Chitosan-Based Hybrid Nanocomplex for siRNA Delivery and Its Application for Cancer Therapy

Purpose

Chitosan, a natural and biocompatible cationic polymer, is an attractive carrier for small interfering RNA (siRNA) delivery. The purpose of this study was to develop a chitosan-based hybrid nanocomplex that exhibits enhanced physical stability in the bloodstream compared with conventional chitosan complexes. Hybrid nanocomplexes composed of chitosan, protamine, lecithin, and thiamine pyrophosphate were prepared for systemic delivery of survivin (SVN) siRNA.

Methods

Physicochemical properties of the nanoparticles including mean diameters and zeta potentials were characterized, and target gene silencing and cellular uptake efficiencies of the siRNA nanocomplexes in prostate cancer cells (PC-3 cells) were measured. In vivo tumor targetability and anti-tumor efficacy by systemic administration were assessed in a PC-3 tumor xenograft mouse model by near-infrared fluorescence (NIRF) imaging and tumor growth monitoring, respectively.

Results

Mean diameters of the SVN siRNA-loaded hybrid nanocomplex (GP-L-CT) were less than 200 nm with a positive zeta potential value in water and were maintained without aggregation in culture media and 50% fetal bovine serum. SVN expression in PC-3 cells was reduced to 21.9% after treating with GP-L-CT. The tumor targetability and growth inhibitory efficacies of GP-L-CT supported the use of this novel hybrid nanocomplex as a cancer therapeutic and as a theranostic system for systemic administration.

Conclusions

A chitosan-based hybrid nanocomplex was successfully developed for the systemic delivery of SVN siRNA, which could serve as an alternative to cationic polymeric nanoparticles that are unstable in serum.     

Method for detecting the reactivity of chemicals towards peptides as an alternative test method for assessing skin sensitization potential

Cosmetics are normally composed of various ingredients. Some cosmetic ingredients can act as chemical haptens reacting toward proteins or peptides of human skin and they can provoke an immunologic reaction, called as skin sensitization. This haptenation process is very important step of inducing skin sensitization and evaluating the sensitizing potentials of cosmetic ingredients is very important for consumer safety. Therefore, animal alternative methods focusing on monitoring haptenation potential are undergoing vigorous research. To examine the further usefulness of spectrophotometric methods to monitor reactivity of chemicals toward peptides for cosmetic ingredients. Forty chemicals (25 sensitizers and 15 non-sensitizers) were reacted with 2 synthetic peptides, e.g., the cysteine peptides (Ac-RFAACAA-COOH) with free thiol group and the lysine peptides (Ac-RFAAKAA-COOH) with free amine group. Unreacted peptides can be detected after incubating with 5,5′-dithiobis-2-nitrobenzoic acid or fluorescamine™ as detection reagents for free thiol and amine group, respectively. Chemicals were categorized as sensitizers when they induced more than 10% depletion of cysteine peptides or more than 30% depletion of lysine peptides. The sensitivity, specificity, and accuracy were 80.0%, 86.7% and 82.5%, respectively. These results demonstrate that spectrophotometric methods can be an easy, fast, and high-throughput screening tools predicting the skin sensitization potential of chemical including cosmetic ingredient.     

Bioavailability of plant pigment phytochemicals in Angelica keiskei in older adults: A pilot absorption kinetic study

BACKGROUND/OBJECTIVES

Angelica keiskei is a green leafy vegetable rich in plant pigment phytochemicals such as flavonoids and carotenoids. This study examined bioavailability of flavonoids and carotenoids in Angelica keiskei and the alteration of the antioxidant performance in vivo.

SUBJECTS AND MATERIALS

Absorption kinetics of phytochemicals in Angelica keiskei were determined in healthy older adults (> 60 y, n = 5) and subjects with metabolic syndrome (n = 5). Subjects consumed 5 g dry Angelica keiskei powder encapsulated in gelatin capsules with a low flavonoid and carotenoid liquid meal. Plasma samples were collected at baseline, 0.5, 1, 2, 3, 4, 5, 6, 7, and 8 h. Samples were analyzed for flavonoids and carotenoids using HPLC systems with electrochemical and UV detection, respectively, and for total antioxidant performance by fluorometry.

RESULTS

After ingestion of Angelica keiskei increases in plasma quercetin concentrations were observed at 1-3 and 6-8 hr in the healthy group and at all time points in the metabolic syndrome group compared to baseline (P < 0.05). Plasma lutein concentrations were significantly elevated in both the healthy and metabolic syndrome groups at 8 hr (P < 0.05). Significant increases in total antioxidant performance were also observed in both the healthy and the metabolic syndrome groups compared to baseline (P < 0.05).

CONCLUSIONS

Findings of this study clearly demonstrate the bioavailability of phytonutrients of Angelica keiskei and their ability to increase antioxidant status in humans.     

Selenium-Enriched Agaricus bisporus Mushroom Protects against Increase in Gut Permeability ex vivo and Up-Regulates Glutathione Peroxidase 1 and 2 in Hyperthermally-Induced Oxidative Stress in Rats

Dietary effects of organic Se supplementation in the form of Se-enriched Agaricus bisporus mushroom on ileal mucosal permeability and antioxidant selenoenzymes status in heat induced oxidative stress in rats were evaluated. Acute heat stress (40 °C, 21% relative humidity, 90 min exposure) increased ileum baseline short circuit current (Isc; 2.40-fold) and epithelial conductance (Ge; 2.74-fold). Dietary supplementation with Se-enriched A. bisporus (1 µg Se/g feed) reduced (p < 0.05) ileum Isc and Ge during heat stress to 1.74 and 1.91 fold, respectively, indicating protection from heat stress-induced mucosal permeability increase. The expression of ileum glutathione peroxidase (GPx-) 1 and 2 mRNAs were up-regulated (p < 0.05) by 1.90 and 1.87-fold, respectively, for non-heat stress rats on the Se-enriched diet relative to the control. The interplay between heat stress and dietary Se is complex. For rats on the control diet, heat stress alone increased ileum expression of GPx-1 (2.33-fold) and GPx-2 (2.23-fold) relative to thermoneutral conditions. For rats on the Se-enriched diet, heat stress increased (p < 0.05) GPx-1 expression only. Rats on Se-enriched + α-tocopherol diet exhibited increased expression of both genes (p < 0.05). Thus, dietary Se-enriched A. bisporus protected against increase in ileum permeability and up-regulated GPx-1 and GPx-2 expression, selenoenzymes relevant to mitigating oxidative stress.     

Effect of Ankle Torque on the Ankle–Foot Orthosis Joint Design Sustainability

The ankle joint of a powered ankle–foot orthosis (PAFO) is a prominent component, as it must withstand the dynamic loading conditions during its service time, while delivering all the functional requirements such as reducing the metabolic effort during walking, minimizing the stress on the user’s joint, and improving the gait stability of the impaired subjects. More often, the life of an AFO is limited by the performance of its joint; hence, a careful design consideration and material selection are required to increase the AFO’s service life. In the present work, a compact AFO joint was designed based on a worm gear mechanism with steel and brass counterparts due to the fact of its large torque transfer capability in a single stage, enabling a compact joint. Further, it provided an added advantage of self-locking due to the large friction that prevents backdrive, which is beneficial for drop-foot recovery. The design was verified using nonlinear finite element analysis for maximum torque situations at the ankle joint during normal walking. The results indicate stress levels within its design performance; however, it is recommended to select high-grade structural steel for the ankle shaft as the highest stresses in AFO were located on it.     

Sodium–glucose cotransporter 2 inhibitors reduce day-to-day glucose variability in patients with type 1 diabetes

Aims/IntroductionSodium–glucose cotransporter 2 inhibitors (SGLT2i) are used worldwide because of their multiple benefits for patients with type 2 diabetes. The purpose of this study was to determine the efficacy and safety of SGLT2i in patients with type 1 diabetes.Materials and MethodsPatients with type 1 diabetes who had been treated with SGLT2i for >12 weeks were included in this retrospective observation study. We recorded the changes in body mass, insulin dose, blood and urine test data, and adverse events. The changes in day‐to‐day glucose variability, as the primary end‐point, was evaluated using the interquartile range (P25/P75) of the ambulatory glucose data obtained using continuous glucose monitoring.ResultsA total of 51 patients (37 women; mean age 52.7 years) were included. Glycated hemoglobin and body mass significantly decreased by 0.4% and 1.6 kg, respectively. The total required insulin dose decreased by 9.4% (42.7 ± 26.6–38.7 ± 24.3 units/day). Continuous glucose monitoring data were obtained from 30 patients. P25/P75 decreased by 17.6 ± 20.7% during SGLT2i treatment (P < 0.001). The percentage of time per day within the target glucose range of 70–180 mg/dL significantly increased (from 42.2 to 55.5%, P < 0.001), without an increase in the percentage of time spent in the hypoglycemic range (<70 mg/dL). Urinary ketone bodies were detected in four patients (7.8%), but none developed ketoacidosis.ConclusionsSGLT2i improved day‐to‐day glucose variability and time in the target glucose range, without increasing frequency of hypoglycemia, in patients with type 1 diabetes, and reduced glycated hemoglobin, body mass and the required insulin dose.     

Development of a clinical risk score for incident diabetes: A 10-year prospective cohort study

Aims/IntroductionWe developed a self‐assessable Korean Diabetes Risk score using the data of the Korean Genome and Epidemiology Study.Materials and MethodsA total of 8,740 participants without diabetes at baseline were followed up biannually over a period of 10 years. We included variables that were significantly different between participants who developed diabetes mellitus and those who did not in the development cohort at baseline. We assigned a maximum score of 100 to the selected variable in each gender group. Next, the 10‐year probability of incident diabetes was calculated and validated in the validation cohort. Finally, we compared the predictive power of Korean Diabetes Risk score with models including fasting plasma glucose or glycated hemoglobin and other cohort models of Atherosclerosis Risk in Communities and Korea National Health and Nutrition Examination Survey.ResultsDuring a median follow‐up period of 9.7 years, 22.7% of the participants progressed to diabetes. The Korean Diabetes Risk score included age, living location (urban or rural area), waist circumference, hypertension, family history of diabetes and smoking history. The developed risk score yielded acceptable discrimination for incident diabetes (area under the curve 0.657) and the predictive power was improved when the model included fasting plasma glucose (area under the curve 0.690) or glycated hemoglobin (area under the curve 0.746). In addition, our model predicted incident diabetes more accurately than previous Western or Korean models.ConclusionsThis newly developed self‐assessable diabetes risk score is easily applicable to predict the future risk of diabetes even without the necessity for laboratory tests. This score is useful for the Korean diabetes prevention program, because high‐risk individuals can be easily screened.     

Sex differences in sarcopenia and frailty among community-dwelling Korean older adults with diabetes: The Korean Frailty and Aging Cohort Study

Aims/IntroductionWe aimed to examine the prevalence of sarcopenia and frailty in Korean older adults with diabetes compared with individuals without diabetes.Materials and MethodsWe analyzed the data of 2,403 participants aged 70–84 years enrolled in the Korean Frailty and Aging Cohort Study. Sarcopenia was defined using the Asian Working Group for Sarcopenia and the Foundation for the National Institutes of Health. Frailty was assessed by the Cardiovascular Health Study frailty phenotype criteria.ResultsThe mean age of the participants was 76.0 ± 3.9 years, and 47.2% were men. The prevalence of diabetes was 30.2% in men and 25.8% in women. Adults with diabetes showed a lower muscle mass index (appendicular skeletal muscle mass/body mass index) and handgrip strength in both sexes, but only the women showed decreased physical performance. Women with diabetes presented a higher prevalence of sarcopenia diagnosed by the Foundation for the National Institutes of Health criteria, and frailty compared with participants without diabetes (sarcopenia 14.7% vs 8.5%, P = 0.001; frailty 9.5% vs 4.9%, P = 0.003). Men in the high and middle tertiles for homeostatic model assessment of insulin resistance presented a significantly higher prevalence of sarcopenia, compared with men in the low tertile homeostatic model assessment of insulin resistance (high tertile 16.6%, middle tertile 13.3%, low tertile 8.6%).ConclusionsIn older adults with diabetes, muscle mass index and muscle strength were lower than in those without diabetes. However, the prevalence of sarcopenia and frailty was higher and physical performance was lower only in women with diabetes.