IntroductionSolar ultraviolet (UV) irradiation damages human skin and causes premature skin aging (photoaging) characterized by thickening, rough texture, coarse wrinkles, and mottled pigmentation (1). Histologic and ultrastructural studies have revealed that the major alterations in photoaged skin are localized in the connective tissue (dermis), which is composed predominantly of type I and type III collagen, elastin, proteoglycans, and fibronectin. Damage induced by UV irradiation is manifested primarily as the disorganization of collagen fibrils (2) that constitute the bulk (90% dry weight) of skin connective tissue and accumulation of abnormal, amorphous, elastin-containing material (3). Since collagen fibrils and elastin are responsible for the strength and resiliency of skin (4), their disarrangement with photoaging causes skin to appear aged.Biochemical evidence of connective tissue alterations in photoaged human skin includes reduced levels of types I and III collagen precursors (5, 6) and cross-links (7), increased ratio of type III to type I collagen (6), and increased levels of elastin (8). Additionally, wrinkle reduction in photodamaged human and mouse skin, after treatment with topical all-trans retinoic acid, correlates with increased dermal procollagen synthesis (9-11).Fibroblasts that reside within skin connective tissue synthesize and secrete type I and type III procollagens. Type I procollagen typically is composed of two α1 chains and one α2 chain, although homotrimers of α1 chains have been described in normal skin and certain diseases (12, 13). Type III procollagen is composed of three identical α1 chains (distinct from type I α1 chains). Type I and III procollagens contain globular amino-and carboxy-terminal domains, which make these proteins soluble. After secretion of type I and type III procollagen, their amino-and carboxy-terminal domains are cleaved by specific proteases (14, 15), resulting in formation of mature collagen, which spontaneously assembles into thin collagen fibrils. Because type I and type III procollagens and their partially processed forms are precursor molecules of mature collagen, their levels generally reflect the level of collagen biosynthesis (16,17).Mature type I collagen in skin undergoes continuous turnover, which is required for optimal connective-tissue function (18). Collagen turnover is regulated by both its rate of synthesis and its rate of breakdown. In mammals, breakdown of collagen fibrils is dependent on the action of one of three known collagenases, MMP-1, MMP-8, or MMP-13, which initiates collagen cleavage at one specific site. Imbalance in collagen syn- The aged appearance of skin following repeated exposure to solar ultraviolet (UV) irradiation stems largely from damage to cutaneous connective tissue, which is composed primarily of type I and type III collagens. We report here that a single exposure to UV irradiation causes significant loss of procollagen synthesis in human skin. Expression of type I and type III procollagens is substantially reduce...

These results indicate that W. cibaria isolates possess the ability to inhibit VSC production under both in vitro and in vivo conditions, demonstrating that they bear the potential for development into novel probiotics for use in the oral cavity.

The objective of this study was to isolate and identify lactic acid bacteria able to inhibit the in vitro formation of Streptococcus mutans biofilm as well as the in vivo formation of oral biofilm. Two strains, CMS1 and CMS3, exhibiting profound inhibitory effects on the formation of S. mutans biofilm and the proliferation of S. mutans, were isolated from children’s saliva and identified as Weissella cibaria by 16S rDNA sequencing. The water-soluble polymers produced from sucrose by the W. cibaria isolates also inhibited the formation of S. mutans biofilm. According to the results of thin-layer chromatographic analysis, the hydrolysates of water-soluble polymers produced by the isolates were identical to those of dextran, forming mostly α-(1–6) glucose linkages. In the clinical study, the subjects mouthrinsed with a solution containing W. cibaria CMS1 evidenced plaque index reduction of approximately 20.7% (p < 0.001). These results indicate that the W. cibaria isolates possess the ability to inhibit biofilm formation, both in vitro and in vivo.

Highlights d The weight of G. mellonella larvae is maintained by feeding wax in germ-free conditions d Intestinal beeswax metabolism is similar regardless of intestinal microbiota d Genome and RNA sequencing provides insights into molecular mechanisms of wax degradation d Polyethylene metabolism can occur independently of intestinal microbiota

Several studies have attempted to identify factors associated with longevity and maintenance of health in centenarians. In this study, we analyzed and compared the gut microbiota of centenarians in longevity villages with the elderly and adults in the same region and urbanized towns. Fecal samples were collected from centenarians, elderly, and young adults in longevity villages, and the gut microbiota sequences of elderly and young adults in urbanized towns of Korea were obtained from public databases. The relative abundance of Firmicutes was found to be considerably higher in subjects from longevity villages than those from urbanized towns, whereas Bacteroidetes was lower. Age-related rearrangement of gut microbiota was observed in centenarians, such as reduced proportions of Faecalibacterium and Prevotella, and increased proportion of Escherichia, along with higher abundances of Akkermansia, Clostridium, Collinsella, and uncultured Christensenellaceae. Gut microbiota of centenarians in rehabilitation hospitals were also different to those residing at home. These differences could be due to differences in diet patterns and living environments. In addition, phosphatidylinositol signaling system, glycosphingolipid biosynthesis, and various types of N-glycan biosynthesis were predicted to be higher in the gut microbiota of centenarians (corrected p < 0.05). These three metabolic pathways of gut microbiota can be associated with the immune status and healthy gut environment of centenarians. Although further studies are necessary to validate the function of microbiota between groups, this study provides valuable information on centenarians' gut microbiota.

Photoaging accounts for most age-related changes in skin appearance. It has been suggested that both astaxanthin, a potent antioxidant, and collagen hydrolysate can be used as antiaging modalities in photoaged skin. However, there is no clinical study using astaxanthin combined with collagen hydrolysate. We investigated the effects of using a combination of dietary astaxanthin and collagen hydrolysate supplementation on moderately photoaged skin in humans. A total of 44 healthy subjects were recruited and treated with astaxanthin (2 mg/day) combined with collagen hydrolysate (3 g/day) or placebos, which were identical in appearance and taste to the active supplementation for 12 weeks. The elasticity and hydration properties of facial skin were evaluated using noninvasive objective devices. In addition, we also evaluated the expression of procollagen type I, fibrillin-1, matrix metalloproteinase-1 (MMP-1) and -12, and ultraviolet (UV)-induced DNA damage in artificially UV-irradiated buttock skin before and after treatment. The supplement group showed significant improvements in skin elasticity and transepidermal water loss in photoaged facial skin after 12 weeks compared with the placebo group. In the supplement group, expression of procollagen type I mRNA increased and expression of MMP-1 and -12 mRNA decreased compared with those in the placebo group. In contrast, there was no significant difference in UV-induced DNA damage between groups. These results demonstrate that dietary astaxanthin combined with collagen hydrolysate can improve elasticity and barrier integrity in photoaged human facial skin, and such treatment is well tolerated.

ObjectiveThe aim of this study was to evaluate the mechanical and biological properties of orthodontic bonding agents containing silver- or zinc-doped bioactive glass (BAG) and determine the antibacterial and remineralization effects of these agents.MethodsBAG was synthesized using the alkali-mediated solgel method. Orthodontic bonding agents containing BAG were prepared by mixing BAG with flowable resin. Transbond™ XT (TXT) and Charmfil™ Flow (CF) were used as controls. Ion release, cytotoxicity, antibacterial properties, the shear bond strength, and the adhesive remnant index were evaluated. To assess the remineralization properties of BAG, micro-computed tomography was performed after pH cycling.ResultsThe BAG-containing bonding agents showed no noticeable cytotoxicity and suppressed bacterial growth. When these bonding agents were used, demineralization after pH cycling began approximately 200 to 300 µm away from the bracket. On the other hand, when CF and TXT were used, all surfaces that were not covered by the adhesive were demineralized after pH cycling.ConclusionsOur findings suggest that orthodontic bonding agents containing silver- or zinc-doped BAG have stronger antibacterial and remineralization effects compared with conventional orthodontic adhesives; thus, they are suitable for use in orthodontic practice.

Transient receptor potential vanilloid type 1 (TRPV1) is activated by various stimuli including capsaicin, heat and acid. While TRPV1 has been localized in the epidermis, little is known about the physiological role of TRPV1 in the skin, especially in skin ageing. In this study, we investigated the effect of acute UV irradiation on TRPV1 expression in human skin and the changes in TRPV1 mRNA and protein in intrinsic ageing and photoageing using human sun-protected (upper inner arm) and sun-exposed (forearm) skin of young and elderly subjects. Western blot analysis of UV-irradiated young buttock skin revealed that the expression of TRPV1 protein was increased at 24 h (2.3-fold) and 48 h (2.4-fold) after UV irradiation. Real-time PCR analysis also showed that the mRNA level of TRPV1 was augmented by 2.4-fold at 4 h after UV irradiation. TRPV1 protein was expressed at higher levels by 2.6-fold in the sun-protected skin of the elderly subjects than in that of young people according to western blotting, real-time PCR analysis and immunohistochemical staining. In addition, the photoaged skin of elderly showed increased expression of TRPV1 mRNA and protein compared with that of the sun-protected skin of the same individuals. Also, we found increased expression of TRPV1 in nerve fibres of elderly persons using double staining of TRPV1 and nerve fibres. Based on the above results, our data suggest that the expression of TRPV1 is affected by both the intrinsic ageing and photoageing processes.