrate Monoester Supplement Improves Hypertension and Kidney Dysfunction in a Young Rat Chronic Kidney Disease Model.

Chronic kidney disease (CKD) remains a public health problem. Certain dietary supplements can assist in the prevention of CKD progression. In this regard, resveratrol is a polyphenol and has a potential therapeutic role in alleviating CKD. We previously utilized butyrate in order to improve the bioavailability of resveratrol via esterification and generated a resveratrol butyrate monoester (RBM). In this study, the hypothesis that RBM supplementation is able to protect against kidney dysfunction and hypertension was tested by using an adenine-induced CKD model. For this purpose, three-week-old male Sprague Dawley rats (n = 40) were equally categorized into: group 1-CN (sham control); group 2-CKD (adenine-fed rats); group 3-REV (CKD rats treated with 50 mg/L resveratrol); group 4-MEL (CKD rats treated with 25 mg/L RBM); and group 5-MEH (CKD rats treated with 50 mg/L RBM). At the end of a 12-week period, the rats were then euthanized. The adenine-fed rats displayed hypertension and kidney dysfunction, which were attenuated by dietary supplementation with RBM. The CKD-induced hypertension coincided with: decreased nitric oxide (NO) bioavailability; augmented renal protein expression of a (pro)renin receptor and angiotensin II type 1 receptor; and increased oxidative stress damage. Additionally, RBM and resveratrol supplementation shaped distinct gut microbiota profiles in the adenine-treated CKD rats. The positive effect of high-dose RBM was shown together with an increased abundance of the genera Duncaniella, Ligilactobacillus, and Monoglobus, as well as a decrease in Eubacterium and Schaedierella. Importantly, the mechanism of action of the RBM supplementation may be related to the restoration of NO, rebalancing of the RAS, a reduction in oxidative stress, and alterations to the gut microbiota. Moreover, RBM supplementation shows promise for the purposes of improving CKD outcomes and hypertension. As such, further translation to human studies is warranted.

Chronic kidney disease to osteoporosis: histopathological analysis on animal model with unilateral ureteral obstruction method

Background: One of the most frequent complications due to the progression of chronic kidney disease (CKD) is the occurrence of disturbances in mineral metabolism.. Increased bone remodeling results in osteopenia, which can progressively lead to osteoporosis. Wistar albino rats (Rattus norvegicus) are one of the most well-known and easy-to-obtain laboratory test animals. Data regarding the duration of bone pathological progression in CKD-induced Wistar strain rats by the unilateral ureteral obstruction method are limited. Methods: This was a descriptive observational study, with a prospective cohort approach. The aim was to determine the histopathological onset of osteoporosis in Wistar rats with the CKD model. We used 13 male Wistar rats (Rattus norvegicus). The CKD rat models were randomized and put into four containers, each containing three rats. Each group was treated in the same way for predetermined durations, which were the 7th day, 14th day, 21st day, and 28th day after CKD modeling, before being sacrificed for femoral bone histopathological collection. Results: On the 7th day after CKD modeling, we discovered thickening of the periosteal fibrous tissue. On the 14th and 21st days, there was an increase in the thickness of the periosteal fibrous tissue in the metaphyseal and diaphyseal areas. This thickening progression was in line with the length of treatment time. On the 21st day, we began to see the increasing gap between the trabecular tissues. On the 28th day, the histopathological analysis of femoral bone tissue showed thinning of the bone trabecular tissue and the most distant inter-trabecular spaces, suggesting the appearance of osteoporosis. Conclusion: The histopathological picture of osteoporosis in the Wistar strain rat model of CKD appeared most clearly and worst on the 28th day after CKD. It was marked by the thinning of the trabecular bone tissue and the most distant spaces between the trabeculae.

Bone marrow mesenchymal stem cells inhibit ferroptosis via regulating the Nrf2-keap1/p53 pathway to ameliorate chronic kidney disease injury in the rats

Purpose Although bone marrow mesenchymal stem cells (BMMSCs) have been reported to exhibit a protective effect on animal models of chronic kidney disease (CKD), the exact mechanisms involved require further investigation. This study aims to investigate the underlying molecular mechanisms of BMMSCs in inhibiting ferroptosis and preventing an Adriamycin (ADR)-induced CKD injury. Methods A rat model of long-term CKD induced through the injection of ADR administered twice weekly via the tail vein was used in this study. After BMMSCs were systemically administered through the renal artery, pathological staining, western blotting, ELISA, and transmission electron microscopy were used to analyze ferroptosis. Results Analyses of renal function and histopathological findings indicated that ADR-mediated renal dysfunction improved in response to the BMMSC treatment, which was also sufficient to mediate the partial reversal of renal injury and mitochondrial pathological changes. BMMSCs decreased the ferrous iron (Fe2+) and reactive oxygen species and elevated glutathione (GSH) and GSH peroxidase 4. Moreover, the BMMSC treatment activated the expression of ferroptosis-related regulator NF-E2-related factor 2 (Nrf2) and inhibited Keap1 and p53 in CKD rat kidney tissues. Conclusions BMMSCs alleviate CKD, possibly resulting from the inhibition of kidney ferroptosis by regulating the Nrf2–Keap1/p53 pathway.

Chronic kidney disease compromises structural and mechanical properties of maxillary cortical bone in a rat model.

This study aimed to investigate the effects of chronic kidney disease (CKD) on the structural and mechanical properties of the maxillary and mandibular cortical bone. The maxillary and mandibular cortical bones from CKD model rats were used in this study. CKD-induced histological, structural, and micro-mechanical alterations were assessed using histological analyses, micro-computed tomography (CT), bone mineral density (BMD) measurements, and nanoindentation tests. Histological analyses indicated that CKD caused an increase in the number of osteoclasts and a decrease in the number of osteocytes in the maxilla. Micro-CT analysis revealed that CKD induced a void volume/cortical volume (%) increase, which was more remarkable in the maxilla than in the mandible. CKD also significantly decreased the BMD in the maxilla. In the nanoindentation stress-strain curve, the elastic-plastic transition point and loss modulus were lower in the CKD group than that in the control group in the maxilla, suggesting that CKD increased micro fragility of the maxillary bone. CKD affected bone turnover in the maxillary cortical bone. Furthermore, the maxillary histological and structural properties were compromised, and micro-mechanical properties, including the elastic-plastic transition point and loss modulus, were altered by CKD.

AST-120 to Target Protein-Bound Uremic Toxins Improves Cardiac Output and Kidney Oxygenation in Experimental Chronic Kidney Disease

Introduction: Chronic kidney disease (CKD) is a global health problem with increasing incidence which is closely associated with cardiac dysfunction. In CKD, uremic toxins accumulate as kidney function declines. Additionally, high salt intake is a growing health issue worldwide which can exacerbate kidney disease. In this study, we investigated the effect of reducing plasma levels of protein-bound uremic toxins in a rat model of CKD, challenged with high salt intake and compared the effects to those of conventional treatment using an angiotensin-converting enzyme inhibitor (ACEI). Methods: In rats, the right kidney and 2/3 of the left kidney were surgically removed (5/6 nephrectomy). Animals were fed a normal-salt diet and randomized to either no treatment (control) or chronic treatment with either the oral absorbent AST-120 to reduce plasma levels of protein-bound uremic toxins or the ACEI enalapril to inhibit angiotensin II signaling for 5 weeks. Following treatment, kidney function was measured before and after a week of high salt intake. Cardiac output and markers of oxidative stress were measured at the end of the study period. Results: Treatment with AST-120 resulted in decreased levels of the uremic toxin indoxyl sulfate, improved cardiac output (mL/min: AST-120 44.9 ± 5.4 compared to control 26.6 ± 2.0; p < 0.05), and decreased urinary oxidative stress. ACEI reduced oxidative stress in kidney tissue and improved the glomerular filtration rate in response to high salt intake (mL/min: ACEI 1.5 ± 0.1; compared to control 1.1 ± 0.1; p < 0.05). Both interventions improved intrarenal oxygen availability (mm Hg: AST-120 42.8 ± 0.8; ACEI 43.2 ± 1.9; compared to control 33.4 ± 1.3; p < 0.05). Conclusion: AST-120 administered to reduce plasma levels of uremic toxins, such as indoxyl sulfate, has potential beneficial effects on both cardiac and kidney function. Targeting uremic toxins and angiotensin II signaling simultaneously could be an efficient strategy to target both cardiac and kidney dysfunction in CKD, to further slow progression of disease in patients with CKD.

Panax notoginseng saponins alleviate damage to the intestinal barrier and regulate levels of intestinal microbes in a rat model of chronic kidney disease

Objectives Chronic kidney disease (CKD) is a long-term condition characterized by poor prognosis and a high mortality rate. Panax notoginseng saponins (PNS) are the main active ingredient of the traditional Chinese herb Panaxnotoginseng(Burk.)F.H.Chen, which has been widely reported to have various pharmacological effects. Here, we examined the effect of PNS on renal function and the modulation of intestinal flora and intestinal barrier in a rat model of adenine-induced CKD. Methods Adenine was used to establish a rat model of CKD, biochemical testing, histopathologic examination, ELISA, immunohistochemical assay, western blot assay, and fecal microbiota 16s rRNA analysis was used to test the effect of PNS on CKD rats. Results Adenine induced a significant decrease in glomerular filtration rate, an increase in urinary protein excretion rate, and pathological damage to renal tissue in CKD rats. TNF-α, MCP-1, IL-1β, IL-18, TMAO, and endotoxin levels were increased in the blood of the model rats. Application of PNS countered the effects of adenine, restoring the above parameters to the level observed in healthy rats. In addition, activation of the inflammatory proteins NF-κB (p65) and NLRP3 and the fibrosis-associated proteins α-SMA and smad3 were inhibited in the kidneys of CKD rats. Furthermore, PNS promoted the expression of the tight junction proteins Occludin and ZO-1, increased SIgA levels, strengthened intestinal immunity, reduced mechanical damage to the intestine, was reduced levels of DAO and D-LA. Our data suggest PNS may delay CKD by restoring gut microbiota, and through the subsequent generation of a microbial barrier and modulation of microbiota metabolites. Conclusions In conclusion, PNS may inhibit the development of inflammation and fibrosis in the kidney tissue through regulation of intestinal microorganisms and inhibition of the activation of pro-inflammatory and pro-fibrotic proteins in the kidney.

Lipidomics reveals the potential mechanism of honokiol against adenine-induced chronic kidney disease.

Honokiol (HKL), a biphenolic compound, is derived from the bark of Magnolia officinalis, which is used in traditional Chinese medicine for gastrointestinal complaints. HKL has diverse pharmacological activities and has protective effects in various disease models. However, the role and mechanism of HKL in treating chronic kidney disease (CKD) remain unclear. This study was designed to investigate whether HKL can alleviate CKD and the potential mechanism by which it acts. Male Sprague-Dawley rats were fed 0.75% w/w adenine feed for 3 weeks to induce CKD. HKL was administered by gavage at a dose of 5 mg/kg/day for 4 weeks. Using a special kit, serum creatinine (Scr) and blood urea nitrogen (BUN) were measured. To assess renal pathology, periodic acid-Schiff and Masson’s trichrome staining were conducted. Renal lipid profiles were analyzed by ultra-high-performance liquid chromatography/mass spectrometry (UHPLC/MS). The results showed that the administration of HKL reduced Scr and BUN and alleviated renal tubular atrophy and tubulointerstitial fibrosis in an adenine-induced CKD rat model. By using lipidomics, we identified 113 lipids (47 lipids in negative ion mode, 66 lipids in positive ion mode) that could be significantly reversed by HKL treatment in CKD rat kidneys. Most of these lipids belonged to the phosphatidylcholine (PC), ceramide (Cer), phosphatidylethanolamine (PE), and triacylglycerol (TAG) classes. Moreover, HKL improved fatty acid oxidation in the kidneys of CKD rats. In conclusion, this study found that HKL can protect against adenine-induced CKD, possibly through the regulation of lipid metabolism.

Rhein Inhibits Proliferation, Extracellular Matrix Deposition, and Inflammation in Mesangial Cells via ROS/Akt Signaling Pathway

It has been reported that rhein, a Chinese herbal compound, has a potent anti-inflammatory effect on various diseases. However, it remains elusive whether rhein has a protective effect on chronic kidney disease (CKD) and what its underlying mechanism may be. In the present study, we evaluated whether rhein could prevent lipopolysaccharide (LPS)-induced proliferation, expression of extracellular matrix (ECM) proteins, and inflammation in rat mesangial cells (MCs), and whether these effects were mediated by reactive oxygen species (ROS) and Akt signaling. We also investigated the protective effect of rhein on renal function in a rat CKD model. Results showed that rhein significantly suppressed LPS-initiated proliferation in MCs in a cell counting kit-8 (CCK8) assay. Meanwhile, rhein significantly inhibited LPS-induced expression of ECM proteins and inflammation, as indicated by the decreased expression of fibronectin, α smooth muscle actin (α-SMA), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), and interferon γ (IFN-γ). Of note, rhein significantly enhanced LPS-induced production of reactive oxygen species (ROS) and inhibited LPS-induced Akt phosphorylation. Furthermore, the inhibitory effect of rhein on Akt phosphorylation was inhibited by H2O2 scavenger catalase. Importantly, the protective effect of rhein was almost totally lost in the presence of phosphatidylinositol 3-kinase (PI3K) protagonist insulin-like growth factor 1 (IGF-1). Finally, rhein significantly decreased 24 h urinary protein, serum creatinine (SCr), and blood urea nitrogen (BUN) in CKD rats. Collectively, these results suggested that rhein improved CKD through inhibition of proliferation, ECM synthesis, and inflammation via ROS/Akt signaling in MCs.

Intact Fibroblast Growth Factor 23 Regulates Chronic Kidney Disease-Induced Myocardial Fibrosis by Activating the Sonic Hedgehog Signaling Pathway.

Background Clinically, myocardial fibrosis is one of the most common complications caused by chronic kidney disease (CKD). However, the potential mechanisms of CKD-induced myocardial fibrosis have not been clarified. Methods and Results In our in vivo study, a rat model of CKD with 5/6 nephrectomy was established. The CKD model was treated with the glioma 1 (Gli-1) inhibitor GANT-61, and myocardial fibrosis and serum intact fibroblast growth factor 23 levels were assessed 16 weeks after nephrectomy. Finally, we found that Gli-1 and Smoothened in the Sonic Hedgehog (Shh) signaling pathway were activated and that collagen-1 and collagen-3, which constitute the fibrotic index, were expressed in CKD myocardial tissue. After administering the Gli-1 inhibitor GANT-61, the degree of myocardial fibrosis was reduced, and Gli-1 expression was also inhibited. We also measured blood pressure, cardiac biomarkers, and other indicators in rats and performed hematoxylin-eosin staining of myocardial tissue. Furthermore, in vitro studies showed that intact fibroblast growth factor 23 promoted cardiac fibroblast proliferation and transdifferentiation into myofibroblasts by activating the Shh signaling pathway, thereby promoting cardiac fibrosis, as manifested by increased expression of the Shh, Patch 1, and Gli-1 mRNAs and Shh, Smoothened, and Gli-1 proteins in the Shh signaling pathway. The protein and mRNA levels of other fibrosis indicators, such as α-smooth muscle actin, which are also markers of transdifferentiation, collagen-1, and collagen-3, were increased. Conclusions On the basis of these results, intact fibroblast growth factor 23 promotes CKD-induced myocardial fibrosis by activating the Shh signaling pathway.

Effects of dietary phosphorus concentration and phosphate salt form on renal tubule function in unilateral nephrectomized rats.

Background: Excessive consumption of phosphorus (P) impairs renal tubule function; however, the effects of different dietary phosphate salts on chronic kidney disease (CKD) are unclear. Aim: To examine the effects of potassium dihydrogen phosphate (KH2PO4) and potassium tripolyphosphate (K5P3O10) and P concentration on renal function in a rat model of early CKD. Methods: Male sham-operated Sprague-Dawley rats were fed a diet containing KH2PO4 with a normal P level. Kidney injury was induced by unilateral nephrectomy (UNx), and the rats were divided into four groups fed dietary KH2PO4 or K5P3O10 with a normal (UNx-NKH, UNx-NKP) or high (UNx-HKH, UNx-HKP) P concentration, respectively, for 21 days. Results: UNx-NKH rats showed significantly lower creatinine clearance (CCr) and higher albumin (ALB) compared with those of sham rats, confirming UNx-induced kidney injury. The urinary levels of liver-type fatty acid-binding protein (L-FABP) and ALB were significantly higher in UNx-HKP rats than in UNx-HKH rats. However, other markers of renal tubule function, such as CCr, serum creatinine (CRE), calcium (Ca), and hormones, only differed among groups according to the P concentration and not the dietary phosphate salt form. Histological examination showed higher incidence and severity of tubulointerstitial lesions, tubule regeneration, tubule dilation, and calcification in the high-phosphorus than in the normal-phosphorus UNx groups. These changes were more severe in the UNx-HKP group compared with the UNx-HKH group. Conclusion: This study highlights the importance of controlling dietary P intake in terms of both concentration and source to prevent the progression of CKD.

Chitin powder enhances growth factor production and therapeutic effects of mesenchymal stem cells in a chronic kidney disease rat model.

Previously, we fabricated a device with polylactic acid nonwoven filters and mesenchymal stem cells (MSCs), which effectively reduced urinary protein levels in a rat model of chronic kidney disease (CKD) but could not suppress CKD progression. Therefore, to improve the therapeutic effects of MSCs, in this study, we analyzed the ability of rat adipose tissue-derived MSCs (ADSCs) in contact with chitin nonwoven filters or chitin powder to produce growth factors and examined their therapeutic effect in an adriamycin (ADR)-induced CKD rat model. Hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) production was significantly enhanced by ADSCs cultured in a medium containing chitin powder (C-ADSCs) compared with that by ADSCs cultured in a standard medium without chitin (N-ADSCs). However, the production of HGF and VEGF by ADSCs on chitin nonwoven filters was not significantly enhanced compared with that by the control. Intravenous C-ADSC injection significantly increased podocin expression and improved proteinuria compared with those in saline-treated CKD rats; however, no such improvements were observed in the N-ADSC-treated group. These results showed that ADSCs cultured in a medium supplemented with chitin powder suppressed proteinuria via enhanced HGF and VEGF production in ADR-induced CKD rats to mitigate podocyte damage, offering a new strategy to reduce the dose of MSC therapy for safe and effective treatment of kidney disease.

Astragaloside IV protects against ischemia/reperfusion (I/R)-induced kidney injury based on the Keap1-Nrf2/ARE signaling pathway.

BackgroundThis study sought to investigate the protective effects of Astragaloside IV (AS-IV) on ischemia-reperfusion (I/R) renal injury based on the keap1-Nrf2/ARE signaling pathway.Methods A total of 36 male Sprague-Dawley rats (aged: 8 weeks; weighing: 200–220 g) were randomly divided into the following 6 groups (n=6 per group): (I) the control group; (II) the sham operation group; (III) the kidney I/R injury group (the I/R group); (IV) the kidney I/R injury group treated with 2 mg/kg of AS-IV (the low-dose group); (V) the kidney I/R injury group treated with 5 mg/kg of AS-IV (the mid-dose group); and (VI) the kidney I/R injury group treated with 10 mg/kg of AS-IV (the high-dose group). Serum creatinine (CRE), serum urea, malondialdehyde (MDA), and superoxide dismutase (SOD) were examined using enzyme-linked immunoassay kits. Cell apoptosis and the pathological damage to the renal tissue were determined by terminal deoxynucleotidyl transferase dUTP nick end labeling, hematoxylin and eosin, and periodic acid-Schiff (PAS) staining. The immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR), and western blot methods were used to determine the expression of Nrf2, HO-1, Bcl-2 and Bax in the kidney tissue.ResultsIn the I/R rat model, the serum CRE level was increased. In the acute kidney injury (AKI) and chronic kidney disease (CKD) models, AS-IV treatment significantly decreased serum CRE levels in a dose-dependent manner. AS-IV treatment also reduced the injury of renal tubular epithelial cells, increased the expression levels of Nrf2 and HO-1, decreased the rate of apoptosis, downregulated the level of MDA, and elevated the activity of SOD. In the CKD rat model, the AS-IV treatment groups had reduced renal tubular epithelial cell injury, increased expression levels of Nrf2 and HO-1, decreased MDA levels, and increased SOD activity compared to the I/R group.ConclusionsAS-IV induced the expression of Nrf2, enhanced the activity of antioxidant enzymes, reduced apoptosis, protected against renal I/R injury, and prevented AKI from transforming into CKD. These findings suggest that AS-IV is a promising drug for treating kidney injury.

Cognitive Sequelae and Hippocampal Dysfunction in Chronic Kidney Disease following 5/6 Nephrectomy.

Neurological disorders are prevalent in patients with chronic kidney disease (CKD). Vascular factors and uremic toxins are involved with cognitive impairment in CKD. In addition, vascular dementia-induced alterations in the structure and function of the hippocampus can lead to deficits in hippocampal synaptic plasticity and cognitive function. However, regardless of this clinical evidence, the pathophysiology of cognitive impairment in patients with CKD is not fully understood. We used male Sprague Dawley rats and performed 5/6 nephrectomy to observe the changes in behavior, field excitatory postsynaptic potential, and immunostaining of the hippocampus following CKD progression. We measured the hippocampus volume on magnetic resonance imaging scans in the controls (n = 34) and end-stage renal disease (ESRD) hemodialysis patients (n = 42). In four cognition-related behavior assays, including novel object recognition, Y-maze, Barnes maze, and classical contextual fear conditioning, we identified deficits in spatial working memory, learning and memory, and contextual memory, as well as the ability to distinguish familiar and new objects, in the rats with CKD. Immunohistochemical staining of Na+/H+ exchanger1 was increased in the hippocampus of the CKD rat models. We performed double immunofluorescent staining for aquaporin-4 and glial fibrillary acidic protein and then verified the high coexpression in the hippocampus of the CKD rat model. Furthermore, results from recoding of the field excitatory postsynaptic potential (fEPSP) in the hippocampus showed the reduced amplitude and slope of fEPSP in the CKD rats. ESRD patients with cognitive impairment showed a significant decrease in the hippocampus volume compared with ESRD patients without cognitive impairment or the controls. Our findings suggest that uremia resulting from decreased kidney function may cause the destruction of the blood–brain barrier and hippocampus-related cognitive impairment in CKD.