The Characteristics and Inheriting Pattern of Skin Aging in Chinese Women: An Intergenerational Study of Mothers and Daughters.

Introduction: The aging of the skin, which is affected by both external and internal causes, can reflect the external age and the internal health status. While the aging characteristics differ across ethnic groups, the specific changes in skin aging within the Chinese population have been underexplored. Moreover, investigating the similarity of aging skin characteristics between parent-offspring pairs remains uncharted territory. This study aims to fill these gaps by examining the skin aging features of Chinese women and assessing the similarity in aging skin characteristics between mother-daughter pairs. Methods: A total of 40 mother-daughter pairs were recruited and analyzed. The perceived ages of the participants were evaluated, and their aging skin traits were systematically graded. Statistical methods were employed to discern the trends of the aging skin characteristics. By introducing a novel similarity parameter, we compared whether various skin aging characteristics have similar patterns between mothers and daughters. Results: Our findings indicate that age 50 represents a pivotal point in skin aging. Beyond this age, the increase in rhytides and laxity scores accelerated noticeably, whereas the escalation in dyschromia scores became less marked. By introducing similar parameters between mother-daughter pairs and the radar map, we discovered that the skin aging characteristics are remarkably consistent between mother-daughter pairs. Conclusion: Understanding the main aging skin characteristics of different age groups can allow caregivers to devise treatments for preventing skin aging in women of various ages. The mother's skin aging trend is also significant for the daughter's skin aging prevention.

Skin aging, a complex process influenced by both internal and external factors, exhibits distinct patterns across ethnic groups. Despite this, the specific aging characteristics within the Chinese population and the hereditary similarities between parents and offspring have not been thoroughly investigated. To address this gap, our study focused on the skin aging features of Chinese women and explored the resemblance in these features between mother-daughter pairs. Eighty-seven women from the same community, including 40 mother-daughter pairs, participated in our study. We assessed how old each participant appeared to be and methodically evaluated their skin aging signs by a modified scale. With the introduction of a new similarity parameter, we further examined the extent to which skin aging traits showed parallel trends between mothers and their daughters. Our findings pinpoint age 50 as a pivotal moment in the skin aging trajectory, where the increase in wrinkles and skin laxity becomes more pronounced, contrasting with a deceleration in skin discoloration. Remarkably, a consistent pattern of aging characteristics was observed between mother-daughter pairs, suggesting a potential genetic influence. This study not only sheds light on the specific skin aging patterns among Chinese women but also underscores the significance of genetic factors in shaping these patterns. The insights gained pave the way for developing targeted interventions for skin aging prevention and treatment, emphasizing the importance of considering familial aging trends.

Fabrication of Fully Positively Charged Layer-by-Layer Polyelectrolyte Nanofilms with pH-Dependent Swelling Properties.

Nanofilms fabricated by layer-by-layer (LbL) assembly from polyelectrolytes (PEs) are important materials for various applications. However, PE films cannot retain the charges along the polymer chains during fabrication, resulting in a low charge density. In this study, the preparation of LbL nanofilms with preserved positive charges via a controllable and efficient approach was achieved. To fabricate fully positively charged (FPC) LbL nanofilms, a polycation, poly-l-lysine, was partially grafted with azide and alkyne groups. Through copper-catalyzed azide-alkyne cycloaddition and the LbL procedure, nanofilms were fabricated with all of the individual layers covalently bonded, improving the pH stability of the nanofilms. Because the resulting nanofilms had a high charge density with positive charges both inside and on the surface, they showed unique pH-dependent swelling properties and adsorption of negatively charged molecules compared with those of traditional polyelectrolyte LbL nanofilms. This kind of FPC nanofilm has great potential for use in sensors, diagnostics, and filter nanomaterials in the biomedical and environmental fields.

In situ fabrication of fully negatively-charged layer-by-layer nanofilms on a living cell surface.

Fully negatively-charged (FNC) layer-by-layer nanofilms were successfully assembled on a living cell surface for the first time using only poly(acrylic acid) (PAA) by introducing strain-promoted click chemistry to crosslink PAA layers. The resulting nanofilms retained their negative charges and showed higher adsorption of positively-charged molecules without affecting the cell viability.

Injectable Dopamine-Polysaccharide In Situ Composite Hydrogels with Enhanced Adhesiveness.

Polysaccharide bio-adhesives used for non-invasive repair often show weak mechanical strength and tissue adhesion, even when covalently modified with dopamine (DA) from mussel proteins and its derivatives. Low cohesion of the polysaccharide adhesives and easy oxidation of DA may result in the low adhesion properties of the polysaccharide-DA adhesives. In this work, we aimed to prepare a series of injectable hydrogel adhesives to improve their cohesion and adhesion by in situ mixing DA with the polysaccharide without covalent modification. The injectable and rapid curing adhesives were prepared by mixing oxidized dextran (ODE) and chitosan (CS) through a Schiff base reaction in the presence (or absence) of DA. The gelation time of the adhesive was customized to be less than 20 s by controlling the amount of ODE, regardless of the amount of DA. Multi-cross-linked (MC) hydrogels were further prepared by adding cross-linking agents such as sodium periodate (NaIO4) and ferric trichloride (FeCl3), and their sol-gel transitions were easily adjusted by changing the amounts of the cross-linking agents. The MC-FeCl3 hydrogel adhesive displayed good tissue adhesion with a lap shear adhesion strength of 345 kPa, which was 43 times that of fibrin glue. Results from Raman spectra, texture profile analyses, and atomic force microscopy images confirmed the enhanced adhesion induced by a higher cohesion of MC-FeCl3, owing to the coordination of Fe3+ and DA and non-covalent and covalent bonds of DA. Moreover, the adhesives showed good biodegradability and biocompatibility. These results demonstrate that the injectable and sticky hydrogels with good adhesion are promising materials for tissue repair.

Layer-by-layer assembly methods and their biomedical applications.

Layer-by-layer (LbL) assembly has attracted much interest because of its ability to provide nanoscale control over film characteristics and because of a wide choice of available materials. The methods of LbL not only determine the process properties, but also directly affect film properties. In this review, we will discuss LbL methodologies that have been used in biomedical fields. Special attention is devoted to different properties arising from methods that allow for diverse biomedical applications, ranging from surface modification to tissue engineering. We conclude with a discussion of the current challenges and future perspectives.

Mussel-Inspired Epoxy Bioadhesive with Enhanced Interfacial Interactions for Wound Repair.

The balance between high mechanical properties and strong adhesion strength is crucial in designing and preparing a bio-based hydrogel adhesive for wound closure. Although the adhesion performance of bioadhesives has been remarkably improved by modification with catechol groups, their mechanical properties are yet to meet the biomedical requirements. In this study, mussel-inspired epoxy bioadhesives (CSD-PEG) were synthesized based on catechol-modified chitosan oligosaccharide (CSD) and polyethylene glycol diglycidyl ether (PEGDGE) through nucleophilic substitution. Notably, the CSD-PEG adhesive showed high mechanical and adhesion strengths, which were up to 50.7 kPa and 136.7 kPa, respectively. It was confirmed that a certain amount of the epoxy and catechol groups provided multiple interfacial interactions among the adhesives, substrates, and polymer chains for enhancing the performance of adhesives. The adhesives showed good binding and repairing effects for wound closure and favorable biocompatibility in vivo. The prepared CSD-PEG adhesives are expected to be a promising candidate for surgical tissue repair, wound closure, and tissue engineering fields. STATEMENT OF SIGNIFICANCE: Current reported adhesives composed of biopolymers generally suffer from poor mechanical properties or weak tissue adhesiveness. Therefore, to achieve simultaneously high mechanical and adhesion properties in a bio-based adhesive for wound closure is a big challenge. In this study, mussel-inspired adhesive hydrogels (CSD-PEG) were prepared based on catechol-modified chitosan oligosaccharide (CSD) and polyethylene glycol diglycidyl ether (PEGDGE). The tensile strength and adhesive strength of CSD-PEG on porcine skin reached 50.7 kPa and 136.7 kPa, respectively, which were higher than those for most reported biopolymeric adhesives, mainly due to the multiple interfacial interactions between the catechol and epoxy groups. The CSD-PEG bioadhesives also showed good binding and repairing effects for wound closure and tissue regeneration in vivo.

Is chemoprophylaxis necessary for all latent tuberculosis infection patients receiving IL-17 inhibitors? A cohort study.

The tuberculosis (TB) burden is high in China, with a 32% prevalence of latent tuberculosis infection (LTBI) in Beijing. Screening for LTBI and the chemoprophylaxis of positive patients are recommended prior to biologic therapy. To evaluate the TB-related safety of secukinumab (SEC) in a cohort of plaque psoriasis patients with LTBI receiving different treatments. Plaque psoriasis patients eligible for SEC treatment were screened for TB. LTBI patients (QuantiFeron-TB test positive, QFT+) receiving SEC were closely monitored by chest radiograph, ESR or hs-CRP, and blood counts every 12 to 20 weeks for active TB infection. QFT_patients receiving SEC treatment were screened for LTBI every 6 to 12 months. Of 42 patients treated with SEC, 19 were QFT+ (45.24%). A QFT_patient became QFT+ after 6 months treatment. Two patients started SEC treatment from 2015 to 2016 and were followed up 268 and 216 weeks later, respectively. Three patients received chemoprophylaxis, 17 did not because of safety concerns or being unable to complete the process. During the 16- to 268-week follow-up, no signs of TB reactivation were observed in the 20 LTBI patients receiving SEC. Plaque psoriasis patients with LTBI who received no chemoprophylaxis could be safely treated with SEC.

Mussel inspired bio-adhesive with multi-interactions for tissue repair.

Bio-adhesives based on biopolymers have been widely researched for tissue repair. However, the adhesive properties are still insufficient to meet the practical applications. Introducing functional groups into the polymer chains that have multi-interactions among inter/intra-molecules and with substrates is an efficient way to increase cohesion force and further improve the adhesive properties. In this study, 3,4-dihydroxyphenyl propionic acid (DPA) and dopamine (DA) containing adhesion functional catechol groups were employed to modify chitosan (CS) and γ-polyglutamic acid (γPGA), respectively. The substituted degrees of the catechol groups were controlled by the catechol compositions. DPA modified chitosan/DA modified γPGA (CS-DPA/γPGA-DA) adhesives prepared by mixing CS-DPA and γPGA-DA. Effects of the substituted degrees and substrates on the adhesion strength were measured by tensile testing machine. The results showed good adhesion property of the CS-DPA/γPGA-DA adhesive on many surfaces of the substrates. Especially on the arthrodial cartilage, the adhesive strength reached around 150 kPa, much higher than commercially available tissue adhesives. The high adhesion property might be due to the adhesion interactions between the catechol groups and substrates and the high cohesion forces induced by the crosslinking interactions formation among the catechol groups and the electrostatic interactions between the CS and γPGA polymers. In vitro experiments demonstrated that the adhesive had good biocompatibility. These results suggested the catechol-based adhesive is a very suitable and promising biomaterial in the clinical medicine field.

Preparation and properties of dopamine-modified alginate/chitosan-hydroxyapatite scaffolds with gradient structure for bone tissue engineering.

Three-dimensional (3D) homogenous scaffolds composed of natural biopolymers have been reported as superior candidates for bone tissue engineering. There are still remaining challenges in fabricating the functional scaffolds with gradient structures to similar with natural bone tissues, as well as high mechanical properties and excellent affinity to surround tissues. Herein, inspired by the natural bone structure, a gradient-structural scaffold composed of functional biopolymers was designed to provide an optimized 3D environment for promoting cell growth. To increase the interactions among the scaffolds, dopamine (DA) was employed to modify alginate (Alg) and needle-like nano-hydroxyapatite (HA) was prepared with quaternized chitosan as template. The obtained dopamine-modified alginate (Alg-DA) and quaternized chitosan-templated hydroxyapatite (QCHA) were then used to fabricate the porous gradient scaffold by "iterative layering" freeze-drying technique with further crosslinking by calcium ions (Ca2+ ). The as-prepared Alg-DA/QCHA gradient scaffolds were possessed seamlessly integrated layer structures and high levels of porosity at around 77.5%. Moreover, the scaffolds showed higher compression modules (1.7 MPa) than many other biopolyermic scaffolds. The gradient scaffolds showed appropriate degradation rate to satisfy with the time of the bone regeneration. Both human chondrocytes and fibroblasts could adhesive and growth well on the scaffolds in vitro. Furthermore, an excellent osteogenetic activity of the gradient scaffold can effectively promote the regeneration of the bone tissue and accelerate the repair of the bone defects in vivo, compared with that of the scaffold with the homogenous structure. The novel multilayered scaffold with gradient structure provided an interesting option for bone tissue engineering. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1615-1627, 2019.

Fabrication of polydopamine nanoparticles knotted alginate scaffolds and their properties.

Polydopamine (PDA) can greatly affect polymer's properties, due to the chemical and physical interactions between the polymers and PDA. In this study, PDA was demonstrated to adjust the pore structures and increase the mechanical properties of alginate hydrogel-based cartilage tissue scaffolds. Dopamine modified alginate (Alg-DA) was firstly synthesized by modification of Alg with DA. Alg-DA interacted with preprepared PDA nanoparticles and further crosslinked with calcium ions (Ca2+ ) to form the hydrogel scaffold (Alg-DA/PDA). The Alg-DA/PDA scaffold combined multiple advantageous features, including continuous pore structure, high level of porosity, well mechanical properties, good biocompatibility and appropriate cycle life of degradation. Moreover, it could provide an optimized forming environment for hydroxyapatite (HAp) by mineralization process, thus accelerating cartilage repair. The improved performances were mainly ascribed to physical enhancement of the PDA nanoparticles and crosslinking points among the polymers and catechol groups in DA. These findings might offer a guideline for fabricating robust biocompatible cartilage tissue scaffold. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3255-3266, 2018.

The Shu complex promotes error-free tolerance of alkylation-induced base excision repair products.

Here, we investigate the role of the budding yeast Shu complex in promoting homologous recombination (HR) upon replication fork damage. We recently found that the Shu complex stimulates Rad51 filament formation during HR through its physical interactions with Rad55-Rad57. Unlike other HR factors, Shu complex mutants are primarily sensitive to replicative stress caused by MMS and not to more direct DNA breaks. Here, we uncover a novel role for the Shu complex in the repair of specific MMS-induced DNA lesions and elucidate the interplay between HR and translesion DNA synthesis. We find that the Shu complex promotes high-fidelity bypass of MMS-induced alkylation damage, such as N3-methyladenine, as well as bypassing the abasic sites generated after Mag1 removes N3-methyladenine lesions. Furthermore, we find that the Shu complex responds to ssDNA breaks generated in cells lacking the abasic site endonucleases. At each lesion, the Shu complex promotes Rad51-dependent HR as the primary repair/tolerance mechanism over error-prone translesion DNA polymerases. Together, our work demonstrates that the Shu complex's promotion of Rad51 pre-synaptic filaments is critical for high-fidelity bypass of multiple replication-blocking lesion.

[Sexual hormone levels in semen and germ cell apoptosis].

OBJECTIVE: To explore the relationship between sexual hormones in semen and germ cell apoptosis in male population. METHODS: Sixty-six infertile patients and thirty fertile males were selected randomly. The levels of folicle stimulating hormone ( FSH), prolactin (PRL), luteinizing hormone (LH), and testosterone (T) in semen were measured by ELISA. Terminal deoxynucleotidyl transferase mediated UTP nick end labeling (TUNEL) was used for the detection of germ cell apoptosis. RESULTS: The levels of FSH, LH, PRL, T in thirty fertile men were (1.63 +/- 0.15) U/L, (2.18 +/- 0.21) U/L, (6.34 +/- 0.30) nmol/L, (1.85 +/- 0.11) nmol/L, respectively, and germ cell apoptosis rate was (4.61 +/- 1.23)%. FSH, LH, PRL, T levels in infertile group were (1.25 +/- 0.18) U/L, (1.76 +/- 0.32) U/L, (5.86 +/- 0.13) nmol/l, (1.45 +/- 0.13) nmol/, respectively, and germ cell apoptosis rate was (18.36 +/- 2.04)%. There were significant differences in all parameters between infertile group and fertile group. The levels of FSH, LH, PRL, T were negatively correlated with germ cell apoptosis rates( r = -0.88, -0.93, -0.90, -0.98). The volume of apoptotic germ cell decreased, and chromatin was compacted to form cell-membrane blebs and apoptotic bodies. CONCLUSION: Low concentration of sexual hormones may increase the apoptosis of germ cells, which can induce male infertility.

[Relationship between the amount of nitric oxide and apoptosis of germ cells in the semen of infertile men].

AIM: To explore the relationship between nitric oxide(NO) and apoptosis of germ cells in the semen of infertile men. METHODS: Copper-coated cadmium reduction fluorescence assay was used to detect nitrate, the metabolic product of NO. The apoptosis and ultrastructure of germ cells were detected and observed by TdT-mediated dUTP nick end labeling (TUNEL) and transmission electronls microscope (TEM), respectively. RESULTS: In normal control group, concentration of NO and the apoptotic rate of germ cells were (56.83+/-11.65) micromol/L and (4.60+/-1.25)%, respectively; while in inferile group were (128.86+/-23.76) micromol/L and (17.36+/-3.05)%, respectively. The differences in NO concentration and the apoptotic rate of germ cells between the two groups were significant (P<0.01). The concentration of NO was positively correlated with the apoptotic rate of germ cells in infertile group (r=0.96). The apoptotic germ cells showed typical morphology of apoptosis, including nuclear chromatin condensation and margination, nuclear memberane folding, and formation of apoptotic bodies. CONCLUSION: The amount of NO in semen from infertile men has close relationship with apoptotic rate of germ cells. High concentration of NO may result in the increase of germ cell apoptosis rate and lead to male infertility.

[Sodium nitroprusside facilitates human sperm capacitation and acrosome reaction].

OBJECTIVE: To explore the effect of nitric oxide (NO) on human sperm capacitation and acrosome reaction (AR). METHODS: Different concentrations of sodium nitroprusside (SNP) were added to the sperm suspension from 48 healthy fertile men, and the suspension was incubated in 1 x Earle at 37 degrees C for 1 hour. Progesterone was used to induce AR for 15, 30, 45 and 60 min, and then acid phosphatase (ACP) activity in the suspension before and after capacitation and at different time of AR was measured by p-nitrophenyl sodium phosphate assay. In the meantime, sperm motile parameters were assayed by CASA to observe sperm capacitation and AR. RESULTS: ACP activity and sperm motile parameters increased in the 50 approximately 100 nmol/L NO concentration group, showed no significant variation in the 150 approximately 200 nmol/L group, and decreased in the 250 approximately 300 nmol/L group. CONCLUSION: NO can facilitate sperm capacitation, AR and sperm motile parameters in low concentration and suppress them in high concentration. ACP activity assay of sperm is an objective and reliable method to evaluate sperm capacitation and AR in whole sperm population.

[Study of zinc in protecting sperm from sodium nitroprusside damage].

OBJECTIVE: To study the function of zinc in preventing human sperm from being damaged by sodium nitroprusside (SNP), an external NO donor. METHODS: Analyses were made of the function of zinc in protecting sperm from being influenced by SNP in such aspects as sperm motility, head-tail connection and the breakage of sperm DNA chain by using phase-contrast microscope and single cell gel electrophoresis (SCGE). RESULTS: Sperm motility was obviously inhibited by SNP. The percentage of comet cells increased significantly but the stability of sperm head-tail connection decreased. Zinc could promote sperm motility, protect the DNA chain and prevent the sperm head-tail connection from breaking. CONCLUSION: Zinc can protect sperm from being damaged by NO. Its mechanism may be related to the mercaptol group of sperm chromatin.