Rodney Sinclair

Comparative Analysis of Paracrine Factor Expression in Human Adult Mesenchymal Stem Cells Derived from Bone Marrow, Adipose, and Dermal Tissue

Human adult mesenchymal stem cells (MSCs) support the engineering of functional tissue constructs by secreting angiogenic and cytoprotective factors, which act in a paracrine fashion to influence cell survival and vascularization. MSCs have been isolated from many different tissue sources, but little is known about how paracrine factor secretion varies between different MSC populations. We evaluated paracrine factor expression patterns in MSCs isolated from adipose tissue (ASCs), bone marrow (BMSCs), and dermal tissues [dermal sheath cells (DSCs) and dermal papilla cells (DPCs)]. Specifically, mRNA expression analysis identified insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor-D (VEGF-D), and interleukin-8 (IL-8) to be expressed at higher levels in ASCs compared with other MSC populations whereas VEGF-A, angiogenin, basic fibroblast growth factor (bFGF), and nerve growth factor (NGF) were expressed at comparable levels among the MSC populations examined. Analysis of conditioned media (CM) protein confirmed the comparable level of angiogenin and VEGF-A secretion in all MSC populations and showed that DSCs and DPCs produced significantly higher concentrations of leptin. Functional assays examining in vitro angiogenic paracrine activity showed that incubation of endothelial cells in ASC(CM) resulted in increased tubulogenic efficiency compared with that observed in DPC(CM). Using neutralizing antibodies we concluded that VEGF-A and VEGF-D were 2 of the major growth factors secreted by ASCs that supported endothelial tubulogenesis. The variation in paracrine factors of different MSC populations contributes to different levels of angiogenic activity and ASCs maybe preferred over other MSC populations for augmenting therapeutic approaches dependent upon angiogenesis.

Male pattern androgenetic alopecia

Androgenetic alopecia is characterised by progressive, patterned hair loss from the scalp. Recently the pathogenesis and genetic basis of the hair loss have been better understood, as has the distress experienced by men who have lost their hair. There have also been breakthroughs in the treatment of androgenetic alopecia. The transition of some terminal hairs into vellus hairs is a universal physiological secondary sexual characteristic.1 Androgenetic alopecia becomes a medical problem only when the hair loss is subjectively seen as excessive, premature, and distressing. The prerequisites for premature androgenetic alopecia are a genetic predisposition and sufficient circulating androgens.2 Eunuchs do not go bald.3 Every white man possesses the autosomal inherited predisposition,4 and 96% lose hair to some degree,5 but because of the variabity of gene expression far fewer have appreciable premature hair loss. #### Summary points This article is based largely on my experience in the management of hair loss. Original articles and expert reviews from major journals cited in Medline between 1966 and 1997 have been supplemented by information and articles cited in recently published textbooks. The following keywords were used for the Medline search: androgenetic alopecia, androgenic alopecia, common baldness and balding, premature baldness and balding, hereditary balding and baldness, male pattern and female pattern alopecia, …

Androgenetic alopecia: pathogenesis and potential for therapy.

Androgenetic alopecia occurs in men and women, and is characterised by the loss of hair from the scalp in a defined pattern. Determining factors appear to be genetic predisposition coupled with the presence of sufficient circulating androgens. The prevalence of this condition is high (up to 50% of white males are affected by 50 years of age) and, although there are no serious direct health consequences, the loss of scalp hair can be distressing. Knowledge of the pathogenesis of androgenetic alopecia has increased markedly in recent years. Pre-programmed follicles on the scalp undergo a transformation from long growth (anagen) and short rest (telogen) cycles, to long rest and short growth cycles. This process is coupled with progressive miniaturisation of the follicle. These changes are androgen dependent, and require the inheritance of several genes. To date, only one of these genes, which encodes the androgen receptor (AR), has been identified. Of the many treatments available for androgenetic alopecia, only two (finasteride and minoxidil) have been scientifically shown to be useful in the treatment of hair loss. However, these therapies are variable in their effectiveness. Discovery of the involvement of the AR gene, and the identification of other genes contributing to the condition, might lead to the development of new and more effective therapies that target the condition at a more fundamental level.

Evidence that the bulge region is a site of relative immune privilege in human hair follicles

Background  Recent gene profiling data suggest that, besides the anagen hair bulb, the epithelial stem cell region in the outer root sheath of hair follicles (HFs), termed the bulge, may also represent an area of relative immune privilege (IP).

Androgenetic alopecia in men aged 40–69 years: prevalence and risk factors

Background  The epidemiology of androgenetic alopecia (AGA) is not fully understood. Although a strong genetic basis has long been identified, little is known of its non‐genetic causes.

The reliability of horizontally sectioned scalp biopsies in the diagnosis of chronic diffuse telogen hair loss in women

BACKGROUND Chronic diffuse telogen hair loss is common in women. Paired 4-mm punch biopsy from the vertex scalp for horizontal and vertical sectioning is commonly used to distinguish between chronic telogen effluvium (CTE) and female pattern hair loss (FPHL). FPHL is now the favored term for androgenetic alopecia in women. OBJECTIVE AND METHODS To evaluate the reliability of a single horizontally sectioned scalp biopsy in the diagnosis of FPHL, 207 women presenting with chronic diffuse hair loss had three 4-mm punch biopsy specimens taken from immediately adjacent skin on the mid scalp, and all 3 biopsy specimens were sectioned horizontally. Findings were compared with 305 women who underwent two biopsies, with one sectioned horizontally and the other vertically. The terminal to vellus-like hair ratio (T:V) at the mid-isthmus level was used to diagnose FPHL (T:V <4:1), CTE (T:V >8:1), or indeterminate hair loss (T:V=5:1, 6:1, or 7:1). To correlate the histologic diagnosis with the clinical severity, a mid-scalp clinical grading scale was developed. RESULTS Among the 305 women who had a single horizontal scalp biopsy, 181 (59%) were diagnosed as having FPHL, 54 (18%) having CTE, and 70 (23%) having indeterminate hair loss. Six hundred twenty-one horizontal biopsy specimens were assessed from 207 patients. On the basis of consensus over 3 biopsies, 159 (77%) were diagnosed as having FPHL, 44 (21%) having CTE, and the remaining 4 women (2%) as having indeterminate hair loss. Among these 207 women, 114 were assessed clinically as having stage 1 or 2 hair loss. Sixty-nine (60%) were diagnosed as having FPHL on the basis of triple biopsy, 42 (37%) having CTE, and 2 having indeterminate hair loss. Ninety-three were graded as having stage 3, 4, or 5 hair loss. FPHL was diagnosed in 90 women (97%), CTE in 2, and indeterminate hair loss in one. By using each single biopsy as the criterion for diagnosis, 398 (61%) were classified as FPHL, 99 (16%) as CTE, and 124 (20%) as indeterminate. In 493 biopsies (79%), the single biopsy conclusion was identical to the 3 biopsy conclusions. Where disagreement was seen (21%), most were classified as indeterminate, rather than as a wrong diagnosis (3.3%). CONCLUSION Application of these diagnostic criteria achieved accurate diagnostic definition in 98% of women with triple horizontal biopsies versus 79% with single horizontal biopsy. Ninety-seven percent of women with a mid-scalp clinical grade of 3, 4, or 5 were given a diagnosis of FPHL on triple biopsy. Scalp biopsy for diagnosis should be reserved for women with a mid-scalp clinical grade of 1 or 2.

Perturbed desmosomal cadherin expression in grainy head-like 1-null mice.

In Drosophila, the grainy head (grh) gene plays a range of key developmental roles through the regulation of members of the cadherin gene family. We now report that mice lacking the grh homologue grainy head‐like 1 (Grhl1) exhibit hair and skin phenotypes consistent with a reduction in expression of the genes encoding the desmosomal cadherin, desmoglein 1 (Dsg1). Grhl1‐null mice show an initial delay in coat growth, and older mice exhibit hair loss as a result of poor anchoring of the hair shaft in the follicle. The mice also develop palmoplantar keratoderma, analogous to humans with DSG1 mutations. Sequence analysis, DNA binding, and chromatin immunoprecipitation experiments demonstrate that the human and mouse Dsg1 promoters are direct targets of GRHL1. Ultrastructural analysis reveals reduced numbers of abnormal desmosomes in the interfollicular epidermis. These findings establish GRHL1 as an important regulator of the Dsg1 genes in the context of hair anchorage and epidermal differentiation, and suggest that cadherin family genes are key targets of the grainy head‐like genes across 700 million years of evolution.

Tildrakizumab versus placebo or etanercept for chronic plaque psoriasis (reSURFACE 1 and reSURFACE 2): results from two randomised controlled, phase 3 trials

BACKGROUND Tildrakizumab is a high-affinity, humanised, IgG1 κ antibody targeting interleukin 23 p19 that represents an evolving treatment strategy in chronic plaque psoriasis. Previous research suggested clinical improvement with inhibition of interleukin 23 p19. We did two phase 3 trials to investigate whether tildrakizumab is superior to placebo and etanercept in the treatment of chronic plaque psoriasis. METHODS We did two three-part, parallel group, double-blind, randomised controlled studies, reSURFACE 1 (at 118 sites in Australia, Canada, Japan, the UK, and the USA) and reSURFACE 2 (at 132 sites in Europe, Israel, and the USA). Participants aged 18 years or older with moderate-to-severe chronic plaque psoriasis (body surface area involvement ≥10%, Physicians Global Assessment [PGA] score ≥3, and Psoriasis Area and Severity Index [PASI] score ≥12) were randomised (via interactive voice and web response system) to tildrakizumab 200 mg, tildrakizumab 100 mg, or placebo in reSURFACE 1 (2:2:1), or to tildrakizumab 200 mg, tildrakizumab 100 mg, placebo, or etanercept 50 mg (2:2:1:2). Randomisation was done by region and stratified for bodyweight (≤90 kg or >90 kg) and previous exposure to biologics therapy for psoriasis. Investigators, participants, and study personnel were blinded to group allocation and remained blinded until completion of the studies. Assigned medication was identical in appearance and packaging. Tildrakizumab was administered subcutaneously at weeks 0 and 4 during part 1 and at week 16 during part 2 (weeks 12 and 16 for participants re-randomised from placebo to tildrakizumab; etanercept was given twice weekly in part 1 of reSURFACE 2 and once weekly during part 2). The co-primary endpoints were the proportion of patients achieving PASI 75 and PGA response (score of 0 or 1 with ≥2 grade score reduction from baseline) at week 12. Safety was assessed in the all-participants-as-treated population, and efficacy in the full-analysis set. These trials are registered with ClinicalTrials.gov, numbers NCT01722331 (reSURFACE 1) and NCT01729754 (reSURFACE 2). These studies are completed, but extension studies are ongoing. FINDINGS reSURFACE 1 ran from Dec 10, 2012, to Oct 28, 2015. reSURFACE 2 ran from Feb 12, 2013, to Sept 28, 2015. In reSURFACE 1, 772 patients were randomly assigned, 308 to tildrakizumab 200 mg, 309 to tildrakizumab 100 mg, and 155 to placebo. At week 12, 192 patients (62%) in the 200 mg group and 197 patients (64%) in the 100 mg group achieved PASI 75, compared with 9 patients (6%) in the placebo group (p<0·0001 for comparisons of both tildrakizumab groups vs placebo). 182 patients (59%) in the 200 mg group and 179 patients (58%) in the 100 mg group achieved PGA responses, compared with 11 patients (7%) in the placebo group (p<0·0001 for comparisons of both tildrakizumab groups vs placebo). In reSURFACE 2, 1090 patients were randomly assigned, 314 to tildrakizumab 200 mg, 307 to tildrakizumab 100 mg, 156 to placebo, and 313 to etanercept. At week 12, 206 patients (66%) in the 200 mg group, and 188 patients (61%) in the 100 mg group achieved PASI 75, compared with 9 patients (6%) in the placebo group and 151 patients (48%) in the etanercept group (p<0·0001 for comparisons of both tildrakizumab groups vs placebo; p<0·0001 for 200 mg vs etanercept and p=0·0010 for 100 mg vs etanercept). 186 patients (59%) in the 200 mg group, and 168 patients (59%) [corrected] in the 100 mg group achieved a PGA response, compared with 7 patients (4%) in the placebo group and 149 patients (48%) in the etanercept group (p<0·0001 for comparisons of both tildrakizumab groups vs placebo; p=0·0031 for 200 mg vs etanercept and p=0·0663 for 100 mg vs etanercept). Serious adverse events were similar and low in all groups in both trials. One patient died in reSURFACE 2, in the tildrakizumab 100 mg group; the patient had alcoholic cardiomyopathy and steatohepatitis, and adjudication was unable to determine the cause of death. INTERPRETATION In two phase 3 trials, tildrakizumab 200 mg and 100 mg were efficacious compared with placebo and etanercept and were well tolerated in the treatment of patients with moderate-to-severe chronic plaque psoriasis. FUNDING Merck & Co.

Male androgenetic alopecia

Importance of the field: Androgenetic alopecia affects up to 80% of males by the age of 80. The synonym ‘male-pattern hair loss’ highlights the fact that hair loss occurs in a defined and reproducible pattern. Hair loss results in reduced self esteem, loss of confidence and anxiety in affected men. An effective treatment for hair baldness would be desirable. Areas covered in this review: In androgenetic alopecia, hair follicles undergo progressive miniaturization. Genetic factors and androgens play a major role in the pathogenesis of the disease. Polymorphism of the androgen receptor gene was first identified in association with androgenetic alopecia. Identification of new susceptibility genes on chromosomes 3q26 and 20p11 suggest that non-androgen-dependent pathways also are involved. What the reader will gain: Topical monoxidil and oral finasteride are commonly in use and have FDA approval for the treatment of male androgenetic alopecia; dutasteride, a type I and II 5-alpha-reductase inhibitor, is on hold in Phase III trials. A combination of medical treatment and hair transplant surgery has shown superior efficacy. Take-home message: Androgenetic alopecia is a progressive condition and although the current available treatments are effective in arresting the progression of the disease, they allow only partial regrowth of hair at its best. Early treatment achieves the best desirable outcome.

Diffuse hair loss

The normal hair cycle (Fig. 1) results in the replacement of every hair on the scalp every 3–5 years.1 Hair growth on the adult human scalp is asynchronous. Thus, rather than all the hairs being replaced at once in a single moult, the shedding occurs continuously so that between 50 and 150 telogen hairs are shed each day. While there is some seasonal variation in the amount of hair lost each day, this amount remains fairly uniform throughout life. Most of this hair loss passes unnoticed, particularly when the hairs are short.2 Disease states that cause large numbers of hairs to fall out may be classified according to whether the follicle remains intact or is destroyed and replaced by scar, and to whether the hair loss is patchy, patterned, or diffuse (Table 1). Diffuse hair loss may be further classified by the type of hairs that are shed, in particular whether they are anagen or telogen hairs. As telogen hairs have a depigmented bulb, examination of the shed hairs with the naked eye will usually clarify this. The focus of this review is diffuse nonscarring telogen hair loss. The cause can usually be established on history together with a few simple screening blood tests, which include thyroid function tests and iron studies. In addition, serum zinc estimation, antinuclear factor antibody titer, and syphilis serology may be required in some cases. Diagnostic difficulty may occur when the pattern of the loss is unclear, as occurs in early androgenetic alopecia in women, rendering it hard to distinguish this condition from other causes of chronic diffuse telogen hair loss such as chronic telogen effluvium. In this situation a scalp biopsy will be required to establish the diagnosis.