Impact of skin sensitivity mechanisms on sebum secretion: Management strategies for oily sensitive skin

Recent epidemiological surveys based on Baumann's classification have revealed a notable rise in the prevalence of oily sensitive skin.The development of oily sensitive skin is primarily linked to the abnormal function of sebaceous glands.The function of sebaceous glands is regulated by several factors,including inflammatory mediators,neurotransmitters,and endocrine signals.Sensitive skin,particularly oily sensitive skin,is prone to local inflammation,which in turn disrupts the normal functioning of sebaceous glands.This creates a loop wherein increased oil production exacerbates sensitivity,while heightened sensitivity further stimulates sebum secretion,perpetuating a vicious cycle.This article summarizes our understanding of the four primary mechanisms underlying skin sensitivity and their impact on sebaceous gland activity.Accordingly,it proposes management strategies for oily sensitive skin and seeks to guide the development of skin care regimens for this skin type.

Telomerase expression in sebaceous carcinoma of the eyelid

Background In humans telomerase is expressed in most ca ncers and immortal cell lines, and astivation of telomerase may play important r oles in tumorigenesis and immortalization. This study was to investigate the rol es of telomerase activity (TA) and human telomerase RNA (hTR) in sebaceous carcinoma of the eyelid.Methods The telomerase repeated amplification protocal (TRAP) was used to demonstrate telomerase activity in 12 cases of sebaceous carcinoma of the eyelid. In situ hybridiza tion (ISH) was used to demonstrate the expression of hTR in 55 cases of paraffin-embedded sebaceous carcinoma of the eyelid, and the results were compared with the proliferative index determined by Mib-1 immuno-labeling, histological patterns and r ecurrence of the tumor.Results Different telomerase activity was shown in the 12 cases of sebaceous carcinoma of the eyelid. The positive expression of hTR was 85.5% (47/55) in tumor cells, but not in the adjacent tissues. The positive expression of hTR was correlated with the proliferative activity (as assessed by Mib-1 immunolabelling, r=0.942, P<0.001) and the dif ferentiation of sebaceous carcinoma of the eyelid (χ 2=17.621, P<0.001), but not si gnificantly related to tumor recurrence. The level of hTR expression increased with the de crease of differentiation of sebaceous carcinoma of the eyelid.Conclusions The results suggest that the up-regulation of telo merase expression plays some roles in tarsal gland carcinogenesis, and the express ion of hTR is a useful marker for malignant degree of sebaceous carcinoma of the eyelid.

Genetic and histological relationship between pheromone-secreting tissues of the musk gland and skin of juvenile Chinese forest musk deer(Moschus berezovskii Flerov,1929)

Background The musk glands of adult male Chinese forest musk deer(Moschus berezovskii Flerov,1929)(FMD),which are considered as special skin glands,secrete a mixture of sebum,lipids,and proteins into the musk pod.Together,these components form musk,which plays an important role in attracting females during the breeding season.However,the relationship between the musk glands and skin of Chinese FMD remains undiscovered.Here,the musk gland and skin of Chinese FMD were examined using histological analysis and RNA sequencing(RNA-seq),and the expression of key regulatory genes was evaluated to determine whether the musk gland is derived from the skin.Methods A comparative analysis of musk gland anatomy between juvenile and adult Chinese FMD was conducted.Then,based on the anatomical structure of the musk gland,skin tissues from the abdomen and back as well as musk gland tissues were obtained from three juvenile FMD.These tissues were used for RNA-seq,hematoxylin-eosin(HE)staining,immunohistochemistry(IHC),western blot(WB),and quantitative real-time polymerase chain reaction(qRT-PCR)experiments.Results Anatomical analysis showed that only adult male FMD had a complete glandular organ and musk pod,while juvenile FMD did not have any well-developed musk pods.Transcriptomic data revealed that 88.24%of genes were co-expressed in the skin and musk gland tissues.Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling pathway analysis found that the genes co-expressed in the abdomen skin,back skin,and musk gland were enriched in biological development,endocrine system,lipid metabolism,and other pathways.Gene Ontology(GO)enrichment analysis indicated that the genes expressed in these tissues were enriched in biological processes such as multicellular development and cell division.Moreover,the Metascape predictive analysis tool demonstrated that genes expressed in musk glands were skin tissue-specific.qRT-PCR and WB revealed that sex-determining region Y-box protein 9(Sox9),Caveolin-1(Cav-1),and androgen receptor(AR)were expressed in all three tissues,although the expression levels differed among the tissues.According to the IHC results,Sox9 and AR were expressed in the nuclei of sebaceous gland,hair follicle,and musk gland cells,whereas Cav-1 was expressed in the cell membrane.Conclusions The musk gland of Chinese FMD may be a derivative of skin tissue,and Sox9,Cav-1,and AR may play significant roles in musk gland development.

A volar skin excisional wound model for in situ evaluation of multiple-appendage regeneration and innervation

Background:Promoting rapid wound healing with functional recovery of all skin appendages is the main goal of regenerative medicine.So far current methodologies,including the commonly used back excisional wound model(BEWM)and paw skin scald wound model,are focused on assessing the regeneration of either hair follicles(HFs)or sweat glands(SwGs).How to achieve de novo appendage regeneration by synchronized evaluation of HFs,SwGs and sebaceous glands(SeGs)is still challenging.Here,we developed a volar skin excisional wound model(VEWM)that is suitable for examining cutaneous wound healing with multiple-appendage restoration,as well as innervation,providing a new research paradigm for the perfect regeneration of skin wounds.Methods:Macroscopic observation,iodine-starch test,morphological staining and qRT-PCR anal-ysis were used to detect the existence of HFs,SwGs,SeGs and distribution of nerve fibres in the volar skin.Wound healing process monitoring,HE/Masson staining,fractal analysis and behavioral response assessment were performed to verify that VEWM could mimic the pathological process and outcomes of human scar formation and sensory function impairment.Results:HFs are limited to the inter-footpads.SwGs are densely distributed in the footpads,scattered in the IFPs.The volar skin is richly innervated.The wound area of the VEWM at 1,3,7 and 10 days after the operation is respectively 89.17%±2.52%,71.72%±3.79%,55.09%±4.94%and 35.74%±4.05%,and the final scar area accounts for 47.80%±6.22%of the initial wound.While the wound area of BEWM at 1,3,7 and 10 days after the operation are respectively 61.94%±5.34%,51.26%±4.89%,12.63%±2.86%and 6.14%±2.84%,and the final scar area accounts for 4.33%±2.67%of the initial wound.Fractal analysis of the post-traumatic repair site for VEWM vs human was performed:lacunarity values,0.040±0.012 vs 0.038±0.014;fractal dimen-sion values,1.870±0.237 vs 1.903±0.163.Sensory nerve function of normal skin vs post-traumatic repair site was assessed:mechanical threshold,1.05±0.52 vs 4.90 g±0.80;response rate to pin-prick,100%vs 71.67%±19.92%,and temperature threshold,50.34◦C±3.11◦C vs 52.13◦C±3.54◦C.Conclusions:VEWM closely reflects the pathological features of human wound healing and can be applied for skin multiple-appendages regeneration and innervation evaluation.