SNR enhanced high-speed two-photon microscopy using a pulse picker and time gating detection.

Two-photon microscopy (TPM) is an attractive biomedical imaging method due to its large penetration depth and optical sectioning capability. In particular, label-free autofluorescence imaging offers various advantages for imaging biological samples. However, relatively low intensity of autofluorescence leads to low signal-to-noise ratio (SNR), causing practical challenges for imaging biological samples. In this study, we present TPM using a pulse picker to utilize low pulse repetition rate of femtosecond pulsed laser to increase the pulse peak power of the excitation source leading to higher emission of two-photon fluorescence with the same average illumination power. Stronger autofluorescence emission allowed us to obtain higher SNR images of arterial and liver tissues. In addition, by applying the time gating detection method to the pulse signals obtained by TPM, we were able to significantly reduce the background noise of two-photon images. As a result, our TPM system using the pulsed light source with a 19 times lower repetition rate allowed us to obtain the same SNR image more than 19 times faster with the same average power. Although high pulse energy can increase the photobleaching, we also observed that high-speed imaging with low total illumination energy can mitigate the photobleaching effect to a level similar to that of conventional illumination with a high repetition rate. We anticipate that this simple approach will provide guidance for SNR enhancement with high-speed imaging in TPM as well as other nonlinear microscopy.

DA-1241, a Novel GPR119 Agonist, Improves Hyperglycaemia by Inhibiting Hepatic Gluconeogenesis and Enhancing Insulin Secretion in Diabetic Mice.

BACKGROUND: We investigated the antidiabetic effects of DA-1241, a novel G protein-coupled receptor (GPR) 119 agonist, in vitro and in vivo. METHODS: DA-1241 was administrated to high-fat diet (HFD)-fed C57BL/6J mice for 12 weeks after hyperglycaemia developed. Oral/intraperitoneal glucose tolerance test and insulin tolerance test were performed. Serum insulin and glucagon-like peptide-1 (GLP-1) levels were measured during oral glucose tolerance test. Insulinoma cell line (INS-1E) cells and mouse islets were used to find whether DA-1241 directly stimulate insulin secretion in beta cell. HepG2 cells were used to evaluate the gluconeogenesis and autophagic process. Autophagic flux was evaluated by transfecting microtubule-associated protein 1 light chain 3-fused to green fluorescent protein and monomeric red fluorescent (mRFP-GFP-LC3) expression vector to HepG2 cells. RESULTS: Although DA-1241 treatment did not affect body weight gain and amount of food intake, fasting blood glucose level decreased along with increase in GLP-1 level. DA-1241 improved only oral glucose tolerance test and showed no effect in intraperitoneal glucose tolerance test. No significant effect was observed in insulin tolerance test. DA-1241 did not increase insulin secretion in INS-1E cell and mouse islets. DA-1241 reduced triglyceride content in the liver thereby improved fatty liver. Additionally, DA-1241 reduced gluconeogenic enzyme expression in HepG2 cells and mouse liver. DA-1241 reduced autophagic flow in HepG2 cells. CONCLUSION: These findings suggested that DA-1241 augmented glucose-dependent insulin release via stimulation of GLP-1 secretion, and reduced hepatic gluconeogenesis, which might be associated with autophagic blockage, leading to improved glycaemic control.

Label-free multimodal microscopy using a single light source and detector for biological imaging.

Multimodal nonlinear microscopy has been widely applied in biology and medicine due to its relatively deep penetration into tissue and its label-free manner. However, current multimodal systems require the use of multiple sources and detectors, leading to bulky, complex, and expensive systems. In this Letter, we present a novel method of using a single light source and detector for nonlinear multimodal imaging of biological samples. Using a photonic crystal fiber, a pulse picker, and multimode fibers, our developed system successfully acquired multimodal images of swine coronary arteries, including two-photon excitation fluorescence, second-harmonic generation, coherent anti-Stokes Raman scattering, and backreflection. The developed system could be a valuable tool for various biomedical applications.

Effect of Ezetimibe on Glucose Metabolism and Inflammatory Markers in Adipose Tissue.

Despite numerous studies, the effects of ezetimibe on glucose metabolism are poorly understood. Here, we aimed to investigate the effects of ezetimibe on glucose metabolism and the expression of inflammatory markers. Thirteen rats were randomly assigned to an ezetimibe (n = 6) or control group (n = 7). The control group received a high fat diet (HFD; 60 Kcal%), whereas the ezetimibe group received an HFD (60 Kcal%) containing 160 mg/kg of ezetimibe. After 14 weeks, adipose and liver tissues, along with plasma, were collected and comparatively analyzed. The effects of combination therapy with ezetimibe and statins on glucose metabolism were investigated over a 1-year period using data from patients with hyperlipidemia. Several indices of glucose metabolism partially improved in the ezetimibe group. The sizes of adipocytes and the accumulation of pro-inflammatory cytokines were reduced in the ezetimibe group. Ezetimibe treatment induced anti-inflammatory cytokines and fatty acid oxidation in adipocytes and reduced serum levels of free fatty acids. Clinical data analysis revealed that statin monotherapy significantly increased insulin resistance. However, combination therapy with ezetimibe and statins did not increase insulin resistance. In conclusion, ezetimibe was found to reduce the sizes of adipocytes in visceral fat and serum levels of free fatty acids, to induce fatty acid oxidation, to improve adipocytic inflammation, and to partially improve glycemic index values.

Differential Diabetogenic Effect of Pitavastatin and Rosuvastatin, in vitro and in vivo.

AIM: Most statins increase the risk of new-onset diabetes. Unlike other statins, pitavastatin is reported to exert neutral effects on serum glucose level, but the precise mechanism is unknown. METHODS: Eight-week-old male C57BL/6J mice (n=26) were fed high-fat diet (HFD, 45% fat) with 0.01% placebo, rosuvastatin, or pitavastatin for 12 weeks. Cultured HepG2, C2C12, and 3T3-L1 cells and visceral adipocytes from HFD-fed mice were treated with vehicle or 10 µM statins for 24 h. The effects of pitavastatin and rosuvastatin on intracellular insulin signaling and glucose transporter 4 (GLUT4) translocation were evaluated. RESULTS: After 12 weeks, the fasting blood glucose level was significantly lower in pitavastatin-treated group than in rosuvastatin-treated group (115.2±7.0 versus 137.4±22.3 mg/dL, p=0.024). Insulin tolerance significantly improved in pitavastatin-treated group as compared with rosuvastatin-treated group, and no significant difference was observed in glucose tolerance. Although plasma adiponectin and insulin levels were not different between the two statin treatment groups, the insulin-induced protein kinase B phosphorylation was weakly attenuated in pitavastatin-treated adipocytes than in rosuvastatin-treated adipocytes. Furthermore, minor attenuation in insulin-induced GLUT4 translocation to the plasma membrane of adipocytes was observed in pitavastatin-treated group. CONCLUSION: Pitavastatin showed lower diabetogenic effects than rosuvastatin in mice that may be mediated by minor attenuations in insulin signaling in adipocytes.

Antioxidant and anti-adipogenic activities of the nuts of Castanopsis cuspidata var. thunbergii.

The antioxidant and anti-adipogenic activities of the water extract (WE) and methanol extract (ME) of the shell and kernel of Castanopsis cuspidata var. thunbergii (CCT) nuts were evaluated. The shell extracts showed higher DPPH and ABTS radical scavenging activities (RSAs) than did the kernel extracts. Furthermore, the RSA of the ME was higher than that of the WE, regardless of the part. The total phenolic contents (TPCs) of the ME of the shell and kernel were 71.38 and 10.56 mg gallic acid equivalent (GAE)/100 mg extract, respectively. The TPCs of the WE of the shell and kernel were 17.44 and 9.27 mg GAE/100 mg extract, respectively. The WE inhibited 3T3-L1 adipogenesis more effectively than did the ME, and the shell extracts suppressed 3T3-L1 adipogenesis more effectively than did the kernel extracts. These results suggest that CCT nut kernels (ME) and shells (WE) may be strategically used to enhance antioxidant or and anti-obesity materials.

Beneficial role and function of fisetin in skin health via regulation of the CCN2/TGF-ß signaling pathway.

Skin is composed of multiple layers, including the epidermis, dermis, and hypodermis. Although several biological activities of fisetin have been reported, beneficial effects and the functions of fisetin in skin remain unclear. B16F10 melanoma cells, human skin fibroblasts, and 3T3-L1 cells were used to examine the beneficial effects of fisetin in skin health. α-MSH- and IBMX-induced melanosis in B16F10 melanoma cells was inhibited by fisetin treatment, which also enhanced mRNA expression levels of skin fibril-related genes via the CCN2/TGF-ß signaling pathway. Decreased intracellular lipid accumulation via down-regulation of transcriptional factors through activation of the CCN2/TGF-ß signaling pathway was observed. A novel function of fisetin in skin health via down-regulation of melanosis and adipogenesis, and up-regulation of skin fibril-related genes was observed. Evidence for development of nutri-cosmetics for skin health is presented.