Dietary Eriodictyon angustifolium Tea Supports Prevention of Hair Graying by Reducing DNA Damage in CD34+ Hair Follicular Keratinocyte Stem Cells.

Hair follicular keratinocyte stem cells (HFKSC) which provide a functional niche for melanocyte stem cells (MSC) are the primary target of hair graying. However, little research has been done on anti-hair graying medicines targeting HFKSC. We focused on Eriodictyon angustifolium (Ea), which reduces human hair graying when applied topically. To investigate the protective effect of dietary Ea tea (EaT) on hair pigmentation, we used an acute mouse model of hair graying that mimics X-ray-induced DNA damage associated with age-related hair graying. Our results suggest that dietary EaT maintained the niche HFKSC function against X-ray-induced DNA damage and hair graying. These results indicate that dietary EaT may prevent age-related hair graying and serve as an anti-hair graying herbal medicine.

A review of the etiologies, clinical characteristics, and treatment of canities.

Hair pigmentation is regulated by follicular melanogenesis, in which the process consists of melanin formation and transfer to keratinocytes in the hair shaft. Human hair follicles contain two types of melanin: the brown-black eumelanin and yellow-red pheomelanin. Eumelanin is commonly present in black and brown hair while pheomelanin is found in auburn and blonde hair. Hair follicle melanogenesis is under cyclical control and is concurrently coupled to hair growth. Many factors including intrinsic and extrinsic factors affect the follicular melanogenesis. Though many studies have been conducted to identify the pathogenesis and regulation of hair pigmentation, the etiology of canities and hair pigmentation is still unclear. The pathogenesis of canities or gray hair is believed to occur either from insufficient melanin formation due to melanocyte degeneration or a defect in melanosomal transfer. Canities is an aging sign which often interferes with one's socio-cultural adjustment. On the other hand, premature canities correlate with diseases such as osteopenia and cardiovascular disease. Risk factors associated with canities are not only genetic but also external causes. For example, smoking, alcohol consumption, and stress are among the most common factors. Camouflage techniques are still used as the primary treatment of canities. Further treatments for canities are being developed to achieve the true reversal of hair pigmentation.

Bispectral index dynamics during propofol hypnosis is similar in red-haired and dark-haired subjects.

BACKGROUND: We have previously shown that red hair is associated with increased desflurane requirement for immobility, compared with dark hair. The effect of red hair on IV anesthetic requirement remains unknown. We tested the hypothesis that the propofol concentration in the effect site associated with half maximal electroencephalogram response, Ce50, is at least 50% higher in subjects with red hair. METHODS: We modeled the propofol concentration versus electroencephalogram response relationship using a 2-step approach in 29 healthy dark- and red-haired volunteers receiving a propofol infusion to produce loss of consciousness. Bispectral Index (BIS) was the measure of drug effect. The parameters of a 3-compartment pharmacokinetic model were fit to measured arterial propofol concentrations. The relationship between effect-site propofol concentration (Ce) and BIS was characterized using a sigmoid Emax model. Model performance and accuracy of the estimated parameters were evaluated using accepted metrics and bootstrap resampling. The effect of hair color on the Ce50 for BIS response in the final model was assessed using a threshold of 6.63 (P<0.01) in reduction of -2 log likelihood. The influence of body weight on the model was also assessed. RESULTS: The inclusion of hair color as a model covariate did not improve either the pharmacokinetic or the pharmacodynamic model. A separate analysis for the dark- and red-haired subjects estimated a median (95% confidence interval) Ce50 BIS of 2.71 µg/mL (2.28-3.36 µg/mL) and 2.57 µg/mL (1.68-3.60 µg/mL), respectively. Body weight was a significant covariate for the CL1 and V1. CONCLUSIONS: Red hair phenotype does not affect the pharmacokinetics or pharmacodynamics of propofol.

Repigmentación del pelo canoso tras tratamiento con hormona tiroidea / Repigmentation of gray hair after thyroid hormone treatment

Introducción y objetivos. Basándonos en dos pacientes con oscurecimiento de sus canas que sufrieron una elevación exógena de T3, debida a un coma mixedematoso y a una descompensación de su enfermedad, sugerimos que la hormona tiroidea puede tener un efecto en la homeostasis del folículo piloso. Para ello se utilizan un modelo animal de ratón y un modelo de cultivo in vitro de unidades foliculares, con el objeto de valorar la influencia de la hormona tiroidea en el ciclo capilar. Métodos. Sobre un modelo de ratón estandarizado para el estudio del ciclo capilar (C57BL/6), aplicamos tópicamente T3 (0,5 g) disuelta en etanol una vez al día durante 10 días en el dorso de ratones depilados en fase de telogen. Cultivamos in vitro unidades foliculares, obtenidas de cirugía capilar, con diferentes concentraciones de T3. Resultados. In vivo, al quinto día del tratamiento el 100 % de los ratones estudiados entraron en anagen, mientras que en el grupo control se apreció un inicio del anagen el día 9, que no se completó en todos los ratones hasta el día 15. In vitro, las unidades foliculares tratadas con 100 nM de T3 crecieron de forma significativa respecto al grupo control. Conclusiones. Estos datos sugieren que los folículos en telogen pueden estimularse para entrar en anagen tras la aplicación tópica de T3. Esta hormona puede revertir el encanecimiento del pelo terminal. En cultivo, la administración de T3 estimula el crecimiento del tallo piloso. Los melanocitos foliculares podrían ser la célula diana para estas acciones

Background and objectives. Darkening of gray and white hairs occurred in 2 patients with increased exogenous triiodothyronine (T3) due to treatment of myxedema coma in one case and iatrogenic hyperthyroidism in the other. We hypothesized that thyroid hormone may affect the homeostasis of hair follicles. To test our hypothesis and investigate the influence of thyroid hormone on the hair cycle, we used an in vivo murine model and an in vitro model based on culture of follicular units. Methods.We used the standard C57BL/6 murine model of the hair cycle. T3 (0.5 g) dissolved in ethanol was applied topically once daily for 10 days to a depilated area in the telogen phase on the backs of the mice. Follicular units, obtained from hair transplant interventions, were cultured in vitro with different concentrations of T3. Results. On day 5, all T3-treated mice entered the anagen phase, whereas the anagen phase started spontaneously in control mice on day 9, and not until day 15 had all controls entered this phase. In the in vitro experiment, follicular units treated with 100 nmol/L T3 grew significantly larger compared to the control group. Conclusions. These data suggest that follicles in the telogen phase can be induced to enter the anagen phase by the topical application of T3. This thyroid hormone may reverse graying of the terminal hair. In the in vitro experiments, T3 stimulated hair shaft growth. Follicular melanocytes may be the target cell for these actions

Selenium concentration in blood and hair of holstein dairy cows.

Four-hundred Holstein cows in 40 dairy farms in north Greece were included in this study, and blood (n=400), black hair (n=400), white hair (n=40), and feed (n=40) samples were obtained. Although the feeding regime in these farms was similar, the selenium content of feeds was variable. The Se content of concentrate feeds was 0.104+/-0.086 mg/kg dry matter (DM), and of silage, it was 0.025+/-0.018 mg/kg. A significantly positive correlation was found between the Se concentration in black hair and the Se concentration in blood (r2=0.610, p<0.001), the Se concentration in white hair and the Se concentration in blood (r2=0.770, p<0.001), and the Se concentration in white hair and the Se concentration in black hair (r2=0.921, p<0.001). The Se concentration in white hair was significantly smaller than that in black hair (p<0.001).

Discrete thalamic lesions attenuate winter adaptations and increase body weight.

The midline thalamus (e.g., the paraventricular thalamic nuclei and the reuniens nucleus) of Siberian hamsters and other mammals has been reported to contain specific binding sites for melatonin, a hormone that is essential for photoperiodically induced winter adaptations such as reproductive quiescence, loss of body weight, daily torpor, and the winter molt. The first experiment investigated whether the midline thalamus is necessary for these winter adaptations. Adult Siberian hamsters received discrete neurotoxic lesions of the paraventricular thalamic nuclei or the reuniens nucleus while under pentobarbital sodium-induced anesthesia. After recovery, the hamsters were monitored for winter adaptations while they were exposed to short photoperiods (10 h light/day) for 12 wk at 22 degrees C then for 60 days at 7 degrees C. Lesions of the reuniens nucleus, but not of the paraventricular thalamic nuclei, significantly inhibited short photoperiod-induced loss of body weight and tended to increase food consumption and decrease daily torpor. The second experiment showed that lesions of the reuniens nucleus increased body weight gain compared with that in controls during exposure to long photoperiods at 22 degrees C for 16 wk. In summary, these findings show that the reuniens nucleus is an important site for regulation of body weight and suggest that lesions of the reuniens nucleus may attenuate winter metabolic adaptations by causing an increase in body weight.