Kidney Hypertrophy Research Articles

In ovo toxico-pathological effects of medicinal plants used against coccidiosis on chicken embryos development and hatchability

TOXICO-pathological effects of herbal plants have always been a major concern, but little information is provided on the toxico-pathological effects of medicinal plants used against coccidiosis. This study aimed to assess the histopathological effects of Carica papaya seeds (CPS), Azadirachta indica leaves (AIL), and Sarcocephalus latifolius root (SLR) used as coccidiostat in traditional poultry farms with various doses using the chick embryo model. A total of 420 Sasso breeder eggs at ED4 of incubation were inoculated with the extract of these plants following a 3×4 factorial design with 3 plant extracts (CPS, AIL and SLR) and 4 inoculation doses (0, 25, 50 and 100 mg/kg egg-weight). From ED6 to ED19, the weights of the albumen and embryo were recorded, and the weights of ED19 embryo organs such as liver, heart, kidney, and lungs were measured. Additionally, histopathological lesions were examined. The results indicated that the presence of various phytoconstituents such as alkaloids, phenolics, flavonoids, tannins, saponins, coumarins, steroids, and triterpenes with statistically significant free-radical-scavenging ability differed among the plant extracts (p < 0.0001). Toxico-pathological examination revealed a dose-dependent slight toxicity (p < 0.0001) of the Azadirachta indica leaves extract compared to the other plants. Additionally, the relative organ weight showed kidney hypertrophy (p = 0.001) and liver hypertrophy (p = 0.0001), as well as dilation of hepatic and cardiac vessels. The conclusion drawn was that chicken embryos are more susceptible to in ovo inoculation with Azadirachta indica leaves compared to Carica papaya seeds and Sarcocephalus latifolius root.

Dietary protein intake and the tubular handling of indoxyl sulfate.

Chronic kidney disease (CKD) patients are advised to limit their protein intake. A high protein diet is known to induce glomerular hyperfiltration, as well as hypertrophy of the remnant kidney, and glomerulosclerosis. Whether the diet causes changes in kidney tubule transport via gut microbiome metabolites is still unknown. We hypothesized that protein intake affects not only the intestinal generation and absorption, but also the kidney disposal of microbial amino acid metabolites. We combined data from animal models and human studies. 5/6th nephrectomy rats were administered a high (HP) or low-protein (LP) diet for 7 weeks. Plasma and urine concentration of the uremic toxins (UTs) indoxyl sulfate (IS), p-cresyl sulfate (PCS), and p-cresyl glucuronide (PCG) were measured. Their fractional excretion (FE) was calculated. The expression of kidney membrane transporters OAT1, OAT3, BCRP, OCT2 and MRP4 was analyzed. Differences in FE of UTs between individuals with higher and lower protein intake in two CKD cohorts were sought. CKD rats on an HP diet showed increased plasma levels of PCS and PCG but not IS compared to rats on a LP diet. Conversely, urinary excretion and FE of IS were higher in the HP CKD group. BCRP, MRP4 and OCT2 were not influenced by the diet. OAT1 and OAT3 were upregulated in the HP CKD group. In two independent cohorts of CKD patients, individuals with a high dietary protein intake showed a significantly higher FE of IS. A HP diet leads to a higher generation and/or absorption of aminoacid-derived UT precursors in CKD rodent models and humans, most likely via gut microbiome modulation. We demonstrate that dietary protein intake modulates transcription and expression of OAT1 and OAT3, corroborating the existence of the remote sensing and signaling hypothesis. Dietary protein intake influences kidney physiology beyond glomerular filtration.

Immune Cells in Compensatory Kidney Hypertrophy after Unilateral Nephrectomy

Immune Cells in Compensatory Kidney Hypertrophy after Unilateral Nephrectomy

Relationship between New-Onset Proteinuria and Remnant Kidney Hypertrophy and/or Pre-donated Kidney Volumes

Relationship between New-Onset Proteinuria and Remnant Kidney Hypertrophy and/or Pre-donated Kidney Volumes

Repurposing Niclosamide to Modulate Renal RNA-Binding Protein HuR for the Treatment of Diabetic Nephropathy in db/db Mice.

Hu antigen R (HuR) plays a key role in regulating genes critical to the pathogenesis of diabetic nephropathy (DN). This study investigates the therapeutic potential of niclosamide (NCS) as an HuR inhibitor in DN. Uninephrectomized mice were assigned to four groups: normal control; untreated db/db mice terminated at 14 and 22 weeks, respectively; and db/db mice treated with NCS (20 mg/kg daily via i.p.) from weeks 18 to 22. Increased HuR expression was observed in diabetic kidneys from db/db mice, which was mitigated by NCS treatment. Untreated db/db mice exhibited obesity, progressive hyperglycemia, albuminuria, kidney hypertrophy and glomerular mesangial matrix expansion, increased renal production of fibronectin and a-smooth muscle actin, and decreased glomerular WT-1+-podocytes and nephrin expression. NCS treatment did not affect mouse body weight, but reduced blood glucose and HbA1c levels and halted the DN progression observed in untreated db/db mice. Renal production of inflammatory and oxidative stress markers (NF-κBp65, TNF-a, MCP-1) and urine MDA levels increased during disease progression in db/db mice but were halted by NCS treatment. Additionally, the Wnt1-signaling-pathway downstream factor, Wisp1, was identified as a key downstream mediator of HuR-dependent action and found to be markedly increased in db/db mouse kidneys, which was normalized by NCS treatment. These findings suggest that inhibition of HuR with NCS is therapeutic for DN by improving hyperglycemia, renal inflammation, and oxidative stress. The reduction in renal Wisp1 expression also contributes to its renoprotective effects. This study supports the potential of repurposing HuR inhibitors as a novel therapy for DN.

Abstract P144: Estrogen Worsens Kidney Function in Hypertensive Menopausal Rats

Introduction: Before menopause, women generally have lower rates of hypertension and cardiovascular events compared with men. After menopause, women lose significant cardiovascular and renal protection. Estrogen's effect on kidney function is controversial, with some studies showing protection and others, including ours, indicating long-term estrogen exposure causes renal damage. The relationship between estrogen, hypertension, and kidney function is still not fully understood. Aim: Our aim was to investigate the interaction between hypertension and menopause on kidney function and determine whether the timing of disease initiation, pre- or post-menopause, influences these effects. Methods: Female Long-Evans rats were ovariectomized at 46 weeks of age to simulate menopause and treated with estradiol (E2) or vehicle. Some groups were infused with angiotensin II (Ang; 700ng/kg/min), either 4 weeks before or at the time of ovariectomy. Blood pressure (BP), proteinuria, creatinine clearance, osmolality, glomerular (GLOM) area, GLOM collagen deposition, and GPER and ERα receptor by droplet digital PCR were assessed by two-way ANOVA. Results: BP was higher with Ang (P=0.003) but was not affected by E2 (P=0.85) or timing (P=0.49). E2 significantly increased kidney hypertrophy (P&lt;0.001) independent of Ang (P=0.27), especially when hypertension was initiated at the time of menopause (P&lt;0.001). Both E2 and Ang increased water intake and urine output (P&lt;0.05), especially when hypertension was initiated at the time of menopause. Proteinuria, an indicator of renal damage, was significantly higher with E2 (P=0.03), Ang increased GLOM area (P&lt;0.05) with no effect of E2. There was no change in the urinary osmolality due to either Ang or E2. GLOM collagen deposition was not different between groups. In the renal cortex, E2 decreased ERα mRNA (P&lt;0.01), with no difference in GPER. Conclusion: Although E2 did not affect blood pressure, it worsened the impact of hypertension on kidney function, particularly when started at the time of ovariectomy. This may be due to decreased ERα in the cortex and likely unrelated to damage in the glomerulus. Keywords: Menopause, hypertension, renal damage

Renal Protective Effect of Boeravinone B against Diabetic Nephropathy Rats via Inhibition of The Inflammatory and JAK2/STAT3 Signalling Pathway.

Chronic inflammation is a common feature in diabetes, especially when blood sugar levels are poorly controlled. This chronic low-grade inflammation can affect various organs, including the kidneys. Podocyte damage play a key role in the development of diabetic nephropathy (DN). The aim of the study was to evaluate the nephroprotective effect of Boeravinone B (BB) against streptozotocin (STZ) induced DN in rats and explore the underlying mechanism. In this experimental study, the rats received intraperitoneal injections of STZ (60 mg/kg) to induce DN. Various doses of BB (2.5, 5, and 7.5 mg/kg) were administered orally. Glucose levels, body weights, and organ weights (hepatic and renal) were assessed. Renal, histomorphological, antioxidant, hepatic, and cytokine levels were determined, as were the mRNA expression levels of JAK2 and STAT3. At end of the experimental study, the rats were sacrificed and their renal tissues were removed for histopathological assessment. BB treatment decreased glucose levels and increased body weights. This treatment suppressed hepatic weights, increased renal tissue weights, and also decreased renal parameters like uric acid, urea, bilirubin, creatinine (Cr) and, albumin. There was a decrease (P<0.001) in histomorphological parameters such as kidney hypertrophy index (KHI), mean glomerular volume (MGV), foot process fusion ratio (FPFR), and glomerular basement membrane thickness (GBMT) after treatment with BB. In addition, this treatment improved the levels of renal podocin, renal CD2- associated protein (CD2AP) and suppressed hepatic parameter levels. BB treatment (P<0.001) altered antioxidant parameters and cytokine levels, and suppressed mRNA expressions of JAK2, STAT3, RAGE, KIM-1, NAGL, and S100A8. Administration of BB showed renal protective effects against STZ-induced DN in rats via the reduction of oxidative stress and inflammatory reactions.

#2592 Tubular cell polyploidy is involved in kidney compensatory hypertrophy

Abstract Background and Aims Chronic kidney disease (CKD) affects more than 10% of the population and it is associated with high risk of death for cardiovascular causes or progression towards end stage kidney disease (ESKD) requiring dialysis or kidney transplantation. CKD is characterized by progressive loss of nephrons, with consequent structural degeneration and fibrosis. Nephron number is established during prenatal kidney development and cannot increase. Consequently, following a reduction in kidney mass or in condition of altered metabolic demands, the remaining nephrons undergo compensatory hypertrophy. Compensatory hypertrophy results in increased functional output and has been observed in the absence of direct tissue injury after nephrectomy. Recently, we have identified a previously unknown mechanism of cellular adaptation: polyploidization of tubular epithelial cells (TC), and demonstrated that this is the essential mediator of kidney hypertrophy after acute kidney injury (AKI). Here, we hypothesize that TC polyploidy is involved in compensatory hypertrophy following nephrectomy. Method Polyploid TC are characterized by an increased DNA content in the absence of cell division. To discriminate polyploid cells from actively proliferating cells, we employed a series of in vitro and in vivo transgenic models based on the Fluorescence Ubiquitin Cell Cycle Indicator (FUCCI2aR) technology. Nephrectomy was performed by removing the left kidney and mice were sacrificed at different days after uni- Nephrectomy (Nfx). Cytofluorimetric techniques were employed to characterize a subpopulation of polyploid TC and histology investigation was employed analyze fibrosis development. These results were further corroborated by single cell RNA-sequencing (scRNA-seq) analyses in vitro and in vivo. Results Employing mice that express the FUCCI2aR reported under the Pax8 promoter (which marks all TC), we found that TC polyploidy increases immediately after uni-Nfx. This was accompanied by an increased kidney to body mass ratio with a maximum peaks 3 days afterwards. Importantly, after uni-Nfx, YAP1 expression and nuclei localization (i.e., implying pathway activation) was exponentially increased, suggesting that the same mechanism that drives TC polyploidy after AKI controls TC polyploidization response after uni-Nfx. However, unlike in AKI, polyploidy after nephrectomy was not accompanied by structural alterations as shown by PAS and Masson's trichrome staining. Conversely, after uni-Nfx YAP1 knock-out mice, that are unable to undergo rapid polyploidization, displayed an impaired kidney function in the long term, characterized by extensive tubular dilations. Conclusion Polyploidization of TC mediates compensatory hypertrophy following nephrectomy via YAP1 activation

Shellac and locust bean gum coacervated curcumin, epigallocatechin gallate nanoparticle ameliorates diabetic nephropathy in a streptozotocin-induced mouse model

Curcumin and epigallocatechin gallate have the disadvantage of low aqueous solubility and first-pass metabolism, resulting in limited bioavailability. This work aimed to enhance oral bioavailability by forming gastric pH-stable shellac nanoparticles containing curcumin and epigallocatechin gallate using locust bean gum by anti-solvent precipitation (CESL-NP). The nanoparticles were characterized by their particle size, morphology, zeta potential, gastric pH stability, release profile, drug loading, and entrapment efficiency. The findings showed that a network of hydrolyzed shellac, locust bean gum, curcumin, and epigallocatechin gallate successfully entrapped individual particles inside a complex system. The morphological investigation of the CESL-NP formulation using FESEM, TEM, and AFM revealed the presence of spherical particles. FTIR, DSC, and XRD analysis revealed that curcumin and epigallocatechin gallate were amorphous due to their bond interactions with the matrix. Streptozotocin-treated mice, upon treatment with CESL-NP, showed kidney and pancreatic improvements with normalized kidney hypertrophy index and histopathology, maintained biochemical parameters, increased beta cell count, and a 38.68-fold higher blood glucose level inhibition were observed when compared to free-(CUR + EGCG). This research affirms that the shellac-locust bean gum complex shows potential for the sustained oral delivery of curcumin and epigallocatechin gallate, specifically for treating diabetic nephropathy.

Effect of SGLT2 and dual SGLT1/2 Inhibition on the Development of Salt-induced Hypertension

In recent years, sodium-glucose co-transporter inhibitors (SGLT2i) have become the new mainstay in treating diabetes mellitus and, lately, cardiovascular diseases. Large clinical trials have shown remarkable benefits of SGLT2i on renal and cardiovascular outcomes. SGLT2i have been reported to slow the progression of chronic kidney disease by reducing hyperfiltration and glomerular capillary pressure, kidney hypertrophy, and albuminuria. Recently, the dual SGLT1/2 inhibitor sotagliflozin (Sota) was approved by the FDA for the treatment of heart failure independent of ejection fraction. However, despite these promising outcomes, the effects of SGLTi, particularly in salt-sensitive hypertension, requires further investigation. The main goal of this study was to define the effects of SGLT inhibition on the development of salt-induced hypertension and characterize potential contributing mechanisms. In our recent studies, we showed that SGLTi dapagliflozin (Dapa) caused an increase of diuresis in 8-weeks old male and female Dahl SS rats when fed a high salt (HS, 4% NaCl for 3 weeks) diet. Additionally, Dapa increased glucose and Na+ excretion. Chronic Dapa treatment also resulted in inhibition of the development of hypertension. Interestingly, male rats had no changes in kidney damage, whereas in females Dapa attenuated kidney fibrosis. To define potential molecular mechanisms involved in the beneficial effects of SGLT2i, we performed additional analyses of tissues collected from SS rats on a HS diet treated with either vehicle or Dapa. Transcriptomics analyses revealed that in the kidney cortex, top biological functions affected by SGLT2 inhibition were related to lipid and amino acid metabolism, molecular transport, as well as cell function. Preliminary studies were performed to test lipid mediators in the kidney cortex of male Dahl SS rats fed 3 weeks with HS diet and treated with Dapa. We found that several tested bioactive lipids, specifically pro-inflammatory mediators, were elevated in Dahl SS rats following HS diet, and these increased levels were completely blocked in Dapa-treated rats. Dual SGLT1/2 inhibition by Sota (30 mg/kg/day in food, n=6 rats/group) resulted in rapid attenuation of salt-induced hypertension. Starting from day 5 of HS challenge, MAP of vehicle-treated Dahl SS male rats was significantly higher compared to Sota-treated rats (~33 mmHg MAP difference on day 21), whichout differences in heart rate. In response to Sota treatment, SS rats had ~1.6-fold greater diuresis (at day 21: vehicle 37±2 vs. treated 61±6 ml/day) and glucosuria (values?). Further studies are ongoing to define the effects on GFR, kidney, and heart damage, and the potential resulting mechanisms. Our preliminary data indicate that dual SGLT1/2 inhibition with Sota had a significant impact on salt-induced hypertension in the Dahl SS rats. Further research will provide a more comprehensive understanding of the mechanisms. This research was supported by National Institutes of Health grant R35 HL135749 (to AS). 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.

Methanolic extract of Merremia emarginata (Burm. f.) Hallier f. attenuates renal damage in streptozotocin-induced diabetic nephropathy in rats

IntroductionMerremia emarginata (syn: Ipomoea reniformis) is used by the traditional healers of the Tirunelveli district of Tamil Nadu and Nelliampathy hills of Kerala for the treatment of diabetes. It contains important phytoconstituents like scopoletin, quercetin, and kaempferol and is reported to have pharmacological activities like antidiabetic antioxidant, antihyperlipidemic, ACE inhibitory, and hypotensive. Diabetic kidney disease is a common microvascular complication seen in patients with long-term diabetes. This study aimed to investigate the efficacy of Merremia emarginata in attenuating diabetic kidney disease. Materials and methodsDiabetes was induced by a single i.p. injection of 55 mg/kg streptozotocin (STZ). The animals were divided into seven groups with six rats in the control group and seven each in the STZ, STZ + Standard drug Ramipril (STD), STZ + Low dose (LD) methanolic extract of Merremia emarginata (MEME), STZ + High dose (HD) MEME, STZ + STD + LD, and STZ + STD + HD groups. The renal function was assessed by estimating various parameters viz, blood glucose, serum and urine creatinine, urine albumin, blood urea nitrogen (BUN), glycosylated haemoglobin (HbA1c) levels, oxidative stress, and kidney hypertrophy. ResultsTreatment with Ramipril and HD MEME showed a decrease in blood glucose levels, urine albumin, a decrease in serum creatinine, an increase in urine creatinine, a decrease in BUN, HbA1c, kidney hypertrophy, and oxidative stress. The combination treatment of Ramipril and HD MEME showed a synergistic effect. ConclusionThe study revealed that MEME attenuates diabetic nephropathy and has the potential to be used in diabetic nephropathy either alone or as an adjuvant.

Renal ischemia and reperfusion impact the purinergic signaling in a vascular bed distant from the injured site

AimsAcute kidney injury (AKI) is a public health problem and represents a risk factor for cardiovascular diseases (CVD) and vascular damage. This study aimed to investigate the impact of AKI on purinergic components in mice aorta. Main methods: The kidney ischemia was achieved by the occlusion of the left kidney pedicle for 60 min, followed by reperfusion for 8 (IR8) and 15 (IR15) days. Renal function was assessed through biochemical assays, while gene expression levels were evaluated by RT-qPCR. Key findings: Analyses of renal parameters showed renal remodeling through mass loss in the left kidney and hypertrophy of the right kidney in the IR15 group. Furthermore, after 15 days, local inflammation was evidenced in the aorta. Moreover, the aorta purinergic components were significantly impacted by the renal ischemia and reperfusion model, with increases in gene expression of the pro-inflammatory purinoceptors P2Y1, P2Y2, P2Y6, and P2X4, potentially contributing to the vessel inflammation. The expression of NTPDase2 and ecto-5′-nucleotidase were also significantly increased in the aorta of the same group. In addition, both ATP and AMP hydrolysis were significantly increased in the aorta from IR15 animals, driving the entire purinergic cascade to the production of the anti-inflammatory adenosine. Significance: In short, this is the first time that inflammation of the aorta due to AKI was shown to have an impact on purinergic signaling components, with emphasis on the adenosinergic pathway. This seems to be closely implicated in the establishment of vascular inflammation in this model of AKI and deserves to be further investigated.

Establishment of a novel mouse model of renal artery coiling-based chronic hypoperfusion-related kidney injury

Renal artery stenosis-induced chronic renal ischemia is an important cause of renal dysfunction, especially in older adults, and its incidence is currently increasing. To elucidate the mechanisms underlying chronic renal hypoperfusion-induced kidney damage, we developed a novel mouse model of renal artery coiling-based chronic hypoperfusion-related kidney injury. This model exhibits decreased renal blood flow and function, atrophy, and parenchymal injury in the coiled kidney, along with compensatory hypertrophy in the non-coiled kidney, without chronic hypertension. The availability of this mouse model, which can develop renal ischemia without genetic modification, will enhance kidney disease research by serving as a new tool to investigate the effects of acquired factors (e.g., obesity and aging) and genetic factors on renal artery stenosis-related renal parenchymal damage.

Endogenous adenine mediates kidney injury in diabetic models and predicts diabetic kidney disease in patients.

Diabetic kidney disease (DKD) can lead to end-stage kidney disease (ESKD) and mortality; however, few mechanistic biomarkers are available for high-risk patients, especially those without macroalbuminuria. Urine from participants with diabetes from the Chronic Renal Insufficiency Cohort (CRIC) study, the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes (SMART2D), and the American Indian Study determined whether urine adenine/creatinine ratio (UAdCR) could be a mechanistic biomarker for ESKD. ESKD and mortality were associated with the highest UAdCR tertile in the CRIC study and SMART2D. ESKD was associated with the highest UAdCR tertile in patients without macroalbuminuria in the CRIC study, SMART2D, and the American Indian study. Empagliflozin lowered UAdCR in nonmacroalbuminuric participants. Spatial metabolomics localized adenine to kidney pathology, and single-cell transcriptomics identified ribonucleoprotein biogenesis as a top pathway in proximal tubules of patients without macroalbuminuria, implicating mTOR. Adenine stimulated matrix in tubular cells via mTOR and stimulated mTOR in mouse kidneys. A specific inhibitor of adenine production was found to reduce kidney hypertrophy and kidney injury in diabetic mice. We propose that endogenous adenine may be a causative factor in DKD.

OR35-02 Novel Androgen Receptor PROTAC Degrader ARV-110 Ameliorates Androgen Mediated Renal Injury in a Mouse Model of Polycystic Ovary Syndrome

Abstract Disclosure: J. Basnet: None. S. Rezq: None. A.M. Huffman: None. T.E. Asala: None. L.L. Yanes Cardozo: None. D.G. Romero: None. Background: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women. PCOS women often have increased central adiposity, insulin resistance, and renal injury. Hyperandrogenism is prevalent in PCOS women and is associated with renal injury and dysfunction. Androgens bind to the androgen receptor (AR) to impart downstream transcriptional activity. Targeting the AR may alleviate PCOS complications; however, the use of AR blockers is limited by their severe adverse effects in females; thus, safer alternative approaches are highly needed. The novel AR Proteolysis Targeting Chimera (PROTAC) degrader ARV-110 has shown high efficacy to prevent AR signaling in prostate cancer; however, its efficacy in PCOS is unknown. Using a well-established hyperandrogenemic mouse model of PCOS, we aim to test the hypothesis that decreasing AR protein levels with ARV-110 ameliorates androgen-mediated derangements in PCOS. Methods: Three-week old female mice (C57BL/6N) were implanted with Silastic tubes filled with the androgen dihydrotestosterone (DHT, 8mg, s.c., 90 days) or vehicle (n=6/grp). Four weeks post-DHT administration, mice were treated with ARV-110 (1 mg/kg/day, s.c.) for an additional 8 weeks. Body composition (EchoMRI) and oral glucose tolerance test (OGTT) were assessed. Kidney weight was measured by gravimetry. AR, extracellular matrix (ECM) remodeling marker MMP9, pro-fibrotic marker TGF-β, renal injury markers (urinary albumin to creatinine ration (UACR), KIM1, and NGAL) were assessed by Western-blot or ELISA. Results: DHT mice showed significant (p&amp;lt;0.05) increases in body weight (27.3±0.6 vs 23.9±0.26 g), fat mass (4.2±0.6 vs 2.1±0.1 g), lean mass (21.6±0.2 vs 19.8±0.2 g), as well as kidney weight (491.3±7.69 vs 303.1±5.5 mg) compared to controls. DHT increased fasting glucose (183.2±25.2 vs 141.5±9.9 mg/dL, p&amp;lt;0.05) and impaired OGTT (AUC:34557±6255 vs 23459±1896 mg.min/dL, p&amp;lt;0.05). ARV-110 treatment ameliorated all aforementioned DHT-mediated changes. At the molecular level, DHT-treated mice had higher renal AR (2.5-fold) and MMP9 (1.5-fold) protein expression. DHT upregulated renal TGF-β levels (2-fold, p&amp;lt;0.05), UACR (966.8±160.9 vs 381.5±41.2 ng albumin/mg creatinine), and urinary KIM1 (3.5-fold) and NGAL (6-fold). ARV-110 successfully decreased renal AR protein levels by 70% in DHT mice compared to vehicle-treated DHT. Excitingly, while ARV-110 did not modulate renal TGF-β levels, it completely abolished DHT-mediated increase in renal MMP9 while significantly lowering the levels of urinary renal injury markers UACR, KIM1 and NGAL. Conclusion and significance: Our findings suggest that DHT-mediated kidney hypertrophy, associated ECM remodeling and injury are ameliorated by ARV-110 in DHT-treated mice. AR PROTACs could be a novel therapeutic approach to treat renal dysfunction in PCOS. Supported by NIH P20GM121334. Presentation Date: Sunday, June 18, 2023

Both sexes develop DKD in the CD1 uninephrectomized streptozotocin mouse model

Diabetic kidney disease (DKD) is characterized by a progressive increase in albuminuria and typical pathologic features. Recent studies have shown that sex is an important factor to consider in the pathogenesis of DKD. Presently, the hallmarks of this disease have primarily been studied in male rodent models. Here we explored the influence of sex in a murine model of DKD. CD1 mice underwent a right nephrectomy followed by intraperitoneal injection with 200 mg/kg streptozotocin to induce type 1 diabetes. Due to a high mortality rate, females required a reduction in streptozotocin to 150 mg/kg. Mice were followed for 12 weeks. Both sexes developed comparable hyperglycemia, while albuminuria and glomerular volume were increased to a greater degree in females and kidney hypertrophy was only seen in females. Males had a greater increase in blood pressure and glomerular basement membrane thickening, and a greater decrease in endpoint weight. Serum TGFβ1 levels were increased only in females. However, both sexes showed a similar increase in induction of kidney fibrosis. T cell and macrophage infiltration were also increased in both sexes. While some differences were observed, overall, both sexes developed clinical and pathologic characteristics of early DKD. Future studies evaluating therapeutic interventions can thus be assessed in both sexes of this DKD model.

Efficacy of Flavonoid Apigenin on Hemodynamic indices, Baroreflex Function, Cardiac and Kidney Remodeling and Vasoactive-Inflammatory Biomarkers in Experimental Renal Hypertension

The hypothesis stated here that, the long-term prevention by natural flavonoid phenolic compound, for example apigenin (Apg), improves baroreflex sensitivity and vascular resistance and occurs beneficial action for attenuation the renal hypertension (RH). One-kidney, 1-clip rats (1K1C) were treated with Apg for 2 weeks after 1 week of surgical intervention. At the end of the study in the control RH group the blood pressure (BP) increased on average by 43.5%, decreased in heart period (HP) by 9.8%, cardiochronotropic (vagal) component of baroreflex sensitivity (BRS) by 50%, and adrenergic component by 34%. Thus, in 1K1C experimental model of hypertension, provides switching to parasympathetic component and accompanied with proportionally nearly two-fold increase in epinephrine (EPN) and norepinephrine (NE) without changes in EPN/NE ratio. Morphometric changes in the kidney and heart confirmed the development of kidney and cardiac hypertrophy and renal functioning disturbances (blood urea nitrogen (BUN) increased in more than two-fold) and markers of sodium reabsorption in proximal tubule, total trans-EETs, decreased in 1.6-fold. The pronounced increased proinflammatory cytokines, interleukin 1b (IL1 b), endothelin -1 (ET-1) and tumor necrosis factor (TNF)-a confirmed the formation of “sterile inflammation” which strengthening by the nearly two-fold decreasing in the level of anti-inflammatory (vasodilatory) mediators, prostaglandin E2 (PGE2). Preventive long-term regime treatment with Apg (5mg/kg i.p./daily) in RH rats significantly decreased BP by 18.6%, increased parasympathetic component of BRS by 38.5% without marked altered its sympathetic component. Such deremodeling in BRS sensitivity associated with significant decreased in heart and kidney hypertrophy and functional activity of kidney, normalization of BUN and total EETs, reducing in circulating plasma level of catecholamines, and markedly attenuated progression of inflammation, decreased of proinflammatory levels of cytokines. Thus, Apg provides preventive beneficial pluripotent action in RH rats by exerting antihypertensive, cardio- and renoprotective effects and attenuation of “sterile inflammation”.

NRF2 Deficiency Attenuates Diabetic Kidney Disease in Db/Db Mice via Down-Regulation of Angiotensinogen, SGLT2, CD36, and FABP4 Expression and Lipid Accumulation in Renal Proximal Tubular Cells.

The role(s) of nuclear factor erythroid 2-related factor 2 (NRF2) in diabetic kidney disease (DKD) is/are controversial. We hypothesized that Nrf2 deficiency in type 2 diabetes (T2D) db/db mice (db/dbNrf2 knockout (KO)) attenuates DKD progression through the down-regulation of angiotensinogen (AGT), sodium-glucose cotransporter-2 (SGLT2), scavenger receptor CD36, and fatty -acid-binding protein 4 (FABP4), and lipid accumulation in renal proximal tubular cells (RPTCs). Db/dbNrf2 KO mice were studied at 16 weeks of age. Human RPTCs (HK2) with NRF2 KO via CRISPR-Cas9 genome editing and kidneys from patients with or without T2D were examined. Compared with db/db mice, db/dbNrf2 KO mice had lower systolic blood pressure, fasting blood glucose, kidney hypertrophy, glomerular filtration rate, urinary albumin/creatinine ratio, tubular lipid droplet accumulation, and decreased expression of AGT, SGLT2, CD36, and FABP4 in RPTCs. Male and female mice had similar results. NRF2 KO attenuated the stimulatory effect of the Nrf2 activator, oltipraz, on AGT, SGLT2, and CD36 expression and high-glucose/free fatty acid (FFA)-stimulated lipid accumulation in HK2. Kidneys from T2D patients exhibited markedly higher levels of CD36 and FABP4 in RPTCs than kidneys from non-diabetic patients. These data suggest that NRF2 exacerbates DKD through the stimulation of AGT, SGLT2, CD36, and FABP4 expression and lipid accumulation in RPTCs of T2D.

Effects and mechanisms of total flavones of Abelmoschus manihot in inhibiting podocyte necroptosis and renal fibrosis in diabetic kidney disease

Previous studies have shown that high blood glucose-induced chronic microinflammation can cause inflammatory podocyte injury in patients with diabetic kidney disease(DKD). Therein, necroptosis is a new form of podocyte death that is closely associated with renal fibrosis(RF). To explore the effects and mechanisms in vivo of total flavones of Abelmoschus manihot(TFA), an extract from traditional Chinese herbal medicine Abelmoschus manihot for treating kidney diseases, on podocyte necroptosis and RF in DKD, and to further reveal its scientific connotation with multi-pathway and multi-target, the authors randomly divided all rats into four groups: a namely normal group, a model group, a TFA group and a rapamycin(RAP) group. After the modified DKD rat models were successfully established, four group rats were given double-distilled water, TFA suspension and RAP suspension, respectively by gavage every day. At the end of the 4th week of drug treatment, all rats were sacrificed, and the samples of their urine, blood and kidneys were collected. And then, the various indicators related to podocyte necroptosis and RF in the DKD model rats were observed, detected and analyzed, respectively. The results indicated that, general condition, body weight(BW), serum creatinine(Scr), urinary albumin(UAlb), and kidney hypertrophy index(KHI) in these modified DKD model rats were both improved by TFA and RAP. Indicators of RF, including glomerular histomorphological characteristics, fibronectin(FN) and collagen type Ⅰ(collagen Ⅰ) staining extent in glomeruli, as well as the protein expression levels of FN, collagen Ⅰ, transforming growth factor-β1(TGF-β1) and Smad2/3 in the kidneys were improved respectively by TFA and RAP. Podocyte damage, including foot process form and the protein expression levels of podocin and CD2AP in the kidneys was improved by TFA and RAP. In addition, tumor necrosis factor-α(TNF-α)-mediated podocyte necroptosis in the kidneys, including the morphological characteristics of podocyte necroptosis, the extent and levels of the protein expression of TNF-α and phosphorylated mixed lineage kinase domain like pseudokinase(p-MLKL) was improved respectively by TFA and RAP. Among them, RAP had the better effect on p-MLKL. More importantly, the activation of the receptor interacting serine/threonine protein kinase 1(RIPK1)/RIPK3/MLKL signaling axis in the kidneys, including the expression levels of its key signaling molecules, such as phosphorylated receptor interacting serine/threonine protein kinase 1(p-RIPK1), p-RIPK3, p-MLKL and cysteinyl aspartate specific proteinase-8(caspase-8) was improved respectively by TFA and RAP. Among them, the effect of TFA on p-RIPK1 was superior. On the whole, in this study, the authors demonstrated that TFA alleviates podocyte necroptosis and RF in DKD through inhibiting the activation of the TNF-α-mediated RIPK1/RIPK3/MLKL signaling axis in diabetic kidneys. The authors' findings provide new pharmacological evidence to reveal the scientific connotation of TFA in treating RF in DKD in more depth.

Accelerated cystogenesis by dietary protein load is dependent on, but not initiated by kidney macrophages.

Disease severity of autosomal dominant polycystic kidney disease (ADPKD) is influenced by diet. Dietary protein, a recognized cyst-accelerating factor, is catabolized into amino acids (AA) and delivered to the kidney leading to renal hypertrophy. Injury-induced hypertrophic signaling in ADPKD results in increased macrophage (MФ) activation and inflammation followed by cyst growth. We hypothesize that the cystogenesis-prompting effects of HP diet are caused by increased delivery of specific AA to the kidney, ultimately stimulating MФs to promote cyst progression. Pkd1flox/flox mice with and without Cre (CAGG-ER) were given tamoxifen to induce global gene deletion (Pkd1KO). Pkd1KO mice were fed either a low (LP; 6%), normal (NP; 18%), or high (HP; 60%) protein diet for 1 week (early) or 6 weeks (chronic). Mice were then euthanized and tissues were used for histology, immunofluorescence and various biochemical assays. One week fed kidney tissue was cell sorted to isolate tubular epithelial cells for RNA sequencing. Chronic dietary protein load in Pkd1KO mice increased kidney weight, number of kidney infiltrating and resident MФs, chemokines, cytokines and cystic index compared to LP diet fed mice. Accelerated cyst growth induced by chronic HP were attenuated by liposomal clodronate-mediated MФ depletion. Early HP diet fed Pkd1KO mice had larger cystic kidneys compared to NP or LP fed counterparts, but without increases in the number of kidney MФs, cytokines, or markers of tubular injury. RNA sequencing of tubular epithelial cells in HP compared to NP or LP diet group revealed increased expression of sodium-glutamine transporter Snat3, chloride channel Clcnka, and gluconeogenesis marker Pepck1, accompanied by increased excretion of urinary ammonia, a byproduct of glutamine. Early glutamine supplementation in Pkd1KO mice lead to kidney hypertrophy. Chronic dietary protein load-induced renal hypertrophy and accelerated cyst growth in Pkd1KO mice is dependent on both infiltrating and resident MФ recruitment and subsequent inflammatory response. Early cyst expansion by HP diet, however, is relient on increased delivery of glutamine to kidney epithelial cells, driving downstream metabolic changes prior to inflammatory provocation.