Identification of small RNAs in extracellular vesicles from the commensal yeast Malassezia sympodialis.

Malassezia is the dominant fungus in the human skin mycobiome and is associated with common skin disorders including atopic eczema (AE)/dermatitis. Recently, it was found that Malassezia sympodialis secretes nanosized exosome-like vesicles, designated MalaEx, that carry allergens and can induce inflammatory cytokine responses. Extracellular vesicles from different cell-types including fungi have been found to deliver functional RNAs to recipient cells. In this study we assessed the presence of small RNAs in MalaEx and addressed if the levels of these RNAs differ when M. sympodialis is cultured at normal human skin pH versus the elevated pH present on the skin of patients with AE. The total number and the protein concentration of the released MalaEx harvested after 48 h culture did not differ significantly between the two pH conditions nor did the size of the vesicles. From small RNA sequence data, we identified a set of reads with well-defined start and stop positions, in a length range of 16 to 22 nucleotides consistently present in the MalaEx. The levels of small RNAs were not significantly differentially expressed between the two different pH conditions indicating that they are not influenced by the elevated pH level observed on the AE skin.

Basic fibroblast growth factor and tumour necrosis factor alpha in vitiligo and other hypopigmented disorders: suggestive possible therapeutic targets.

BACKGROUND: In healthy skin, there is a molecular microenvironment that favours the survival of melanocytes and regulates their function. Keratinocytes synthesize and secrete several cytokines that have stimulatory and inhibitory effects on melanocytes. AIM OF THE WORK: This work was conducted to evaluate the expression of basic fibroblast growth factor (bFGF) and tumour necrosis factor alpha (TNF-α) mRNA levels in lesional skin of vitiligo, hypopigmented mycosis fungoides and hypopigmented tinea versicolor. PATIENTS AND METHODS: Forty eight patients (25 vitiligo, 14 hypopigmented mycosis fungoides, 9 hypopigmented tinea versicolor) and 10 healthy controls were included. A 4 mm punch skin biopsy was taken from lesional skin of patients, and the normal skin of controls for quantitative PCR examination of TNF-α and bFGF mRNA. RESULTS: The level of TNF-α mRNA in lesional skin of the three studied disorders was significantly higher than in the control group, while the level of bFGF mRNA was significantly lower in lesional skin of the three diseases than the control skin. A significant inverse correlation was demonstrated between the mRNA levels of the two studied cytokines in vitiligo and hypopigmented MF lesions. CONCLUSION: The study's findings demonstrate that the studied hypopigmented (vitiligo, hypopigmented MF, hypopigmented TV) disorders show similar changes in their cutaneous microenvironment with increased TNF-α and decreased bFGF mRNA expression. This cytokine microenvironment change may be implicated in the pigment loss and hence these cytokines may have future therapeutic implications.

The genetic epidemiology of tinea versicolor in China.

To study the clinical and epidemiological profile of Pityriasis versicolor (PV) and to determine the possible genetic model for PV in Chinese Han, we investigated 503 patients with PV who were recruited by a questionnaire method. Statistical analysis, heritability and complex segregation analysis were performed using EPI INFO 6.0, SPSS 10.0, the Falconer method and the SAGE-REGTL programs. In the total 503 PV patients, the mean age of onset was 22.85 +/- 10.36 years. For male and female patients, the peak ages of initial onset were both 20-29 years. A total of 106 (21.1%) patients were reported to have a positive family history of PV. The mean age of onset in males with positive family history was earlier than those with negative family history (t = 3.58, P < 0.01). Higher rate of recurrence and longer duration were seen in the patients with positive family history than those with negative family history. The heritability of PV in first-, second- and third-degree relatives was 48.13%, 40.11% and 27.20% respectively. Based on the REGTL results, the best model was a polygenic additive model for PV.

Apolipoprotein E gene polymorphism and serum lipids in patients with superficial fungal disease.

Superficial mycosis, including dermatophytic infections, tinea versicolor, and cutaneous candidiasis is mostly limited to the outer layers of the skin, nails, and mucous membranes. In this study, Apolipoprotein E (ApoE) polymorphism and lipoprotein cholesterol concentrations were compared between 42 patients with superficial fungal disease and 27 control subjects. Both the patients and controls were found to be normolipemic. The patients with superficial fungal disease had significantly higher concentrations of high-density cholesterol (HDL) compared to the control group (p=0.0462). However, there was no difference in the serum triglyceride, low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) cholesterol concentrations. A significantly higher incidence of heterozygosity E2/3 was found in the patients (p=0.0228), and significantly lower incidence of homozygosity E3/3 in all patients, and those with candidiasis and dermatophytosis (p=0.0139, 0.0194 and 0.0337, respectively) compared to the control group. The E3/4 genotype differences between patients and controls were not statistically significant. There were slight differences in the allele frequencies between the two groups, but these did not reach statistically significant levels. It was concluded that the presence of apoE2/3 genotype, high HDL-cholesterol levels and the absence of apoE3/3 genotype can be regarded as risk factors for superficial fungal disease, especially dermatophytosis.

[Pityriasis versicolor due to Malassezia ovalis]. / Pitiriasis versicolor por Malassezia ovalis.

In a randomly collected series of 175 cases of pityriasis versicolor in residents of the central-northern part of Venezuela, 13% of the patients were infected with ovoid unicellular units of the causal fungus (Malassezia ovalis) and 87% with globous unicellular units in the scales (M. furfur). Only globous unicellular units (Pityrosporum orbiculare) were seen outside the active lesions and in these, after the successful treatment with ketoconazole. The median age of 40 'ovalis' patients was 37.5 years; the same in 40 'furfur' patients was 24.5 years. The median age at the moment of discovering the first lesions among 'ovalis' patients was 31; among 'furfur' patients this was 20 years. There were 16 male patients among the 'ovalis' and 24 among the 'furfur' groups of 40. The topographic distribution of the lesions varied according to the type of the invader. M. ovalis prevailed on the trunk below the waist-line and on the limbs, mainly on buttocks and upper legs. M. furfur prevailed on the chest, neck, face and upper limbs. The hypothesis is offered that the ovoid agent of pityriasis versicolor preferentially occupies the less sweating and sebum-producing parts of the body in older (and drier) persons than the globous type does.

Genetic susceptibility in pityriasis versicolor.

300 patients with pityriasis versicolor, 168 males and 132 females, of different ages were included in this study. Each was subjected to a detailed structured questionnaire. All the available relatives had been examined. Pedigrees were constructed and segregation analysis was done using the mathematics of population genetics. The collected data showed genetic susceptibility which is inconsistent with any of the single gene defects but fulfill the criteria of multifactorial (genetic-environmental) inheritance. The heritability was estimated to be 22.2% in the first-degree relatives.