Search Results (67)

Background: Growth factor therapy often fails in diabetic foot ulcers (DFUs). The reason remains unclear. Standard differential expression analysis may miss functionally critical genes with modest expression changes. Methods: We performed a secondary computational analysis of a longitudinal DFU transcriptomic dataset (Dryad; 17 patients, 117 serial biopsy samples, 12-week follow-up). Co-expression networks were built separately for healed (n = 37) and non-healed (n = 80) samples. Virtual gene knockout (VGK) was used to rank genes by topological impact on network cohesion. Single-cell analysis (GSE165816) assessed the association between endogenous KIF13A expression and keratinocyte migration-related signatures. A conceptual Hill-equation simulation was used to illustrate the transport-signaling threshold relationship. Drug repurposing used DSigDB enrichment. An independent bulk DFU cohort (GSE134431) was used for external validation. Results: KIF13A showed no differential expression (log₂FC = 0.173, p = 0.263) yet ranked first by VGK topological impact. In keratinocytes, high KIF13A expression correlated with greater migration scores versus zero-detection cells (p = 0.0058). A clear threshold effect emerged: below the 30th expression percentile, EGF, PDGF, and FGF pathway activation scores remained near baseline. In a structural-equation model, transport activity negatively predicted inflammation (standardized β = −0.92, p < 0.001). HIF1A showed the strongest positive correlation with KIF13A in keratinocytes (Spearman ρ = 0.26, p < 0.001), and FOS showed a negative correlation in the single-cell analysis (ρ = −0.16, p < 0.001) and in the bulk longitudinal cohort (ρ = −0.32, p < 0.001, n = 117). Recurrent AKR1B1-related drug signatures nominated the aldose-reductase pathway, and epalrestat was therefore prioritized as a hypothesis-generating candidate compound rather than a direct top-ranked enrichment hit. External validation confirmed consistent upregulation of KIF13A (Fold-Change = 1.58, adj. p = 0.0075), EPN1, and CLIP1 in DFU tissue. Despite population-level upregulation, a subset of cells fell below the functional signaling threshold. Conclusions: These computational findings suggest that KIF13A-associated vesicle transport impairment may represent a candidate systems-level bottleneck for growth-factor responsiveness in DFUs, a network-level pattern not captured by standard differential-expression analysis. Epalrestat, an AKR1B1 inhibitor prioritized through recurrent AKR1B1-related drug signatures, is presented as a candidate compound for further evaluation. As the present analysis is observational and computational, the findings should be interpreted as hypothesis-generating; experimental perturbation studies and prospective clinical validation are required. Full article

Aldose Reductase (AR; AKR1B1) is an enzyme that plays a key role in the metabolism of glucose and other carbonyl compounds, and whose hyperactivity contributes to oxidative stress and vascular dysfunction. Despite decades of investigation into this enzyme, inhibitors have failed to translate into clinical application for Diabetic Retinopathy (DR). We argue that these failures might arise from non-selective inhibition, considering the dual roles of AR, which contribute not only to DR pathology but also support retinal health, as AR is an important detoxifying enzyme for aldehydes produced during oxidative stress. Here, we discuss missing structural information, despite more than one hundred crystal structures of AR in complex with inhibitors. Our review bridges this gap by discussing how recent advances in structural biology, e.g., fragment-based drug discovery and MicroED, provide novel ways to selectively modulate AR functions, offering advantages for the detection of weak, allosteric, or conformation-dependent binding events. Despite past challenges, we suggest that therapeutic targeting of AR to find new-generation inhibitors will become more effective once we have a clearer understanding of the requirements for selective inhibition of AR, blocking its pathological impact while preserving its physiological functions. By integrating fragment screening and structural biology, we outline a strategy to reinvigorate AR modulation as a viable retina-specific approach for managing DR, with potentially broader relevance toward multiple diabetic microvascular complications. Full article

Background/Objectives: Epalrestat (EPL), an aldose reductase inhibitor, exhibits poor aqueous solubility and limited ocular bioavailability, which significantly restricts its therapeutic efficacy in the treatment of diabetic retinopathy. To overcome these limitations, a novel nanostructured lipid carrier (NLCs)-laden contact lens system was developed to achieve sustained and enhanced ocular delivery of EPL. Methods: In this study EPL-loaded NLCs were prepared using Compritol^® 888 ATO (solid lipid), Labrafac™ WL 1349 (liquid lipid), and Solutol^® HS 15 (surfactant) using high-speed homogenization method. The formulations were statistically optimized using a D-optimal mixture design, considering globule size (Y₁), swelling index (Y₂), and drug release at 6 h (Y₃) as key responses. The optimized NLCs were incorporated into contact lenses via the soaking technique and evaluated for physicochemical properties, drug content, in vitro release, ex vivo corneal permeability, and in vivo ocular tolerance. Results: The optimized NLCs formulation showed a globule size of 41.85 ± 2.14 nm, zeta potential of −20.3 ± 1.8 mV, and entrapment efficiency of 93.32 ± 1.27%, indicating excellent physical stability with high drug encapsulation. The swelling index of the optimized NLCs-laden contact lens was 140.69 ± 4.32%, and the optical transmittance was 80.54 ± 1.12%, confirming adequate hydration and transparency for ocular use. The drug content was 96.32 ± 0.84%, ensuring uniform distribution throughout the hydrogel matrix. In vitro release studies demonstrated a sustained drug release of 98.12 ± 2.08% over 24 h, whereas ex vivo corneal permeation indicated significantly higher permeation (97.26 ± 1.95% at 6 h) compared with the control contact lens (38.14 ± 2.41% at 5 h). The in vivo Draize test confirmed that both blank and drug-loaded contact lenses were non-irritating and biocompatible. Conclusions: Thus, the optimized EPL NLCs-laden contact lens demonstrated enhanced corneal permeation, prolonged drug retention, and excellent ocular safety, offering a promising advancement in the management of diabetic retinopathy by improving bioavailability, reducing dosing frequency, and enhancing therapeutic efficacy. Full article

This study explores the design, synthesis and preliminary in silico screening of novel thiadiazole-isatin hybrid derivatives targeting diabetes mellitus. Building on thiadiazole and isatin compounds’ demonstrated antidiabetic potential, the research objectives were to design and synthesize thiadiazole-isatin hybrids and evaluate their antidiabetic potential. The methodology encompassed a literature review, computational screening using “molecular docking, ADME prediction, Lipinski’s rule”, and the synthesis of thiadiazole intermediates from thiosemicarbazide combined with isatin derivatives. The key findings revealed that compounds 2a and 2b exhibit favorable binding affinity with “human aldose reductase, monoglyceride lipase, GLP-1, and alpha-amylase”, satisfying Lipinski’s rule for optimal drug likeness. Docking scores ranged from −10.6 to −7.0 for 2a and −10.2 to −7.0 for 2b. Thiadiazole-isatin derivatives, particularly 2a and 2b, demonstrate promise as antidiabetic agents through multi-enzyme inhibition, warranting pre-clinical and in vitro validation. This research offers a novel therapeutic strategy for diabetes management and potential pharmaceutical lead compounds. Future directions include experimental validation, in vitro and in vivo efficacy studies, and structure–activity relationship exploration, contributing to innovative antidiabetic therapies. Full article

Background/Objectives: Dipeptidyl peptidase-4 (DPP-4) inhibitors are antidiabetic agents that regulate blood glucose by preventing the degradation of active incretin hormones. Although clinically effective, this drug class is associated with adverse effects, creating the need for new molecular scaffolds with improved safety and efficacy. Methods: We evaluated the antihyperglycemic activity of β-aminohydrazine and β-amino-N-acylhydrazone derivatives (LASSBio-2123, 2125, 2129, and 2130) using a combined in vivo and in silico approach. Male C57BL/6 mice underwent glucose tolerance tests (GTT) and dexamethasone-induced insulin resistance protocols. Hepatic and skeletal muscle glycogen levels, as well as GLUT4 mRNA expression, were quantified. In silico studies included ADMET predictions and molecular docking analyses against aldose reductase and glucokinase enzymes. MTT was performed on the pancreatic cell line MIN6 (Mus musculus). Results: Among the compounds tested, LASSBio-2129 demonstrated the most promising profile, with favorable ADMET parameters, metabolic stability, and high docking affinity for aldose reductase and glucokinase. In vivo, LASSBio-2129 (10 mg/kg, i.p.) reduced blood glucose, increased hepatic and muscle glycogen storage, and upregulated GLUT4 mRNA expression in skeletal muscle. Additionally, LASSBio-2129 improved insulin sensitivity in the dexamethasone-induced insulin resistance model, with effects comparable to sitagliptin. Conclusions: The combined pharmacological, docking, and ADMET analyses identified LASSBio-2129 as aldose reductase inhibitor candidate and glucokinase activator. Its ability to improve glucose tolerance, enhance glycogen storage, and increase GLUT4 expression highlights its potential as a promising molecule for the treatment of type 2 diabetes mellitus. Full article

Diabetic retinopathy (DR), traditionally considered a microvascular complication, is now recognized as a neuroinflammatory disorder involving retinal glial cells. Aldose reductase (AKR1B1), a key enzyme in the polyol pathway, has been implicated in the hyperglycemia-induced inflammatory response in various cell types, although its role in retinal Müller glial cells under acute glucose stress remains unclear. This study investigates AKR1B1 activity and its contribution to inflammatory signaling in MIO-M1 human Müller cells exposed to acute hyperglycemia. AKR1B1 expression and activity, as well as NF-κB activation and COX-2 expression, were evaluated. Sorbinil, a specific AKR1B1 inhibitor, was used to determine the enzyme’s contribution to acute hyperglycemia-induced inflammation. Acute high-glucose treatment significantly increased AKR1B1 activity and sorbitol accumulation without affecting cell viability. In addition, activation of NF-κB and increased expression of cyclooxygenase-2 (COX-2) were observed, both of which were significantly reduced by Sorbinil. Our findings highlight the role of macroglia as active contributors to early inflammatory events in DR and suggest that transient hyperglycemic spikes are sufficient to trigger AKR1B1-dependent glial activation. Full article

The rising prevalence of type 2 diabetes is linked to an increased risk of cardiovascular diseases, with the diabetic heart being particularly vulnerable to ischemia–reperfusion (IR) injury. Chronic hyperglycemia contributes to an increase in reactive oxygen species and impacts the homeostasis of biochemical pathways, including the polyol pathway, increasing susceptibility to damage. Aldose reductase (AR), a key enzyme in this pathway, has been targeted for therapeutic intervention, with AR inhibitors showing potential in mitigating diabetic complications. This study investigated IR injury in cardiomyocytes following high glucose exposure and assessed the AR inhibitor Epalrestat as a protective agent. Cardiomyocyte function was evaluated by measuring lactate dehydrogenase (LDH) release, FM1-43 membrane incorporation, cell viability, intracellular calcium accumulation, and superoxide anion formation. High glucose exposure and simulated IR led to increased LDH release, FM1-43 incorporation, intracellular calcium, and superoxide levels, alongside reduced cell viability in a dose-dependent manner. However, Epalrestat treatment during high glucose exposure significantly reduced IR-induced injury. These findings suggest that high glucose exacerbates IR injury in cardiomyocytes, with the polyol pathway playing a critical role. Targeting this pathway with AR inhibitors like Epalrestat may offer a protective strategy against diabetic heart complications. Full article

Background/Objectives: Diabetes mellitus is a group of chronic metabolic disorders characterized by persistent hyperglycemia. Aldose reductase, the first enzyme in the polyol pathway, plays a key role in the onset of long-term diabetic complications. Aldose reductase inhibition has been widely established as a potential pharmacotherapeutic approach to prevent and treat diabetes mellitus-related comorbidities. Although several promising aldose reductase inhibitors have been developed over the past few decades, they have failed in clinical trials due to unacceptable pharmacokinetic properties and severe side effects. This paper describes the design, synthesis, and pharmacological evaluation of four novel 5-halogenated N-indolylsulfonyl-2-fluorophenol derivatives (3a-d) as aldose reductase inhibitors. Methods: The design of compounds was based on a previously published lead compound (IIc) developed by our research group to enhance its inhibitory capacity. Compounds 3a-d were screened for their ability to inhibit in vitro partially purified aldose reductase from rat lenses, and their binding modes were investigated through molecular docking. Results: The presence of a sulfonyl linker between indole and o-fluorophenol aromatic rings is mandatory for potent aldose reductase inhibition. The 5-substitution of the indole core with halogens resulted in a slight decrease in the inhibitory power of 3a-c compared to IIc. Among halogens, bromine was the most capable of filling the selectivity pocket through hydrophobic interactions with Thr113 and Phe115 residues. Conclusions: Although our strategy to optimize the inhibitory potency of IIc via inserting halogen atoms in the indole scaffold was not fruitful, aromatic ring halogenation can be still utilized as a promising approach for designing more potent aldose reductase inhibitors. Full article

Advanced glycation end-products (AGEs) and oxidative stress are recognized as central contributors to the pathogenesis of age-related or diabetic cataracts, diabetic retinopathy (DR), and age-related macular degeneration (AMD). These glycation-related diseases are characterized by impaired redox balance and decreased glutathione (GSH) levels. This review aims to examine the mechanistic links between AGEs and GSH depletion across ocular tissues by integrating in vitro, ex vivo, in vivo, and clinical studies relevant to this topic. The multiple levels of evidence highlight GSH homeostasis as both a biomarker and therapeutic target in glycation-related ocular disorders. Therapeutic strategies aimed at restoring GSH homeostasis under glycation stress are categorized into four mechanistic domains: (I) promoting GSH supply and synthesis, (II) enhancing GSH recycling, (III) mitigating glycation stress, and (IV) reducing oxidative and nitrosative stress. Most of these strategies have been explored via different approaches, and experimental findings with various interventions have shown promise in restoring GSH balance and mitigating AGE-induced damage. A pathological link between GSH depletion and vascular endothelial growth factor (VEGF) overexpression is observed in DR and wet AMD. GSH-centered interventions act upstream to modulate redox homeostasis while anti-VEGF therapies target downstream angiogenesis. This study supports the rationale for a dual-targeting strategy that combines redox-based interventions with VEGF inhibition in glycation-related ocular diseases. Full article

Cataracts, characterized by the opacification of the eye lens, remain a leading cause of reversible blindness globally. Age and diabetes are key risk factors, and with the increasing aging and diabetic population, the global burden of cataracts is projected to rise significantly. Current treatment is predominantly surgical; however, pharmacological strategies could offer a non-invasive alternative with the potential to delay, prevent, or even reverse cataract progression. Recent research has enhanced our understanding of cataractogenesis, emphasizing oxidative stress as a key underlying mechanism, but also including other processes such as calcium dysregulation and altered lens homeostasis or specific events induced by hyperglycemia in diabetic cataracts. New therapeutic approaches have emerged considering the molecular mechanisms involved in cataracts, most of which focus on pharmacological agents with antioxidant properties. Additionally, small-molecule chaperones, aldose reductase inhibitors, and protein aggregation inhibitors have also demonstrated potential in stabilizing or restoring lens protein structure and transparency. While experimental results have shown encouraging results, further research is needed to optimize drug delivery systems to the lens, assess long-term safety, and confirm the clinical efficacy of these treatments. This article reviews current progress in pharmacological treatments for cataracts, outlining challenges and prospects for future integration into clinical practice. Full article

Aldose reductase (AR), a rate-limiting enzyme in the polyol pathway, mediates the conversion of several substrates, including glucose and galactose. In rodents, galactosemia induced by galactose feeding has been shown to develop peripheral nerve lesions resembling diabetic peripheral neuropathy. However, the mechanisms by which AR-mediated responses elicited Schwan cell lesions under galactosemic conditions remain unresolved. To investigate this, we examined the mechanism of high-galactose-induced damage mediated by AR using AR inhibitors such as ranirestat and epalrestat. The exposure of IMS32 Schwann cells under high-galactose conditions led to galactitol accumulation, the increased production of reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, impaired mitochondrial morphology and membrane potential, decreased glycolysis, and aberrant glycosylation. Under these experimental conditions, ranirestat inhibited intracellular galactitol in a dose-dependent manner, whereas epalrestat failed to inhibit it. Interestingly, even at low concentrations where epalrestat did not inhibit AR activity, it prevented increased ROS production, ER stress, decreased glycolysis, and aberrant RCA120-binding glycosylation; however, no effect of ranirestat on the glycosylation was observed. Epalrestat and ranirestat did not recover mitochondrial morphology. These findings suggest that ER stress is induced by aberrant glycosylation under galactosemic conditions and that epalrestat may be effective in maintaining proper glycosylation in Schwann cells in these conditions. Full article

Diabetes mellitus (DM) is a complex metabolic disorder characterized by chronic hyperglycemia, with aldose reductase playing a critical role in the pathophysiology of diabetic complications. This study aimed to investigate the efficacy of flavonoid compounds as potential aldose reductase inhibitors using a combination of molecular docking and molecular dynamics (MD) simulations. The three-dimensional structures of representative flavonoid compounds were obtained from PubChem, minimized, and docked against aldose reductase using Discovery Studio’s CDocker module. The top 10 compounds Daidzein, Quercetin, Kaempferol, Butin, Genistein, Sterubin, Baicalein, Pulchellidin, Wogonin, and Biochanin_A were selected based on their lowest docking energy values for further analysis. Subsequent MD simulations over 100 ns revealed that Daidzein and Quercetin maintained the highest stability, forming multiple conventional hydrogen bonds and strong hydrophobic interactions, consistent with their favorable interaction energies and stable RMSD values. Comparative analysis of hydrogen bond interactions and RMSD profiles underscored the ligand stability. MMPBSA analysis further confirmed the significant binding affinities of Daidzein and Quercetin, highlighting their potential as aldose reductase inhibitors. This study highlights the potential of flavonoids as aldose reductase inhibitors, offering insights into their binding interactions and stability, which could contribute to developing novel therapeutics for DM complications. Full article

The escalating global prevalence of diabetes mellitus (DM) over the past two decades has led to a persistent high incidence of diabetic retinopathy (DR), necessitating screening for early symptoms and proper treatment. Effective management of DR aims to decrease vision impairment by controlling modifiable risk factors including hypertension, obesity, and dyslipidemia. Moreover, systemic medications and plant-based therapy show promise in advancing DR treatment. One of the key mechanisms related to DR pathogenesis is the polyol pathway, through which aldose reductase (AR) catalyzes the conversion of glucose to sorbitol within various tissues, including the retina, lens, ciliary body and iris. Elevated glucose levels activate AR, leading to osmotic stress, advanced glycation end-product formation, and oxidative damage. This further implies chronic inflammation, vascular permeability, and angiogenesis. Our comprehensive narrative review describes the therapeutic potential of aldose reductase inhibitors in treating DR, where both synthetic and natural inhibitors have been studied in recent decades. Our synthesis aims to guide future research and clinical interventions in DR management. Full article

Rhodanine-3-acetic acid derivatives are attractive compounds with versatile effects. What is very important is that compounds of this type have many biological properties. They are tested, among others, as fluorescent probes for bioimaging and aldose reductase inhibitors. Rhodanine-3-acetic acid derivatives also have antibacterial, antifungal and anticancer activity. The presented work demonstrates that a slight change in the five-membered heterocyclic substituent significantly affects the properties of the compounds under consideration. Three rhodanine-3-acetic acid derivatives (A-1–A-3) were obtained in the Knoevenagel condensation reaction with good yields, ranging from 54% to 71%. High thermal stability of the tested compounds was also demonstrated above 240 °C. The absorption and emission maxima in polar and non-polar solvents were determined. Then, the possibility of using the considered derivatives for fluorescence bioimaging was checked. Compounds A-1 and A-2 were successfully used as fluorescent dyes of fixed cells of mammalian origin. In addition, biological activity tests against bacteria and fungi were carried out. Our results showed that A-1 and A-2 showed the most excellent antimicrobial activity among the newly synthesized compounds, especially against Gram-positive bacteria. Full article

Tetrazole heterocycle is a promising scaffold in drug design, and it is incorporated into active pharmaceutical ingredients of medications of various actions: hypotensives, diuretics, antihistamines, antibiotics, analgesics, and others. This heterocyclic system is metabolically stable and easily participates in various intermolecular interactions with different biological targets through hydrogen bonding, conjugation, or van der Waals forces. In the present review, a systematic analysis of the activity of tetrazole derivatives against type 2 diabetes mellitus (T2DM) has been performed. As it was shown, the tetrazolyl moiety is a key fragment of many antidiabetic agents with different activities, including the following: peroxisome proliferator-activated receptors (PPARs) agonists, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase (AR) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) agonists, G protein-coupled receptor (GPCRs) agonists, glycogen phosphorylases (GP) Inhibitors, α-glycosidase (AG) Inhibitors, sodium glucose co-transporter (SGLT) inhibitors, fructose-1,6-bisphosphatase (FBPase) inhibitors, IkB kinase ε (IKKε) and TANK binding kinase 1 (TBK1) inhibitors, and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). In many cases, the tetrazole-containing leader compounds markedly exceed the activity of medications already known and used in T2DM therapy, and some of them are undergoing clinical trials. In addition, tetrazole derivatives are very often used to act on diabetes-related targets or to treat post-diabetic disorders. Full article