Renal Reabsorption Research Articles

Host-derived Lactobacillus plantarum alleviates hyperuricemia by improving gut microbial community and hydrolase-mediated degradation of purine nucleosides.

The gut microbiota is implicated in the pathogenesis of hyperuricemia (HUA) and gout. However, it remains unclear whether probiotics residing in the host gut, such as Lactobacillus, can prevent HUA development. Herein, we isolated Lactobacillus plantarum SQ001 from the cecum of HUA geese and conducted in vitro assays on uric acid (UA) and nucleoside co-culture. Metabolomics and genome-wide analyses, revealed that this strain may promote nucleoside uptake and hydrolysis through its nucleoside hydrolase gene. The functional role of iunH gene was confirmed via heterologous expression and gene knockout studies. Oral administration of L. plantarum SQ001 resulted in increased abundance of Lactobacillus species and reduced serum UA levels. Furthermore, it downregulated hepatic xanthine oxidase, a key enzyme involved in UA synthesis, as well as renal reabsorption protein GLUT9, while enhancing the expression of renal excretion protein ABCG2. Our findings suggest that L. plantarum has potential to ameliorate gut microbial dysbiosis with HUA, thereby offering insights into its potential application as a probiotic therapy for individuals with HUA or gout.

Uninephrectomy and sodium-glucose cotransporter 2 inhibitor administration delay the onset of hyperglycemia.

The kidneys are essential for glucose homeostasis, as they perform gluconeogenesis, utilize glucose, and reabsorb glucose. Reabsorption is performed by SGLT2, which is responsible for about 90%. However, little is known about how renal glucose handling is altered in patients with chronic kidney disease (CKD). SGLT2 inhibitors have demonstrated efficacy in suppressing CKD progression in clinical trials, but their mechanisms are not fully understood. Therefore, this study aimed to evaluate how each uninephrectomy (UNx) and SGLT2 inhibitor affects blood glucose concentrations and SGLTs dynamics in rats with type 2 diabetes mellitus. Male rats were divided into four treatment groups: sham + placebo, sham + dapagliflozin, UNx + placebo, and UNx + dapagliflozin. There were few group differences in food intake or body weight, but blood glucose concentrations continued to rise in the sham + placebo, whereas this rise was delayed for several weeks in the UNx + placebo, and largely suppressed by dapagliflozin. SGLT2 mRNA expression was significantly lower in the UNx group, but SGLT1 mRNA expression did not significantly differ. Dapagliflozin did not alter SGLT1 or SGLT2 mRNA expression. In animal models of diabetes, renal glucose reabsorption appears likely to be a major contributor to the development of hyperglycemia.

Association of magnesium deficiency scores with risk of rheumatoid arthritis and osteoarthritis in adults: a cross-sectional population-based study.

The magnesium depletion score (MDS) is a scoring system developed to predict magnesium deficiency based on pathophysiological factors that affect renal reabsorption. The relationship between systemic magnesium status and arthritis is unclear. The purpose of this study was to determine the association between the MDS and rheumatoid arthritis (RA) as well as osteoarthritis (OA). This study was conducted through a cross-sectional survey of 20,513 adults aged ≥ 20years who participated in NHANES from 2007 to 2018. The four dimensions of the MDS included diuretics, proton pump inhibitors, glomerular filtration rate, and excessive alcohol consumption. Univariate and multivariable-weighted logistic regression were used to assess the associations between MDS and RA/OA, and a test for trend was performed to analyze the presence of a dose-response relationship. Subgroup analyses and interaction tests were performed according to confounders. After adjustment for all covariates, we found a graded dose-response relationship between MDS and RA or OA. When MDS was considered as a continuous variable, each onefold increase in MDS was associated with a 1.21-fold increase in the odds of having RA (OR = 1.21, 1.10, 1.33) and a 1.12-fold increase in the odds of having OA (OR = 1.12, 1.04, 1.21). There was an interaction of sex in the effect of MDS on RA (Pinteraction = 0.004) and age in the effect of MDS on OA (Pinteraction = 0.006). In addition, these associations were further confirmed in sensitivity and subgroup analyses. Our study identified significant dose-response associations between MDS and both RA and OA. More biological mechanisms are needed in the future to validate and clarify the results of this study.

The FSGS protein actinin-4 (ACTN4) interacts with NKCC2 to regulate Thick Ascending Limb (TAL) NaCl reabsorption.

In the kidney, the thick Ascending Limb (TAL) of the loop of Henle is crucial for NaCl homeostasis and blood pressure regulation. In animal models of salt-sensitive hypertension, NaCl reabsorption via the apical Na+/K+/2Cl cotransporter (NKCC2) is abnormally increased in the TAL. We showed that NaCl reabsorption is controlled by the presence of NKCC2 at the apical surface of TALs. However, the molecular mechanisms that maintain the steady-state levels of NKCC2 at the apical surface are not clearly understood. Here, we report that NKCC2 interacts with the F-actin cross-linking protein actinin-4 (ACTN4). We find that ACTN4 is expressed in TALs by Western blot and immunofluorescence microscopy. ACTN4 immunoprecipitated with NKCC2 and recombinant GST-ACTN4 pulled down NKCC2 from TAL lysates. ACTN4 is involved in endocytosis in other cells. Therefore, we hypothesized that ACTN4 binds apical NKCC2 and regulates its trafficking. To study this, we silenced ACTN4 in vivo via shRNA or CRISPR/Cas9 system to decrease ACTN4 expression in TALs. We observed that silencing ACTN4 in vivo via shRNA or CRISPR/Cas9 system increased the amount NKCC2 at the apical surface of TALs. Bumetanide-induced diuresis and natriuresis were enhanced by 35% after silencing of ACTN4 in vivo (AV-NKCC2-Cas9: 3841±709 vs AAV-gRNA-ACTN4: 5546±622 µmols Na/8h, n=5, p<0.05). We conclude that ACTN4, binds NKCC2 to regulate its surface expression. Selective depletion of ACTN4 in TALs using shRNA or CRISPR/Cas9 enhances surface NKCC2 and TAL NaCl reabsorption, indicating that regulation of the ACTN4-NKCC2 interaction is important for renal NaCl reabsorption and could be related to hypertension.

The Paradise Renal Denervation System: An FDA-approved catheter-based treatment option for resistant hypertension

Resistant hypertension is defined as office blood pressure &gt;140/90 mm Hg with a mean 24-hour ambulatory blood pressure of &gt;130/80 mm Hg in patients who are compliant with 3 or more antihypertensive medications. Those who persistently fail pharmaceutical therapy may benefit from interventional treatment, such as renal denervation. Sympathetic nervous activity in the kidney is a known contributor to increased blood pressure because it results in efferent and afferent arteriole vasoconstriction, reduced renal blood flow, increased sodium and water reabsorption, and the release of renin. The Recor Paradise Renal Denervation System is designed to target renal sympathetic nerves via ultrasound ablation. The RADIANCE trials have demonstrated that patients who underwent renal denervation had a significant decrease in systolic blood pressure as compared with those who underwent a sham procedure. Furthermore, the device was found to have a favorable safety profile, with minimal major adverse events. The Food and Drug Administration granted approval to Recor, and the Paradise system is expected to serve as an adjunctive therapy for patients with true-resistant hypertension.

Molecular Insight into Obesity-Associated Nephropathy: Clinical Implications and Possible Strategies for its Management.

Obesity is a significant health concern due to its rapid increase worldwide. It has been linked to the pathogenic factors of renal diseases, cancer, cardiovascular diseases, hypertension, dyslipidemia, and type 2 diabetes. Notably, obesity raises the likelihood of developing chronic kidney disease (CKD), leading to higher adult mortality and morbidity rates. This study explores the molecular mechanisms that underlie obesity-associated nephropathy and its clinical implications. Obesity-Associated Nephropathy (OAN) develops and worsens due to insulin resistance and hyperinsulinemia, which promote renal sodium reabsorption, glomerular hyperfiltration, and hypertension, leading to progressive kidney damage. Renal damage is further aggravated by persistent inflammation and redox damage, mediated by adipokines and proinflammatory cytokines, such as TNF-α and IL-6. Furthermore, stimulation of the sympathetic nervous system and the renin-angiotensin- aldosterone system (RAAS) intensifies glomerular hypertension and fibrosis. These elements cause glomerular hyperfiltration, renal hypertrophy, and progressive kidney damage. Clinical manifestations of obesity-associated nephropathy include proteinuria, reduced glomerular filtration rate (GFR), and ultimately, CKD. Management strategies currently focus on lifestyle modifications, such as weight loss through diet and exercise, which have been effective in reducing proteinuria and improving GFR. Pharmacological treatments targeting metabolic pathways, including GLP-1 receptor agonists and SGLT2 inhibitors, have shown renoprotective properties. Additionally, traditional RAAS inhibitors offer therapeutic benefits. Early detection and comprehensive management of OAN are essential to prevent its progression and lessen the burden of CKD.

A-039 Parathyroid Hormone and Vitamin D Follow an Inversely Correlated Serum Level

Abstract Background Parathyroid hormone (PTH) is a polypeptide responsible for regulating the physiological level of serum calcium through a complex homeostatic process closely associated with bone metabolism. In response to a decreased serum concentration of calcium, PTH level is increased leading to the elevation of calcium via bone resorption. Furthermore, Vitamin D (Vit-D) is a critical component of the endocrine system that also contributes to calcium homeostasis. Vit-D increases the level of serum calcium by stimulating intestinal absorption and renal reabsorption. Vit-D impacts the serum level of PTH by two distinct mechanisms. First indirectly, an increase in serum concentration of calcium, caused by Vit-D-mediated intestinal absorption and renal reabsorption disengages the process of PTH release through interaction with calcium-sensing receptors on parathyroid cells. Secondly, Vit-D directly interacts with parathyroid cells resulting in a reduced expression of PTH. Taken together, Vit-D is assumed to negatively impact the serum level of PTH. This study examined the homeostatic correlation between the circulating concentrations of Vit-D and PTH. Methods Retrospective serum concentrations of PTH and Vit-D were retrieved from the biochemical profiles of hospitalized and ambulatory patients who presented to or admitted at the tertiary care level hospital of University of Texas Southwestern Medical Center during the period between July-to-September of 2021. Correlation analysis between Vit-D and PTH was performed using GraphPad-PRISM-version-8. Results A total of 163 corresponding serum Vit-D and PTH values were obtained. Vit-D and PTH values displayed an inverse correlation (Figure 1). Pearson r values for linear and logarithmic trendlines (-0.6745 and -0.785, respectively) demonstrated a negative correlation between Vit-D and PTH. Conclusions Measuring Vit-D and PTH levels are critically important for assessing the homeostatic status of calcium. PTH level maintains an inverse relationship with Vit-D. Therefore, therapeutic targeting of Vit-D or PTH would mutually affect their concentration eventually reflected in calcium homeostasis.

Muscle weakness after intravenous iron replacement

After a young female patient received an intravenous iron infusion for severe symptomatic iron-deficiency-anemia, a severe hypophosphatemia was diagnosed with associated mild muscle weakness. With renal phosphate loss and elevated serum FGF23 (Fibroblast Growth Factor 23), the diagnosis of a hypophosphatemia caused by ferric carboxymaltose was made. Upregulation of FGF23 inhibits renal phosphate reabsorption and also the activation of vitamin D, which additionally reduces intestinal phosphate absorption. The symptoms of hypophosphatemia may be masked after iron replacement.

Elucidation of DPP-4 involvement in systemic distribution and renal reabsorption of linagliptin by PBPK modeling with a cluster Gauss-Newton method.

The dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin (LNG) exhibits target-mediated drug disposition (TMDD) in clinical settings, characterized by saturable binding to plasma soluble DPP-4 (sDPP-4) and tissue transmembrane DPP-4 (tDPP-4). Previous studies have indicated that saturable renal reabsorption of LNG contributes to its nonlinear urinary excretion observed in humans and wild-type mice, but not in Dpp-4 knockout mice. To elucidate the mechanisms underlying these complex phenomena, including DPP-4-related renal reabsorption of LNG, we employed physiologically-based pharmacokinetic (PBPK) modeling combined with a cluster Gauss-Newton method (CGNM). The CGNM facilitated the exploration of parameters in rat and human PBPK models for LNG and the determination of parameter identifiability. Through PBPK-CGNM analysis using reported autoradiography data ([14C]-LNG) in wild-type and Dpp-4-deficient rats, DPP-4-specific distributions of LNG in various tissues were clearly differentiated from nonspecific parts. By fitting to human plasma concentrations and urinary and fecal excretions of LNG after intravenous and oral administrations, multiple unknown PBPK parameters were simultaneously estimated by the CGNM. Notably, the amount of tDPP-4 and the reabsorption clearance for LNG-DPP-4 complexes were identifiable, indicating their critical role in explaining the complex nonlinear pharmacokinetics of LNG. Compared with previous PBPK analyses, the CGNM allowed us to incorporate greater model complexity (e.g., consideration of tDPP-4 expressions and invitro binding kinetics), ultimately resulting in a more accurate reproduction of LNG's TMDD. In conclusion, by considering LNG as a high-affinity probe for DPP-4, comprehensive PBPK-CGNM analyses suggested a dynamic whole-body distribution of DPP-4, including its involvement in the renal reabsorption of LNG.

A novel HER2-specific sensor based on DARPin_9–29 and albumin binding domain for real-time fluorescence-guided tumor detection in animal model of cancer

In animal models of cancer, targeted fluorescence bioimaging, performed non-invasively and in real time, is indispensable tool for assessing tumor location, spread of metastasis, and the therapeutic potential of anticancer drugs under development.To overcome the limitation of antibodies in bioimaging applications, small artificial scaffold proteins based on ankyrin repeats (DARPins, designed ankyrin repeat proteins) are used as tumor-associated antigen binders. In this study for the first time, we assessed the potential of DARPin_9–29, the human epidermal growth factor receptor 2 (HER2) subdomain I-specific protein, genetically fused with albumin binding domain (ABD) and conjugated with Cyanine5.5 as a NIR sensor for fluorescence bioimaging of HER2-positive cancer in animal model.In vivo biodistribution studies have revealed sufficient tumor-to-background ratios at 48 h (3.17 ± 0.55) and 72 h (3.49 ± 0.64) postinjection, providing excellent contrast between the primary tumor and tissue background and allowing clear breast tumor detection. Ex vivo biodistribution has shown that ABD module in DARP-ABD sensor prevents renal reabsorption and increases tumor accumulation in more than 10-folds compared to excreting organs.To verify if DARP-ABD-Cy5.5 can demarcate HER2-positive tumor in vivo, HER2-positive syngeneic breast cancer cell line with constitutive gene expression of luciferase eFFLuc, was created. The powerful combination of bioluminescence and fluorescence imaging let to track the fluorescent anti-HER2 DARP-ABD sensor in bioluminescent HER2-positive breast tumors.Our results validate DARP-ABD as a promising sensor for fluorescence-guided imaging of HER2-positive solid cancer, which can be used in the development of improved anticancer treatment strategies.

L-carnitine for valproic acid-induced toxicity.

Review the effectiveness and dosing of L-carnitine for valproic-acid induced toxicity. A literature review of the pharmacokinetics and clinical use of L-carnitine was performed. Valproic acid is a fatty acid used for numerous therapeutic indications ranging from epilepsy to bipolar disorder. The metabolism of valproic acid produces both therapeutic and toxic metabolites. Whilst it has a good safety profile, adverse effects of valproic acid in chronic use include hepatotoxicity ranging from transient elevation of liver enzymes to fulminant liver failure and hyperammonaemia with resultant encephalopathy. L-carnitine is an essential cofactor for mitochondrial fatty acid metabolism, which is an important source of energy in cardiac and skeletal muscle. Physiological concentrations of L-carnitine are maintained in man by exogenous dietary intake and endogenous synthesis. Following exogenous oral administration of L-carnitine, the bioavailability ranges from 14% to 18%. After bolus intravenous administration of L-carnitine in doses ranging from 20 to 100 mg/kg, the volume of distribution is 0.2-0.3 L/kg, and the fraction excreted unchanged in urine is 0.73-0.95, suggesting that renal clearance of L-carnitine is dose dependent due to saturable renal reabsorption at supraphysiological concentrations. There is evidence supporting the use of L-carnitine in treating hyperammonaemia and hepatotoxicity following chronic therapeutic use and after acute overdose of valproic acid, but the optimal dose and route of administration is unknown. Based on the pharmacokinetics of L-carnitine, we advocate the administration of L-carnitine for valproic-acid induced hyperammonaemia or hepatotoxicity as an intravenous loading dose of 5 mg/kg followed by a continuous intravenous infusion instead of the oral or intravenous boluses that are currently advocated.

Update on Tolvaptan for the Treatment of Refractory Ascites in Liver Cirrhosis

Ascites is the most prevalent complication of decompensated cirrhosis, and approximately 5%-10% of cirrhotic ascites will develop into refractory ascites (RA). With complicated pathogenesis, obscure treatment strategies and poor prognosis, it is still a challenge for physicians to manage RA properly. Tolvaptan (TLV) is a new type of non-peptide selective arginine vasopressin V2 receptor antagonist targeting at suppressing renal water reabsorption, promoting free water excretion and raising blood sodium levels, which provides a new option for the treatment of RA in liver cirrhosis. In this review, we summarized the mechanisms of TLV's effect and described its efficacy, safety and predictive factors of response in treating RA, intending to provide a supplement for clinical application of tolvaptan in the management of RA.

Abstract P456: Loss of Renal Resident Tissue Macrophages Reduces Nitric Oxide-Mediated Relaxation during Salt-Sensitive Hypertension

Salt-sensitive hypertension (SS-HTN) associates with increased renal sodium reabsorption, arterial dysfunction, and heightened pro-inflammatory cytokines such as interleukin 6 (IL-6). Renal resident tissue macrophages (rRTMs) function to both maintain tissue homeostasis and once activated, can secrete IL-6. We reported that loss of the rRTM population prevents SS-HTN but their influence on arterial reactivity has not been tested. We hypothesize that rRTM-induced IL-6 production impairs endothelial function. Wild-type (Wt) or rRTM-depleted (CX 3 CR 1 - EGFP+/+ ) male mice (12wks) were used. Mice were given the nitric oxide synthase (NOS) inhibitor, L-NAME (0.5mg/mL, in drinking water, 2wks) and allowed to washout (1-2wks) before fed normal chow (NC), high salt (HS) chow (4%) for 2 days (early salt-sensitive, eSS) or for 3wks HS (SS-HTN). eSS mice were salt-sensitive, but not yet hypertensive. Mice were also given HS chow alone (3wks). Serum was collected for systemic cytokines (Meso-Scale Discovery; n=4-15) and second-order mesenteric resistance arteries (MRAs) were obtained (n=3-5). Concentration response curves (CRCs) to phenylephrine (Phe) and acetylcholine (ACh) were performed in the presence or absence of potassium chloride (KCl) or L-NMMA. Serum IL-6 levels were not increased following HS diet alone, but concentrations trended higher during SS-HTN (1.46 ± 0.2 pg/mL vs. 1.07 ± 0.2 pg/mL NC). The nadir was observed in eSS mice, before the development of SS-HTN, and was prevented in rRTM-depleted mice (1.81 ± 0.3 pg/mL vs. 0.58 ± 0.17, **p&lt;0.001, grouped ANOVA). No differences were observed between NC-fed Wt and rRTM-depleted MRAs, but the development of SS-HTN did impair relaxation responses. Overall, ACh-mediated relaxation responses were generally lower in MRAs from rRTM-depleted mice compared to Wt. Interestingly, rRTM-depleted MRAs from SS-HTN animals exhibited a near complete inhibition of all relaxation responses with NOS inhibition (R max 6.20% ± 8 rRTM SS-HTN vs. 63.0% ± 10 Wt SS-HTN, *p&lt;0.05), suggesting greater dependence on NO-mediated relaxation. Together, these data suggest that rRTMs contribute to an early, hypertension-independent spike in IL-6 which may reduce endothelial function later during SS-HTN. We also show that rRTM-depletion affects the function of the resistance vasculature, including loss of non-NO-mediated relaxation during SS-HTN. These data suggest that renal-derived cytokines, via rRTMs, may influence endothelial function.

Paracellular Transport and Renal Tubule Calcium Handling: Emerging Roles in Kidney Stone Disease.

The kidney plays a major role in maintenance of serum calcium concentration, which must be kept within a narrow range to avoid disruption of numerous physiologic processes that depend critically on the level of extracellular calcium, including cell signaling, bone structure, and muscle and nerve function. This defense of systemic calcium homeostasis comes, however, at the expense of the dumping of calcium into the kidney tissue and urine. Because of the large size and multivalency of the calcium ion, its salts are the least soluble among all the major cations in the body. The potential pathologic consequences of this are nephrocalcinosis and kidney stone disease. In this review, we discuss recent advances that have highlighted critical roles for the proximal tubule and thick ascending limb in renal calcium reabsorption, elucidated the molecular mechanisms for paracellular transport in these segments, and implicated disturbances in these processes in human disease.

Impact of Sodium Glucose Cotransporter 2 Inhibitors (SGLT2i) Therapy on Dementia and Cognitive Decline.

Dementia is an age-related syndrome characterized by the progressive deterioration of cognition and capacity for independent living. Diabetes is often associated with cognitive decline and shares similar pathophysiological mechanisms with dementia, such as systemic inflammation, oxidative stress, insulin resistance, and advanced glycation end-products formation. Therefore, adequate diabetes management may reduce the risk of cognitive decline, especially in patients with other comorbidities and risk factors. The sodium glucose cotransporter inhibitors (SGLT2i) regulate renal glucose reabsorption by blocking the SGLT2 cotransporters located in the proximal tubules, causing glycosuria and intraglomerular pressure reduction. Their use helps to lower blood pressure by modifying sodium and water homeostasis; these drugs are also commonly used in the treatment of heart failure and chronic kidney disease, while recently, a potential neuroprotective role in the central nervous system has been suggested. The aim of our scoping review is to analyze current evidence about the potential neuroprotective effects of SGLT2i in adult patients. We performed a scoping literature review to evaluate the effect of SGLT2i on dementia, mild cognitive impairment (MCI) and Alzheimer's disease incidence and progression. The screening process was performed through different searches on PubMed and EMBASE, evaluating original works published up to January 2024. In conclusion, the use of SGLT2i could be associated with a neuroprotective effect in patients with diabetes, reducing the incidence or the progression of MCI and dementia. Further prospective studies are needed to validate this hypothesis and to evaluate the effectiveness of this class of drugs in normal glycemic profile patients.

A Review of Sotagliflozin: The First Dual SGLT-1/2 Inhibitor.

Sotagliflozin (trade name INFEPA) is a novel dual sodium-glucose cotransporter-1 and -2 (SGLT-1/2) inhibitor that was developed by Lexicon Pharmaceuticals. It has emerged as a promising therapy for managing heart failure and other cardiovascular complications associated with type 2 diabetes mellitus (T2DM). Its dual inhibition of SGLT-1 and SGLT-2 receptors uniquely decreases glucose absorption in the intestine in addition to decreasing renal glucose reabsorption, leading to improved glycemic control and cardio-reno protection. Clinical trials have demonstrated its efficacy in reducing cardiovascular death, heart failure hospitalizations, and urgent visits, particularly in T2DM patients with chronic kidney disease (CKD). The drug was approved in 2023 by the Food and Drug Administration for reducing cardiovascular death and heart failure in T2DM patients with CKD and those with heart failure, irrespective of diabetic status or ejection fraction. However, despite its considerable therapeutic potential, sotagliflozin does pose notable adverse effects, including diabetic ketoacidosis, genital infections, and diarrhea. As a result, it has faced regulatory challenges in certain regions, notably the United States. The Food and Drug Administration has so far withheld approval for sotagliflozin in the treatment of type 1 diabetes due to concerns about its safety profile, specifically the risk of diabetic ketoacidosis, although Lexicon Pharmaceuticals plans to submit another new drug application for this use in 2024. Further investigation and clinical trials are warranted to fully elucidate sotagliflozin's impact on diabetes and CKD.

Sodium-Glucose Co-Transporter 2 Inhibitors and the Risk of Genitourinary Infections at HbA1c ≥10%: A Population Health-Based Retrospective Review.

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are first-line treatment for type 2 diabetes. Evidence has shown a 3- to 5-fold increase in the risk of genitourinary infections with their use due to inhibition of renal glucose reabsorption, resulting in glucosuria. Increased glucosuria is thought to increase the risk of genitourinary infections at a greater degree in patients with a significantly elevated HbA1c (≥10%), and initiation of SGLT2i is often delayed in these patients. While a limited body of evidence exists indicating that A1c level is not an independent risk factor for SGLT2i-induced genitourinary infection, pragmatically this concern remains a barrier to SGLT2i utilization. Evaluate the real-world genitourinary (GU) infection rate in patients receiving SGLT2i with a baseline HbA1c ≥10% compared to patients with a baseline HbA1c <10%. This retrospective cohort study evaluated data from 5542 adult patients treated between January 2013 and January 2023, who were prescribed an SGLT2i. Data collected included sex, age, race/ethnicity, renal function, date of SGLT2i start, number of SGLT2i orders, name and dose of SGLT2i, HbA1c, and a predetermined set of diagnosis codes related to bacterial and fungal genitourinary infections. The primary outcome was the overall GU infection rate after SGLT2i initiation within groups of baseline HbA1c of ≥10% and <10%, and the secondary outcome was total GU infections within these same groups. The primary outcome was equivalent between those with HbA1c <10% and HbA1c ≥10% (0.0064 ± 0.0565 vs 0.0030 ± 0.0303 infection per month [mean ± standard deviation]; P < 0.0001 for both lower and upper bounds). There was no statistically significant difference in total GU infections between the same groups (0.027 ± 0.21 vs 0.015 ± 0.14, P = 0.11). Female gender and prior recurrent infection were associated with increased GU infection after SGLT2i. A baseline HbA1c ≥ 10% was not significantly associated with an increased risk of GU infection following the initiation of SGLT2i compared to those with a baseline HbA1c of <10%.

EValuating the Effect of periopeRaTIve empaGliflOzin on cardiac surgery associated acute kidney injury: rationale and design of the VERTIGO study.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a serious complication in patients undergoing cardiac surgery with extracorporeal circulation (ECC) that increases postoperative complications and mortality. CSA-AKI develops due to a combination of patient- and surgery-related risk factors that enhance renal ischemia-reperfusion injury. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) such as empagliflozin reduce renal glucose reabsorption, improving tubulo-glomerular feedback, reducing inflammation and decreasing intraglomerular pressure. Preclinical studies have observed that SGLT2i may provide significant protection against renal ischemia-reperfusion injury due to their effects on inadequate mitochondrial function, reactive oxygen species activity or renal peritubular capillary congestion, all hallmarks of CSA-AKI. The VERTIGO (EValuating the Effect of periopeRaTIve empaGliflOzin) trial is a Phase 3, investigator-initiated, randomized, double-blind, placebo-controlled, multicenter study that aims to explore whether empagliflozin can reduce the incidence of adverse renal outcomes in cardiac surgery patients. The VERTIGO study (EudraCT: 2021-004938-11) will enroll 608 patients that require elective cardiac surgery with ECC. Patients will be randomly assigned in a 1:1 ratio to receive either empagliflozin 10mg orally daily or placebo. Study treatment will start 5days before surgery and will continue during the first 7days postoperatively. All participants will receive standard care according to local practice guidelines. The primary endpoint of the study will be the proportion of patients that develop major adverse kidney events during the first 90days after surgery, defined as ≥25% renal function decline, renal replacement therapy initiation or death. Secondary, tertiary and safety endpoints will include rates of AKI during index hospitalization, postoperative complications and observed adverse events. The VERTIGO trial will describe the efficacy and safety of empagliflozin in preventing CSA-AKI. Patient recruitment is expected to start in May 2024.

Complex actions of sodium glucose transporter-2 inhibitors on lipids, calcific atherosclerosis, and bone density.

Inhibitors of sodium-glucose cotransporter-2 (SGLT2) lower renal glucose reabsorption and, thus, are used to treat patients with type 2 diabetes mellitus. Clinical trials coincidentally showed that SGLT2 inhibitors also benefitted patients with heart failure. This review explores the impact of SGLT2 inhibitors on other aspects of cardiovascular disease and skeletal health. In some, but not all, clinical and preclinical studies, SGLT2 inhibitors are found to reduce serum levels of free fatty acids and triglycerides. Their effects on total and low-density lipoprotein cholesterol and cardiac function also vary. However, SGLT2 inhibitors reduce lipid accumulation in the liver, kidney, and heart, and alter expression of lipid metabolism genes. Effects on free fatty acid uptake in abdominal fat depots depend on the location of adipose tissue. In male, but not female, mice, SGLT2 inhibitors reduce the atherosclerotic lesions and aortic calcium deposition. With respect to skeletal health, recent literature has reported conflicting associations with the risks of fracture and amputation. Studies suggest that SGLT2 inhibitors reduce tissue lipid accumulation, and in a sex-dependent manner, atherosclerosis and vascular calcification. However, their effects on lipid levels and bone health are complex and remain to be established.

Effects of Sodium-Glucose Cotransporter 2 Inhibitors on Transcription Regulation of AgRP and POMC Genes.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors regulate plasma glucose levels in patients with type 2 diabetes mellitus (T2DM) by inhibiting renal glucose reabsorption. This study investigated the impact of empagliflozin (EMPA), an SGLT2 inhibitor, on hypothalamic energy regulation. To directly investigate the role of SGLT2 inhibitors in the hypothalamus, we administered EMPA through intracerebroventricular (i.c.v.) injections into the murine ventricles. After dental cementing the i.c.v. cannula onto the skull, the mice were given 5 days to recover before receiving vehicle or EMPA (50 nM/2 μL) injections. In a high-fat diet (HFD)-induced obesity model, we determined the gene expression levels of agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) in the hypothalamus. Additionally, we assessed FoxO1 expression, which regulates AgRP and POMC gene transcription in hypothalamic cell lines. We found that EMPA directly influenced the expression of endogenous mRNA of POMC and AgRP, which are critical for energy homeostasis, and modulated their transcription in high-fat diet-induced obese mice. Additionally, EMPA affected the expression of FoxO1, a key transcriptional regulator of glucose homeostasis, thereby regulating the transcriptional activity of POMC and AgRP. These results indicate that EMPA significantly influences hypothalamic energy homeostasis, highlighting its potential as a regulator in obesity and T2DM management.