Search Results (260)

Background and Objectives: This study was designed to evaluate the potential cardioprotective effect of Exenatide against doxorubicin (DOX)-induced myocardial injury in rats by assessing scintigraphic alterations together with oxidative stress and inflammation. Materials and Methods: This study included 28 adult male Wistar albino rats that were randomized to 4 groups (n = 7): control, Exenatide alone, DOX (receiving DOX (18 mg/kg, i.p) on days 5–7; Exenatide + DOX (treated with Exenatide together with the DOX). On day 8, ECG, 99mTc-PYP scintigraphy, and biochemical parameters were evaluated. Results: DOX caused ECG abnormalities—bradycardia, significant QT prolongation, and elevated ST-segment amplitude—along with increased myocardial PYP uptake. Exenatide + DOX group significantly improved ECG changes. Biochemically, DOX markedly increased cardiac injury biomarkers (cTnT, CK, CK-MB), hepatic and renal injury markers (ALT, AST, LDH, BUN, creatinine), SIRT-1 level, inflammatory marker (NF-κB, TNF-α, IL-6, NO) and oxidative stress indicators (MDA, TOS), while decreasing antioxidant defenses (GSH, TAS, Nrf2). Exenatide co-treatment significantly attenuated all DOX-induced changes. Conclusions: Exenatide markedly attenuates DOX-induced cardiotoxicity by improving electrical conduction, reducing myocardial radiotracer uptake, and restoring oxidative–inflammatory balance through partial recovery of the SIRT-1/Nrf2/NF-κB pathway. Full article

Background/Objectives: NANOBODY^® molecules (VHHs) are attractive vectors for radiopharmaceuticals due to their small size and high target affinity, but rapid clearance and pronounced kidney retention limit their therapeutic applicability. Binding to serum albumin is a widely used strategy to prolong circulation, yet the respective contributions of albumin-binding affinity and molecular format remain insufficiently defined. This study aimed to systematically evaluate how affinity and valency modulate VHH pharmacokinetics. Methods: Four monovalent albumin-binding VHHs spanning nanomolar to micromolar affinities and two bivalent constructs were engineered, generated by fusing an albumin-binding VHH to an irrelevant non-binding VHH. All constructs incorporated a site-specific cysteine for DFO* conjugation, enabling uniform zirconium-89 labeling with high radiochemical purity. Pharmacokinetics were assessed in healthy mice using serial blood sampling and positron emission tomography. Blood and kidney exposure were quantified by non-compartmental analysis. Results: All albumin-binding constructs showed increased systemic exposure and reduced kidney uptake relative to a non-binding control. Nanomolar-affinity binders reached maximal exposure, and further affinity increases (K_D < ~100 nM) did not improve pharmacokinetics, suggesting a threshold. The micromolar binder showed intermediate exposure but still reduced renal retention compared with control. Valency effects were affinity-dependent. They were negligible at high affinity but pronounced at low affinity, where bivalency reduced systemic exposure and increased kidney uptake toward control levels. Conclusions: Albumin binding enables tuning of VHH pharmacokinetics in an affinity-dependent manner. Above an apparent affinity threshold, pharmacokinetics become format independent, whereas below this threshold, molecular format substantially influences systemic and renal disposition. Full article

Introduction: Radiotracer-based nuclear imaging, including positron emission tomography (PET) and single-photon emission computed tomography (SPECT), can complement conventional cross-sectional imaging in renal cell carcinoma (RCC) by providing biological characterisation of tumour metabolism, angiogenesis, hypoxia, and the tumour microenvironment. While computed tomography (CT) and magnetic resonance imaging (MRI) remain the diagnostic standard, accumulating evidence suggests that selected nuclear imaging techniques may offer incremental value in specific clinical scenarios. Methods: A narrative literature review was performed using PubMed, Embase, and Web of Science to identify preclinical, retrospective, and prospective studies evaluating PET and SPECT radiotracers in localised and metastatic RCC. Priority was given to meta-analyses, multicentre prospective trials, and studies with histopathological correlation. Results: [¹⁸F]fluorodeoxyglucose (FDG) PET/CT demonstrates limited sensitivity for primary renal tumours (pooled sensitivity of approximately 60%) but performs substantially better in metastatic and recurrent disease (pooled sensitivity and specificity of approximately 85–90%), where uptake correlates with tumour grade, progression-free survival, and overall survival. [^99mTc]sestamibi SPECT/CT differentiates oncocytoma and hybrid oncocytic/chromophobe tumours from malignant RCC with pooled sensitivity and specificity of around 85–90%, supporting its role in evaluating indeterminate renal masses rather than staging. Prostate-specific membrane antigen (PSMA) PET/CT shows high detection rates in clear-cell RCC, particularly in metastatic disease, with reported sensitivities of approximately 85–90% and management changes in up to 40–50% of selected cohorts. Carbonic anhydrase IX (CAIX)-targeted PET/CT enables the biologically specific visualisation of clear-cell RCC, achieving sensitivities and specificities in the range of 85–90% in prospective phase II and III trials for primary tumour characterisation. Fibroblast activation protein inhibitor (FAPI) PET/CT demonstrates high tumour-to-background uptake in early RCC studies, but evidence remains preliminary, with small cohorts and recognised non-specific uptake in benign inflammatory and fibrotic conditions. Conclusions: Radiotracer-based nuclear imaging provides complementary, biology-driven insights in RCC that extend beyond anatomical assessment. While most modalities remain adjunctive or investigational and are not recommended for routine use, selective application in carefully chosen clinical scenarios may enhance tumour characterisation, prognostication, and personalised treatment planning. Full article

Chronic kidney disease (CKD) is a major complication of diabetes, affecting approximately 30–40% of patients. In many cases, CKD progresses to end-stage renal disease (ESRD). The peptide apelin and its receptor, APLNR, which is expressed in the endothelial cells of renal blood vessels, play a key role in glucose uptake and the regulation of vasodilation in the afferent and efferent glomerular arterioles. Numerous studies have demonstrated that the apelinergic system is dysregulated in various pathologies, including CKD in people with diabetes. In recent years, the apelinergic system has emerged as a promising therapeutic target for several diseases, with various apelin analogs and inhibitors being developed. In this review, we summarize the most recent literature on apelin and its cellular mechanisms of action, highlighting the role of the apelinergic system in various pathologies and its impact on patients with CKD and diabetes. Additionally, we explore the currently available analogs and inhibitors and discuss their potential therapeutic applications. Full article

Glomerular filtration rate (GFR) is a key indicator of renal function. Traditional methods for GFR measurement have limitations including invasiveness, low spatial resolution, and lengthy protocols. Positron emission tomography (PET) radiotracers have emerged as promising tools for non-invasive, accurate, and dynamic renal function assessment. Objectives: This systematic literature review evaluates the clinical utility, and current evidence surrounding PET radiotracers used for GFR measurement in humans, emphasizing advances over conventional renal imaging modalities. Methods: A systematic literature search was conducted in PubMed, Web of Science, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, from database inception to November 2024. The search identified studies evaluating PET-based measurement of glomerular filtration rate (GFR) and renal perfusion. Inclusion criteria encompassed human studies using PET radiotracers (e.g., ⁶⁸Ga, ¹⁸F) with comparisons to reference standards (estimated GFR or serum creatinine). Two authors independently screened titles/abstracts, extracted data, and assessed bias using Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). Exclusions included animal studies, reviews, and non-English articles. Results: Eleven studies met inclusion criteria, with ⁶⁸Ga-EDTA showing the highest validation against reference standards such as ⁵¹Cr-EDTA plasma clearance, demonstrating strong correlation. PET imaging offered superior spatial–temporal resolution, enabling accurate split renal function assessment and quantitative analysis of both filtration and perfusion. ⁶⁸Ga-somatostatin analogues exhibited moderate correlations between renal SUV and estimated GFR, with post-PRRT uptake changes indicating early nephrotoxicity. Among novel tracers, ⁶⁸Ga-FAPI showed a strong inverse SUV–GFR relationship, reflecting renal fibrosis and suggesting potential as a chronic kidney disease (CKD) biomarker but requires further clinical validation. Limitations across studies include small sample sizes, retrospective designs, and variability in reference standards. Conclusions: PET radiotracers, particularly ⁶⁸Ga-EDTA, represent a significant advancement for non-invasive, quantitative GFR measurement with improved precision and renal anatomical detail compared to traditional methods. Future prospective, large-scale human studies with standardized protocols are needed to establish these PET tracers as routine clinical tools in nephrology. Integration of hybrid PET/MRI and novel tracer development may further enhance renal diagnostic capabilities. Full article

Objectives: Pretargeting strategies enhance the specificity and safety of radiopharmaceuticals by separating tumor targeting from radionuclide delivery. To address the rapid clearance and systemic exposure of directly labeled small-molecule agents, a DZ-1–based pretargeting system was developed, utilizing its broad-spectrum tumor-targeting characteristics. Methods: Three DZ-TCO precursors (DZ-1-TCO, DZ-Lys-TCO, and DZ-Lys-PEG₄-TCO) were synthesized and evaluated by near-infrared fluorescence imaging in HeLa and U87MG tumor-bearing mice. Two tetrazine probes (methyl-tetrazine and mono-substituted tetrazine) were labeled with ⁶⁸Ga to yield ⁶⁸Ga-DOTA-Me-Tz and ⁶⁸Ga-DOTA-H-Tz, whose stability was assessed in PBS and serum. Pretargeted PET imaging was performed using different precursor/probe combinations and pretargeting intervals (24, 48, and 72 h). Results: All precursors exhibited tumor accumulation peaking at 24 h and signal retention up to 96 h. Both ⁶⁸Ga-DOTA-Me-Tz and ⁶⁸Ga-DOTA-H-Tz maintained >85% radiochemical stability after 4 h. PET imaging identified DZ-Lys-TCO as the most effective precursor (1.98 ± 0.72 %ID/g, T/M 3.86 ± 0.91). Using ⁶⁸Ga-DOTA-H-Tz, the 48 h interval achieved optimal uptake (3.24 ± 0.95 %ID/g) with the highest tumor-to-muscle ratio (8.30 ± 3.39). Biodistribution confirmed rapid renal clearance, low off-target accumulation, and peak tumor uptake of 3.53 ± 1.76 %ID/g (T/M 10.9 ± 0.3 at 30 min). Conclusions: The DZ-TCO/⁶⁸Ga-DOTA-Tz pretargeting system enables high-contrast tumor imaging with low background. The combination of DZ-Lys-TCO and ⁶⁸Ga-DOTA-H-Tz at a 48 h interval provides optimal performance, representing a promising platform for precise and safe radiopharmaceutical imaging. Full article

FDG PET/CT often underperforms in characterizing hyper-enhancing, FDG-non-avid renal masses. We present two cases illustrating the potential of ⁶⁸Ga-NY104, a novel small-molecule tracer targeting carbonic anhydrase IX (CAIX), for this differential diagnosis. Both patients presented with a hyper-enhancing right renal mass suspicious for clear cell renal carcinoma (ccRCC) and subsequently underwent both ¹⁸F-FDG and ⁶⁸Ga-NY104 PET/CT, with histopathology and CAIX immunohistochemistry (IHC) as the reference standard. On ¹⁸F-FDG, both lesions were non-avid (SUVmax 2.6 and 2.2, Tumor-to-Liver Ratio [TLR] 0.87 and 0.69, respectively). However, on ⁶⁸Ga-NY104 PET/CT, Patient 1 (a 65-year-old man) showed intense, homogeneous uptake (SUVmax 26.0, TLR 4.64), while Patient 2 (a 67-year-old woman) showed negligible uptake (SUVmax 2.5, TLR 0.68). It was consistent with histopathology and IHC results that Patient 1 was CAIX-positive ccRCC, while Patient 2 was CAIX-negative hemangioma. Our preliminary cases suggest the potential utility of CAIX-targeted PET/CT imaging with ⁶⁸Ga-NY104 in differentiating ccRCC from benign mimickers like renal hemangioma, which warrants further prospective evaluation. Full article

Legumain (LGMN), a lysosomal cysteine protease, is crucial for tumor progression, invasion, and metastasis, making it a promising target for cancer imaging and therapy. This study developed novel ⁶⁷Ga-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)-conjugated LGMN-cleavable peptide probes ([⁶⁷Ga]Ga-NOTA-LCPs) composed of polyarginine and polyglutamic acid sequences linked by LGMN-cleavable sites for nuclear medicine imaging of LGMN activity. The probes were synthesized via fluorenylmethoxycarbonyl solid-phase peptide synthesis and radiolabeled in high radiochemical yields. In vitro assays with HCT116 cells showed significantly higher uptake of [⁶⁷Ga]Ga-NOTA-LCPs compared to non-cleavable controls, confirming efficient cleavage and cellular uptake. In vivo studies in tumor-bearing mice revealed rapid renal clearance, low non-specific binding, and favorable tumor-to-blood ratios, particularly for [⁶⁷Ga]Ga-NOTA-LCP-1. These results demonstrate the potential of [⁶⁷Ga]Ga-NOTA-LCPs as effective LGMN-responsive imaging agents, with further optimization needed to improve tumor specificity and reduce off-target accumulation. Full article

Background/Objectives: Ochratoxin A (OTA) is a widespread foodborne mycotoxin linked to chronic kidney disease of unknown etiology. Despite evidence from animal models showing OTA accumulation in the kidney, the molecular mechanisms underlying its renal disposition in humans remain only partially understood. Here, we identify human renal transporters responsible for OTA kidney accumulation, elimination, and establish Michaelis–Menten kinetics under matched conditions to directly compare transport mechanisms. We also aim to identify inhibition potential of these transport mechanisms with common dietary polyphenols. Methods: Mammalian cells and membrane vesicles overexpressing human renal transporters were used to screen and profile the uptake and efflux of OTA. Miquelianin, (-)-Epicatechin-3-O-gallate, myricetin, luteolin, and caffeic acid were tested as potential concentration-dependent transporter inhibitors. Results: We demonstrate that OTA is a substrate for human organic anion transporter (hOAT) 1 (K_m: 2.10 ± 0.50 μM, V_max: 396.9 ± 27.0 pmol/mg/min), hOAT3 (K_m: 2.58 ± 0.83 μM, V_max: 141.4 ± 30.3 pmol/mg/min), hOAT4 (K_m: 6.38 ± 1.45 μM, V_max: 96.9 ± 18.8 pmol/mg/min), and human organic anion transporting polypeptide (hOATP) 1A2 (K_m: 37.3 ± 6.2 μM, V_max: 801.0 ± 133.9 pmol/mg/min). Among efflux transporters, OTA was transported only by human breast cancer resistance protein (hBCRP), which has minimal renal expression. While none of the uptake transporters were potently inhibited (>90%) by polyphenols at 10 μM, luteolin inhibited hBCRP-mediated transport of OTA with an IC₅₀ of 22 μM and caffeic acid stimulated hBCRP-mediated efflux with an EC₅₀ of 713.8 μM, both of which are physiologically relevant intestinal lumen concentrations. Conclusions: Our results confirm that exposure to OTA will lead to renal accumulation and increased health risks in affected populations, necessitating increased scrutiny of our food sources. Full article

Background/Objectives: GPA is a PR3-ANCA–predominant small vessel vasculitis with organ involvement. Real-world, single-centre data are needed to interpret evolving therapies and phenotype patterns in national conditions. Material and Methods: Retrospective cohort study of consecutive GPA patients managed at the National Institute of Geriatrics, Rheumatology and Rehabilitation (Warsaw, Poland) from 1 September 2010 to 1 September 2025. Data included demographics, phenotype, BVAS, organ involvement, PR3/MPO-ANCA serology, and induction/maintenance therapies. Results: Fifty patients were included (54.0% men). Mean age was 52.5 years; mean BMI was 26.15 kg/m². Ear-nose-throat (ENT) disease was frequent: rhinosinusitis 76.0%, nasal cartilage destruction 64.0%, subglottic stenosis 34.0%. Pulmonary nodules occurred in 52.0%, cavitation in 28.0%, and diffuse alveolar haemorrhage in 34.0%. Renal involvement included haematuria in 42.0%, chronic kidney disease (CKD) in 32.0%, and rapidly progressive kidney disease in 22.0%. Orbital inflammation was 36.0%, and PR3-ANCA was positive in 70.0%. All patients received glucocorticoids for induction; cyclophosphamide 28/50 (56.0%), rituximab 6/50 (12.0%), and mycophenolate with methotrexate 6/50 (32%). Maintenance therapy included methotrexate (78.0%), mycophenolate (64.0%), rituximab (52.0%), and azathioprine (12.0%). Conclusions: This Polish single-centre cohort shows an ear-nose-throat-lung-kidney (ELK)-dominant, PR3-predominant GPA phenotype and frequent but variable kidney involvement. Over 2010–2025, practice changed toward rituximab-based strategies, steroid minimisation, selective use of plasma exchange, and early avacopan uptake, with tofacitinib for maintenance therapy as a possible new therapeutic option. Full article

Brown tumors (BTs) are rare osteolytic lesions that typically occur in association with primary or secondary hyperparathyroidism (PHP and SHP). Excessive secretion of parathyroid hormone induces increased bone resorption, resulting in lesions characterized by fibrosis, vascularization, and hemosiderin deposition. The most common sites include the jaws, ribs, pelvis, and long bones. Clinical manifestations may involve pain, swelling, or pathological fractures. We present the case of a mandibular BT in a 48-year-old female with chronic renal failure and secondary hyperparathyroidism. The patient exhibited progressive mandibular swelling with radiological features resembling an aggressive odontogenic or malignant lesion. Laboratory analysis confirmed markedly elevated parathyroid hormone levels, while scintigraphy demonstrated increased focal uptake in the mandible and ribs. Histopathological evaluation revealed multinucleated giant cells within a fibrous stroma, consistent with BT. Despite initiation of systemic endocrine therapy, the lesion continued to enlarge, necessitating complete surgical excision of the mandibular mass. This case underscores the diagnostic dilemmas of mandibular BT, which may closely mimic aggressive jaw pathologies. Importantly, while many BTs regress after systemic management of hyperparathyroidism, this case illustrates that surgical excision may be unavoidable in patients with unstable systemic status or progressive local disease. Comprehensive clinical, radiological, laboratory, and histopathological evaluation remains essential to ensure timely diagnosis and appropriate treatment. Full article

Background/Objectives: Lipid nanoparticles (LNPs) have demonstrated notable clinical success as advanced drug delivery systems. However, the development of novel covalently bonded ionizable lipids faces substantial technical challenges, as their modification is difficult and they have a high molecular weight. To address this issue, we report the use of host–guest complexes in supramolecular chemistry as functional lipid motifs for constructing LNPs. Methods: Ionizable amine β-cyclodextrin (amine β-CD)-derived host–guest amphiphilic lipid molecules (HGLs) were designed for the construction of multi-stage assembly supramolecular LNPs (MSLNPs). The structure–function relationships and stability of MSLNPs were explored by screening eight types of amine β-CDs and varying the ratio of HGL to yolk phosphatidylcholine. Stability screening and molecular dynamics simulations were performed to clarify the self-assembly mechanisms and optimal formulations, followed by a systematic evaluation of delivery performance. Results: MSLNPs showed a high drug-loading efficiency (> 30%), a rapid-response release in acidic environments, and multi-pathway cellular uptake. In vivo delivery experiments using ethylenediamine β-CD-based MSLNPs in mice revealed no significant immunogenicity, no significant abnormalities in organs/tissues or their functions, a unique biodistribution pattern, and pronounced renal targeting. The successful development of MSLNPs with acidic pH-responsive control, a high delivery efficiency, and renal-targeting properties simplifies LNP preparation. Conclusions: This study offers novel insights into the design of simplified LNPs and the optimization of targeted delivery, with potential applications in renal disease therapy. Full article

Two diphosphonates, etidronic acid (HEDP) and zoledronic acid (ZOL), were radiolabelled with ¹⁶¹Tb and evaluated as potential bone-targeting radiopharmaceuticals. Radiolabeling was performed at pH 7, achieving high radiolabeling yields (greater than 98%) and demonstrating excellent in vitro stability in saline and human serum. Both radiolabeled complexes exhibited hydrophilic behavior, a strong binding affinity to hydroxyapatite, and moderate to high plasma protein binding. Biodistribution studies in healthy Wistar rats demonstrated that ¹⁶¹Tb-HEDP and ¹⁶¹Tb-ZOL achieve high and stable skeletal uptake with rapid blood clearance and minimal soft tissue accumulation. ¹⁶¹Tb-HEDP favored higher initial bone localization, while ¹⁶¹Tb-ZOL showed lower renal and hepatic accumulation, indicating higher safety and selectivity. Compared to unchelated ¹⁶¹TbCl₃, both diphosphonate complexes exhibited significantly higher bone-to-kidney and bone-to-liver ratios, resulting in superior targeting. Complementary experiments with non-radioactive terbium were performed to investigate the redox behavior and confirm complex formation, providing valuable insight into the stability and binding modes of the ligands. Both terbium and the ligands displayed well-defined redox behavior within the potential range of −1 to 1.7 V, with complex formation evidenced by shifts in the oxidation peaks. Density functional theory (DFT) calculations further supported these findings, showing that both phosphonate groups of a ligand coordinate to Tb³⁺, while the hydroxyl groups in HEDP enable intermolecular hydrogen bonding, contributing to additional structural stabilization. Results encourage further investigations of ¹⁶¹Tb-labeled diphosphonates as promising candidates for radionuclide therapy of bone metastases and other skeletal diseases. Full article

Malnutrition afflicts millions of the world’s children and predisposes to death from diarrhea and infectious diseases. Children with severe acute malnutrition (SAM) are at highest risk. Our review of the endocrinology and metabolomics of SAM implicates critical roles for white adipose tissue and its regulatory hormones and growth factors in the adaptation to nutritional deprivation and the restoration of metabolic homeostasis: white adipose provides substrates and energy for hepatic glucose production and cardiopulmonary and central nervous system function, and products of fat metabolism inhibit muscle glucose uptake and utilization and spare muscle protein. Collectively, these effects maintain glucose availability for the brain, red blood cells, and renal medulla and conserve muscle mass. White adipose tissue also secretes leptin, which facilitates the immune response and may protect against mortality from infection. Euglycemia and survival in SAM are thereby prioritized over linear growth, which is suppressed owing to inhibition of insulin-like growth factor 1 production and action. Diversion of energy from growth serves to maintain essential bodily functions in critically ill malnourished children, who have limited energy reserves. Thus, short-term reductions in growth rate have adaptive benefits in SAM. Under favorable conditions, clinical and metabolic recovery are accompanied by catch-up growth, which can mitigate, and in many cases reverse, the stunting of growth in childhood. Nevertheless, clinical recovery can be complicated by preferential accrual of central fat and a relative deficiency of lean/skeletal mass, with potential long-term complications including insulin resistance, glucose intolerance, and metabolic syndrome. Full article

Type 2 diabetes (T2D) is a chronic metabolic disorder marked by insulin resistance and impaired glucose metabolism, with skeletal muscle being a major site of systemic glucose disposal. This review examines the bidirectional relationship between T2D and sarcopenia, and synthesizes current evidence on how skeletal muscle deterioration and insulin resistance interact to disrupt glucose homeostasis. We summarize molecular mechanisms by which physical exercise enhances glucose uptake via insulin-dependent and insulin-independent pathways, and review the ergogenic and metabolic effects of creatine monohydrate (CrM). We also evaluate studies combining CrM supplementation with resistance or aerobic training and their effects on glycaemic control, muscle mass and function. Overall, combined exercise and creatine supplementation show potential to improve glucose regulation and attenuate muscle loss in older adults and people with T2D. Available data indicate that CrM is well tolerated in healthy and clinical populations when used at recommended doses, with no consistent evidence of adverse renal or hepatic effects. Further large randomized trials are needed to define optimal dosing, training modalities and long-term benefits for metabolic outcomes. Full article