Age-Related Changes in Female Scalp Dermal Sheath and Dermal Fibroblasts: How the Hair Follicle Environment Impacts Hair Aging

In women, aging leads to reduced hair density and thinner fibers and can result in female-pattern hair loss. However, the impact of the aging dermal environment on female scalp hair follicles remains unclear. In this study, we document in situ changes in 22 women (aged 19-81 years) and primary cultures of dermal fibroblast and dermal sheath cells. In situ, the papillary reticular boundary was indistinguishable in the young scalp but prominent in the scalp of those aged >40 years, accompanied by reduced podoplanin (PDPN) expression, increased versican expression, and changes in collagen organization. Hair follicles were shorter, not reaching the adipose layer. Hyaluronic acid synthase 2 was highly expressed, whereas matrix metalloproteinase 1 was elevated in the dermal papilla and dermal sheath in situ. Primary dermal fibroblast cultures confirmed that matrix metalloproteinase 1 mRNA, MMP1, increased with aging, whereas in dermal sheath cells, hyaluronic acid synthase 2, HAS2, and PDPN increased and α-smooth muscle actin αSMA mRNA decreased. Both exhibited increased cartilage oligomeric protein, COMP mRNA expression. Proteomics revealed an increase in dermal sheath proteins in the dermal fibroblast secretome with aging. In summary, aging female scalp shows striking structural and biological changes in the hair follicle environment that may impact hair growth.

The bright and dark side of skin senescence. Could skin rejuvenation anti-senescence interventions become a "bright" new strategy for the prevention of age-related skin pathologies?

The number of senescent cells in the skin is increasing with age. Numerous studies have attempted to elucidate the role of these cells in normal aging of the skin as well as in age-related skin conditions. In recent years, attempts have also been made to find treatments that aim either to cleanse the skin tissues of senescent cells or to neutralize their effects (referred to as senolytics and senomorphics respectively) and thus prevent the consequences, particularly on the skin's appearance in advanced age. Through this review, we have tried to gather data on the role of senescent cells in the skin, in treatments aimed at removing them, and we are asking a reasonable question as to whether anti-senescence treatments may contribute to the protection against age-related skin pathologies, including skin cancer, such as non-melanoma skin cancer, in addition to their involvement in skin rejuvenation.

The new paradigm for androgenetic alopecia and plant-based folk remedies: 5α-reductase inhibition, reversal of secondary microinflammation and improving insulin resistance

ETHNOPHARMACOLOGICAL RELEVANCE

Research in the past half a century has gradually sketched the biological mechanism leading to androgenetic alopecia (AGA). Until recently the aetiological paradigm has been too limited to enable intelligent commentary on the use of folk remedies to treat or reduce the expression of this condition. However, our understanding is now at a point where we can describe how some folk remedies work, predict how effective they will be or why they fail.

RESULTS

The new paradigm of AGA is that inheritance and androgens (dihydrotestosterone) are the primary contributors and a secondary pathology, microinflammation, reinforces the process at more advanced stages of follicular miniaturisation. The main protagonist to microinflammation is believed to be microbial or Demodex over-colonisation of the infundibulum of the pilosebaceous unit, which can be ameliorated by antimicrobial/acaricidal or anti-inflammatory therapies that are used as adjuvants to androgen dependent treatments (either synthetic or natural). Furthermore, studies reveal that suboptimal androgen metabolism occurs in both AGA and insulin resistance (low SHBG or high DHT), suggesting comorbidity. Both can be ameliorated by dietary phytochemicals, such as specific classes of phenols (isoflavones, phenolic methoxy abietanes, hydroxylated anthraquinones) or polycyclic triterpenes (sterols, lupanes), by dual inhibition of key enzymes in AGA (5α-reductase) and insulin resistance (ie., DPP-4 or PTP1B) or agonism of nuclear receptors (PPARγ). Evidence strongly indicates that some plant-based folk remedies can ameliorate both primary and secondary aetiological factors in AGA and improve insulin resistance, or act merely as successful adjuvants to mainstream androgen dependent therapies.

CONCLUSION

Thus, if AGA is viewed as an outcome of primary and secondary factors, then it is better that a 'multimodal' or 'umbrella' approach, to achieve cessation and/or reversal, is put into practice, using complementation of chemical species (isoflavones, anthraquinones, procyanidins, triterpenes, saponins and hydrogen sulphide prodrugs), thereby targeting multiple 'factors'.

Immunohistochemical patterns in the interfollicular Caucasian scalps: influences of age, gender, and alopecia

Skin ageing and gender influences on the scalp have been seldom studied. We revisited the changes in the interfollicular scalp. The study was performed on a population of 650 volunteers (300 women and 350 men) for over 7 years. Three age groups were selected in both genders, namely, subjects aged 20–35, 50–60, and 60–70 years. The hair status was further considered according to nonalopecic and alopecic patterns and severity (discrete, moderate, and severe). Biopsies from the parietal area were processed for immunohistochemistry. Stromal cells were distinguished according to the presence of vimentin, Factor XIIIa, CD117, and versican. Blood and lymphatic vessels were highlighted by Ulex europaeus agglutinin-1 and human podoplanin immunoreactivities, respectively. Actinic elastosis was identified by the lysozyme coating of elastic fibres. The epidermis was explored using the CD44 variant 3 and Ki67 immunolabellings. Biplot analyses were performed. Immunohistochemistry revealed a prominent gender effect in young adults. Both Factor XIIIa+ dermal dendrocytes and the microvasculature size decreased with scalp ageing. Alopecia changes mimicked stress-induced premature senescence.

Malignant melanoma and its stromal nonimmune microecosystem

In recent years, rapid advances were reached in the understanding of a series of biologic signals influencing cutaneous malignant melanoma (CMM) cells. CMM is in close contact with a peculiar dermal extracellular matrix (ECM). Stromal cells store and release various structural ECM components. The impact on CMM growth and progression is mediated through strong and long-lasting effects of ECM products. This paper summarizes some peculiar aspects of the peri-CMM stroma showing intracytoplasmic loads in Factor XIIIa, CD34, versican, and α (IV) collagen chains. The restricted peri-CMM skin territory exhibiting such changes corresponds to the area showing neoangiogenesis and extravascular unicellular metastatic spread. The latter inconspicuous migratory CMM cells possibly correspond to CMM stem cells or to CMM cells with aberrant HOX gene expression. Their presence is associated with an increased risk for metastases in the regional sentinel lymph nodes. In conclusion, the CMM-stroma connection appears crucial to the growth regulation, invasiveness and initial metastatic spread of CMM cells. Although much remains to be learned in this field, the active intervention of the peri-CMM stroma is likely involved in the inconspicuous early metastatic migration of CMM cells.

'Malignant melanoma microecosystem': Immunohistopathological insights into the stromal cell phenotype

Cutaneous malignant melanoma (MM) is rooted in the dermal connective tissue, which consists of apparently unremarkable stromal cells as they appear upon regular histopathological examination. However, a number of in vitro studies have shown that these cells produce diverse types of cytokines, growth factors and enzymes in excess. In addition, they store and probably release various structural components of the extracellular matrix (ECM). Most of the current information comes from in vitro experiments, and these findings do not always correlate with investigations carried out using excised human MM tissue. The MM-stroma connection appears crucial to the regulation of neoplastic growth, invasiveness and initial metastatic spread. However, little is known about the in vivo intracellular storage and extracellular deposits of specific ECM macromolecules located inside and around MM lesions. This review summarizes various distinct features of the peri-MM stroma, which shows an intracytoplasmic abundance of Factor XIIIa, versican and various α (IV) collagen chains. The area exhibiting such changes corresponds to the location where neoangiogenesis commonly develops and where extravascular unicellular metastatic MM lesions are possibly found. Some of these inconspicuous migratory malignant melanocytes may actually correspond to MM stem cells. Their presence was found to be significantly associated with an increased risk for distant metastases, particularly in the sentinel lymph nodes. Although much remains to be learned, active intervention of the ECM appears likely in the inconspicuous early dermal metastatic migration of MM cells.

The riddle of genuine skin microrelief and wrinkles

Wrinkles result from distinct structural changes occurring in specific parts of the dermis and subcutaneous tissue. There is a need for evidenced-based cosmetology identifying and quantifying the different aspects of wrinkling. Histology allows to detect specific changes associated with particular types of wrinkles. Four main types of wrinkles can thus be recognized, including the atrophic crinkling rhytids, the permanent elastotic creases, the dynamic expression lines, and the gravitational folds. Each type usually develops on specific skin regions exhibiting distinct microanatomical characteristics. Whereas skin microrelief, expression lines and skin folds appear clearly marked at the histological level, only little dermal changes are identified under other reducible or permanent wrinkles compared with the skin immediately adjacent to them. Distinguishing different types of wrinkles brings more precision to the clinical practice. This is of importance because the different types of wrinkles respond differently to cosmetic, dermatological and surgical treatments.

Aging of hair

The appearance of hair plays an important role in people's overall physical appearance and self-perception. With today's increasing life expectation, the desire to look youthful plays a bigger role than ever. The hair care industry has become aware of this and also more capable to deliver active products that are directed toward meeting this consumer demand. The discovery of pharmacological targets and the development of safe and effective drugs also indicate strategies of the drug industry for maintenance of healthy and beautiful hair. Hair aging comprises weathering of the hair shaft and aging of the hair follicle. The latter manifests as decrease of melanocyte function or graying, and decrease in hair production in androgenetic and senescent alopecia. The scalp is also subject to intrinsic or physiologic aging and extrinsic aging caused by external factors. Intrinsic factors are related to individual genetic and epigenetic mechanisms with interindividual variation. Prototypes are familial premature graying and androgenetic alopecia. Extrinsic factors include ultraviolet radiation and smoking. Experimental evidence supports the hypothesis that oxidative stress plays a role in skin and hair aging. Topical anti-aging compounds for hair include humefactants, hair conditioners, photoprotectors, and antioxidants. Current available treatment modalities with proven efficacy for treatment of androgenetic alopecia are topical minoxidil, oral finasteride, and autologous hair transplantation. In the absence of another way to reverse hair graying, hair colorants are the mainstays of recovering lost hair color. Topical liposome targeting for melanins, genes, and proteins selectively to hair follicles are under current investigation.

Shampoos: Ingredients, efficacy and adverse effects

Shampoos are the most frequently prescribed treatment for the hair and scalp. The different qualities demanded from a shampoo go beyond cleansing. A cosmetic benefit is expected, and the shampoo has to be tailored to variations associated with hair quality, age, hair care habits, and specific problems related to the condition of the scalp. The reciprocal relationship between cosmetic technology and medical therapy is reflected in the advances of shampoo formulation that has made applications possible that combine benefits of cosmetic hair care products with efficacy of medicinal products. A shampoo is composed of 10 to 30 ingredients: cleansing agents (surfactants), conditioning agents, special care ingredients, and additives. Since the cleansing activity depends on the type and amount of surfactants utilized, shampoos are composed of a blend of different surfactants, depending on the requirements of the individual hair type. Development time from the concept to the commercial shampoo may take longer than a year. Much effort is invested in the development of conditioning agents, which impart luster, smoothness, volume and buoyancy. Another prerequisite is a scalp free of scaling. Current anti-dandruff agents primarily have an antimicrobial mode of action, and inhibit growth of Malassezia spp. Recent developments in shampoo technology have led to increased efficacy of anti-dandruff agents, allowing shorter contact time, and reducing irritation.

EEMCO Guidance for the Assessment of Hair Shedding and Alopecia

Knowledge of the hair follicle anatomy and the dynamics of hair cycling is substantial. Recognizing the anagen, catagen and telogen phases as well as teloptosis and the hair eclipse phenomenon clearly characterizes the typical hair chronobiology. Physiological modulators include hormones, neuromediators, miscellaneous biomolecules, seasons, micro-inflammation and ageing. For individuals who present with the complaint of increased hair shedding or alopecia, a host of evaluation techniques are available in addition to history, physical examination and laboratory assessment. Various clinical hair techniques can help in assessing the efficacy of drugs and cosmetics on hair growth. The methods are quite similar to those used to establish a definite diagnosis in dermatological practice. Great strides have been made during the recent decades in the methodology of hair growth trials in dermatology and cosmetology. Clinical evaluations benefit from a few additional specific techniques that enhance the perception of hair (re-) growth, shedding and alopecia. These assessments include the determination of hair patterning and density that may be helped by the 'black-and-white felt' examination. Daily hair counts, the 'hair pull test' and the 'hair feathering test' are also available. Instrumental methods provide reliable quantitative information that is useful if there are adequate controls. Some photographic methods, the trichogram, hair weighing and variants of the hair growth window technique including the phototrichogram, videotrichogram and tractio-phototrichogram provide insight into the complexities of hair cycling and shedding. Skin biopsy is indicated for diagnostic purposes, especially when the hair loss is accompanied by scarring.

From skin microrelief to wrinkles. An area ripe for investigation

Skin microrelief alters progressively with age. Wrinkles do not result from these changes but are superimposed upon them. Wrinkles result from structural changes in the epidermis, dermis and hypodermis. Four types of wrinkles can be recognized. Type 1 wrinkles are atrophic. Type 2 wrinkles are elastotic. Type 3 wrinkles are expressional. Type 4 wrinkles are gravitational. Each type of wrinkle is characterized by distinct microanatomical changes and each type of wrinkle develops in specific skin regions. Each is likely to respond differently to treatment. Skin microrelief and skin folds can be identified on histological examination. By contrast, only minimal dermal changes are found beneath permanent or reducible wrinkles compared with immediately adjacent skin. A series of objective and non-invasive methods is available to quantify the severity of wrinkling.