Kidney Accumulation Research Articles

Combining Metformin and Drug-Loaded Kidney-Targeting Micelles for Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease that leads to eventual renal failure. Metformin (MET), an AMP-activated protein kinase (AMPK) activator already approved for type 2 diabetes, is currently investigated for ADPKD treatment. However, despite high tolerability, MET showed varying therapeutic efficacy in preclinical ADPKD studies. Thus, newer strategies have combined MET with other ADPKD small molecule drug candidates, thereby targeting multiple ADPKD-associated signaling pathways to enhance therapeutic outcomes through potential drug synergy. Unfortunately, the off-target side effects caused by these additional drug candidates pose a major hurdle. To address this, our group has previously developed kidney-targeting peptide amphiphile micelles (KMs), which displayed significant kidney accumulation in vivo, for delivering drugs to the site of the disease. To mitigate the adverse effects of ADPKD drugs and evaluate their therapeutic potential in combination with MET, herein, we loaded KMs with ADPKD drug candidates including salsalate, octreotide, bardoxolone methyl, rapamycin, tolvaptan, and pioglitazone, and tested their in vitro therapeutic efficacy when combined with free MET. Specifically, after determining the 40% inhibitory concentration for each drug (IC40), the size, morphology, and surface charge of drug-loaded KMs were characterized. Next, drug-loaded KMs were applied in combination with MET to treat renal proximal tubule cells derived from Pkd1flox/-:TSLargeT mice in 2D proliferation and 3D cyst model. MET combined with all drug-loaded KMs demonstrated significantly enhanced efficacy as compared to free drugs in inhibiting cell proliferation and cyst growth. Notably, synergistic effects were found for MET and KMs loaded with either salsalate or rapamycin as determined by Bliss synergy scores. Together, we show drug synergy using drug-loaded nanoparticles and free MET for the first time and present a novel nanomedicine-based combinatorial therapeutic approach for ADPKD with enhanced efficacy. The online version contains supplementary material available at 10.1007/s12195-022-00753-9.

225Ac-MACROPATATE: A Novel α-Particle Peptide Receptor Radionuclide Therapy for Neuroendocrine Tumors.

Neuroendocrine tumors (NETs) express somatostatin receptors (SSTRs) 2 and 5. Modified variants of somatostatin, the cognate ligand for SSTR2 and SSTR5, are used in treatment for metastatic and locoregional disease. Peptide receptor radionuclide therapy with 177Lu-DOTATATE (DOTA-octreotate), a β-particle-emitting somatostatin derivative, has demonstrated survival benefit in patients with SSTR-positive NETs. Despite excellent results, a subset of patients has tumors that are resistant to treatment, and alternative agents are needed. Targeted α-particle therapy has been shown to kill tumors that are resistant to targeted β-particle therapy, suggesting that targeted α-particle therapy may offer a promising treatment option for patients with 177Lu-DOTATATE-resistant disease. Although DOTATATE can chelate the clinically relevant α-particle-emitting radionuclide 225Ac, the labeling reaction requires high temperatures, and the resulting radioconjugate has suboptimal stability. Methods: We designed and synthesized MACROPATATE (MACROPA-octreotate), a novel radioconjugate capable of chelating 225Ac at room temperature, and assessed its invitro and invivo performance. Results: MACROPATATE demonstrated comparable affinity to DOTATATE (dissociation constant, 21 nM) in U2-OS-SSTR2, a SSTR2-positive transfected cell line. 225Ac-MACROPATATE demonstrated superior serum stability at 37°C over time compared with 225Ac-DOTATATE. Biodistribution studies demonstrated higher tumor uptake of 225Ac-MACROPATATE than of 225Ac-DOTATATE in mice engrafted with subcutaneous H69 NETs. Therapy studies showed that 225Ac-MACROPATATE exhibits significant antitumor and survival benefit compared with saline control in mice engrafted with SSTR-positive tumors. However, the increased accumulation of 225Ac-MACROPATATE in liver and kidneys and subsequent toxicity to these organs decreased its therapeutic index compared with 225Ac-DOTATATE. Conclusion: 225Ac-MACROPATATE and 225Ac-DOTATATE exhibit favorable therapeutic efficacy in animal models. Because of elevated liver and kidney accumulation and lower administered activity for dose-limiting toxicity of 225Ac-MACROPATATE, 225Ac-DOTATATE was deemed the superior agent for targeted α-particle peptide receptor radionuclide therapy.

Development and comparison of 68Ga/18F/64Cu-labeled nanobody tracers probing Claudin18.2

Claudin 18.2 (CLDN18.2) is an emerging target for the treatment of gastric cancers. We aim to develop tracers to image the expression of CLDN18.2. A humanized nanobody targeting CLDN18.2 (clone hu19V3) was produced and labeled with 68Ga, 64Cu, and 18F. The tracers were investigated in subcutaneous and metastatic models established using two different mouse types (nude and Balb/c mice) and two different cell lines (CHO-CLDN18.2 and CT26-CLDN18.2). Gastric cancer patient-derived xenograft (PDX) models were further established for validation experiments. Three novel CLDN18.2-targeted tracers (i.e., [68Ga]Ga-NOTA-hu19V3, [64Cu]Cu-NOTA-hu19V3, and [18F]F-hu19V3) were developed with good radiochemical yields and excellent radiochemical purities. [68Ga]Ga-NOTA-hu19V3 immuno-positron emission tomography (immunoPET) rapidly delineated subcutaneous CHO-CLDN18.2 lesions and CT26-CLDN18.2 tumors, as well as showing excellent diagnostic value in PDX models naturally expressing CLDN18.2. While [68Ga]Ga-NOTA-hu19V3 had high kidney accumulation, [64Cu]Cu-NOTA-hu19V3 showed reduced kidney accumulation and improved image contrast at late time points. Moreover, [18F]F-hu19V3 was developed via click chemistry reaction under mild conditions and precisely disseminated CHO-CLDN18.2 lesions in the lungs. Furthermore, region of interest analysis, biodistribution study, and histopathological staining results correlated well with the invivo imaging results. Taken together, immunoPET imaging with the three tracers can reliably visualize CLDN18.2 expression.

Sodium Chloride Induces Human Tubular Epithelial Cell CCL26 Expression That Associates With Monocyte Accumulation in the Human Kidney

Sodium Chloride Induces Human Tubular Epithelial Cell CCL26 Expression That Associates With Monocyte Accumulation in the Human Kidney

Selenium-enriched yeast modulates the metal bioaccumulation, oxidant status, and inflammation in copper-stressed broiler chickens.

Copper (Cu) could be seriously hazardous when present at excessive levels, despite its vital contribution to various cellular processes. Selenium-enriched yeast (SeY) was reported to improve the health and metabolic status in broiler chicken. Hence, our study was endeavored to illustrate the mitigating efficacy of SeY on Cu-induced hepatic and renal damage. Cobb chicks aged 1 day were allocated into four experimental groups and offered a basal diet, SeY (0.5 mg/kg), CuSO4 (300 mg/kg), or SeY plus CuSO4 in their diets for 42 days. Our results revealed that SeY supplement antagonized significantly the Cu accumulation in livers and kidneys of exposed birds. Marked declines were also detected in the AST, ALT, urea, and creatinine levels, besides marked increases in total protein, glycerides, and cholesterol in the SeY-supplemented group. Moreover, enhancement of cellular antioxidant biomarkers (superoxide dismutase, CAT, GPx, and GSH) along with lowered MDA contents were achieved by SeY in hepatic and renal tissues. Further, SeY exerted a noteworthy anti-inflammatory action as indicated by decreased inflammatory biomarkers (IL-1β and TNF-α) and NO levels in both organs. Noticeable histopathological alterations of both organs further validated the changes in the markers mentioned above. To sum up, our findings indicate that SeY can be considered a potential feed supplement for alleviating Cu-induced hepatic and renal damage in broilers, possibly via activation of antioxidant molecules and lessening the inflammatory stress.

Hydrogenated Germanene Nanosheets as an Antioxidative Defense Agent for Acute Kidney Injury Treatment.

Acute kidney injury (AKI) is a sudden kidney dysfunction caused by aberrant reactive oxygen species (ROS) metabolism that results in high clinical mortality. The rapid development of ROS scavengers provides new opportunities for AKI treatment. Herein, the use of hydrogen-terminated germanene (H-germanene) nanosheets is reported as an antioxidative defense nanoplatform against AKI in mice. The simulation results show that 2D H-germanene can effectively scavenge ROS through free radical adsorption and subsequent redox reactions. In particular, the H-germanene exhibits high accumulation in injured kidneys, thereby offering a favorable opportunity for treating renal diseases. In the glycerol-induced murine AKI model, H-germanene delivers robust antioxidative protection against ROS attack to maintain normal kidney function indicators without negative influence in vivo. This positive in vivo antioxidative defense in living animals demonstrates that the present H-germanene nanoplatform is a powerful antioxidant against AKI and various anti-inflammatory diseases.

Effects of Temperature and Different Feed Uptake on Mercury (Hg) and Cadmium (Cd) Accumulation in Nile Tilapia

Climate warming due to increases in atmospherictemperature and heavy metal contamination constitutesa major issue for the aquatic ecosystem. Heavy metal toxicity hinges on an organism’s tolerable limit ofexposure to these elements, and in the aquatic environment, higher temperatures enhances this toxicity infish. The purpose of this study was to investigate the combined effects of higher temperature and differentfeed uptake on Hg and Cd accumulation in Nile tilapia (Oreochromis niloticus). Fish were exposed to asingle concentration of 10 μg/l mercury (Hg) or 100 μg/l cadmium (Cd) for 30 days under 24 °C (roomtemperature) and 32 °C (elevated temperature) conditions in a 7-L aquaria. The feed used in this experimentcomprised pellets, water and pellets, and water and silkworms, in combination with temperature andheavy metal exposure. Results demonstrated Hg and Cd accumulation in flesh, kidney and liver increasedwith increasing temperature. The influence of different uptake mediahas an effect onHg and Cdconcentration levels in fish organs. The order of Hg and Cd accumulation in organs, from the highest levelto the lowest, was kidney, liver and flesh.

Role of insulin action in the pathogenesis of diabetic complications.

Among the various pathological conditions associated with type 2 diabetes, insulin resistance has long been reported to be a potent risk factor for diabetic complications. The liver, skeletal muscle, and adipose tissue are the major organs of action of insulin in systemic glucose metabolism, but insulin receptors and their downstream insulin signaling molecules are also constitutively expressed in vascular endothelial cells, vascular smooth muscle, and monocytes/macrophages. Forkhead box class O family member proteins (FoxOs) of transcription factors are essential regulators of cellular homeostasis, including glucose and lipid metabolism, oxidative stress response and redox signaling, cell cycle progression and apoptosis. In vascular endothelial cells, FoxOs strongly promote atherosclerosis via suppressing nitric oxide production and enhancing inflammatory responses. In liver sinusoidal endothelial cells, FoxOs induces hepatic insulin resistance by inducing nitration of insulin receptor in hepatocytes. Insulin resistance in adipose tissue limits capacity of lipid accumulation in adipose tissue, which promotes ectopic lipid accumulation and organ dysfunction in liver, vascular, and kidney. Modulation of insulin sensitivity in adipose tissue to induce healthy adipose expansion is expected to be a promising strategy for diabetic complications.

Influence of homoarginine on creatine accumulation and biosynthesis in the mouse.

Organisms obtain creatine from their diet or by de novo synthesis via AGAT (L-arginine:glycine amidinotransferase) and GAMT (Guanidinoacetate N-methyltrasferase) in kidney and liver, respectively. AGAT also synthesizes homoarginine (hArg), low levels of which predict poor outcomes in human cardiovascular disease, while supplementation maintains contractility in murine heart failure. However, the expression pattern of AGAT has not been systematically studied in mouse tissues and nothing is known about potential feedback interactions between creatine and hArg. Herein, we show that C57BL/6J mice express AGAT and GAMT in kidney and liver respectively, whereas pancreas was the only organ to express appreciable levels of both enzymes, but no detectable transmembrane creatine transporter (Slc6A8). In contrast, kidney, left ventricle (LV), skeletal muscle and brown adipose tissue must rely on creatine transporter for uptake, since biosynthetic enzymes are not expressed. The effects of creatine and hArg supplementation were then tested in wild-type and AGAT knockout mice. Homoarginine did not alter creatine accumulation in plasma, LV or kidney, whereas in pancreas from AGAT KO, the addition of hArg resulted in higher levels of tissue creatine than creatine-supplementation alone (P < 0.05). AGAT protein expression in kidney was downregulated by creatine supplementation (P < 0.05), consistent with previous reports of end-product repression. For the first time, we show that hArg supplementation causes a similar down-regulation of AGAT protein (P < 0.05). These effects on AGAT were absent in the pancreas, suggesting organ specific mechanisms of regulation. These findings highlight the potential for interactions between creatine and hArg that may have implications for the use of dietary supplements and other therapeutic interventions.

Omeprazole Prevents Colistin-Induced Nephrotoxicity in Rats: Emphasis on Oxidative Stress, Inflammation, Apoptosis and Colistin Accumulation in Kidneys.

The clinical value of colistin, a polymyxin antibiotic, is limited by its nephrotoxicity. Omeprazole is a commonly prescribed proton pump inhibitor. The current study aimed to evaluate the effects of the concomitant administration of omeprazole on colistin-induced nephrotoxicity in rats. Omeprazole significantly ameliorated colistin nephrotoxicity as evidenced by prevention in the rise in the serum level of creatinine, urea and cystactin C as well as urinary N-acetylglucosamine activity. This was confirmed by histological studies that indicated a decreased incidence of interstitial nephritis, degenerative cortical changes and collagen deposition. This was accompanied by the prevention of oxidative stress as omeprazole significantly inhibited the lipid peroxidation, glutathione depletion and enzymatic exhaustion of superoxide dismutase as well as catalase. Additionally, omeprazole inhibited the expression of interleukin-6 and tumor necrosis factor-α. Further, omeprazole inhibited the colistin-induced rise in Bax and the down-regulation of Bcl2 mRNA expression. An assessment of the serum levels of colistin revealed that omeprazole had no significant impact. However, it was observed that omeprazole significantly inhibited the accumulation of colistin in kidney tissues. In conclusion, omeprazole protects against colistin-induced nephrotoxicity. This can be attributed to, at least partly, omeprazole’s anti-oxidant, anti-inflammatory and anti-apoptotic activities in addition to its ability to prevent the toxic accumulation of colistin in kidneys.

Characterization of cellular senescence in doxorubicin-induced aging mice.

With a rise in the need to develop anti-aging drugs, a growing number of in vivo studies evaluating the efficacy of potential drug candidates have used doxorubicin-induced aging mice. However, changes in the biomarkers of senescent cells have not been reported in detail in these animals. To lay a foundation for the use of doxorubicin-induced aging mice, we examined the biomarkers of hepatic and renal senescent cells in these mice. We found that the 5mg/kg doxorubicin dose is optimal to induce cellular senescence in mice. Subsequently, using this dose, we found that doxorubicin-induced an increase in senescence-associated β-galactosidase (SA-β-gal) positive cells in the kidney and lipofuscin accumulation in the liver. Some markers of senescent cells (p21WAF1/CIP1, p16INK4A, and γH2AX) were also significantly upregulated by doxorubicin and then counteracted by metformin treatment. These preliminary findings support the application of doxorubicin-induced aging mice as an animal model to evaluate the efficacy of anti-aging drug candidates.

Hydrogels for localized chemotherapy of liver cancer: a possible strategy for improved and safe liver cancer treatment

The systemic drug has historically been preferred for the treatment of the majority of pathological conditions, particularly liver cancer. Indeed, this mode of treatment is associated with adverse reactions, toxicity, off-target accumulation, and rapid hepatic and renal clearance. Numerous efforts have been made to design systemic therapeutic carriers to improve retention while decreasing side effects and clearance. Following systemic medication, local administration of therapeutic agents allows for higher ‘effective’ doses with fewer side effects, kidney accumulation, and clearance. Hydrogels are highly biocompatible and can be used for both imaging and therapy. Hydrogel-based drug delivery approach has fewer side effects than traditional chemotherapy and can deliver drugs to tumors for a longer time. The chemical and physical flexibility of hydrogels can be used to achieve disease-induced in situ accumulation as well as subsequent drug release and hydrogel-programmed degradation. Moreover, they can act as a biocompatible depot for localized chemotherapy when stimuli-responsive carriers are administrated. Herein, we summarize the design strategies of various hydrogels used for localized chemotherapy of liver cancer and their delivery routes, as well as recent research on smart hydrogels.

MO443: Accumulation of REG-1Α in Proximal Tubules of a Rat Model of Chronic Kidney Disease: A New Biomarker at the Interface Between Renal Impairment and Neurodegenerative Diseases

Abstract BACKGROUND AND AIMS Chronic kidney disease (CKD) increases the risk of developing cognitive dysfunction and it has been identified as a modifiable risk factor for Alzheimer's disease (AD) [1]. Regenerating family member 1 alpha (Reg-1α) protein, originally identified as a 16 kDa polypeptide in the pancreas, is increased in cerebrospinal fluid (CSF) and in neurons of AD patients [2, 3]. Reg-1α is also elevated in blood in inflammatory conditions and chronic illnesses such as diabetes and interestingly, in patients with renal function impairment [4, 5]. It is not known whether Reg-1α is synthesized in the kidney or the modifications observed in CKD are merely due to a decline in the glomerular filtration rate. The aim of our study was to localize and quantify the Reg-1α protein in the kidneys of normal rats or CKD rats (5/6 nephrectomized rats) and determine, in a second time, if serum Reg-1α level is a suitable marker for assessment of renal function. As Reg-1a is able to cross the altered blood-brain barrier, it might be a new interesting biomarker at the interface between renal impairment and neurodegenerative diseases. METHOD A total of 16 3-month-old rats were randomly allocated to 5/6 nephrectomy (Nx) or Sham operation. Three months after surgery, serum creatinine and urea, systolic blood pressure (SBP) were measured and renal fibrosis (Sirius Red) was quantified. The expression of Reg-1α was evaluated by double-immunofluorescence using anti-Reg-1α and anti-Aquaporin-1 (Aqp-1) (as a proximal tubule marker) antibodies to determine the localization of Reg-1α in the kidney. RESULTS 5/6Nx rats showed increased serum creatinine levels (97.3 ± 17.6 versus Sham 26.3 ± 0.8 µmol/L; P &amp;lt; 0.05) and serum urea levels (23.9 ± 8.9 versus Sham 4.7 ± 0.1 mmol/L). They also had a higher SBP (158 ± 12 versus Sham 133 ± 5 mmHg) and renal fibrosis increased in the 5/6Nx group (8.1 ± 1.5 versus Sham 2.7 ± 0.2% staining). The double-immunofluorescence revealed an increased expression of Reg-1α of 5/6Nx rats compared with the Sham group. This expression seemed to be specific to the cytoplasm of the proximal tubules, with a ring-shaped distribution (preliminary results, Figure 1). CONCLUSION Our data show, for the first time, a proximal tubule-specific accumulation in Reg-1α in CKD suggesting an influence of impaired renal function on Reg-1α accumulation. Further assessment of Reg-1a in the blood, the blood-brain barrier and neuroinflammation status in this model is needed to better understand the potential effect of kidney accumulation of Reg-1α on brain dysfunction. Should this effect be confirmed, Reg-1α would be a new actor involved in the kidney-brain dialogue.

Modified chitosan for effective renal delivery of siRNA to treat acute kidney injury

Acute kidney injury (AKI) is characterized by a sudden decrease in renal function and impacts growing number of people worldwide. RNA interference (RNAi) showed potential to treat diseases with no or limited conventional therapies, including AKI. Suitable carriers are needed to protect and selectively deliver RNAi to target cells to fully explore this therapeutic modality. Here, we report on the synthesis of chitosan modified with α-cyclam-p-toluic acid (C-CS) as a novel siRNA carrier for targeted delivery to injured kidneys. We demonstrate that conjugation of the α-cyclam-p-toluic acid to chitosan imparts the C-CS polymer with targeting and antagonistic properties to cells overexpressing chemokine receptor CXCR4. In contrast, the parent α-cyclam-p-toluic acid showed no such properties. Self-assembled C-CS/siRNA nanoparticles rapidly accumulate in the injured kidneys and show long retention in renal tubules. Apoptosis and metabolic and inflammatory pathways induced by p53 are important pathological mechanisms in the development of AKI. Nanoparticles with siRNA against p53 (sip53) were formulated and intravenously injected for attenuation of IRI-AKI. Due to the favorable accumulation in injured kidneys, the treatment with C-CS/sip53 decreased renal injury, extent of renal apoptosis, macrophage and neutrophil infiltration, and improved renal function. Overall, our study suggests that C-CS/siRNA nanoparticles have the potential to effectively accumulate and deliver therapeutic siRNAs to injured kidneys through CXCR4 binding, providing a novel way for AKI therapy.

Study of Renal Accumulation of Targeted Polycations in Acute Kidney Injury.

Acute kidney injury (AKI) is a global healthcare burden characterized by rapid loss of renal function and high morbidity and mortality. Chemokine receptor CXCR4 participates in the renal infiltration of immune cells following injury and in local inflammatory enhancement. Injured renal tubule cells overexpress CXCR4, which could be used as a target for improved drug delivery in AKI. Plerixafor is a small-molecule CXCR4 antagonist that has shown beneficial effects against AKI and has been previously developed into a polymeric analog (polymeric plerixafor, PP). With the goal of gaining a better understanding of how overall charge and hydrophilicity affect renal accumulation of PP, we have synthesized PP copolymers containing hydroxyl, carboxyl, primary amine, and alkyl moieties using Michael-type addition copolymerization. All synthesized copolymers showed excellent CXCR4-binding and inhibiting ability in vitro and improved cellular uptake in hypoxia-reoxygenation stimulated mouse tubule cells. Analysis of serum protein binding revealed that polymers with hydroxyl group modification showed the least amount of protein binding. Biodistribution of the polymers was tested in a unilateral ischemia reperfusion-induced AKI mouse model. The results showed significant differences in accumulation in the injured kidneys depending on the net charge and hydrophilicity of the polymers. The findings of this study will guide the development of polymeric drug carriers for targeted delivery to injured kidneys for better AKI therapy.

Ochratoxin A potentiates citrinin accumulation in kidney and liver of rats.

Ochratoxin A (OTA) and citrinin (CTN) are nephrotoxic mycotoxins often found together in grain. The aim of this study was to measure their accumulation in the kidney and liver of adult male Wistar rats, see how it would be affected by combined treatment, and to determine if resveratrol (RSV) would decrease their levels in these organs. The rats received 125 or 250 mg/kg bw of OTA by gavage every day for 21 days and/or 20 mg/kg bw of CTN a day for two days. Two groups of rats treated with OTA+CTN were also receiving 20 mg/kg bw of RSV a day for 21 days. In animals receiving OTA alone, its accumulation in both organs was dose-dependent. OTA+CTN treatment resulted in lower OTA but higher CTN accumulation in both organs at both OTA doses. RSV treatment increased OTA levels in the kidney and liver and decreased CTN levels in the kidney. Our findings point to the competition between CTN and OTA for organic anion transporters 1 and 3.

A translational rat model to assess glomerular function changes with vancomycin

Vancomycin (VAN) causes acute kidney injury as defined by serum creatinine (SCr) increase. Glomerular filtration rate (GFR) is the gold standard for defining kidney function, and SCr is often used as a GFR surrogate; however, SCr changes can lag behind acute functional decline. We sought to define the rate and extent of GFR change for VAN in a translational rat model. Male Sprague Dawley rats received VAN 150 mg/kg/day intravenously (n=6) or saline (n=5) once daily followed by an intravenous injection of fluorescein isothiocyanate-sinistrin (FITC-sinistrin) for 3 days. FITC-sinistrin fluorescence was monitored transdermally prior to VAN administration and daily during treatment. GFR was calculated from FITC-sinistrin clearance. A mixed-effects model compared urinary biomarkers and GFRs between treatments and across days of dosing. Urinary biomarkers for injury and GFR were compared between treatment groups and correlated with VAN kidney accumulation. Mean GFR for saline-treated animals was 1.07, 1.20, 1.15 and 1.24 mL/min/100g body weight (b.w.) pre-treatment and at Days 1-3, respectively. VAN-treated rats had lower GFR after treatment (0.457, 0.584 and 0.759 mL/min/100g b.w. on Days 1-3, respectively; P ≤ 0.05). KIM-1 and clusterin were elevated on Day 1 for VAN-treated animals. The relationship between VAN accumulation in the kidney with GFR and biomarkers followed a four-parameter Hill slope (R2=0.6 and R2=0.9, respectively). Rats receiving VAN had a significant decline in GFR immediately following the first dose, which correlated with increasing VAN concentrations in the kidney and urinary biomarkers.

A Comparison of Evans Blue and 4-(p-Iodophenyl)butyryl Albumin Binding Moieties on an Integrin αvβ6 Binding Peptide.

Serum albumin binding moieties (ABMs) such as the Evans blue (EB) dye fragment and the 4-(p-iodophenyl)butyryl (IP) have been used to improve the pharmacokinetic profile of many radiopharmaceuticals. The goal of this work was to directly compare these two ABMs when conjugated to an integrin αvβ6 binding peptide (αvβ6-BP); a peptide that is currently being used for positron emission tomography (PET) imaging in patients with metastatic cancer. The ABM-modified αvβ6-BP peptides were synthesized with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid (DOTA) chelator for radiolabeling with copper-64 to yield [64Cu]Cu DOTA-EB-αvβ6-BP ([64Cu]1) and [64Cu]Cu DOTA-IP-αvβ6-BP ([64Cu]2). Both peptides were evaluated in vitro for serum albumin binding, serum stability, and cell binding and internalization in the paired engineered melanoma cells DX3puroβ6 (αvβ6 +) and DX3puro (αvβ6 −), and pancreatic BxPC-3 (αvβ6 +) cells and in vivo in a BxPC-3 xenograft mouse model. Serum albumin binding for [64Cu]1 and [64Cu]2 was 53–63% and 42–44%, respectively, with good human serum stability (24 h: [64Cu]1 76%, [64Cu]2 90%). Selective αvβ6 cell binding was observed for both [64Cu]1 and [64Cu]2 (αvβ6 (+) cells: 30.3–55.8% and 48.5–60.2%, respectively, vs. αvβ6 (−) cells <3.1% for both). In vivo BxPC-3 tumor uptake for both peptides at 4 h was 5.29 ± 0.59 and 7.60 ± 0.43% ID/g ([64Cu]1 and [64Cu]2, respectively), and remained at 3.32 ± 0.46 and 4.91 ± 1.19% ID/g, respectively, at 72 h, representing a >3-fold improvement over the non-ABM parent peptide and thereby providing improved PET images. Comparing [64Cu]1 and [64Cu]2, the IP-ABM-αvβ6-BP [64Cu]2 displayed higher serum stability, higher tumor accumulation, and lower kidney and liver accumulation, resulting in better tumor-to-organ ratios for high contrast visualization of the αvβ6 (+) tumor by PET imaging.

A systematic evaluation of the cucurbit[7]uril pharmacokinetics and toxicity after a single dose and short-term repeated administration in mice.

Cucurbit[n]urils are macrocyclic compounds capable of forming host-guest complexes with different molecules. In this study, we focused on cucurbit[7]uril (CB[7]) safety and pharmacokinetics. We investigated CB[7] cytotocixity in human renal cells ACHN using the xCELLigence system. We also determined maximum tolerated doses (MTD) and no observed adverse effect levels (NOAEL) after intramuscular (i.m.), intraperitoneal (i.p.), and intragastric (i.g.) administration in mice using clinical observation, blood biochemistry, and histopathology. At NOAELs, we studied its pharmacokinetics in plasma and kidneys. Finally, we performed a 7day repeated-dose toxicity study at 50% of NOAEL after i.p. administration, assaying CB[7] concentration in plasma, brain, kidney, and liver; we also assessed the liver and kidney histopathology. In vitro, CB[7] did not show toxicity up to 0.94mg/mL. MTDs in vivo were set at 300, 350, and 600mg/kg, and NOAEL were established at 150, 100, and 300mg/kg after i.m., i.p., and i.g. administration, respectively. Parenteral administration produced tissue damage mainly to the kidney, while i.g. administration caused only minor liver damage. Parenteral CB[7] administration led to fast elimination from blood, accompanied with kidney accumulation; absorption from the gastrointestinal tract was minimal. Short repeated i.p. administration was well tolerated. After initial CB[7] accumulation in blood and kidney, the concentrations stabilised and decreased during the experiment. Approximately 3.6% of animals showed signs of nephrotoxicity. Although CB[7] appears to be a promising molecule, nephrotoxicity may be the most critical drawback of its parenteral use, because the kidney represents the main organ of its elimination.

Adverse effects of triclosan on kidney in mice: Implication of lipid metabolism disorders

Triclosan (TCS) is a ubiquitous antimicrobial used in daily consumer products. Previous reports have shown that TCS could induce hepatotoxicity, endocrine disruption, disturbance on immune function and impaired thyroid function. Kidney is critical in the elimination of toxins, while the effects of TCS on kidney have not yet been well-characterized. The aim of the present study was to investigate the effects of TCS exposure on kidney function and the possible underlying mechanisms in mice. Male C57BL/6 mice were orally exposed to TCS with the doses of 10 and 100 mg/(kg•day) for 13 weeks. TCS was dissolved in dimethyl sulfoxide (DMSO) and diluted by corn oil for exposure. Corn oil containing DMSO was used as vehicle control. Serum and kidney tissues were collected for study. Biomarkers associated with kidney function, oxidative stress, inflammation and fibrosis were assessed. Our results showed that TCS could cause renal injury as was revealed by increased levels of renal function markers including serum creatinine, urea nitrogen and uric acid, as well as increased oxidative stress, pro-inflammatory cytokines and fibrotic markers in a dose dependent manner, which were more significantly in 100 mg/(kg•day) group. Mass spectrometry-based analysis of metabolites related with lipid metabolism demonstrated the occurrence of lipid accumulation and defective fatty acid oxidation in 100 mg/(kg•day) TCS-exposed mouse kidney. These processes might lead to lipotoxicity and energy depletion, thus resulting in kidney fibrosis and functional decline. Taken together, the present study demonstrated that TCS could induce lipid accumulation and fatty acid metabolism disturbance in mouse kidney, which might contribute to renal function impairment. The present study further widens our insights into the adverse effects of TCS.