Tag Archive for 'Sebum' | Sci.News

Model of dynamic interactions between the skin immune system (SIS) and its microbial/chemical milieu in human facial skin: (A) infancy -- before the development of stabilized microbial communities, an early tolerogenic interaction between the maturing SIS and the microbiota is prevalent; (B) after this initial period, a homeostatic crosstalk evolves between the developed SIS and a childhood-type stable microbiota; (C) adolescence -- enhanced sebum secretion and shift in the microbiota composition (and probably other uncovered events, e.g., barrier breach) might contribute to a dynamic change in the communication between the SIS and the microbiota in the skin, leading to inflammatory interactions; cytokines associated with a homeostatic dialog may become highly increased in acne lesions (relative to non-lesions), promoting inflammation together with newly secreted proinflammatory mediators produced by keratinocytes, dendritic cells (DCs), and subsequently, infiltrating inflammatory T helper (Th)1 and Th17(23) (for IL-23) cells, neutrophils, and macrophages; these mediators initiate follicular hyperkeratinization, closure of the follicular infundibulum, comedone formation, and the development of acne papules, pustules, and nodules; the extent and time course of inflammation can vary across a wide spectrum among teenagers; (D) following the resolution of acne, in adult SGR skin, under steady-state, SIS and region-specific microbes carry on a homeostatic dialog with the microbiota again, mediated by the controlled production of innate immune-cell-derived factors, including complement components, AMPs, IL-1, TSLP, and IL-7; hair follicles may play a pivotal role in this crosstalk, supporting the residency and recruitment of LCs, Tregs, ILCs, as well as nonpathogenic Th17(β) cells to maintain homeostasis; upward arrows depict increases (expression, concentrations, and ratios). Propionibacterium acnes (Propionibacteriaceae) = Cutibacterium acnes. Other relevant bacterial genera are noted in the schematic. Abbreviations: AMP - antimicrobial peptide, IL – interleukin, ILC - innate lymphoid cell, LC - Langerhans cell, mDC - myeloid dendritic cell, RORγt - RAR-related orphan receptor γt, SGR - sebaceous gland rich, SIS - skin immune system, TGF - transforming growth factor, Th - T helper, Treg - regulatory T cell, TSLP - thymic stromal lymphopoietin. Image credit: Szegedi et al, doi: 10.1016/j.it.2019.08.006.

Adolescent Acne Vulgaris is Naturally Developing, Transient Inflammatory State, Researchers Say

Oct 1, 2019 by News Staff

Acne vulgaris, which occurs in 44-95% of teenagers of varying ethnicities, represents a natural, transient inflammatory interaction of adolescent facial...