Effect of Age on Epidermal Immune Function

Prospective randomized controlled pilot study on the effects of almond consumption on skin lipids and wrinkles

OBJECTIVE

Almonds are a rich source of fatty acids and antioxidants, and their supplementation is known to significantly modulate serum lipids. The effects of almond on the skin's lipid barrier and the appearance of wrinkles have not yet been elucidated. The aim of this study was to investigate the effects of almond consumption on facial sebum production and wrinkles.

METHODS

This was a prospective, investigator-blinded, randomized controlled trial in which subjects consumed 20% of their daily energy consumption in either almonds or a calorie-matched snack for 16 weeks. This study was completed at the UC Davis Dermatology clinic. Participants were a volunteer sample of generally healthy postmenopausal females with Fitzpatrick skin types 1 and 2. A facial photograph and image analysis system was used to obtain standardized photographs and information on wrinkle width and severity at 0, 8, and 16 weeks. Measurements of transepidermal water loss and sebum production were also completed at 0, 8, and 16 weeks.

RESULTS

Fifty healthy postmenopausal females were recruited, 31 participants were enrolled, and 28 completed the study. Under photographic analysis, the almond group had significantly decreased wrinkle severity and width compared with the control group at 16 weeks (p < .02). Changes in skin barrier function were nonsignificant, measured by the transepidermal water loss (p = .65) between the almond and control groups relative to baseline after 16 weeks. No adverse effects were reported.

CONCLUSION

Our study demonstrates that daily almond consumption may reduce wrinkle severity in postmenopausal females to potentially have natural antiaging benefits.

[The third dimension of the face aging, improvement of its understanding]

OBJECTIVES

Over the past 30 years, surface imaging has made tremendous progress. Surgical management has also been subject of numerous technical and strategic developments. For a better understanding of the curative strategies of face aging, the authors have put into perspective the three-dimensional data acquired up to date.

METHOD

A review of the literature focused on the three-dimensional study of facial aging was carried out.

RESULTS

Thanks to the precision of new surface acquisition systems and larger patient cohorts, our understanding of surfaces and volumes is now much more accurate. 3D, particularly highlights the major impact of aging on the perioral area, which was up to now neglected compared to other facial areas.

CONCLUSION

A technical discussion is needed to identify the best techniques to correct the defects and provide a natural result for those anatomical areas that are heavily impacted by aging but not corrected in the final.

Aging affects epidermal Langerhans cell development and function and alters their miRNA gene expression profile

Immunosenescence is a result of progressive decline in immune system function with advancing age. Epidermal Langerhans cells (LCs), belonging to the dendritic cell (DC) family, act as sentinels to play key roles in the skin immune responses. However, it has not been fully elucidated how aging affects development and function of LCs. Here, we systemically analyzed LC development and function during the aging process in C57BL/6J mice, and performed global microRNA (miRNA) gene expression profiles in aged and young LCs. We found that the frequency and maturation of epidermal LCs were significantly reduced in aged mice starting at 12 months of age, while the Langerin expression and ability to phagocytose Dextran in aged LCs were increased compared to LCs from < 6 month old mice. The migration of LCs to draining lymph nodes was comparable between aged and young mice. Functionally, aged LCs were impaired in their capacity to induce OVA-specific CD4⁺ and CD8⁺ T cell proliferation. Furthermore, the expression of miRNAs in aged epidermal LCs showed a distinct profile compared to young LCs. Most interestingly, aging-regulated miRNAs potentially target TGF-β-dependent and non- TGF-β-dependent signal pathways related to LCs. Overall, our data suggests that aging affects LCs development and function, and that age-regulated miRNAs may contribute to the LC developmental and functional changes in aging.

The elderly as a sensitive population in environmental exposures: making the case

The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.

Dermatite de contato em idosos

FUNDAMENTOS: A dermatite alérgica de contato é freqüente, com variações de acordo com o grupo estudado. OBJETIVOS: Verificar a freqüência da dermatite alérgica de contato em idosos; demonstrar os principais sensibilizantes nesse grupo; comparar os resultados dos testes epicutâneos com um grupo de adultos atendidos no mesmo período. PACIENTES: Durante o período 1998-2003, entre os pacientes submetidos aos testes de contato na Clínica de Dermatologia da Santa Casa de São Paulo, selecionaram-se idosos (>65 anos) e adultos (20-65 anos). RESULTADOS: Foram avaliados 80 (9%) idosos e 581 (63%) adultos. Entre os idosos, 70 tiveram testes positivos, e 10, negativos. Nos adultos, 436 apresentaram testes positivos, e 145, negativos. A diferença entre os grupos em relação ao número de testes positivos e negativos foi estatisticamente significante (p= 0,02). Demonstrou-se maior freqüência de sensibilização nos idosos às seguintes substâncias - sulfato de níquel (p=0,001), perfume-mix (p=0,004), neomicina (p=0,0008), nitrofurazona (p=0,02), prometazina (p=0,03) e benzocaína (p=0,007). CONCLUSÕES: A dermatite alérgica de contato nos idosos é comum como em outras faixas etárias. As substâncias relacionadas aos medicamentos tópicos são importantes agentes etiológicos da dermatite alérgica de contato nesse grupo.

Fifty years of skin aging

In developed countries, interest in cutaneous aging is in large part the result of a progressive, dramatic rise over the past century in the absolute number and the proportion of the population who are elderly (Smith et al, 2001). The psychosocial as well as physiologic effects of skin aging on older individuals have created a demand for better understanding of the process and particularly for effective interventions. Skin aging is a complex process determined by the genetic endowment of the individual as well as by environmental factors. The appearance of old skin and the clinical consequences of skin aging have been well known for centuries, but only in the past 50 y have mechanisms and mediators been systematically pursued. Still, within this relatively short time there has been tremendous progress, a progress greatly enhanced by basic gerontologic research employing immunologic, biochemical, and particularly molecular biologic approaches (Figs 1, 2).

Influence of ageing on Langerhans cell migration in mice: identification of a putative deficiency of epidermal interleukin-1beta

Previous studies in mice have reported a decrease in epidermal Langerhans cell (LC) density in aged skin, however, the impact of this reduction on LC function and cutaneous immune responses is unclear. In the present series of experiments, the frequency of major histocompatibility complex class II+ LC in the epidermis of older (6-month-old) mice was found to be reduced significantly compared with that observed for young (6-8-week-old) mice. LC mobilization and the subsequent accumulation of dendritic cells (DC) in regional lymph nodes in response to topical challenge with a chemical allergen were found to be less vigorous in older mice. Flow cytometric analyses of DC derived from the draining lymph nodes of fluorescein isothiocyanate (FITC)-sensitized mice revealed that the frequency of FITC+-DC arriving in draining lymph nodes was also reduced in older mice but that the fluorescence intensity was comparable. Control and allergen-treated-older mice also displayed decreased total lymph node cellularity. Contact hypersensitivity responses were found not to be compromised in older mice. However, the cytokine regulation of LC migration in the two age groups of mice did differ. LC migration provoked by intradermal injection of tumour necrosis factor-alpha (TNF-alpha) was reduced in older animals, whereas, the percentage of LC that migrated in response to exogenous interleukin-1beta (IL-1beta) was comparable for both young and aged mice. Since both allergen- and TNF-alpha-induced LC responses are known to require receipt by LC of a signal from IL-1beta for effective migration, the suggestion is that impaired LC migration in older mice may be due to a reduced availability of epidermal IL-1beta.

Tumour necrosis factor-alpha-induced migration of human Langerhans cells: the influence of ageing

BACKGROUND

Langerhans cells (LCs) play essential roles in the initiation and regulation of cutaneous immune responses mediated through their successful migration from the epidermis to draining lymph nodes while carrying antigen. Tumour necrosis factor (TNF)-alpha, a keratinocyte-derived cytokine, has recently been shown to play an important role in the mobilization of LCs from human epidermis. Although it is known that with age the immune system changes, the influence of increasing age on the function of human LCs has not been defined clearly.

OBJECTIVES

To examine the influence of age on the ability of TNF-alpha to induce LC migration.

METHODS

Ten elderly (six men, four women; mean age 76 years, range 72-79) and 10 young (six men, four women; mean age 23 years, range 18-35) volunteers received intradermal injections of 200 U of human recombinant TNF-alpha diluted in sterile saline, and control injections of sterile saline alone, at each of two paired sites identified on photoprotected buttock skin. Two hours later, paired injection sites were excised by punch biopsy. One set of paired biopsies was processed for assessment of the frequency and morphology of epidermal LCs, following preparation of epidermal sheets and immunofluorescence staining for the LC marker CD1a. The remaining paired biopsies were processed in formalin and the inflammatory response to TNF-alpha was assessed by standard histological examination.

RESULTS

Mean +/- SEM baseline values for LC frequency within epidermal sheets were significantly different between young (1156.3 +/- 38.5 cells mm(-2)) and elderly subjects (835.7 +/- 48.2 cells mm(-2); P < 0.01). Intradermal injections of 200 U of TNF-alpha caused a significant reduction in the frequency of LCs in both elderly and young subjects (P < 0.01). However, the extent of TNF-alpha-induced LC migration was substantially different between the two groups, with a mean 9% reduction in LC frequency in elderly volunteers compared with a mean 23% decrease in young subjects. Exposure to TNF-alpha was associated with a perivascular polymorphonuclear infiltrate at 2 h in all young subjects; in contrast, only 50% of the elderly individuals showed evidence of such a response.

CONCLUSIONS

There are significant differences between young and old skin with respect to both resting LC numbers and their response to TNF-alpha. These age-related changes in LC frequency and function may contribute to the altered cutaneous immune function observed in the elderly.

Skin aging: postulated mechanisms and consequent changes in structure and function

Aging is a complex process influenced by telomere shortening and damage to cellular DNA. New insights into age-associated decrements in DNA damage repair are reviewed. Age-associated gross, histologic, and functional cutaneous deficits are delineated. Different treatment options for aged skin are examined.

Intrinsically aged epidermis displays diminished UVB-induced alterations in barrier function associated with decreased proliferation

Ultraviolet (UV) irradiation of the skin induces a variety of responses in the epidermis, including sunburn cell formation, epidermal hyperplasia, and a dose-dependent permeability barrier abnormality, an effect that appears to be dependent upon both UVB-induced hyperplasia and T-cell activation. Since intrinsically aged epidermis displays decreased epidermal turnover, diminished inflammatory response to various stimuli, including UVR, and impaired immune function, we investigated the effects of UVB on both epidermal barrier function and proliferation in hairless mice of increasing chronologic age (27, 61, and 90 wk). After a single UVB exposure (0.15 J/cm2 7.5 MED), a barrier abnormality developed (i.e., increased transepidermal water loss; TEWL), after a delay of > or = 48 h, regardless of age. In young mice (27 wk old), TEWL levels peaked at 72-96 h (9.9-fold over untreated controls), whereas increased epidermal [3H]thymidine incorporation preceded the peak TEWL increase (i.e., approximately 570% increase over controls at 48 h). In contrast, the UVB-induced increased in both TEWL and DNA synthesis were significantly diminished, with decreased epidermal hyperplasia evident, in intrinsically aged versus young mouse epidermis. Baseline epidermal thickness decreased with animal age (i.e., 16.8 +/- 3.1 vs. 27.9 +/- 0.7 microm for 90- vs. 27-wk-old animals, respectively; p < 0.02), suggesting that the diminished barrier response with aging reflects an attenuation of events subsequent to initial UVB exposure, rather than an increase in the UV dose delivered. These results demonstrate that (i) murine epidermis becomes less sensitive to UVB-induced barrier alterations with age and (ii) decreased DNA synthesis after UVB correlates with the age-related decrease in barrier dysfunction.

Langerhans cell density in normal human oral mucosa and skin: relationship to age, smoking and alcohol consumption

The immune function of skin has been studied extensively and it has been suggested that epidermal Langerhans cell (LC) density and function decreases with increasing age. Little is known, however, about the effect of age on oral mucosal LC. Cryostat sections from biopsies of buccal mucosa, lip, hard palate, lateral border of tongue, floor of mouth and abdominal skin, obtained from 91 subjects (aged 16-96 yr), were reacted immunocytochemically with a monoclonal antibody against CD1a and then LC density was expressed as LC/mm epithelial surface length. No significant effect of age on mucosal or skin LC density was found, whilst a history of smoking was associated with an increase in LC density in lateral border of tongue and in biopsies of labial mucosa taken from men (P < 0.05). There was no significant difference between LC density in men and women in oral mucosa. Oral mucosal LC may therefore form a relatively stable population in the adult and thus the increased incidence of mucosal disease in the elderly may be the result of subtle changes in cell mediated immune function rather than changes in LC density.

Replacement of Langerhans cells in murine palate

Palates from C3H mice were implanted onto prepared graft beds in histocompatible F1 hybrid mice. Biopsies taken 1, 2, 4, 8, and 16 wk later were prepared to demonstrate Langerhans cells (LC) of C3H and F1 (host) origin. After 1 wk only occasional LC (all of C3H origin) were present. By 2 wk total LC numbers had increased to a level approximately 50% greater than in control (non-implanted) palate, with most of this increase due to C3H LC proliferation. From 4 through 16 wk total LC numbers were not significantly different from those of control palate. During weeks 2 through 16 the percentages of LC of F1 origin were 31, 70, 39, and 19% respectively. These results indicate an increased proliferation of C3H LC with an initial migration of F1 LC which stops as C3H LC numbers increase.

Reversal by lymphokines of the age-related hyporesponsiveness to contact sensitization and reduced Ia expression on Langerhans cells

Contact sensitivity responses were evaluated in young adult (3-5 months) and aged (16-26 months) BALB/c mice which were systemically treated with interleukin-2 (IL-2), interferon-gamma (IFN-gamma) or saline. Mice older than 16 months of age have deficient numbers of Ia+ Langerhans cells in addition to their well-known impaired T cell functions. They also have an impaired cell-mediated response to contact sensitization with 1-chloro-2,4,6-trinitrobenzene. This hyporesponsiveness in aged mice can be almost completely reversed by IL-2 and is marginally improved by IFN-gamma. Exposure of skin from aged mice to interleukin-2 or interferon-gamma, both in vivo and in vitro, causes increases in the density of Ia+ Langerhans cells to levels approximating those in young mice. Since IFN-gamma causes partial restitution while IL-2 fully restores the contact hypersensitivity in aged animals, we conclude that the hyporesponsiveness in aged mice results both from defective Ia antigen expression on the antigen-presenting Langerhans cells and from deficient T cell function.

Age-associated changes in Langerhans cells of murine oral epithelium and epidermis

Oral mucosa and skin of older individuals are immunologically less responsive to a range of allergens, but it is not known whether this is due to changes in the number of Langerhans cells or to impaired cell function. EDTA-separated epithelial sheets from the cheek and palate mucosa, and from ear aN< footpad skin of three-month-old and 24-month-old C57BL/6NNia mice were stained for ATPase, beta-glucuronidase activity and Iab-surface antigen to demonstrate Langerhans cells. The general distribution of such cells was unchanged with age, but those in epithelia from the old mice were more varied in shape, with irregular celL bodies and more elongated dendritic processes. The numerical density of Langerhans cells in old mice was reduced by 30-59 per cent compared with that in young mice.