Folate conjugated nanomedicines for selective inhibition of mTOR signaling in polycystic kidneys at clinically relevant doses.

Although rapamycin is a very effective drug for rodents with polycystic kidney disease (PKD), it is not encouraging in the clinical trials due to the suboptimal dosages compelled by the off-target side effects. We here report the generation, characterization, specificity, functionality, pharmacokinetic, pharmacodynamic and toxicology profiles of novel polycystic kidney-specific-targeting nanoparticles (NPs). We formulated folate-conjugated PLGA-PEG NPs, which can be loaded with multiple drugs, including rapamycin (an mTOR inhibitor) and antioxidant 4-hydroxy-TEMPO (a nephroprotective agent). The NPs increased the efficacy, potency and tolerability of rapamycin resulting in an increased survival rate and improved kidney function by decreasing side effects and reducing biodistribution to other organs in PKD mice. The daily administration of rapamycin-alone (1 mg/kg/day) could now be achieved with a weekly injection of NPs containing rapamycin (379 µg/kg/week). This polycystic kidney-targeting nanotechnology, for the first time, integrated advances in the use of 1) nanoparticles as a delivery cargo, 2) folate for targeting, 3) near-infrared Cy5-fluorophore for in vitro and in vivo live imaging, 4) rapamycin as a pharmacological therapy, and 5) TEMPO as a combinational therapy. The slow sustained-release of rapamycin by polycystic kidney-targeting NPs demonstrates a new era of nanomedicine in treatment for chronic kidney diseases at clinically relevant doses.

The use of advanced spectral imaging to reveal nanoparticle identity in biological samples.

Nanoparticles (NPs) have been used in drug delivery therapies, medical diagnostic strategies, and as current Covid-19 vaccine carriers. Many microscope-based imaging systems have been introduced to facilitate detection and visualization of NPs. Unfortunately, none can differentiate the core and the shell of NPs. Spectral imaging has been used to distinguish a drug molecule and its metabolite. We have recently integrated this technology to a resolution of 9 nm by using artificial intelligence-driven analyses. Such a resolution allowed us to collect many robust datapoints for each pixel of an image. Our analyses could recognize 45 spectral points within a pixel to detect unlabeled Ag-NPs and Au-NPs in single live cells and tissues (liver, heart, spleen and kidneys). The improved resolution and software provided a more specific fingerprinting for each single molecule, allowing simultaneous analyses of 990 complex interactions from the 45 points for each molecule within a pixel of an image. This in turn allowed us to detect surface-functionalization of Ag-NPs to distinguish the core from the shell of Ag-NPs for the first time. Our studies were validated using various laborious and time-consuming conventional techniques. We propose that spectral imaging has tremendous potential to study NP localization and identification in biological samples at a high temporal and spatial resolution, based primarily on spectral identity information.

Cyclic-RGDfK peptide conjugated succinoyl-TPGS nanomicelles for targeted delivery of docetaxel to integrin receptor over-expressing angiogenic tumours.

Docetaxel (DTX) is an anticancer drug that is used alone and in combination with other drugs to treat tumours. However, it suffers from the drawback of non-specific cytotoxicity. To improve the therapeutic potential of DTX, we report the synthesis of cRGDfK peptide-conjugated succinoyl-TPGS (tocopheryl polyethylene glycol succinate) nanomicelles for targeted delivery of DTX. Among RGD (Arg-Gly-Asp) peptides, cRGDfK peptide shows specificity towards αvß3 integrin receptors that are most commonly over-expressed in tumour cells. To cRGDfK peptide, succinoylated TPGS was synthesised and conjugated to cRGDfK peptide using a carbodiimide reaction. Peptide-conjugated DTX loaded nanomicelles (PDNM) displayed small particle size with a narrow distribution, controlled drug release and high physicochemical stability. Cytotoxicity, cellular uptake, apoptosis and anti-angiogenic comparisons of unconjugated nanomicelles to PDNM in DU145 human prostate cancer cells and HUVECs (Human Umblical Vein Endothelial Cells) clearly revealed the importance of the cRGDfK peptide in enhancing the drug delivery performance of nanomicelles. FROM THE CLINICAL EDITOR: Common to many chemotherapeutic agents for cancer, systemic toxicity remains a big concern. In this article, the authors attempted to address this issue by conjugating RGD based peptides to Docetaxel, which would target integrins expressed on tumor cell surface. The experimental data revealed enhanced drug delivery.

Hyperglycaemia enhances nitric oxide production in diabetes: a study from South Indian patients.

BACKGROUND: We have previously reported that increased glucose levels were associated with higher serum nitric oxide (NO) levels in fructose-fed insulin resistant rats. However, the relationship between hyperglycemia and serum NO level was not clear. Therefore, the present study was designed to find the association between hyperglycemia and serum NO levels in Type 2 diabetic (T2DM) patients and T2DM with cardiovascular complication. METHODS: Endothelial cells (HUVEC) were treated with of D-glucose (10-100mM), and NO levels and NOS gene expression was measured. Hyperglycaemia was induced in Sprague-Dawley rats, and serum NO levels were measured after 8 weeks. For clinical evaluation, five groups of patients were recruited: Control (CT, n=48), Type 2 diabetes (T2DM, n=26), T2DM with hypertension (DMHT, n=46), Coronary artery diseases (CAD, n=29) and T2DM with coronary artery diseases (DMCD, n=38). NO (nitrite + nitrate) levels were measured from human serum. RESULTS: We found a significant (p<0.05) and dose-dependent increase in NO levels in HUVEC cells after 4 hours of high glucose exposure. eNOS and iNOS gene expression was increased in HUVEC cells after different concentrations and time periods of glucose treatment. We also observed significant (149.1 ± 25 µM, p<0.01) increase in serum NO levels in hyperglycaemic rats compared to control (76.6 ± 13.2 µM). Serum NO level was significantly higher in T2DM (111.8 µM (81.7-122.4), p<0.001) and DMCD patients ((129.4 µM (121.2-143.5), p <0.001) but not in CAD patients (76.4 µM (70.5-87)), as compared to control (68.2 µM (56.4-82.3)). We found significantly lower NO levels (83.5 µM (60.5-122.9)) in subjects suffering from diabetes since more than 5 years, compared to subjects (115.3 µM (75.2-127.1), p<0.001) with less than 5 years. CONCLUSION: In conclusion, high NO levels were observed in South Indian diabetic patients. Higher glucose levels in serum might be responsible for activation of endothelial cells to enhance NO levels.