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Asian Journal of Urology Apr 2024Rheumatoid nephropathy is one of the most severe extra-articular manifestations of rheumatoid arthritis (RA) associated with a very unfavorable prognosis. This study...
OBJECTIVE
Rheumatoid nephropathy is one of the most severe extra-articular manifestations of rheumatoid arthritis (RA) associated with a very unfavorable prognosis. This study aimed to identify changes in renal function and morphological variations of kidney diseases in RA patients.
METHODS
The study enrolled patients (126 patients) between 18 and 55 years of age with a confirmed active RA of more than 12 months. Each patient underwent the following range of laboratory and instrumental research methods: general clinical analysis of blood and urine, performing urinalysis according to Nechiporenko method; determining daily proteinuria; determining the blood content of glucose, urea, creatinine, uric acid, total bilirubin, liver transaminase level, ionogram, lipidogram, and coagulogram; determining the blood content of rheumatoid factor, anti-streptolysin O, and C-reactive protein; and X-ray of the joints of hands and feet. Renal function was examined by estimating glomerular filtration rate, tubular reabsorption index, and renal functional reserve. For studying the morphological changes in the kidneys under ultrasound examination, renal biopsy was performed in 31 patients with RA with urinary syndrome (proteinuria more than 0.3 g per day and hematuria).
RESULTS
Nephropathy in RA is characterized by impaired renal function and manifested by an increased blood creatinine and a decrease in glomerular filtration rate and renal functional reserve. Among morphological variations of nephropathy at RA, mesangial proliferative glomerulonephritis prevails, accounting for 48.4% of patients. Other disorders include the secondary amyloidosis (29.0% of patients), tubulointerstitial nephritis (16.1%), membranous glomerulonephritis (3.2%), and focal-segmental glomerulosclerosis (3.2%).
CONCLUSION
Kidney damage is a common systemic manifestation of RA with a long and active course, a major nephropathy trigger.
PubMed: 38680581
DOI: 10.1016/j.ajur.2022.06.005 -
Food Chemistry Sep 2024Hyperuricemia (HU) is a metabolic disorder caused by the overproduction or underexcretion of uric acid (UA) in the human body. Several approved drugs for the treatment... (Review)
Review
Hyperuricemia (HU) is a metabolic disorder caused by the overproduction or underexcretion of uric acid (UA) in the human body. Several approved drugs for the treatment of HU are available in the market; however, all these allopathic drugs exhibit multiple side effects. Therefore, the development of safe and effective anti-HU drugs is an urgent need. Natural compounds derived from foods and plants have the potential to decrease UA levels. Recently, food-derived bioactive peptides (FBPs) have gained attention as a functional ingredient owing to their biological activities. In the current review, we aim to explore the urate-lowering potential and the underlying mechanisms of FBPs. We found that FBPs mitigate HU by reducing blood UA levels through inhibiting key enzymes such as xanthine oxidase, increasing renal UA excretion, inhibiting renal UA reabsorption, increasing anti-oxidant activities, regulating inflammatory mediators, and addressing gut microbiota dysbiosis. In conclusion, FBPs exhibit strong potential to ameliorate HU.
Topics: Humans; Peptides; Hyperuricemia; Animals; Uric Acid; Gastrointestinal Microbiome; Antioxidants; Xanthine Oxidase; Bioactive Peptides, Dietary
PubMed: 38678657
DOI: 10.1016/j.foodchem.2024.139444 -
International Journal of Molecular... Apr 2024Designed ankyrin repeat protein (DARPin) G3 is an engineered scaffold protein. This small (14.5 kDa) targeting protein binds with high affinity to human epidermal growth...
Designed ankyrin repeat protein (DARPin) G3 is an engineered scaffold protein. This small (14.5 kDa) targeting protein binds with high affinity to human epidermal growth factor receptor 2 (HER2). HER2 is overexpressed in several cancers. The use of the DARPin G3 for radionuclide therapy is complicated by its high renal reabsorption after clearance via the glomeruli. We tested the hypothesis that a fusion of the DARPin G3 with an albumin-binding domain (ABD) would prevent rapid renal excretion and high renal reabsorption resulting in better tumour targeting. Two fusion proteins were produced, one with the ABD at the C-terminus (G3-ABD) and another at the N-terminus (ABD-G3). Both variants were labelled with Lu. The binding properties of the novel constructs were evaluated in vitro and their biodistribution was compared in mice with implanted human HER2-expressing tumours. Fusion with the ABD increased the retention time of both constructs in blood compared with the non-ABD-fused control. The effect of fusion with the ABD depended strongly on the order of the domains in the constructs, resulting in appreciably better targeting properties of [Lu]Lu-G3-ABD. Our data suggest that the order of domains is critical for the design of targeting constructs based on scaffold proteins.
Topics: Animals; Female; Humans; Mice; Albumins; Ankyrin Repeat; Cell Line, Tumor; Lutetium; Protein Binding; Protein Domains; Radioisotopes; Radiopharmaceuticals; Receptor, ErbB-2; Recombinant Fusion Proteins; Tissue Distribution; Molecular Targeted Therapy
PubMed: 38673831
DOI: 10.3390/ijms25084246 -
The Journal of Pharmacology and... Jun 2024Dotinurad was developed as a uricosuric agent, inhibiting urate (UA) reabsorption through the UA transporter URAT1 in the kidneys. Due to its high selectivity for URAT1...
Dotinurad was developed as a uricosuric agent, inhibiting urate (UA) reabsorption through the UA transporter URAT1 in the kidneys. Due to its high selectivity for URAT1 among renal UA transporters, we investigated the mechanism underlying this selectivity by identifying dotinurad binding sites specific to URAT1. Dotinurad was docked to URAT1 using AutoDock4, utilizing the AlphaFold2-predicted structure. The inhibitory effects of dotinurad on wild-type and mutated URAT1 at the predicted binding sites were assessed through URAT1-mediated [C]UA uptake in oocytes. Nine amino acid residues in URAT1 were identified as dotinurad-binding sites. Sequence alignment with UA-transporting organic anion transporters (OATs) revealed that H142 and R487 were unique to URAT1 among renal UA-transporting OATs. For H142, values of dotinurad increased to 62, 55, and 76 nM for mutated URAT1 (H142A, H142E, and H142R, respectively) compared with 19 nM for the wild type, indicating that H142 contributes to URAT1-selective interaction with dotinurad. H142 was predicted to interact with the phenyl-hydroxyl group of dotinurad. The of the hydroxyl group methylated dotinurad (F13141) was 165 M, 8420-fold higher than dotinurad, suggesting the interaction of H142 and the phenyl-hydroxyl group by forming a hydrogen bond. Regarding R487, URAT1-R487A exhibited a loss of activity. Interestingly, the URAT1-H142A/R487A double mutant restored UA transport activity, with the value of dotinurad for the mutant (388 nM) significantly higher than that for H142A (73.5 nM). These results demonstrate that H142 and R487 of URAT1 determine its selectivity for dotinurad, a uniqueness observed only in URAT1 among UA-transporting OATs. SIGNIFICANCE STATEMENT: Dotinurad selectively inhibits the urate reabsorption transporter URAT1 in renal urate-transporting organic ion transporters (OATs). This study demonstrates that dotinurad interacts with H142 and R487 of URAT1, located in the extracellular domain and unique among OATs when aligning amino acid sequences. Mutations in these residues reduce affinity of dotinurad for URAT1, confirming their role in conferring selective inhibition. Additionally, the interaction between dotinurad and URAT1 involving H142 is found to mediate hydrogen bonding.
Topics: Animals; Organic Anion Transporters; Uric Acid; Binding Sites; Humans; Uricosuric Agents; Organic Cation Transport Proteins; Xenopus laevis; Kidney; Oocytes; Benzothiazoles; Molecular Docking Simulation
PubMed: 38670801
DOI: 10.1124/jpet.124.002096 -
Cardiology in Review Apr 2024Dapagliflozin (trade name FARXIGA) is a sodium-glucose cotransporter-2 (SGLT-2) inhibitor that has transcended its initial antidiabetic application to demonstrate...
Dapagliflozin (trade name FARXIGA) is a sodium-glucose cotransporter-2 (SGLT-2) inhibitor that has transcended its initial antidiabetic application to demonstrate benefits in cardiac and renal diseases. It was first approved by the food and department administration for type 2 diabetes in 2014. Since then, it has gained food and department administration approval for chronic kidney disease in 2021, heart failure with reduced ejection fraction in 2020, and heart failure with preserved ejection fraction in 2023. Thus, dapagliflozin plays a pivotal role in improving patient outcomes. By competitive binding to renal SGLT-2 cotransporters, dapagliflozin effectively prevents glucose and sodium reabsorption, leading to glucosuria. Its pharmacokinetic profile involves minimal cytochrome P450-induced metabolism, rapid absorption with an 18-hour duration of action, and stable effects. Clinical trials have revealed dapagliflozin's efficacy in glycemic control without the risk of hypoglycemia, making it an advantageous choice for patients insufficiently managed on other antidiabetic drugs. Comparative analysis with other SGLT-2 inhibitors suggests dapagliflozin's potential superiority in preventing heart failure. Compared to empagliflozin, it has more extended effects, contributing to stable sodium diuresis, reduced blood pressure fluctuations, and potentially lower cardiovascular disease risks. However, it leads to less urinary glucose excretion compared with canagliflozin. Dapagliflozin has specific contraindications, such as type 1 diabetes and end-stage chronic kidney disease. Adverse effects include an increased risk of genital infections, urinary tract infections, and Fournier's gangrene. A nuanced understanding of dapagliflozin's benefits and limitations is imperative for informed clinical decision-making in the management of diabetes and its complications.
PubMed: 38666776
DOI: 10.1097/CRD.0000000000000694 -
Hepatology Research : the Official... Apr 2024Renal dysfunction is a common complication of cirrhosis, occurring either as part of multiorgan involvement in acute illness or secondary to advanced liver disease. To...
AIM
Renal dysfunction is a common complication of cirrhosis, occurring either as part of multiorgan involvement in acute illness or secondary to advanced liver disease. To date, no study has comprehensively assessed multiple renal function parameters in hospitalized patients with cirrhosis through a multiparametric analysis of renal biochemistry markers.
METHODS
We conducted a retrospective, observational study including all consecutive patients hospitalized with cirrhosis who underwent a 43-multiparametric renal function assessment between January 1, 2021, and June 30, 2023.
RESULTS
All patients showed at least one of the following renal abnormalities: Kidney Disease: Improving Global Outcomes stage G2 or higher, sodium and/or chloride excretion fraction <1%, electrolyte-free water clearance <0.4 mL/min, or tubular maximum phosphate reabsorption capacity <0.8 mmol/L. The estimated glomerular filtration rate equations significantly overestimated the measured creatinine clearance with median differences of +14 mL/min/1.73 m (95% CI 6-29) and +9 mL/min/1.73 m (95% CI 2-15) for European Kidney Function Consortium equations, respectively. Notably, 54% and 39% of patients demonstrated estimated glomerular filtration rates exceeding 30% of the measured creatinine clearance when the Chronic Kidney Disease - Epidemiology Collaboration and European Kidney Function Consortium formulas were employed, respectively. Substantial discrepancies in Kidney Disease: Improving Global Outcomes stage assignments were observed between the estimated glomerular filtration rate- and measured creatinine clearance-based assessments.
CONCLUSIONS
This study underscores the value of a multiparametric renal function assessment as a routine tool for evaluating renal function in patients with cirrhosis. A high prevalence of medically actionable renal abnormalities spanning multiple renal function modules, including alterations in glomerular function, salt and solute-free water excretion, and proximal tubule phosphate reabsorption, has been demonstrated in hospitalized patients with cirrhosis.
PubMed: 38662338
DOI: 10.1111/hepr.14050 -
Journal of Cellular and Molecular... Apr 2024X-linked nephrogenic diabetes insipidus (X-NDI) is a rare congenital disease caused by inactivating mutations of the vasopressin type-2 receptor (AVPR2), characterized...
X-linked nephrogenic diabetes insipidus (X-NDI) is a rare congenital disease caused by inactivating mutations of the vasopressin type-2 receptor (AVPR2), characterized by impaired renal concentrating ability, dramatic polyuria, polydipsia and risk of dehydration. The disease, which still lacks a cure, could benefit from the pharmacologic stimulation of other GPCRs, activating the cAMP-intracellular pathway in the kidney cells expressing the AVPR2. On the basis of our previous studies, we here hypothesized that the β3-adrenergic receptor could be such an ideal candidate. We evaluated the effect of continuous 24 h stimulation of the β3-AR with the agonist BRL37344 and assessed the effects on urine output, urine osmolarity, water intake and the abundance and activation of the key renal water and electrolyte transporters, in the mouse model of X-NDI. Here we demonstrate that the β3-AR agonism exhibits a potent antidiuretic effect. The strong improvement in symptoms of X-NDI produced by a single i.p. injection of BRL37344 (1 mg/kg) was limited to 3 h but repeated administrations in the 24 h, mimicking the effect of a slow-release preparation, promoted a sustained antidiuretic effect, reducing the 24 h urine output by 27%, increasing urine osmolarity by 25% and reducing the water intake by 20%. At the molecular level, we show that BRL37344 acted by increasing the phosphorylation of NKCC2, NCC and AQP2 in the renal cell membrane, thereby increasing electrolytes and water reabsorption in the kidney tubule of X-NDI mice. Taken together, these data suggest that human β3-AR agonists might represent an effective possible treatment strategy for X-NDI.
Topics: Male; Animals; Mice, Inbred C57BL; Disease Models, Animal; Adrenergic beta-3 Receptor Agonists; Antidiuretic Agents; Kidney Concentrating Ability; Polydipsia
PubMed: 38652212
DOI: 10.1111/jcmm.18301 -
BioRxiv : the Preprint Server For... May 2024The mitochondrial-rich renal tubule cells are key regulators of blood homeostasis via excretion and reabsorption of metabolic waste. With age, tubules are subject to...
The mitochondrial-rich renal tubule cells are key regulators of blood homeostasis via excretion and reabsorption of metabolic waste. With age, tubules are subject to increasing mitochondrial dysfunction and declining nicotinamide adenine dinucleotide (NAD+) levels, both hampering ATP production efficiency. We tested two mitochondrial interventions in young (6-mo) and aged (26-mo) adult male mice: elamipretide (ELAM), a tetrapeptide in clinical trials that improves mitochondrial structure and function, and nicotinamide mononucleotide (NMN), an NAD+ intermediate and commercially available oral supplement. Kidneys were analyzed from young and aged mice after eight weeks of treatment with ELAM (3 mg/kg/day), NMN (300 mg/kg/day), or from aged mice treated with the two interventions combined (ELAM+NMN). We hypothesized that combining pharmacologic treatments to ameliorate mitochondrial dysfunction and boost NAD+ levels, would more effectively reduce kidney aging than either intervention alone. Unexpectedly, in aged kidneys, NMN increased expression of genetic markers of inflammation (IL-1-beta; and Ccl2) and tubule injury (Kim-1). Metabolomics of endpoint sera showed that NMN-treated aged mice had higher circulating levels of uremic toxins than either aged controls or young NMN-treated mice. ELAM+NMN-treated aged mice accumulated uremic toxins like NMN-only aged mice, but reduced IL-1-beta; and Ccl2 kidney mRNA. This suggests that pre-existing mitochondrial dysfunction in aged kidney underlies susceptibility to inflammatory signaling with NMN supplementation in aged, but not young, mice. These findings demonstrate age and tissue dependent effects on downstream metabolic accumulation from NMN and highlight the need for targeted analysis of aged kidneys to assess the safety of anti-aging supplements in older populations.
PubMed: 38645109
DOI: 10.1101/2024.04.09.588624 -
Current Opinion in Nephrology and... Jul 2024Salt-sensitive (SS) hypertension and its associated kidney damage have been extensively studied, yet proper therapeutic strategies are lacking. The interest in altering... (Review)
Review
PURPOSE OF REVIEW
Salt-sensitive (SS) hypertension and its associated kidney damage have been extensively studied, yet proper therapeutic strategies are lacking. The interest in altering the metabolome to affect renal and cardiovascular disease has been emerging. Here, we discuss the effect and potential mechanism behind the protective effect of lysine, an essential amino acid, on the progression of SS hypertension.
RECENT FINDINGS
We have recently demonstrated that administering lysine in an SS rodent model can control the progression of hypertension. Both the animal and pilot human studies showed that lysine can efficiently inhibit tubular reabsorption of albumin and protect the kidneys from further damage. In addition, we conducted multilevel omics studies that showed increased lysine conjugation and excretion, leading to the depletion of harmful metabolites and an increase in useful ones.
SUMMARY
Lysine's twofold action involves both mechanically flushing protein from proximal tubules to shield the kidneys and initiating metabolic adaptations in the kidneys. This results in a net positive impact on SS hypertension. While further research is necessary to apply the current findings in clinical settings, this study offers some evidence suggesting that lysine supplementation holds promise as a therapeutic approach for hypertensive kidney disease.
Topics: Lysine; Humans; Animals; Hypertension; Sodium Chloride, Dietary; Kidney; Blood Pressure
PubMed: 38639736
DOI: 10.1097/MNH.0000000000000994