The differential cellular uptake of curcuminoids in vitro depends dominantly on albumin interaction

BACKGROUND

Curcuminoids, mainly present in the plant rhizomes of turmeric (Curcuma longa), consist of mainly three forms (curcumin (CUR), bisdemethoxycurcumin (BDMC) and demethoxycurcumin (DMC)). It has been reported that different forms of curcuminoids possess different biological activities. However, the mechanisms associated with these differences are not well-understood. Recently, our laboratory found differences in the cellular uptake of these curcuminoids. Therefore, it has been inferred that these differences contribute to the different biological activities.

PURPOSE

In this study, we investigated the mechanisms of differential cellular uptake of these curcuminoids.

METHOD

Based on our previous study, we hypothesized the differential cellular uptake is caused by (I) polarity, (II) transporters, (III) metabolism rate of curcuminoids and (IV) medium components. These four hypotheses were each investigated by (I) neutralizing the polarities of curcuminoids by encapsulation into poly(lactic-co-glycolic) acid nanoparticles (PLGA-NPs), (II) inhibition of polyphenol-related absorption transporters, (III) analysis of the cellular curcuminoids and their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and (IV) use of different mediums in cell study.

RESULTS

The differential cellular uptake was not affected by (I-III). However, when investigating (IV), not only CUR but also BDMC and DMC were incorporated into cells when serum free media was used. Furthermore, when we used the serum free medium containing bovine serum albumin (BSA), only CUR was taken up but BDMC and DMC were not. Therefore, we identified that the differential cellular uptake of curcuminoids is caused by the medium components, especially BSA. Also, the fluorescence quenching study suggested that differential cellular uptake is due to the different interaction between BSA and each curcuminoid.

CONCLUSION

The differential cellular uptake of curcuminoids was caused by the different interaction between curcuminoids and BSA. The results from this study might give clues on the mechanisms by which curcuminoids exhibit different physiological activities.

Relationship between cerebral blood flow estimated by transcranial Doppler ultrasound and single-photon emission computed tomography in elderly people with dementia

Transcranial Doppler (TCD) ultrasonography is a noninvasive technique allowing continuous recording of cerebral blood flow (CBF) velocity. However, it is unclear whether the CBF estimated by TCD would be reliable for the comparison between individuals. The present study aimed to clarify the relationship between middle cerebral artery blood flow (MCA BF) measured by TCD and regional and total CBF measured by single-photon emission computed tomography (SPECT-CBF) with a quantification software program, a three-dimensional stereotaxic region of interest template. We recruited 91 elderly subjects with and without dementia. MCA blood flow velocity (MCA V) and middle cerebral artery cross-sectional area (AM) were measured by TCD and magnetic resonance angiography, respectively. MCA BF was calculated by the product of MCA V and AM. Diastolic or mean MCA V and MCA BF were significantly correlated with SPECT-CBF in several segments. Interestingly, the correlation coefficient in the temporal segment of SPECT-CBF was higher than those of the other segments. Moreover, correlations between MCA BF and SPECT-CBF were stronger as compared with those between MCA V and SPECT-CBF. These findings suggest that both mean MCA V and MCA BF with TCD ultrasonography would be useful for CBF comparison between individuals especially in the temporal region, although estimated blood flow with arterial area seems to be better than using simple flow velocity.

NEW & NOTEWORTHY Correlations between middle cerebral artery blood flow (MCA BF) calculated by the product of MCA blood flow velocity (MCA V) and middle cerebral artery cross-sectional area and regional and total cerebral blood flow (CBF) measured by single-photon emission computed tomography (SPECT-CBF) were stronger as compared with those between MCA V and SPECT-CBF. These findings suggest that both mean MCA V and MCA BF would be useful for CBF comparison between individuals although estimated blood flow with arterial area seems to be better than using simple flow velocity.

Curcumin and piperine supplementation of obese mice under caloric restriction modulates body fat and interleukin-1β

Background

Dietary bioactive compounds capable of improving metabolic profiles would be of great value, especially for overweight individuals undergoing a caloric restriction (CR) regimen. Curcumin (Cur), a possible anti-obesity compound, and piperine (Pip), a plausible enhancer of Cur’s bioavailability and efficacy, may be candidate agents for controlling body fat, metabolism and low grade inflammation.

Methods

47 eight-week-old male C57BL/6 mice were fed a high fat diet (HFD) for 23 weeks to induce obesity. Then, mice were divided into 5 groups. Group 1 continued on HFD ad libitum. The other 4 groups underwent CR (reduced 10% HFD intake for 10 weeks, 20% for 20 weeks) with Cur, Pip, Cur + Pip or none of these. Percent body fat, plasma inflammatory markers associated with obesity (interferon (IFN)-γ, interleukin (IL)-10, IL-12 p70, IL-1β, IL-6 and KC/GRO), plasma Cur metabolites and liver telomere length were measured.

Results

Compared to the other groups, obese mice who underwent CR and received Cur + Pip in their diet lost more fat and had significantly lower IL-1β and KC/GRO. Tandem mass spectrometry analysis of plasma from obese mice under CR showed no difference in Cur metabolite levels between groups supplemented with Cur alone or combined with Pip. However, plasma IL-1β levels were inversely correlated with curcumin glucuronide. Minor modulation of telomere length were observed.

Conclusions

It is plausible that supplementing the high fat diet of CR mice with Cur + Pip may increase loss of body fat and suppresses HFD induced inflammation. Combination of Cur and Pip has potential to enhance CR effects for the prevention of metabolic syndrome.

Amadori-glycated phosphatidylethanolamine enhances the physical stability and selective targeting ability of liposomes

Liposomes consisting of 100% phosphatidylcholine exhibit poor membrane fusion, cellular uptake and selective targeting capacities. To overcome these limitations, we used Amadori-glycated phosphatidylethanolamine, which is universally present in animals and commonly consumed in foods. We found that liposomes containing Amadori-glycated phosphatidylethanolamine exhibited significantly reduced negative membrane potential and demonstrated high cellular uptake.

Synthetic "smart gel" provides glucose-responsive insulin delivery in diabetic mice

Although previous studies have attempted to create "electronics-free" insulin delivery systems using glucose oxidase and sugar-binding lectins as a glucose-sensing mechanism, no successful clinical translation has hitherto been made. These protein-based materials are intolerant of long-term use and storage because of their denaturing and/or cytotoxic properties. We provide a solution by designing a protein-free and totally synthetic material-based approach. Capitalizing on the sugar-responsive properties of boronic acid, we have established a synthetic polymer gel-based insulin delivery device confined within a single catheter, which exhibits an artificial pancreas-like function in vivo. Subcutaneous implantation of the device in healthy and diabetic mice establishes a closed-loop system composed of "continuous glucose sensing" and "skin layer"-regulated insulin release. As a result, glucose metabolism was controlled in response to interstitial glucose fluctuation under both insulin-deficient and insulin-resistant conditions with at least 3-week durability. Our "smart gel" technology could offer a user-friendly and remarkably economic (disposable) alternative to the current state of the art, thereby facilitating availability of effective insulin treatment not only to diabetic patients in developing countries but also to those patients who otherwise may not be strongly motivated, such as the elderly, infants, and patients in need of nursing care.

Heterocyclic boronic acids display sialic acid selective binding in a hypoxic tumor relevant acidic environment

A group of heterocyclic boronic acids demonstrating unusually high affinity and selectivity for sialic acids are described, with strong interactions under the weakly acidic pH conditions associated with a hypoxic tumoral microenvironment.

Boronic acids are well known for their ability to reversibly interact with the diol groups found in sugars and glycoproteins. However, they are generally indiscriminate in their binding. Herein we describe the discovery of a group of heterocyclic boronic acids demonstrating unusually high affinity and selectivity for sialic acids (SAs or N-acetylneuraminic acid), which are sugar residues that are intimately linked with tumor growth and cancer progression. Remarkably, these interactions strengthen under the weakly acidic pH conditions associated with a hypoxic tumoral microenvironment. In vitro competitive binding assays uncovered a significantly higher ability of 5-boronopicolinic acid, one of the derivatives identified in this work as a strong SA-binder, to interact with cell surface SA in comparison to a gold-standard structure, 3-propionamidophenylboronic acid, which has proven to be an efficient SA-binder in numerous reports. This structure also proved to be suitable for further chemical conjugation with a well-preserved SA-binding capability. These findings suggest an attractive alternative to other ongoing boronic acid based chemistry techniques aiming to achieve tumor-specific chemotherapies and diagnoses.

Metabolic fate of poly-(lactic-co-glycolic acid)-based curcumin nanoparticles following oral administration

Purpose

Curcumin (CUR), the main polyphenol in turmeric, is poorly absorbed and rapidly metabolized following oral administration, which severely curtails its bioavailability. Poly-(lactic-co-glycolic acid)-based CUR nanoparticles (CUR-NP) have recently been suggested to improve CUR bioavailability, but this has not been fully verified. Specifically, no data are available about curcumin glucuronide (CURG), the major metabolite of CUR found in the plasma following oral administration of CUR-NP. Herein, we investigated the absorption and metabolism of CUR-NP and evaluated whether CUR-NP improves CUR bioavailability.

Methods

Following oral administration of CUR-NP in rats, we analyzed the plasma and organ distribution of CUR and its metabolites using high-performance liquid chromatography-tandem mass spectrometry. To elucidate the mechanism of increased intestinal absorption of CUR-NP, we prepared mixed micelles comprised of phosphatidylcholine and bile salts and examined the micellar solubility of CUR-NP. Additionally, we investigated the cellular incorporation of the resultant micelles into differentiated Caco-2 human intestinal cells.

Results

Following in vivo administration of CUR-NP, CUR was effectively absorbed and present mainly as CURG in the plasma which contained significant amounts of the metabolite compared with other organs. Thus, CUR-NP increased intestinal absorption of CUR rather than decreasing metabolic degradation and conversion to other metabolites. In vitro, CUR encapsulated in CUR-NP was solubilized in mixed micelles; however, whether the micelles contained CUR or CUR-NP had little influence on cellular uptake efficiency. Therefore, we suggest that the high solubilization capacity of CUR-NP in mixed micelles, rather than cellular uptake efficiency, explains the high intestinal absorption of CUR-NP in vivo.

Conclusion

These findings provide a better understanding of the bioavailability of CUR and CUR-NP following oral administration. To improve the bioavailability of CUR, future studies should focus on enhancing the resistance to metabolic degradation and conversion of CUR to other metabolites, which may lead to novel discoveries regarding food function and disease prevention.

Distribution of β-carotene-encapsulated polysorbate 80-coated poly(D, L-lactide-co-glycolide) nanoparticles in rodent tissues following intravenous administration

Purpose

Biodegradable nanoparticles (NPs) composed of poly(D, L-lactide-co-glycolide) (PLGA) have attracted considerable attention as delivery systems of drugs and antioxidative compounds, such as β-carotene (BC). Intravenous (IV) administration of BC-containing PLGA-NPs (BC-PLGA-NPs) coated with polysorbate 80 (PS80) has been shown to effectively deliver BC to the brain. However, the whole-body distribution profile of BC is still not clear. Therefore, we investigated the accumulation of BC in various organs, including the brain, following IV administration of PS80-coated BC-PLGA-NPs in rats.

Methods

PS80-coated and uncoated BC-PLGA-NPs were prepared by solvent evaporation, and administered intravenously to Sprague Dawley rats at a BC dose of 8.5 mg/rat. Accumulation of BC in various organs (brain, heart, liver, lungs, and spleen) and blood plasma was evaluated by high performance liquid chromatography with ultraviolet (UV) detection, 1 hour after administration.

Results

We prepared PS80-coated BC-PLGA-NPs with an entrapment efficiency of 14%, a particle size of 260 nm, and a zeta potential of −26 mV. Coating with PS80 was found to result in significant accumulation of BC in the lungs, rather than in the brain and other tissues. Further, plasma levels of BC in the PS80-coated BC-PLGA-NP group were much lower than those of the uncoated BC-PLGA-NP group.

Conclusion

Following IV administration, PS80-coated BC-PLGA-NPs are quickly transferred from plasma circulation to the lungs, rather than the brain. Significant accumulation of BC in the lungs may be useful for health-related applications.

Comparison between S+L- assay and LacZ marker rescue assay for detecting replication-competent gammaretroviruses

To avoid contamination of adventitious gammaretroviruses in biological products such as vaccines, it is necessary to check the master seed cells for manufacturing. There are several assays to detect infectious gammaretroviruses. Among these, sarcoma-positive, leukemia-negative (S+L-) assay is a classical infectivity assay, which is often recommended in governmental guidelines. The S+L- cells used in S+L- assay generate unique focus upon the infection of replication-competent gammaretroviruses. Although S+L- assay is well recognized for the detection, their applicability is questionable in some cases. On the other hand, LacZ marker rescue (LMR) assay detects infectious gammaretroviruses by transducing LacZ marker gene to the target cells, which shows lacZ-positive foci if the infectious virus is present. In this study, we compared LMR and S+L- assays for detection of a variety of endogenous and exogenous gammaretroviruses. As results, LMR assay could detect all gammaretroviruses examined. On the other hand, S+L- assay using feline S+L- cells, termed QN10S, could not detect porcine endogenous retrovirus (PERV) subgroups A/B. Further, S+L- mink cells could not detect feline leukemia virus subgroups B in addition to PERV-A/B. These data indicate that LMR assay is better suited to detect wider range of gammaretroviruses.

Carbon tetrachloride-induced hepatic and renal damages in rat: inhibitory effects of cacao polyphenol

Here, we investigated the protective effect of cacao polyphenol extract (CPE) on carbon tetrachloride (CCl4)-induced hepato-renal oxidative stress in rats. Rats were administered CPE for 7 days and then received intraperitoneal injection of CCl4. Two hours after injection, we found that CCl4 treatment significantly increased biochemical injury markers, lipid peroxides (phosphatidylcholine hydroperoxide (PCOOH) and malondialdehyde (MDA)) and decreased glutathione peroxidase activity in kidney rather than liver, suggesting that kidney is more vulnerable to oxidative stress under the present experimental conditions. CPE supplementation significantly reduced these changes, indicating that this compound has antioxidant properties against CCl4-induced oxidative stress. An inhibitory effect of CPE on CCl4-induced CYP2E1 mRNA degradation may provide an explanation for CPE antioxidant property. Together, these results provide quantitative evidence of the in vivo antioxidant properties of CPE, especially in terms of PCOOH and MDA levels in the kidneys of CCl4-treated rats.

Influence of regular exercise training on post-exercise hemodynamic regulation to orthostatic challenge

To prevent orthostatic hypotension, arterial blood pressure (BP) is neurally and hormonally regulated via increases in heart rate (HR) and peripheral vascular tone. After dynamic exercise, however, the latter arm is blunted because of the increased vasodilators in exercised muscles. Orthostatic tachycardia is likely a more important compensatory mechanism for post-exercise orthostatic intolerance in individuals who have higher leg vasodilator capacity, such as endurance-trained athletes. To test the hypothesis that regular endurance training was associated with the greater augmentation of tachycardia response to post-exercise orthostasis, we compared hemodynamic responses to 5-min 60° head-up tilt (HUT) before and after 60 min of cycling at 70% of HR reserve in the endurance-trained (n = 8) and sedentary men (n = 9). Calf peak vascular conductance was 62% greater in the endurance-trained than the sedentary (P < 0.001). After the exercise, the HUT-induced reduction of SV was significantly augmented in the endurance-trained (from −27.7 ± 6.9 to −33.7 ± 7.7 ml, P = 0.03) but not in their sedentary peers. Nevertheless, MAP was well maintained during post-exercise HUT even in the endurance-trained (from 81 ± 10 to 80 ± 8 mmHg). Tachycardia responses during sustained orthostasis were significantly increased in the sedentary (1.3-fold vs. pre-exercise) and more in the endurance-trained (2.0-fold). The augmented response of HUT-induced tachycardia was greater in the endurance-trained than the sedentary (P = 0.04). Additionally, cardiovagal baroreflex sensitivity (BRS), evaluated by the HR response to the hypotensive perturbation, was improved after the exercise in the endurance-trained (from −0.56 ± 0.32 to −1.03 ± 0.26 bpm/mmHg, P = 0.007) but not in the sedentary. These results suggest that in the endurance-trained men the increased orthostatic tachycardia and augmented cardiovagal BRS may favorably mitigate accumulated risks for orthostatic intolerance in the early phase of post-exercise.

Ingestion of Chlorella reduced the oxidation of erythrocyte membrane lipids in senior Japanese subjects

Accumulation of phospholipid hydroperoxide (PLOOH) in erythrocyte membranes is an abnormality found in patients with senile dementia, including those with Alzheimer's disease. In our previous studies, dietary xanthophylls (polar carotenoids such as lutein) were hypothesized to inhibit lipid peroxidation. In the present study, we conducted a randomized, double-blind, placebo-controlled human trial to assess the impact for a total of 2 months Chlorella supplementation (8 g Chlorella/day/person; equivalent to 22.9 mg lutein/day/person) on PLOOH and carotenoid concentrations in erythrocytes as well as plasma of 12 normal senior subjects. After 1 or 2 months of treatment, erythrocytes and plasma lutein concentrations increased in the Chlorella group but not in the placebo group. In the Chlorella-supplemented group, erythrocyte PLOOH concentrations after a total of 2 months of treatment were lower than the concentrations before supplementation. These results suggest that Chlorella ingestion improved erythrocyte antioxidant status and lowered PLOOH concentrations. These reductions might contribute to maintaining the normal function of erythrocytes and prevent the development of senile dementia.

Chlorella is an effective dietary source of lutein for human erythrocytes

Chlorella contains a high amount of carotenoids, especially lutein, and has received attention as a possible dietary source for improving carotenoid levels in human blood. In the present study, we performed a 2-month single arm human study, and investigated the efficacy of Chlorella supplementation (9 g Chlorella/day; equivalent to 32 mg lutein/day) on lutein and other carotenoid concentrations in plasma as well as erythrocytes of 12 healthy subjects. Following Chlorella supplementation, lutein was the predominant carotenoid in erythrocytes, showing a 4-fold increase (from 14 to 54 pmol/mL packed cells). After the one month without Chlorella ingestion, erythrocyte lutein then decreased to a basal level (17 pmol/mL packed cells). Erythrocyte carotenoid (lutein, zeaxanthin, α-carotene, and β-carotene) levels were proportional to plasma carotenoid levels. The results suggest the transfer of Chlorella carotenoids, especially lutein, from plasma lipoprotein particles to the erythrocyte membrane. Chlorella intake would be effective for improving and maintaining lutein concentrations in human erythrocytes.

Software defined networking (SDN) over space division multiplexing (SDM) optical networks: features, benefits and experimental demonstration

We present results from the first demonstration of a fully integrated SDN-controlled bandwidth-flexible and programmable SDM optical network utilizing sliceable self-homodyne spatial superchannels to support dynamic bandwidth and QoT provisioning, infrastructure slicing and isolation. Results show that SDN is a suitable control plane solution for the high-capacity flexible SDM network. It is able to provision end-to-end bandwidth and QoT requests according to user requirements, considering the unique characteristics of the underlying SDM infrastructure.