Epithelial stem cells in the skin: definition, markers, localization and functions

In recent years, cutaneous epithelial stem cells have attained a genuine celebrity status. They are considered the key resource for epidermal and skin appendage regeneration, and are proposed as a preferential target of cutaneous gene therapy. Follicular epithelial stem cells may also give rise to a large variety of epithelial tumors, and cutaneous epithelial stem cells likely are crucial targets for physical or chemical agents (including carcinogens) that damage the skin and its appendages. However, as this Controversies feature illustrates, few experts can agree on how exactly to define and identify these elusive cells, or on where precisely in the skin they are localized. Given their potential importance in skin biology, pathology and future dermatological therapy, it is, therefore, timely to carefully reconsider the basic questions: What exactly is a stem cell, and how can we reliably identify epithelial stem cells? How many different kinds are there, and how do they differ functionally? Where exactly in the skin epithelium is each of the putative stem cell subpopulations located, and can we selectively manipulate any of them?     

Short-term methotrexate therapy in psoriasis: a study of 197 patients

Methotrexate (MTX) is one of the most effective antipsoriatic drugs available. Although it is undeniably hepatotoxic, it can be used safely in most patients with severe psoriasis if established guidelines are followed. Current opinion on the monitoring of hepatic damage is divided, however, and the need for repeated liver biopsies during MTX therapy is being re-examined. We have used MTX in a short-term protocol in our patients with psoriasis for the past 20 years, and have recently attempted to minimize or eliminate the need for liver biopsies using this regimen. Data on 244 psoriatics who were given MTX from 1981 to 2000 have been reviewed. Our protocol entailed the use of weekly oral MTX at the full therapeutic dose during episodes of peak disease activity, with tapering off of MTX when the disease subsided in response to treatment combined with natural/seasonal remission. Intensive topical and heliotherapy were encouraged throughout to facilitate the earliest possible drug withdrawal and the longest possible drug-free interval before the next relapse. Strict inclusion criteria were applied before starting MTX. A total of 243 cycles of MTX therapy have been given to 197 evaluable patients. More than 75% improvement occurred in 88% of patients in 8.5 +/- 5.1 weeks. The mean cumulative dose was 709.3 +/- 369.2 mg and the mean duration of follow-up was 16.5 +/- 9.1 months. Fifteen (6.1%) patients had serious adverse effects requiring the cessation of therapy. Only three patients had deranged liver function tests. Thirty-four pre-MTX and 13 post-MTX liver biopsies were taken, which revealed grade I or II changes that were nonprogressive. Our experience with short-term MTX therapy has enabled us to safely administer MTX to our patients with minimal recourse to liver biopsy. In developing countries, where advanced noninvasive methods for the assessment of liver damage are unaffordable or unavailable, this interrupted, short-term regimen may present an acceptable and safe method of using MTX in carefully selected patients with severe psoriasis.     

Facility-based active management of the third stage of labour: assessment of quality in six countries in sub-Saharan Africa

Objective

To assess the quality of facility-based active management of the third stage of labour in Ethiopia, Kenya, Madagascar, Mozambique, Rwanda and the United Republic of Tanzania.

Methods

Between 2009 and 2012, using a cross-sectional design, 2317 women in 390 health facilities were directly observed during the third stage of labour. Observers recorded the use of uterotonic medicines, controlled cord traction and uterine massage. Facility infrastructure and supplies needed for active management were audited and relevant guidelines reviewed.

Findings

Most (94%; 2173) of the women observed were given oxytocin (2043) or another uterotonic (130). The frequencies of controlled cord traction and uterine massage and the timing of uterotonic administration showed considerable between-country variation. Of the women given a uterotonic, 1640 (76%) received it within three minutes of the birth. Uterotonics and related supplies were generally available onsite. Although all of the study countries had national policies and/or guidelines that supported the active management of the third stage of labour, the presence of guidelines in facilities varied across countries and only 377 (36%) of 1037 investigated providers had received relevant training in the previous three years.

Conclusion

In the study countries, quality and coverage of the active management of the third stage of labour were high. However, to improve active management, there needs to be more research on optimizing the timing of uterotonic administration. Training on the use of new clinical guidelines and implementation research on the best methods to update such training are also needed.     

Immunolocalization of Musashi1 and Fibronectin Type III Domain Containing 3B in Water Buffalo Mammary Glands

Water buffaloes are the principle source of milk in south Asia and Africa. Mammary gland repeatedly undergoes the cycles of growth and regeneration during pregnancy, lactation and involution. It is assumed that buffalo mammary gland has mammary stem and progenitor cells that regulate gland growth and regeneration. In the present study the authors analyzed percentage of cellular composition, proliferation status and putative mammary stem/progenitor cell population. Identification of putative buffalo mammary stem/progenitor cells was attempted using immunohistochemical staining with Musashi1 (MSI1), an adult stem cell marker and fibronectin type III domain containing 3B (FNDC3B), a mammary stem and cancer cell marker. Immunolocalization of MSI1 and FNDC3B showed nuclear and cytoplasmic staining of alveolar and ductal mammary epithelial cells (MEC) and a few stromal cells. The percentage of MSI1-positive MEC in non-lactating (3.31 ± 1.11 %), lactating (2.73 ± 0.78 %) and mastitic glands (3.30 ± 0.97 %) were equivalent, indicating that the proportion of putative stem/progenitor cell population did not differ during various physiological stages. Likewise, the percentage of FNDC3B-positive MEC in non-lactating (12.40 ± 3.22 %) tended to be higher than lactating (8.19 ± 2.71 %) and mastitic glands (4.88 ± 2.37 %). In some cases, expression of MSI1 and FNDC3B was exceptionally high with high proliferative indices (37.6 ± 2.4 %)-an indication of tumor cells. This is the first report on expression of MSI1 and FNDC3B in buffalo mammary gland. Identification of buffalo mammary stem cells using MSI1 and FNDC3B requires further studies and functional validation.     

Emerging role of non‐coding RNA in health and disease

Metabolic Brain Disease - Human diseases have always been a significant turf of concern since the origin of mankind. It is cardinal to know the cause, treatment, and cure for every disease...     

Chronic Obstructive Pulmonary Disease and its Non-Smoking Risk Factors in India

The rising prevalence of the chronic obstructive pulmonary disease (COPD) is generally attributed to smoking, since the role of other risk factors among non-smokers are not well established especially in low and middle income countries like India. This is also reflected by the limited literature available on non-smoking related COPD risk factors like indoor and outdoor air pollution. The present review is an attempt to assess the influence of non-smoking risk factors on COPD and its measures in Indian subcontinent. The most noteworthy factors among non-smokers appear to be the use of biomass fuel for cooking and heating purposes. We observed that the studies undertaken to evaluate the role of such risk factors are inconclusive due to weak methodologies and small sample sizes, may be due to limited financial resources. The present review suggests the need of a nationally representative study to estimate the effect of each of the potential modifiable risk factor (other than smoking) for framing impactful public health policies to prevent and manage COPD at community and population level in India.     

Enrichment for murine keratinocyte stem cells based on cell surface phenotype

The identification and physical isolation of epithelial stem cells is critical to our understanding of their growth regulation during homeostasis, wound healing, and carcinogenesis. These stem cells remain poorly characterized because of the absence of specific molecular markers that permit us to distinguish them from their progeny, the transit amplifying (TA) cells, which have a more restricted proliferative potential. Cell kinetic analyses have permitted the identification of murine keratinocyte stem cells (KSCs) as slowly cycling cells that retain [(3)H]thymidine ([(3)H]Tdr) label, termed label-retaining cells (LRCs), whereas TA cells are visualized as rapidly cycling cells after a single pulse of [(3)H]Tdr, termed pulse-labeled cells (PLCs). Here, we report on the successful separation of KSCs from TA cells through the combined use of in vivo cell kinetic analysis and fluorescence-activated cell sorting. Specifically, we demonstrate that murine dorsal keratinocytes characterized by their high levels of alpha(6) integrin and low to undetectable expression of the transferrin receptor (CD71) termed alpha(6)(bri)CD71(dim) cells, are enriched for epithelial stem cells because they represent a minor ( approximately 8%) and quiescent subpopulation of small blast-like cells, with a high nuclear:cytoplasmic ratio, containing approximately 70% of label-retaining cells, the latter being a well documented characteristic of stem cells. Conversely, TA cells could be enriched in a phenotypically distinct subpopulation termed alpha(6)(bri)CD71(bri), representing the majority ( approximately 60%) of basal keratinocytes that are actively cycling, and importantly contain approximately 70% of [(3)H]Tdr pulse-labeled cells. Importantly, immunostaining of dorsal skin revealed the presence of CD71(dim) cells in the hair follicle bulge region, a well documented location for KSCs.