Adenine-induced Chronic Kidney Disease Research Articles

New Model for Adenine-Induced Chronic Kidney Disease (CKD) in Mice, and the Effect of [6]-Gingerol Capped Colloidal Gold Treatment: Histopathological Evaluation of Gold (Nanoparticles, Nanosheets and Nanorods)

New Model for Adenine-Induced Chronic Kidney Disease (CKD) in Mice, and the Effect of [6]-Gingerol Capped Colloidal Gold Treatment: Histopathological Evaluation of Gold (Nanoparticles, Nanosheets and Nanorods)

#2671 Renal tubular epithelial FFAR4 improves cellular senescence to alleviate interstitial fibrosis in CKD

Abstract Background and Aims Chronic kidney disease (CKD) is defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 or pathological albuminuria, which is known as one of the major contributors to worldwide mortality. Although there have been substantial advances in understanding CKD mechanisms, at present, there are no effective therapies to treat it. We had formerly found that TUG891, a free fatty acid receptor 4 (FFAR4) (a member of the G protein-coupled receptor (GPCR) family) agonist, alleviated tubular damage as well as interstitial fibrosis in mice with CKD. Nevertheless, the multifunctional effects of FFAR4 in the kidney have not been well described. Method In the current research, the FFAR4 expression was abnormally reduced in tubular epithelial cells (TECs) of unilateral ureteral obstruction (UUO) and adenine-induced CKD mice. Systemic and conditional TEC-specific knockout of FFAR4 aggravated renal function, pathological damage and interstitial fibrosis, whereas FFAR4 activation by TUG-891 alleviated the severity of disease in UUO and adenine-induced CKD mice. Results Notably, FFAR4, as a key determinant, was firstly explored to regulate the cellular senescence in TECs and CKD mice injured kidneys, as represented through the activity of senescence associated β-galactosidase (SA-β-gal), marker protein p21, p53, Lamin B1, phospho-histone H2A.X, phospho-Rb expression, and secretory phenotype IL-6 level. Mechanistically, pharmacological activation and overexpression of FFAR4 reversed the decrease of aging-related SirT3 protein, where FFAR4 regulated SirT3 expression to exhibit anti-senescent effect via Gq subunit-mediated CaMKKβ/AMPK signaling in UUO and adenine-induced CKD mice. Conclusion These results underline the primordial role of renal tubular FFAR4 in the cellular senescence through AMPK/SirT3 signaling and define FFAR4 as a target for underlying drugs against CKD.

#2104 Neutrophil extracellular traps have a pivotal role in tubulointerstitial fibrosis

Abstract Background and Aims Tubulointerstitial fibrosis (TIF) is a typical pathological change in chronic kidney disease (CKD). However, the mechanisms underlying tubulointerstitial fibrosis are still to be fully elucidated. Neutrophil extracellular traps (NETs) participate in the pathophysiological processes of various kidney diseases, but their role in CKD-TIF has not been reported. Here, we investigated the role of NETs in tubulointerstitial fibrosis. Method Immunofluorescence was employed to assess the levels and localization of NETs in the renal tissues of CKD patients. The GSE66494 human CKD microarray dataset was explored to analyze the changes of PAD4 levels. Three CKD mice models, including 14d unilateral ureteral obstruction (UUO), 28d ischemia/reperfusion (I/R) injury, and adenine-induced models were constructed to detect the expression levels of NETs in the kidneys. Then, we established a NETs-deficient (PAD4−/−) CKD mice model and assessed changes in renal function, NETs levels, and renal fibrosis. In vitro, phorbol-12-myristate-13-acetate (the classic inducer of NETs) was used to induce the generation of NETs. Intervention was performed on rat fibroblast NRK49F cells to investigate the mechanism of TIF induced by NETs. Results We first identified NETs levels were significantly elevated in the renal tissues of CKD patients. Additionally, chip data results also indicated elevated PAD4 levels in the renal tissues of CKD patients. NETs levels were elevated in the kidneys of UUO, I/R, and adenine-induced CKD mice, with deposition in the renal interstitium. PAD4-deficient mice did not form neutrophil extracellular traps. Knocking out PAD4 alleviated tubulointerstitial fibrosis in UUO, adenine, and I/R mice after blocking NETs formation. In vitro, NETs intervention in fibroblasts can promote their activation and transformation into myofibroblasts. Conclusion The deletion of NETs by PAD4−/− could significantly improve CKD-TIF. The inhibition of NETs might provide a new molecular target for the prevention and treatment of CKD.

Gut microbes regulate glomerular filtration rate in health and in a model of chronic kidney disease

Gut microbes have been implicated in varied physiological and pathophysiological processes. In this study, we hypothesized that gut microbes modulate glomerular filtration rate (GFR). Gut microbiota was depleted using a modified antibiotic (ABX) treatment protocol with a mixture of 1g/L ampicillin, 1g/L neomycin, and 0.5 g/L vancomycin (modified from Rakoff-Nahoum et al. 2004). C57BL/6J male and female mice (6-weeks-old) were treated with ABX in drinking water for five weeks. Bacteria reduction with ABX treatment was confirmed by qPCR of fecal samples using pan-bacterial primers (Ct value for Females, F: ctrl 13±0.18 vs ABX 21±0.41; Males, M: 13±0.11 vs ABX 20±0.44, n=8). GFR measurements were performed in conscious and unrestrained mice by transcutaneous detection of fluorescent FITC-sinistrin. The GFR was significantly increased in ABX-treated mice (F: ctrl 1190±14 vs ABX 1638±21, p=0.03; M: ctrl 1020±25 vs ABX 1381±29, p=0.005, n=8). To investigate if the increased GFR was due to the absence of gut microbiota, we measured GFR in germ-free (GF) mice (born and raised without gut microbes), conventional mice (Ctrl, born with gut microbes), and conventionalized GF mice (CGF, born without gut microbes but given a fecal slurry containing gut microbes by oral gavage). GFR was increased in GF mice (F: 1853±32, p=0.003; M: 1308±16, p=0.02) versus both conventional (F: 1217±17; M: 1087±18) and CGF (F: 1326±31, p=0.02; M: 1101±10, p=0.03, n=7-8). GFR was similar in Ctrl and CGF mice. To further investigate if ABX can increase GFR in chronic kidney disease (CKD) when GFR is impaired, GFR was measured in adenine-induced CKD. Adenine (in food pellets) and ABX (in drinking water) treatments were begun simultaneously; adenine decreased GFR in females at weeks 4 and 6, and in males at weeks 2, 4 and 6. In females, mice co-treated with ABX and adenine had increased GFR on week 4 (chow: 1298±11 vs adenine: 853±8, p<0.0001; adenine vs adenine+ABX: 1040±9, p=0.04) but not week 6 (chow: 1238±21 vs adenine: 618±9, p=0.0001; adenine vs adenine+ABX: 881±14, p=0.09, n=7-9). Of note, GFR exhibited no difference between chow vs adenine (data not shown) on week 2. In males, ABX increased GFR on week 2 (chow: 1116±31 vs adenine: 913±47, p=0.002; adenine vs adenine+ABX: 1150±49, p=0.0003) but not week 4 (chow: 1154±38 vs adenine: 732±58, p<0.0001; adenine vs adenine+ABX: 877±81, p=0.37) or 6 (chow: 1157±43 vs adenine: 513±51, p<0.0001; adenine vs adenine+ABX: 591±50, p=0.56, n=7-9). To explore the mechanism by which ABX increase GFR we tested the hypothesis that, in the absence of gut microbes, proximal tubular Na+ reabsorption increases, leading to a reduced Na+ delivery to the macula densa and altering tubuloglomerular feedback (TGF) to increase GFR. To test this, we used the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin (EMPA) to impair Na+ reabsorption and increase Na+ delivery to the macula densa. As seen previously, treatment with ABX increased GFR on week 3 (F: 1430±13, p=0.04; M:1341±9, p=0.01) and week 5 (F: 1857±21, p=0.002, M: 1443±10, p=0.0001) compared to before treatment (F: 1140±10, M: 1090±11, n=8-9). Co-treatment of EMPA and ABX impaired GFR increases on week 3 (F: 1281±18, p=0.9, M: 1201±11, p=0.9) but not week 5 (F: 1650±21, p=0.01; M: 1281±20, p=0.003) when comparing to before the treatment (F: 1199±15; M: 1109±8, n=8-9). In this study, both the absence (GF) and suppression (ABX) of gut microbes increased GFR in healthy females and males. Moreover, ABX partially restored GFR in adenine-induced CKD females and males. These data suggest that gut microbes influence GFR in both health and disease, and that the mechanism may partially involve TGF. AHA Career Development Award (JX) and NIDDK Diabetic Complications Consortium (RRID:SCR_001415m www.diacomp.org, grants DK076169 and DK 115255 (subaward to JLP)) and American Heart Association Established Investigator Award (to JLP). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Group2 innate lymphoid cells ameliorate renal fibrosis and dysfunction associated with adenine-induced CKD

Renal fibrosis is a common pathway of chronic kidney disease (CKD) progression involving primary kidney injury and kidney diseases. Group 2 innate lymphoid cells (ILC2s) mediate type 2 immune responses irrespective of antigen presentation and play a reno-protective role in kidney injury and disease. In the present study, we observed a decrease in kidney-resident ILC2s in CKD and found that enrichment of ILC2s in the kidney ameliorates renal fibrosis. In CKD kidney, ILC2s preferentially produced IL-13 over IL-5 in response to IL-33 stimulation, regardless of ST2L expression. Moreover, GATA3 expression was decreased in ILC2s, and T-bet+ ILC1s and RORγt+ ILC3s were increased in CKD kidney. Adoptive transfer of kidney ILC2s into adenine-induced CKD model mouse improved renal function and fibrosis. Renal fibroblasts cultured with IL33-activated kidney ILC2s suppressed myofibroblast trans-differentiation through Acta2 and Fn-1 regulation. These results suggest that kidney ILC2s prevent CKD progression via improvement of renal fibrosis. Our findings also suggest that ILC2s may contribute to the development of new therapeutic agents and strategies for tissue fibroses.

Exercise Pressor Reflex Function Is Exacerbated in Decerebrate Adenine-Induced Chronic Kidney Disease Rats

Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD). While the underlying mechanisms are not completely understood, elevated sympathetic nerve activity (SNA) and exercise intolerance are thought to play an important role. In normal physiological conditions, sympathetic modulation of the cardiovascular system during physical activity is largely governed by a peripheral neural reflex originating in contracting skeletal muscle, known as the exercise pressor reflex (EPR). Pioneering work by Park et al. demonstrated that CKD patients exhibited abnormal SNA and blood pressure (BP) elevations during both static and rhythmic handgrip exercise, suggesting an overactive EPR. However, due to experimental design constraints inherent to humans, the contribution of the EPR to the augmented SNA and BP responses to exercise could not be fully addressed. Therefore, the purpose of this study was to specifically test EPR function in CKD using a reduced animal model. Sprague-Dawley rats were randomly assigned to receive either a powdered chow diet containing adenine (0.25%w/w in feed) to induce CKD or a powdered chow diet alone (control group) for 12 weeks. Subsequently, in decerbrate animals, we measured mean arterial pressure (MAP) and renal SNA (RSNA) in response to isolated EPR activation during hindlimb muscle contraction (i.e., simulated exercise). We further assessed cardiovascular and sympathetic responses to passive muscle stretch to stimulate the mechanoreflex (i.e., activation of the mechanically-sesnsitive component of the EPR), and intra-arterial capsaicin administratration to activate the metaboflex (i.e., stimulation of the metabolically-sensitive component of the EPR). After completion of the diet, levels of plasma creatinine were significantly increased in adenine-fed rats compared to control rats (2.57±1.05 vs. 0.34±0.05 mg/dL, P<0.01), suggesting impaired renal function (i.e., adenine-induced CKD). We found that CKD animals exhibited augmentations in RSNA (Δ=153±75 vs. 61±50 %, P<0.05) and MAP (Δ=35±18 vs. 17±8 mmHg, P<0.05) in response to muscle contraction when compared to control animals. Importantly, the muscle tension developed during contraction was similar between the two groups (Δ=0.9±0.2 vs. 1.0±0.3 kg, P>0.1, CKD vs. control). During stimulation of the mechanoreflex, CKD rats also exhibited significantly greater RSNA (Δ=100±54 vs. 32±26 %, P<0.05) and MAP responses (Δ=25±14 vs. 10±7 mmHg, P<0.05) than control rats. The developed muscle tension during passive stretch was similar between the two groups (Δ=0.9±0.2 vs. 1.0±0.4 kg, P>0.1, CKD vs. control). There was a tendency for the responses to metaboreflex activation to be heightened in the CKD group compared with the control group, but the difference did not reach statistical significance (ΔRSNA=212±68 vs. 107±105 %, P=0.06, ΔMAP=67±12 vs. 48±21 mmHg, P=0.06, CKD vs. control, respectively). Our findings suggest that EPR function, particularly muscle mechanoreflex function, is exaggerated in CKD, leading to sympathetic activation and hypertensive responses during exercise. P30 DK079307 Subaward to H.K. and R01HL-133179 to W.V. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A Tryptophan-derived Uremic Metabolite-Ahr-Pdk4 Axis Promotes Skeletal Muscle Mitochondriopathy in Chronic Kidney Disease

Introduction: Chronic kidney disease (CKD) and the subsequent accumulation of tryptophan-derived uremic metabolites (UMs) in circulation negatively impact skeletal muscle (SkM) health and function. Specifically, indoles and kynurenines are strongly associated with SkM atrophy, weakness, and fatigue found in CKD patients. Notably, these tryptophan-derived UMs are known agonist to the ubiquitously expressed aryl hydrocarbon receptor (AHR), a ligand activated transcription factor, which has been shown to be activated in the blood of CKD patients and whose chronic activation has been proven toxic to multiple tissue types. Purpose: The purpose of this study was to determine whether chronic activation of the AHR by tryptophan-derived UMs contributes to CKD associated SkM atrophy and metabolic dysfunction. Methods: Muscle biopsies from CKD patients and adult controls with normal renal function were used to examine AHR signaling and mitochondrial function. The mechanistic role of the AHR was explored using SkM-specific AHR knockout mice (AHRmKO) and SkM-specific AHR knockdown via adeno-associated virus in mice with adenine-induced CKD, as well as ectopic expression of a constitutively active AHR (CAAHR) in mice with normal kidney function. Additional mechanistic experiments were carried out in cultured muscle cells. Outcome measures included gene and protein expression, mitochondrial bioenergetic testing, and robust muscle functional phenotyping. Results: Compared to controls with normal kidney function, AHR-dependent gene expression ( CYP1A1 and CYP1B1) was significantly upregulated in gastrocnemius SkM of CKD patients ( P=0.032) and the magnitude of AHR activation was inversely correlated with mitochondrial respiration ( P<0.001). In mice with CKD, SkM mitochondrial oxidative phosphorylation (OXPHOS) was significantly impaired and strongly correlated with both the level of tryptophan-derived UMs and AHR activation. AHRmKO significantly improved mitochondrial OXPHOS in mice with CKD (~28% increase, P=0.045) and abolished the relationship between UMs and OXPHOS. The uremic metabolite-AHR-mitochondrial axis in SkM was further confirmed using SkM-specific AHR knockdown in C57BL6J that express a high-affnity AHR allele, as well as ectopic viral expression of CAAHR in mice with normal renal function. AHR activation led to impairments in pyruvate dehydrogenase (PDH) enzyme function (~29% decrease, P<0.05), significant increases in Pdk4 expression ( P<0.05) and phosphorylation of PDH enzyme ( P<0.05), mechanistically contributing to impaired pyruvate-supported OXPHOS function. Conclusion: These findings establish a uremic metabolite-AHR-Pdk4 axis in SkM that governs mitochondrial deficits in CKD. Supported by grants from the National Institutes of Health R01-HL149704 (TER) and F31-DK128920 (TT). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Renoprotective effect of Nesfatin-1 in Adenine-Induced Chronic kidney Disease: An in vitro and in vivo study

Chronic Kidney Disease (CKD) presents a significant global health challenge with limited treatment options. Nesfatin-1, an anorexigenic peptide, has demonstrated antioxidant, anti-inflammatory, and anti-apoptotic properties in various diseases. However, the role of nesfatin-1 in CKD remains unclear. This study investigates the potential renoprotective effects of nesfatin-1 in adenine-induced CKD mice and in NRK-52E renal epithelial cells.Male C57BL/6J mice and NRK-52E renal epithelial cells were administered adenine to induce CKD. Various aspects of renal function, histopathology, oxidative stress, inflammation, apoptosis, and renal interstitial fibrosis were assessed and downstream pathways were investigated.Adenine-fed mice exhibited reduced nesfatin-1 expression and increased markers of kidney damage, including elevated blood urea nitrogen (BUN), serum creatinine, and histological abnormalities, reactive oxygen species (ROS), inflammation, apoptosis, and fibrosis. Treatment with nesfatin-1 in adenine induced mice significantly reversed these changes. Nesfatin-1 also lowered calcium levels and the expression of inflammatory markers, including IL-1β, IL-6, TNF-α, and Nf-kB. Furthermore, nesfatin-1 reduced the expression of apoptotic markers (Caspase-3, Caspase-1, Bax/Bcl2 ratio) and restored the balance of Bcl2 and MMP. Lastly, nesfatin-1 attenuated fibrotic markers (Tgf-β, Smad2/3,4, type IV collagen, α-SMA) in both adenine-induced CKD mice and NRK-52E cells.In conclusion, our results suggest that nesfatin-1 may enhance kidney function in adenine-induced CKD mice and NRK-52E cells. The renoprotective effects of nesfatin-1 are likely associated with its antioxidant, anti-inflammatory, anti-apoptotic, and anti-fibrotic properties.

Possible curative effect of venom collected from Algerian bees (Apis mellifera intermissa) on adenine-induced chronic kidney damage in mice

ABSTRACT Chronic kidney disease (CKD) is a world-wide health concern, and thus curative approach becomes highly valuable. Herein, we examined the possible therapeutic effect of bee venom collected from Algeria (Apis mellifera intermissa) on adenine-induced chronic kidney damage. Mice received intraperitoneal injection of adenine at a dose of 50 mg/kg for four weeks to induce CKD. After that, bee venom was administered intraperitoneally (i.p) to mice at a dose of 0.76 mg/kg BW for a week. Adenine-treated mice decreased the body weight evolution, and significantly increased the kidney weight, water intake, and urine output compared with controls. In addition, serum and urine urea and creatinine levels, and serum albumin concentrations were significantly increased, while serum creatinine clearance level was significantly decreased in adenine-treated mice compared with controls. Adenine-induced oxidative stress was evidenced by increased MDA content, and decreased catalase and GST activity, and GSH content in renal tissue. Meanwhile, the administration of bee venom to adenine-treated mice markedly recovered kidney function via improvement of the altered physiological and biochemical parameters. These were confirmed by the morphological and histopathological results. In conclusion, bee venom is a prising therapeutic natural agent for improving kidney function in adenine-induced CKD.

Clam Peptides Attenuated Adenine-Induced Chronic Kidney Disease by Improving Inflammation, Oxidative Stress, and Intestinal Flora Composition

Clam Peptides Attenuated Adenine-Induced Chronic Kidney Disease by Improving Inflammation, Oxidative Stress, and Intestinal Flora Composition

Inhibition of RANKL improves the skeletal phenotype of adenine-induced chronic kidney disease in mice.

Skeletal fragility and high fracture rates are common in CKD. A key component of bone loss in CKD with secondary hyperparathyroidism is high bone turnover and cortical bone deterioration through both cortical porosity and cortical thinning. We hypothesized that RANKL drives high bone resorption within cortical bone leading to the development of cortical porosity in CKD (study 1) and that systemic inhibition of RANKL would mitigate the skeletal phenotype of CKD (study 2). In study 1, we assessed the skeletal properties of male and female Dmp1-cre RANKLfl/fl (cKO) and control genotype (Ranklfl/fl; Con) mice after 10wk of adenine-induced CKD (AD; 0.2% dietary adenine). All AD mice regardless of sex or genotype had elevated blood urea nitrogen and high PTH. Con AD mice in both sexes had cortical porosity and lower cortical thickness as well as high osteoclast-covered trabecular surfaces and higher bone formation rate. cKO mice had preserved cortical bone microarchitecture despite high circulating PTH as well as no CKD-induced increases in osteoclasts. In study 2, male mice with established AD CKD were either given a single injection of an anti-RANKL antibody (5mg/kg) 8wk post-induction of CKD or subjected to 3×/wk dosing with risedronate (1.2μg/kg) for 4wk. Anti-RANKL treatment significantly reduced bone formation rate as well as osteoclast surfaces at both trabecular and cortical pore surfaces; risedronate treatment had little effect on these bone parameters. In conclusion, these studies demonstrate that bone-specific RANKL is critical for the development of high bone formation/high osteoclasts and cortical bone loss in CKD with high PTH. Additionally, systemic anti-RANKL ligand therapy in established CKD may help prevent the propagation of cortical bone loss via suppression of bone turnover.

A novel enzyme-based functional correlation algorithm for multi-omics reveals the potential mechanisms of traditional Chinese medicines: Taking Jian-Pi-Yi-Shen formula as an example

The integrated analysis of host metabolome and intestinal microbiome is an opportunity to explore the complex therapeutic mechanisms of traditional Chinese medicines. Currently, researchers mainly employ various statistical correlation analytical methods to investigate metabolome-microbiome correlations. However, these conventional correlation techniques often focus on statistical correlations and their biological meanings are always ignored, especially the functional relevance between them. Here, we developed a novel enzyme-based functional correlation (EBFC) algorithm to further improve the interpretability and the identified scope of microbe-metabolite correlations based on the conventional Spearman’s analysis. The proposed EBFC algorithm is successfully utilized to reveal the therapeutic mechanisms of Jian-Pi-Yi-Shen (JPYS) formula on the treatment of adenine-induced chronic kidney disease (CKD) rats. JPYS, a TCM formula for treating CKD, has beneficial clinical effects. We tentatively revealed the potential mechanism of JPYS for treating CKD rats from the perspective of the serum metabolome, gut microbiome, and their interactions. Specifically, 11 metabolites and 19 bacterial genera in the CKD rats were significantly regulated to approaching normal status after JPYS treatment, suggesting that JPYS could ameliorate the pathological symptoms of CKD rats by reshaping the disturbed metabolome and gut microbiota. Further correlation analysis between the significantly perturbed metabolites, microbiota, and the related enzymes provided more strong evidence for the study of host metabolism-microbiota interactions and the therapeutic mechanism of JPYS on CKD rats. In conclusion, these findings will help us to deeply understand the pathogenesis of CKD and provide new insights into the therapeutic mechanism of JPYS.

Effects of Waterpipe Smoke Exposure on Experimentally Induced Chronic Kidney Disease in Mice.

Tobacco smoking is an independent risk factor in the onset of kidney disease. To date, there have been no reports on the influence of waterpipe smoke (WPS) in experimentally induced chronic kidney disease (CKD) models. We studied the effects and mechanisms of actions of WPS on a mouse model of adenine-induced CKD. Mice fed either a normal diet, or an adenine-added diet and were exposed to either air or WPS (30 min/day and 5 days/week) for four consecutive weeks. Plasma creatinine, urea and indoxyl sulfate increased and creatinine clearance decreased in adenine + WPS versus either WPS or adenine + saline groups. The urinary concentrations of kidney injury molecule-1 and adiponectin and the activities of neutrophil gelatinase-associated lipocalin and N-acetyl-β-D-glucosaminidase were augmented in adenine + WPS compared with either adenine + air or WPS groups. In the kidney tissue, several markers of oxidative stress and inflammation were higher in adenine + WPS than in either adenine + air or WPS groups. Compared with the controls, WPS inhalation in mice with CKD increased DNA damage, and urinary concentration of 8-hydroxy-2-deoxyguanosine. Furthermore, the expressions of nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) were elevated in the kidneys of adenine + WPS group, compared with the controls. Likewise, the kidneys of adenine + WPS group revealed more marked histological tubular injury, chronic inflammation and interstitial fibrosis. In conclusion, WPS inhalation aggravates kidney injury, oxidative stress, inflammation, DNA damage and fibrosis in mice with adenine-induced CKD, indicating that WPS exposure intensifies CKD. These effects were associated with a mechanism involving NF-κB, ERK and p38 activations.

Huang Gan Formula Alleviates Systemic Inflammation and Uremia in Adenine-Induced Chronic Kidney Disease Rats May Associate with Modification of Gut Microbiota and Colonic Microenvironment.

This study aims to investigate the effects of Huang Gan formula (HGF), a Chinese herbal prescription used for chronic kidney disease (CKD), on the regulation of the gut microbiota and colonic microenvironment of CKD. CKD rats were induced by 150 mg/kg adenine gavage for 4 weeks, then orally treated with or without 3.6 g/kg or 7.2 g/kg of HGF for 8 weeks. The renal function and structure were analyzed by biochemical detection, hematoxylin and eosin, Masson's trichrome, Sirius red and immunochemical staining. Average fecal weight and number in the colon were recorded to assess colonic motility. Further, the changes in the gut microbiota and colonic microenvironment were evaluated by 16S rRNA sequencing, RT-PCR or immunofluorescence. The levels of inflammatory cytokines, uremic toxins, and NF-κB signaling pathway were detected by RT-PCR, ELISA, chloramine-T method or Western blotting. Redundancy analysis biplot and Spearman's rank correlation coefficient were used for correlation analysis. HGF significantly improved renal function and pathological injuries of CKD. HGF could improve gut microbial dysbiosis, protect colonic barrier and promote motility of colonic lumens. Further, HGF inhibited systemic inflammation through a reduction of TNF-α, IL-6, IL-1β, TGF-β1, and a suppression of NF-κB signaling pathway. The serum levels of the selected uremic toxins were also reduced by HGF treatment. Spearman correlation analysis suggested that high-dose HGF inhibited the overgrowth of bacteria that were positively correlated with inflammatory factors (eg, TNF-α) and uremic toxins (eg, indoxyl sulfate), whereas it promoted the proliferation of bacteria belonging to beneficial microbial groups and was positively correlated with the level of IL-10. Our results suggest that HGF can improve adenine-induced CKD via suppressing systemic inflammation and uremia, which may associate with the regulations of the gut microbiota and colonic microenvironment.

Downregulation of PDZK1 by TGF-β1 promotes renal fibrosis via inducing epithelial-mesenchymal transition of renal tubular cells

Transforming growth factor-beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) of renal tubular cells promotes renal fibrosis and the progression of chronic kidney disease (CKD). PDZ domain-containing 1 (PDZK1) is highly expressed in renal tubular epithelial cells; however, its role in TGF-β1-induced EMT remains poorly understood. The present study showed that PDZK1 expression was extremely downregulated in fibrotic mouse kidneys and its negative correlation with TGF-β1 expression and the degree of renal fibrosis. In addition, TGF-β1 downregulated the mRNA expression of PDZK1 in a time- and concentration-dependent manner in vitro. The downregulation of PDZK1 exacerbated TGF-β1-induced EMT upon oxidative stress, while the overexpression of PDZK1 had the converse effect. Subsequent investigations demonstrated that TGF-β1 downregulated PDZK1 expression via p38 MAPK or PI3K/AKT signaling in vitro, but independently of ERK/JNK MAPK signaling. Meanwhile, inhibition of the p38/JNK MAPK or PI3K/AKT signaling using chemical inhibitors restored the PDZK1 expression, mitigated renal fibrosis, and elevated renal levels of endogenous antioxidants carnitine and ergothioneine in adenine-induced CKD mice. These findings provide the first evidence suggesting a negative correlation between PDZK1 and renal fibrosis, and identifying PDZK1 as a novel suppressor of renal fibrosis in CKD through ameliorating oxidant stress.

Biomechanical and histomorphological analysis of the mandible in rats with chronic kidney disease

The present study aimed to investigate the biomechanical and histomorphological features of mandibles in an adenine-induced chronic kidney disease–mineral and bone disorder (CKD-MBD) rat model of CKD. A total of 14 Sprague-Dawley rats were randomized into the following two groups: control group and CKD group. At the end of the sixth week, all rats were euthanized, and serum was collected for biochemical marker tests. Macroscopic bone growth and biomechanical parameters were measured in the right hemimandible, while the left hemimandible was used for bone histomorphometric analysis. Compared to the control group, the CKD group showed a significant increase in serum creatinine, blood urea nitrogen, and serum parathyroid hormone at the end of the sixth week. The biomechanical structural properties significantly decreased in the CKD group compared to the control group. Bone histomorphometric analysis indicated that the trabecular bone volume of rats in the CKD group was significantly lower than that of the control group. In the CKD groups, the bone formation parameters of the trabecular bone were significantly increased, while the bone mineralization apposition rates of both the trabecular bone and periosteal cortical bone were significantly increased. The rat CKD model showed deteriorated structural mechanics, low trabecular bone volume, high trabecular bone formation, increased trabecular bone mineralization apposition rate, and increased cortical bone mineralization apposition rate, which met the characteristics of osteitis fibrosa, indicating that this model is a useful tool for the study of mandible diseases in CKD patients.

The Effect of Sildenafil on Adenine-Induced Chronic Kidney Disease in Mice

This study was done to find the potential renal protective effects of sildenafil and its underlying mechanisms in mice with adenine-induced CKD. For the experiment, 40 male mice were split into four groups. The control group (A) received the same food without medication until the research ends, while the other three collections (B, C, and D) were given adenine (0.25% w/w in feed daily for 8 weeks), groups (C and D) were given sildenafil (0.5 and 2.5 mg/kg) respectively orally every day for 30 days, and then blood samples were taken to assess the function of the kidneys (Urea, total protein, and creatinine), total antioxidant capacity (TAC), superoxide dismutase (SOD), and catalase (CAT) in addition to kidney histopathology, as well as body and kidney weight. Administration of adenine caused weight loss, increased TAC, SOD, and CAT, and increased plasma concentrations of urea, total protein, and creatinine. Damage-related renal histopathological indicators (fibrosis and inflammation) were considerably elevated by adenine. Most of the aforementioned metrics improved with sildenafil, indicating that it might be utilized as an adjuvant treatment for CKD in people through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms.

Effects of cerium oxide nanoparticles on adenine-induced chronic kidney disease model rats.

Cerium oxide, particularly in nanoparticle form (nanoceria), has been investigated for biomedical applications as a promising new agent for treating several pathologies. The aim of the present study was to characterize the pharmacologic effects of nanoceria in an animal model of chronic kidney disease. We created the chronic kidney disease animal model by feeding rats a 0.25% adenine diet. Male Wistar rats were divided into five groups: normal diet, 0.25% adenine diet, or adenine diet containing three different doses or durations of nanoceria treatment. Blood was collected weekly from the tail veins of each rat and analyzed for renal function markers. After 5 weeks, various biochemical markers in serum, plasma, and urine were also analyzed. In the adenine-treated group, body weight was significantly decreased, and the kidneys lost much of their healthy reddish color and became lumpy and white in appearance. In addition, levels of serum creatinine, blood urea nitrogen, and plasma uremic toxins were significantly increased in adenine-treated rats compared with controls. Renal functional and structural damage in adenine diet model rats tended to be ameliorated by nanoceria ingestion. The high-dose cerium-treated group maintained reddish areas in the kidneys, and the increases in biomarker levels of creatinine, blood urea nitrogen, and inorganic phosphorus were markedly reduced, regardless of treatment duration. Ingestion of nanoceria may be effective for improving or preventing renal damage caused by adenine. Geriatr Gerontol Int 2024; 24: 88-95.

Huangqi-Danshen decoction protects against cisplatin-induced acute kidney injury in mice.

Background: Acute kidney injury (AKI) induced by cisplatin remains a major impediment to the clinical application of cisplatin, necessitating urgent exploration for promising solutions. Huangqi-Danshen decoction (HDD), a Chinese herbal preparation, has been shown by our group to have a reno-protective effect in adenine-induced chronic kidney disease mice and diabetic db/db mice. However, the effect of HDD on cisplatin-induced AKI and its underlying mechanisms are unknown. Methods: The AKI model was established by intraperitoneal injection of cisplatin (20mg/kg) in C57BL/6 mice. The mice in the treatment group were administrated with HDD (6.8g/kg/d) for 5 consecutive days before cisplatin challenge. After 72h cisplatin injection, blood and kidney tissue were subsequently collected for biochemical detection, histopathological evaluation, Western blot analysis, immunohistochemical staining, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling assay. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to detect changes in renal metabolites. Results: The results showed that HDD significantly reduced serum creatinine and blood urea nitrogen levels and alleviated renal histopathological injury in cisplatin-induced AKI mice. And HDD treatment demonstrated a significant inhibition in apoptosis, inflammation, and oxidative stress in AKI mice. Moreover, non-target metabolomics revealed that HDD significantly restored 165 altered metabolites in AKI mice. Subsequent enrichment analysis and pathway analysis of these metabolites indicated that nicotinate and nicotinamide metabolism was the primary pathway affected by HDD intervention. Further investigation showed that HDD could upregulate nicotinamide adenine dinucleotide (NAD+) biosynthesis-related enzymes quinolinate phosphoribosyltransferase, nicotinamide mononucleotide adenylyltransferase 1, and nicotinamide phosphoribosyltransferase to replenish NAD+ content in the kidney of AKI mice. Conclusion: In summary, HDD exerted a protective effect against cisplatin-induced AKI and suppressed apoptosis, inflammation, and oxidative stress in the kidney of AKI mice, which may be attributed to the modulation of NAD+ biosynthesis.

Renoprotective Effects of Solid-State Cultivated Antrodia cinnamomea in Juvenile Rats with Chronic Kidney Disease.

Antrodia cinnamomea (AC), a medicinal mushroom, has multiple beneficial actions, such as acting as a prebiotic. The incidence of chronic kidney disease (CKD) in children has steadily increased year by year, and CKD is related to gut microbiota dysbiosis. Herein, we investigated the renoprotection of solid-state cultivated AC in adenine-induced CKD juvenile rats. CKD was induced in 3-week-old male rats by feeding with adenine (0.5%) for three weeks. Treated groups received oral administration of AC extracts at either a low (10 mg/kg/day) or high dose (100 mg/kg/day) for six weeks. At nine weeks of age, the rats were sacrificed. Renal outcomes, blood pressure, and gut microbiome composition were examined. Our results revealed that AC treatment, either low- or high-dose, improved kidney function, proteinuria, and hypertension in CKD rats. Low-dose AC treatment increased plasma concentrations of short-chain fatty acids (SCFAs). Additionally, we observed that AC acts like a prebiotic by enriching beneficial bacteria in the gut, such as Akkermansia and Turicibacter. Moreover, the beneficial action of AC against CKD-related hypertension might also be linked to the inhibition of the renin-angiotensin system. This study brings new insights into the potential application of AC as a prebiotic dietary supplement in the prevention and treatment of pediatric CKD.