Molecular heterogeneity of quiescent melanocyte stem cells revealed by single-cell RNA-sequencing.

Melanocyte stem cells (McSCs) of the hair follicle are a rare cell population within the skin and are notably underrepresented in whole-skin, single-cell RNA sequencing (scRNA-seq) datasets. Using a cell enrichment strategy to isolate KIT+/CD45- cells from the telogen skin of adult female C57BL/6J mice, we evaluated the transcriptional landscape of quiescent McSCs (qMcSCs) at high resolution. Through this evaluation, we confirmed existing molecular signatures for qMcCS subpopulations (e.g., Kit+, Cd34+/-, Plp1+, Cd274+/-, Thy1+, Cdh3+/-) and identified novel qMcSC subpopulations, including two that differentially regulate their immune privilege status. Within qMcSC subpopulations, we also predicted melanocyte differentiation potential, neural crest potential, and quiescence depth. Taken together, the results demonstrate that the qMcSC population is heterogeneous and future studies focused on investigating changes in qMcSCs should consider changes in subpopulation composition.

Prognostic models and factors identifying end-of-life in non-cancer chronic diseases: a systematic review.

BACKGROUND: Precise prognostic information, if available, is very helpful for guiding treatment decisions and resource allocation in patients with non-cancer non-communicable chronic diseases (NCDs). This study aimed to systematically review the existing evidence, examining prognostic models and factors for identifying end-of-life non-cancer NCD patients. METHODS: Electronic databases, including Medline, Embase, CINAHL, Cochrane Library, PsychINFO and other sources, were searched from the inception of these databases up until June 2023. Studies published in English with findings mentioning prognostic models or factors related to identifying end-of-life in non-cancer NCD patients were included. The quality of studies was assessed using the Quality in Prognosis Studies tool. RESULTS: The analysis included data from 41 studies, with 16 focusing on chronic obstructive pulmonary diseases (COPD), 10 on dementia, 6 on heart failure and 9 on mixed NCDs. Traditional statistical modelling was predominantly used for the identified prognostic models. Common predictors in COPD models included dyspnoea, forced expiratory volume in 1 s, functional status, exacerbation history and body mass index. Models for dementia and heart failure frequently included comorbidity, age, gender, blood tests and nutritional status. Similarly, mixed NCD models commonly included functional status, age, dyspnoea, the presence of skin pressure ulcers, oral intake and level of consciousness. The identified prognostic models exhibited varying predictive accuracy, with the majority demonstrating weak to moderate discriminatory performance (area under the curve: 0.5-0.8). Additionally, most of these models lacked independent external validation, and only a few underwent internal validation. CONCLUSION: Our review summarised the most relevant predictors for identifying end-of-life in non-cancer NCDs. However, the predictive accuracy of identified models was generally inconsistent and low, and lacked external validation. Although efforts to improve these prognostic models should continue, clinicians should recognise the possibility that disease heterogeneity may limit the utility of these models for individual prognostication; they may be more useful for population level health planning.

Contraceptive use and contraceptive counselling interventions for women of reproductive age with cancer: a systematic review and meta-analysis.

BACKGROUND: A lack of clarity exists regarding contraceptive uptake and counselling among women with cancer, despite these women having unique family planning needs. This study aimed to systematically review the available literature and produce an overall summary estimate of contraceptive use and counselling among women with cancer across the cancer care continuum. METHODS: A systematic search of articles reporting on contraceptive counselling and/or contraceptive use among women of reproductive age (15-49 years) with cancer across the cancer care continuum (e.g. diagnosis, treatment, survivorship) was conducted in MEDLINE, Embase, CINAHL, Maternity and Infant Care and Cochrane Library. Two independent reviewers conducted the data screening, data extraction and risk of bias assessment. Qualitative synthesis and meta-analyses were conducted to summarise the key findings. RESULTS: We included 21 articles involving 3835 participants in this review. Studies varied according to the cancer population and time along the cancer care continuum it was assessed. Of the studies that reported the overall contraceptive prevalence among women diagnosed with cancer (n = 8), contraceptive use ranged from 25 to 92%. Of the four studies that focused on cancer survivors, the contraceptive prevalence ranged from 47 to 84%. When the prevalence of these studies was pooled, a crude summary prevalence of 64% (62% among women with cancer versus 68% among cancer survivors) was found. The rate of contraceptive counselling was assessed in ten studies. A pooled prevalence of 50% (44% among women with cancer versus 58% among cancer survivors) was found, with the prevalence ranging from 12 to 78% among individual studies depending on the point in the cancer care continuum that it was provided. When contraceptive counselling was provided, it was found to significantly increase contraceptive use although biases were identified in its application. CONCLUSIONS: Contraceptive counselling interventions as part of standard cancer care have the potential to not only empower women with cancer and cancer survivors to make informed choices regarding their reproductive health but also provide the ability to plan future pregnancies for times of better health.

Increased chronic disease prevalence among the younger generation: Findings from a population-based data linkage study to inform chronic disease ascertainment among reproductive-aged Australian women.

BACKGROUND: Chronic disease represents an ongoing public health challenge in Australia with women disproportionately affected and at younger ages compared to men. Accurate prevalence and ascertainment of chronic disease among women of reproductive age at the population level is essential for meeting the family planning and reproductive health challenges that chronic diseases pose. This study estimated the prevalence of chronic disease among younger Australian women of reproductive age, in order to ascertain key conditions that would benefit from targeted family planning support strategies. METHODS AND FINDINGS: Population-level survey data from the 1973-78 and 1989-95 cohorts of the Australian Longitudinal Study on Women's Health were linked to health service use, pharmaceutical, cancer and cause of death data to ascertain the prevalence and chronic disease trends for ten chronic health conditions associated with poor maternal and foetal outcomes. Individual chronic disease algorithms were developed for each chronic disease of interest using the available linked datasets. Lifetime prevalence of chronic disease varied substantially based on each individual data source for each of the conditions of interest. When all data sources were considered, all conditions with the exception of mental health conditions were higher among women in the 1973-78 cohort. However, when focused on point prevalence at similar ages (approximately 25-30 years), the chronic disease trend for women in the 1989-95 cohort was substantially higher, particularly for mental health conditions (70.4% vs 23.6%), diabetes (4.5% vs 1.3%) and multimorbidity (17.9% vs 9.1%). CONCLUSIONS: Given the low concordance between individual data sources, the use of multiple data sources are recommended for chronic disease research focused on women of reproductive age. In order to reduce the increasing chronic disease and multimorbidity trend among women, strategic chronic disease interventions are required to be implemented in childhood and adolescence to ensure the long-term health of not only current but also future generations.

Mitochondrial DNA-depleter mouse as a model to study human pigmentary skin disorders.

Pigmentation abnormalities are reported in the spectrum of phenotypes associated with aging and in patients with mitochondrial DNA depletion syndrome (MDS). Yet, a relevant animal model that mimics these effects and would allow us to evaluate the detrimental aspects of mtDNA depletion on melanocyte function has not been described. Here, we characterize the pigmentary changes observed in the ears of a mtDNA-depleter mouse, which phenotypically includes accentuation of the peri-adnexal pseudonetwork, patchy hyper- and hypopigmentation, and reticular pigmentation. Histologically, these mice show increased epidermal pigmentation with patchy distribution, along with increased and highly dendritic melanocytes. These mtDNA-depleter mice mimic aspects of the cutaneous, pigmentary changes observed in humans with age-related senile lentigines as well as MDS. We suggest that this mouse model can serve as a novel resource for future interrogations of how mitochondrial dysfunction contributes to pigmentary skin disorders. The mtDNA-depleter mouse model also serves as a useful tool to identify novel agents capable of treating pigmentary changes associated with age-related mitochondrial dysfunction in humans.

Polypharmacy trajectories among older women with and without dementia: A longitudinal cohort study.

Background: Although multiple medications are often utilized to achieve optimal treatment outcomes, polypharmacy (use of five or more medications) among older population is associated with several detrimental effects. Trajectories of polypharmacy among older population over time has not been described. Objective: This study estimated polypharmacy prevalence and clusters of individuals with similar patterns of change in polypharmacy among a cohort of older Australian women with and without dementia. Method: Longitudinal prospective cohort data from the oldest birth cohort (1921-1926) of the Australian Longitudinal Study on women's Health (ALSWH) were analysed. Survey data were linked with Pharmaceutical Benefit Schemes (PBS) data to obtain information about the type and number of prescription medications for each year 2003-2015. Group based trajectory modelling was used to identify distinct trajectory groups, based on the presence of polypharmacy for each year of observation. Trajectories were named based on distinctive and meaningful subgroups that followed approximately the same developmental course and probability assignment rule. Generalized estimating equation was used to identify factors associated with polypharmacy. Results: A total of 10,372 women were eligible for the inclusion in the study. Prevalence of polypharmacy increased over time and reached as high as 71.19% and 71.29% in 2014 for women with and without dementia, respectively. Four distinct polypharmacy trajectories were identified: 'Consistent Polypharmacy' (55.88%);'Low Polypharmacy' (24.52%); 'Rapid Increasing Polypharmacy' (12.50%); and 'Moderate Polypharmacy' (7.12%). Dementia, Residential Aged Care (RAC), frailty and comorbid condition were the key drivers of polypharmacy in this cohort. Conclusion: The prevalence of polypharmacy among older women increased over time, with most women have a pattern of consistent polypharmacy or rapidly increasing polypharmacy. Appropriate, sustainable, and effective strategies for reducing medication use should be implemented for women as they age, and particularly for those with dementia and those in residential care.

Topical RT1640 treatment effectively reverses gray hair and stem cell loss in a mouse model of radiation-induced canities.

Gray hair is a visible sign of tissue degeneration during aging. Graying is attributed to dysfunction of melanocyte stem cells (McSCs) that results in depletion of their melanin-producing progeny. This non-lethal phenotype makes the hair follicle and its pigment system an attractive model for investigating mechanisms that contribute to tissue aging and therapeutic strategies to combat this process. One potential combination therapeutic is RT1640, which is comprised of two drugs that are known to stimulate hair growth (cyclosporine A [CsA] and minoxidil), along with RT175, a non-immunosuppressive immunophilin ligand that is implicated in tissue regeneration. Using the ionizing radiation-induced acute mouse model of hair graying, we demonstrate that RT1640, over CsA alone, promotes regeneration of the hair pigment system during and following treatment. In non-irradiated mice, RT1640 is also physiologically active and successfully speeds hair growth and expands the McSC pool. It appears that this effect relies on the combined activities of the three drugs within RT1640 to simultaneously activate hair growth and McSCs as RT175 alone was insufficient to induce hair cycling in vivo, yet sufficient to drive the upregulation of the melanogenic program in vitro. This study sets the stage for further investigation into RT1640 and its components in McSC biology and, ultimately, melanocyte hypopigmentary disorders associated with disease and aging.

Use of medication reviews among older women with dementia, 2003-2015: A longitudinal cohort study.

OBJECTIVE: To identify factors associated with incidence of medication reviews (MRs), particularly in women with dementia and in residential aged care (RAC). METHODS: Data from 10 359 women in the 1921-1926 cohort of the Australian Longitudinal Study on Women's Health were linked to Medicare Benefits Schedule data to identify MRs for each year from 2003 to 2015. RESULTS: Incidence of MR increased from 2003 to 2013 (age 87-92 years) when 37.1% of women with dementia had a MR compared to 19.8% of women without dementia. Adjusting for time and other factors, the odds of having a MR were higher for women with dementia (AOR = 1.18, 95% CI: 1.06-1.32) and women in RAC (AOR = 3.61, 95% CI: 3.28-3.98). CONCLUSIONS: Although higher in women with dementia and those in RAC, utilisation of MR was modest. System-level interventions may be required to ensure the use and benefits of MRs.

Barriers and facilitators to smoking cessation within pregnant Aboriginal and/or Torres Strait Islander women: An integrative review.

OBJECTIVE: To synthesise primary research regarding the facilitators and barriers to smoking cessation amongst Aboriginal and/or Torres Strait Islander women during pregnancy. DESIGN: An integrative review. REVIEW METHODS: A systematic search of peer-reviewed literature from five databases published from January 2008 to April 2018. Articles were reviewed using the approach outlined by Whittemore and Knafl, with the identified themes collated and synthesised according to study characteristics and barriers and facilitators of smoking cessation. FINDINGS: Of the 310 papers retrieved, nine studies were included within the review (five quantitative and four qualitative). The quality of the studies were ascertained via Joanna Briggs Institute checklists for cross sectional analysis, randomized controlled trials, and qualitative research. The overall quality of the research was deemed acceptable. Two facilitators to smoking cessation within the studied population were identified: 'support to quit' and 'information and advice', while four barriers to smoking cessation within pregnant Aboriginal and/or Torres Strait Islander women were identified: 'smoking prevalence', 'high daily stress', 'ambivalence regarding adverse effects of smoking', and 'attitudes, knowledge and training of the healthcare professional'. CONCLUSIONS: Social and familial influences and daily stress have a strong impact on whether a woman feels she can quit smoking during pregnancy. However, in this study, information and advice regarding potential adverse effects of smoking on the foetus, or lack thereof, from health professionals either facilitated cessation of smoking in pregnancy or was a barrier to quitting. Likewise, a lack of awareness from midwives and doctors on smoking cessation strategies, such as nicotine replacement therapy, was a barrier for women. IMPLICATIONS FOR PRACTICE: The findings indicate that education regarding the adverse effects of smoking in pregnancy, as well as strategies on smoking cessation from midwives, doctors, and Aboriginal Health Workers within the antenatal period may have a positive effect on current smoking rates among pregnant Aboriginal and/or Torres Strait Islander women. Involving the partner/support person and family of the woman in this education may have a greater impact on smoking cessation rates through the woman gaining social and familial support in her decision to quit. Thus, healthcare workers require additional professional development to provide information and knowledge within a culturally competent manner. Successful smoking cessation programs for Aboriginal and Torres Strait Islander women during pregnancy could have measurable impacts on mortality rates for Indigenous infants and significantly contribute to 'Closing the Gap'.

Predictors of 15-year survival among Australian women with diabetes from age 76-81.

AIMS: To assess the impact of diabetes on the survival of older women, adjusted for other all-cause mortality predictors. METHODS: Data were used from the 1921-26 cohort of the Australian Longitudinal Study on Women's Health, when the women were aged 76-81 years at baseline, with linkage to the National Death Index. Survival curves were plotted to compare the survival of women with no diabetes, incident diabetes and prevalent diabetes over 15 years. Cox proportional hazards models were used to examine the association between diabetes and all-cause mortality risks. RESULTS: A total of 972 (11.7%) of 8296 eligible women reported either incident, 522 (6.3%) or prevalent, 450 (5.4%) diabetes. The median survival times were 10.1, 11.4 and 12.7 years among women with prevalent, incident and no diabetes, respectively. The risks of death were 30% [HR: 1.30 (95% CI: 1.16-1.45)] and 73% [HR: 1.73 (CI: 1.57-1.92)] higher for women with incident and prevalent diabetes compared to women without diabetes. These associations were sustained after controlling for demographics, body mass index, smoking status, comorbidities and health care use. CONCLUSIONS: This study revealed that diabetes is associated with reduced survival probabilities for older women with minimal moderation after adjustment for other predictors. Our findings suggest that diabetes management guidelines for older women need to integrate factors such as comorbidities, smoking and being underweight to reduce the risk of mortality.

Factors associated with length of stay in hospital for men and women aged 85 and over: A quantile regression approach.

OBJECTIVES: Explore characteristics of hospital use for adults aged 85 and over in their last year of life and examine factors associated with cumulative overnight length of stay (LOS). DATA SOURCE/STUDY SETTING: NSW 45 and Up Study linked with hospital data. STUDY DESIGN: Longitudinal cohort study. METHODS: Quantile regression models were performed for men and women (N = 3145) to examine heterogeneity in predictors of overnight hospital admissions. Coefficients were estimated at the 25th, 50th, 75th and 90th percentiles of the LOS distribution. PRINCIPAL FINDINGS: 86% had at least one hospitalisation in their last year of life, with 60% dying in hospital. For men, first admission for organ failure was associated with a 26 day increase at the 90th LOS percentile, and a 0.22 day increase at the 10th percentile compared to men with cancer. Women admitted with influenza had decreased LOS of 20.5 days at the 75th percentile and 6 to 8 fewer days at the lower percentiles compared to those women with cancer. CONCLUSIONS: Poor health behaviours were a major driver of highest LOS among older men, pointing to opportunities to achieve health care savings through prevention. For older women, influenza was associated with shorter LOS, which could be an indicator of the high and rapid mortality rates at older ages, and may be easily prevented. Other factors associated with LOS among women, included where they lived before they were admitted, and discharge destination.

Stress increases the risk of type 2 diabetes onset in women: A 12-year longitudinal study using causal modelling.

BACKGROUND: Type 2 diabetes is associated with significant morbidity and mortality. Modifiable risk factors have been found to contribute up to 60% of type 2 diabetes risk. However, type 2 diabetes continues to rise despite implementation of interventions based on traditional risk factors. There is a clear need to identify additional risk factors for chronic disease prevention. The aim of this study was to examine the relationship between perceived stress and type 2 diabetes onset, and partition the estimates into direct and indirect effects. METHODS AND FINDINGS: Women born in 1946-1951 (n = 12,844) completed surveys for the Australian Longitudinal Study on Women's Health in 1998, 2001, 2004, 2007 and 2010. The total causal effect was estimated using logistic regression and marginal structural modelling. Controlled direct effects were estimated through conditioning in the regression model. A graded association was found between perceived stress and all mediators in the multivariate time lag analyses. A significant association was found between hypertension, as well as physical activity and body mass index, and diabetes, but not smoking or diet quality. Moderate/high stress levels were associated with a 2.3-fold increase in the odds of diabetes three years later, for the total estimated effect. Results were only slightly attenuated when the direct and indirect effects of perceived stress on diabetes were partitioned, with the mediators only explaining 10-20% of the excess variation in diabetes. CONCLUSIONS: Perceived stress is a strong risk factor for type 2 diabetes. The majority of the effect estimate of stress on diabetes risk is not mediated by the traditional risk factors of hypertension, physical activity, smoking, diet quality, and body mass index. This gives a new pathway for diabetes prevention trials and clinical practice.

End of life hospitalisations differ for older Australian women according to death trajectory: a longitudinal data linkage study.

BACKGROUND: Hospitalisations are the prime contributor to healthcare expenditure, with older adults often identified as high hospital users. Despite the apparent high use of hospitals at the end of life, limited evidence currently exists regarding reasons for hospitalisation. Understanding complex end of life care needs is required for future health care planning as the global population ages. This study aimed to investigate patterns of hospitalisation in the last year of life by cause of death (COD) as well as reasons for admission and short-term predictors of hospital use. METHODS: Survey data from 1,205 decedents from the 1921-1926 cohort of the Australian Longitudinal Study on Women's Health were matched with the state-based hospital records and the National Death Index. Hospital patterns based on COD were graphically summarised and multivariate logistic regression models examined the impact of short-term predictors of length of stay (LOS). RESULTS: 85 % of women had at least one admission in the last year of life; and 8 % had their first observed admission during this time. Reasons for hospitalisation, timing of admissions and LOS differed by COD. Women who died of cancer, diabetes and 'other' causes were admitted earlier than women who died of organ failure, dementia and influenza. Women who died of organ failure overall spent the longest time in hospital, and women with cancer had the highest median LOS. Longer LOS was associated with previous short- and medium-term- hospitalisations and type of hospital separation. CONCLUSIONS: Reducing acute care admissions and LOS at the end of life is complex and requires a shift in perceptions and treatment regarding end of life care and chronic disease management.

Genomic analysis reveals distinct mechanisms and functional classes of SOX10-regulated genes in melanocytes.

SOX10 is required for melanocyte development and maintenance, and has been linked to melanoma initiation and progression. However, the molecular mechanisms by which SOX10 guides the appropriate gene expression programs necessary to promote the melanocyte lineage are not fully understood. Here we employ genetic and epigenomic analysis approaches to uncover novel genomic targets and previously unappreciated molecular roles of SOX10 in melanocytes. Through global analysis of SOX10-binding sites and epigenetic characteristics of chromatin states, we uncover an extensive catalog of SOX10 targets genome-wide. Our findings reveal that SOX10 predominantly engages 'open' chromatin regions and binds to distal regulatory elements, including novel and previously known melanocyte enhancers. Integrated chromatin occupancy and transcriptome analysis suggest a role for SOX10 in both transcriptional activation and repression to regulate functionally distinct classes of genes. We demonstrate that distinct epigenetic signatures and cis-regulatory sequence motifs predicted to bind putative co-regulatory transcription factors define SOX10-activated and SOX10-repressed target genes. Collectively, these findings uncover a central role of SOX10 as a global regulator of gene expression in the melanocyte lineage by targeting diverse regulatory pathways.

Ectopic differentiation of melanocyte stem cells is influenced by genetic background.

Hair graying in mouse is attributed to the loss of melanocyte stem cell function and the progressive depletion of the follicular melanocyte population. Single-gene, hair graying mouse models have pointed to a number of critical pathways involved in melanocyte stem cell biology; however, the broad range of phenotypic variation observed in human hair graying suggests that additional genetic variants involved in this process may yet be discovered. Using a sensitized approach, we ask here whether natural genetic variation influences a predominant cellular mechanism of hair graying in mouse, melanocyte stem cell differentiation. We developed an innovative method to quantify melanocyte stem cell differentiation by measuring ectopically pigmented melanocyte stem cells in response to the melanocyte-specific transgene Tg(Dct-Sox10). We make the novel observation that the production of ectopically pigmented melanocyte stem cells varies considerably across strains. The success of sensitizing for melanocyte stem cell differentiation by Tg(Dct-Sox10) sets the stage for future investigations into the genetic basis of strain-specific contributions to melanocyte stem cell biology.

Postnatal lineage mapping of follicular melanocytes with the Tyr::CreER(T) (2) transgene.

One of the main advantages of using inducible and conditional transgenes to study pigment cell biology is that they allow for genetic manipulation within melanocytes after roles in general neural crest or melanoblast development have been fulfilled. Specifically, we focus here on the ability of the Tyr::CreER(T) (2) transgenic line to alter genes within follicular melanocytes postnatally. Using the Gt(ROSA)26Sor(tm1sor) reporter allele, we present in detail the expression and activity of Tyr::CreER(T) (2) when induced during hair morphogenesis and adult hair cycling. We find that despite similarities in expression pattern to endogenous TYR, Tyr::CreER(T) (2) is effective at targeting both undifferentiated and differentiated melanocytes within the hair follicle. We also find that Tyr::CreER(T) (2) provides the highest levels of recombination when induced during the early phases of hair growth. In conclusion, the descriptions provided here will guide future analyses of gene function within the melanocyte system of the hair follicle when using this Tyr::CreER(T) (2) transgene.

Sox proteins in melanocyte development and melanoma.

Over 10 years have passed since the first Sox gene was implicated in melanocyte development. Since then, we have discovered that SOX5, SOX9, SOX10 and SOX18 all participate as transcription factors that affect key melanocytic genes in both regulatory and modulatory fashions. Both SOX9 and SOX10 play major roles in the establishment and normal function of the melanocyte; SOX10 has been shown to heavily influence melanocyte development and SOX9 has been implicated in melanogenesis in the adult. Despite these advances, the precise cellular and molecular details of how these SOX proteins are regulated and interact during all stages of the melanocyte life cycle remain unknown. Improper regulation of SOX9 or SOX10 is also associated with cancerous transformation, and thus understanding the normal function of SOX proteins in the melanocyte will be key to revealing how these proteins contribute to melanoma.

Directing pathfinding along the dorsolateral path - the role of EDNRB2 and EphB2 in overcoming inhibition.

Neural crest cells that become pigment cells migrate along a dorsolateral route between the ectoderm and the somite, whereas most other neural crest cells are inhibited from entering this space. This pathway choice has been attributed to unique, cell-autonomous migratory properties acquired by neural crest cells when they become specified as melanoblasts. By shRNA knockdown and overexpression experiments, we investigated the roles of three transmembrane receptors in regulating dorsolateral pathfinding in the chick trunk. We show that Endothelin receptor B2 (EDNRB2) and EphB2 are both determinants in this process, and that, unlike in other species, c-KIT is not. We demonstrate that the overexpression of EDNRB2 can maintain normal dorsolateral migration of melanoblasts in the absence of EphB2, and vice versa, suggesting that changes in receptor expression levels regulate the invasion of this pathway. Furthermore, by heterotopic grafting, we show that neural crest cell populations that do not rely on the activation of these receptors can migrate dorsolaterally only if this path is free of inhibitory molecules. We conclude that the requirement for EDNRB2 and EphB2 expression by melanoblasts is to support their migration by helping them to overcome repulsive or non-permissive cues in the dorsolateral environment.