Perspectives on telehealth implementation in Australia: An exploratory qualitative study with practice managers and general practitioners.

BACKGROUND: There is a lack of understanding regarding the impact of telehealth on clinical delivery and the feasibility of sustained implementation by health services. The COVID-19 pandemic provided an ideal opportunity to identify factors related to the implementation of telehealth. This study assessed factors that influenced telehealth implementation during COVID-19 in the Western region of Victoria, Australia, from the perspectives of practice managers and general practitioners (GPs). METHODS: Employing a qualitative approach, we conducted semi-structured interviews with 14 GPs and 11 practice managers across metropolitan and rural settings in the Western region of Victoria, Australia. Interviews were conducted between December 2021 to June 2022, which included periods during and beyond the peak of the COVID-19 pandemic. Themes were synthesised using the Consolidated Framework for Implementation Research, which comprised five domains: innovation, inner setting, outer setting, individuals and implementation process. An additional domain related to billing and finances was added. RESULTS: The innovation domain revealed that telehealth was identified by both stakeholder groups as a critical tool for improving healthcare access for vulnerable patients. GPs highlighted the role of telehealth in follow-up care and the need for extended telephone consultation services. For the implementation process, both stakeholder groups identified a shift in attitudes among GPs from reluctance to acceptance of telehealth. In terms of outer setting, constant changes in regulations posed challenges to administrative staff. Practice managers faced difficulties in acquiring information on changes, but those with robust professional networks were well supported. Initial loss of incentive funding and government-imposed billing methods posed hurdles for clinics. Both stakeholder groups highlighted the need for education around videoconference and a standardised telehealth platform. CONCLUSION: Evolving telehealth regulations during the emergence of COVID-19 posed financial, operational and administrative challenges to primary care clinics. To ensure sustainability, policymakers should improve stakeholder communication, set interoperability standards, and ensure sustainable funding for telehealth.

Class IIa HDACs inhibit cell death pathways and protect muscle integrity in response to lipotoxicity.

Lipotoxicity, the accumulation of lipids in non-adipose tissues, alters the metabolic transcriptome and mitochondrial metabolism in skeletal muscle. The mechanisms involved remain poorly understood. Here we show that lipotoxicity increased histone deacetylase 4 (HDAC4) and histone deacetylase 5 (HDAC5), which reduced the expression of metabolic genes and oxidative metabolism in skeletal muscle, resulting in increased non-oxidative glucose metabolism. This metabolic reprogramming was also associated with impaired apoptosis and ferroptosis responses, and preserved muscle cell viability in response to lipotoxicity. Mechanistically, increased HDAC4 and 5 decreased acetylation of p53 at K120, a modification required for transcriptional activation of apoptosis. Redox drivers of ferroptosis derived from oxidative metabolism were also reduced. The relevance of this pathway was demonstrated by overexpression of loss-of-function HDAC4 and HDAC5 mutants in skeletal muscle of obese db/db mice, which enhanced oxidative metabolic capacity, increased apoptosis and ferroptosis and reduced muscle mass. This study identifies HDAC4 and HDAC5 as repressors of skeletal muscle oxidative metabolism, which is linked to inhibition of cell death pathways and preservation of muscle integrity in response to lipotoxicity.

Use of a gene expression signature to identify trimetazidine for repurposing to treat bipolar depression.

OBJECTIVES: The aim of this study was to repurpose a drug for the treatment of bipolar depression. METHODS: A gene expression signature representing the overall transcriptomic effects of a cocktail of drugs widely prescribed to treat bipolar disorder was generated using human neuronal-like (NT2-N) cells. A compound library of 960 approved, off-patent drugs were then screened to identify those drugs that affect transcription most similar to the effects of the bipolar depression drug cocktail. For mechanistic studies, peripheral blood mononuclear cells were obtained from a healthy subject and reprogrammed into induced pluripotent stem cells, which were then differentiated into co-cultured neurons and astrocytes. Efficacy studies were conducted in two animal models of depressive-like behaviours (Flinders Sensitive Line rats and social isolation with chronic restraint stress rats). RESULTS: The screen identified trimetazidine as a potential drug for repurposing. Trimetazidine alters metabolic processes to increase ATP production, which is thought to be deficient in bipolar depression. We showed that trimetazidine increased mitochondrial respiration in cultured human neuronal-like cells. Transcriptomic analysis in induced pluripotent stem cell-derived neuron/astrocyte co-cultures suggested additional mechanisms of action via the focal adhesion and MAPK signalling pathways. In two different rodent models of depressive-like behaviours, trimetazidine exhibited antidepressant-like activity with reduced anhedonia and reduced immobility in the forced swim test. CONCLUSION: Collectively our data support the repurposing of trimetazidine for the treatment of bipolar depression.

Understanding weight status and dietary intakes among Australian school children by remoteness: a cross-sectional study.

OBJECTIVE: To determine whether primary school children's weight status and dietary behaviours vary by remoteness as defined by the Australian Modified Monash Model (MMM). DESIGN: A cross-sectional study design was used to conduct secondary analysis of baseline data from primary school students participating in a community-based childhood obesity trial. Logistic mixed models estimated associations between remoteness, measured weight status and self-reported dietary intake. SETTING: Twelve regional and rural Local Government Areas in North-East Victoria, Australia. PARTICIPANTS: Data were collected from 2456 grade 4 (approximately 9-10 years) and grade 6 (approximately 11-12 years) students. RESULTS: The final sample included students living in regional centres (17·4 %), large rural towns (25·6 %), medium rural towns (15·1 %) and small rural towns (41·9 %). Weight status did not vary by remoteness. Compared to children in regional centres, those in small rural towns were more likely to meet fruit consumption guidelines (OR: 1·75, 95 % CI (1·24, 2·47)) and had higher odds of consuming fewer takeaway meals (OR: 1·37, 95 % CI (1·08, 1·74)) and unhealthy snacks (OR = 1·58, 95 % CI (1·15, 2·16)). CONCLUSIONS: Living further from regional centres was associated with some healthier self-reported dietary behaviours. This study improves understanding of how dietary behaviours may differ across remoteness levels and highlights that public health initiatives may need to take into account heterogeneity across communities.

A cross-sectional health literacy profile of Australian regional adults using the Health Literacy Questionnaire©.

OBJECTIVE: Health literacy is the resources and abilities required to make and enact health decisions. This study aimed to describe the health literacy of a diverse cross-section of adults in regional Victoria. METHODS: Participants were recruited from two primary care clinics differing in socioeconomic scope and through non-clinical recruitment via the town's largest football club. Health Literacy Questionnaire© measured nine distinct scales, and comprehensive demographic data were also collected. Effect-sizes and regression were used for health literacy comparison between groups. RESULTS: In this sample of 351 adults, health literacy strengths were observed in Scale 1: 'Feeling understood and supported by healthcare providers' (mean 3.29/4 ±0.5) and Scale 9: 'Understanding health information well enough to know what to do' (mean 4.10/5 ±0.6). Challenging areas were Scale 5: 'Appraising health information' (mean 2.88/4 ±0.5) and Scale 7: 'Navigating the healthcare system' (mean 3.84/5 ±0.6). After adjustment, living alone predicted lower scores across most scales. CONCLUSIONS: This study showed greater health literacy barriers experienced by certain groups, particularly those who live alone and those who weren't clinically recruited. IMPLICATIONS FOR PUBLIC HEALTH: These findings have implications for further research into addressing health literacy barriers in marginalised individuals and non-clinical settings. Results from this study may inform interventions which address identified barriers.

Use of General Practitioner Telehealth Services During the COVID-19 Pandemic in Regional Victoria, Australia: Retrospective Analysis.

BACKGROUND: In March 2020, the Australian Government expanded general practitioner (GP) telehealth services in response to the COVID-19 pandemic. OBJECTIVE: This study sought to assess use patterns of GP telehealth services in response to changing circumstances (before and during the COVID-19 pandemic and with or without a lockdown) in regional Victoria, Australia. METHODS: We conducted a secondary analysis of monthly Medicare claims data from July 2019 to June 2021 from 140 regional GP practices in Western Victoria. The longitudinal patterns of proportion of GP telehealth consultations stratified by type of consultation (ie, videoconference vs telephone) and by geographical, consumer, and consultation characteristics were analyzed. RESULTS: Telehealth comprised 25.8% (522,932/2,025,615) of GP consultations over the 2-year period. After the introduction of the Australian telehealth expansion policy in March 2020, there was a rapid uptake in GP telehealth services (including telephone and video services), from 0% before COVID-19 to 15% (11,854/80,922) of all consultations in March 2020, peaking at 55% (50,828/92,139) in August 2020. Thereafter, the use of telehealth declined steadily to 31% (23,941/77,344) in January 2021 and tapered off to 28% (29,263/103,798) in June 2021. Telephone services and shorter consultations were the most dominant form, and those aged 15-64 years had higher telehealth use rates than younger or older age groups. The proportion of video consultations was higher during periods with government-imposed lockdowns and higher in the most socioeconomically advantaged areas compared to less socioeconomically advantaged areas. CONCLUSIONS: Our findings support the continuation of telehealth use in rural and regional Australia post pandemic. Future policy must identify mechanisms to reduce existing equity gaps in video consultations and consider patient- and system-level implications of the dominant use of short telephone consultations.

Healthy weight, health behaviours and quality of life among Aboriginal children living in regional Victoria.

OBJECTIVE: To report the prevalence of healthy weight and related behaviours among Victorian Aboriginal and non-Aboriginal children and explore associations between these factors and health-related quality of life (HRQoL). METHODS: Analysis of cross-sectional data from two cluster randomised controlled trials using logistic and linear mixed models. The sample included Aboriginal (n=303) and non-Aboriginal (n=3,026) children aged 8-13 years. RESULTS: More than two-thirds of Aboriginal children met guidelines for fruit (75.9%), sweetened drinks (66.7%), sleep (73.1%), screen time (67.7%) and objectively measured physical activity (83.6%); and 79.1% reported consuming take-away foods less than once per week. Aboriginal children were more likely to meet vegetable consumption guidelines (OR=1.42, 95%CI: 1.05, 1.93), but less likely to have a healthy weight (OR=0.66, 95%CI: 0.52, 0.85) than non-Aboriginal children. Mean HRQoL scores were significantly higher among non-Aboriginal children and both Aboriginal and non-Aboriginal children meeting health guidelines. CONCLUSIONS: Most Aboriginal children in this study met guidelines for fruit, physical activity, screen time and sleep, and those meeting these guidelines had significantly higher HRQoL. IMPLICATIONS FOR PUBLIC HEALTH: Promoting nutrition, physical activity and sleep is likely to benefit all children. Aboriginal community-controlled organisations can use these data to design culturally-specific programs that may improve disparities in healthy weight and HRQoL.

The use of a gene expression signature and connectivity map to repurpose drugs for bipolar disorder.

OBJECTIVES: To create a gene expression signature (GES) to represent the biological effects of a combination of known drugs for bipolar disorder (BD) on cultured human neuronal cells (NT2-N) and rat brains, which also has evidence of differential expression in individuals with BD. To use the GES to identify new drugs for BD using Connectivity Map (CMap).Methods: NT2-N (n = 20) cells and rats (n = 8) were treated with a BD drug combination (lithium, valproate, quetiapine and lamotrigine) or vehicle for 24 and 6 h, respectively. Following next-generation sequencing, the differential expression of genes was assessed using edgeR in R. The derived GES was compared to differentially expressed genes in post-mortem brains of individuals with BD. The GES was then used in CMap analysis to identify similarly acting drugs.Results: A total of 88 genes showed evidence of differential expression in response to the drug combination in both models, and therefore comprised the GES. Six of these genes showed evidence of differential expression in post-mortem brains of individuals with BD. CMap analysis identified 10 compounds (camptothecin, chlorambucil, flupenthixol, valdecoxib, rescinnamine, GW-8510, cinnarizine, lomustine, mifepristone and nimesulide) acting similarly to the BD drug combination.Conclusions: This study shows that GES and CMap can be used as tools to repurpose drugs for BD.

Drugs used in the treatment of bipolar disorder and their effects on cholesterol biosynthesis - A possible therapeutic mechanism.

Objectives: To understand the therapeutic mechanisms of bipolar disorder (BD) drugs at molecular and cellular levels.Methods: Next generation sequencing was used to determine the transcriptional effects of a combination of four commonly prescribed BD drugs (lithium, valproate, lamotrigine and quetiapine) or vehicle (0.2% DMSO) in NT2-N (human neuronal) cells and rats. Differential expression of genes and pathway analysis were performed using edgeR in R and Gene Set Enrichment Analysis software respectively. Free cholesterol levels and neurite outgrowth were quantified in NT2-N cells following combination and individual BD drug treatments.Results: Pathway analysis showed up-regulation of many elements of the cholesterol biosynthesis pathway in NT2-N cells and oxidative phosphorylation in rat brains. Intracellular cholesterol transport genes were upregulated (NPC1, NPC2 and APOE), while the cholesterol efflux gene (ABCA1) was downregulated. BD drug combination tended to increase intracellular cholesterol levels and neurite outgrowth, but these effects were not seen for the drugs when used individually.Conclusions: These data suggest that BD drug combination is increasing cholesterol biosynthesis and the newly synthesised cholesterol is being utilised within the cells, possibly for synthesis of new membranes to facilitate neurite outgrowth. This mechanism possibly underpins clinical efficacy in individuals with BD treated with polypharmacy.

Evaluation of clinical quality improvement interventions: feasibility of an integrated approach.

BACKGROUND: Cardiovascular diseases (CVD) are the largest cause of death and disability in Australia. Australian national guidelines for the primary prevention of CVD recommend that all adults without CVD and aged 45 years or more are screened for their absolute risk of CVD every 2 years. Despite the compelling evidence to address CVD risk, treatment gaps remain and evidence suggests that much of the shortcomings are attributed to the performance of primary care practices. To address this issue, a quality improvement initiative is being implemented in a large urban multidisciplinary primary care practice in the South West region of Victoria, Australia. The key outcome of this intervention will be to increase the use and acceptability of CVD risk assessment guidelines. To ensure the intervention is tracking toward its objectives, a robust monitoring and evaluation framework was established. METHOD/DESIGN: A novel framework that assimilates key traditional and theory-driven evaluation practices was developed to assess the impact of the intervention. The framework approach is termed the integrated model of evaluation (IMoE). Researchers and stakeholders convened several times to discuss and develop the evaluation protocol and align it with the quality intervention. The main objective here is to explore the feasibility of an integrated approach to evaluating clinical quality improvement interventions. The sub-objectives are to test the alignment of the IMoE to clinical quality improvement projects and its ability to derive findings to the satisfaction of stakeholders. The design and establishment of the evaluation approach is discussed in further detail in this article. DISCUSSION: The novel feature of the IMoE is its emphasis on tracking 'change' in practices that lead to quality improvement. This emphasis suits the quality improvement theme of this initiative as identification of change elements and explanation behind change is necessary to sustain and promote quality improvement. The other principle behind development of this model, which emphasises practicality in implementation, is to ensure stakeholders gain greatest value from the commissioning of program evaluation. By incorporating practical components and leaving out esoteric concepts, this approach ensures evaluation can be undertaken in realistic timeframes. ETHICS APPROVAL: The quality improvement intervention and evaluation framework received approval from the Deakin University Human Research Ethics Committee (Approval Number: 2017-313).

PGC-1α and PGC-1ß Increase Protein Synthesis via ERRα in C2C12 Myotubes.

The transcriptional coactivators peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and PGC-1ß are positive regulators of skeletal muscle mass and energy metabolism; however, whether they influence muscle growth and metabolic adaptations via increased protein synthesis is not clear. This study revealed PGC-1α or PGC-1ß overexpression in C2C12 myotubes increased protein synthesis and myotube diameter under basal conditions and attenuated the loss in protein synthesis following the treatment with the catabolic agent, dexamethasone. To investigate whether PGC-1α or PGC-1ß signal through the Akt/mTOR pathway to increase protein synthesis, treatment with the PI3K and mTOR inhibitors, LY294002 and rapamycin, respectively, was undertaken but found unable to block PGC-1α or PGC-1ß's promotion of protein synthesis. Furthermore, PGC-1α and PGC-1ß decreased phosphorylation of Akt and the Akt/mTOR substrate, p70S6K. In contrast to Akt/mTOR inhibition, the suppression of ERRα, a major effector of PGC-1α and PGC-1ß activity, attenuated the increase in protein synthesis and myotube diameter in the presence of PGC-1α or PGC-1ß overexpression. To characterize further the biological processes occurring, gene set enrichment analysis of genes commonly regulated by both PGC-1α and PGC-1ß was performed following a microarray screen. Genes were found enriched in metabolic and mitochondrial oxidative processes, in addition to protein translation and muscle development categories. This suggests concurrent responses involving both increased metabolism and myotube protein synthesis. Finally, based on their known function or unbiased identification through statistical selection, two sets of genes were investigated in a human exercise model of stimulated protein synthesis to characterize further the genes influenced by PGC-1α and PGC-1ß during physiological adaptive changes in skeletal muscle.

Networks for prevention in 19 communities at the start of a large-scale community-based obesity prevention initiative.

Community-based obesity prevention efforts are dependent on the strength and function of collaborative networks across multiple community members and organizations. There is little empirical work on understanding how community network structure influences obesity prevention capacity. We describe network structures within 19 local government communities prior to a large-scale community-based obesity prevention intervention, Healthy Together Victoria, Australia (2012-2015). Participants were from a large, multi-site, cluster randomized trial (cRCT) of a whole-of-systems chronic disease prevention initiative. Community leaders from 12 intervention and seven comparison (non-intervention) regions identified and described their professional networks in relation to dietary, physical activity, and weight status among young children (<5 years of age). Social network measures of density, modularity, clustering, and centrality were calculated for each community. Comparison of means and tests of association were conducted for each network relationship. One-hundred and seven respondents (78 intervention; 29 comparison) reported on 996 professional network relationships (respondent average per region: 10 intervention; 8 comparison). Networks were typically sparse and highly modular. Networks were heterogeneous in size and relationship composition. Frequency of interaction, close and influential relationships were inversely associated with network density. At baseline in this cRCT there were no significant differences between community network structures of key actors with influence over environments affecting children's diet and physical activity. Tracking heterogeneity in both networks and measured outcomes over time may help explain the interaction between professional networks and intervention effectiveness of community-based obesity prevention.

Social network analysis of stakeholder networks from two community-based obesity prevention interventions.

INTRODUCTION: Studies of community-based obesity prevention interventions have hypothesized that stakeholder networks are a critical element of effective implementation. This paper presents a quantitative analysis of the interpersonal network structures within a sub-sample of stakeholders from two past successful childhood obesity prevention interventions. METHODS: Participants were recruited from the stakeholder groups (steering committees) of two completed community-based intervention studies, Romp & Chomp (R&C), Australia (2004-2008) and Shape Up Somerville (SUS), USA (2003-2005). Both studies demonstrated significant reductions of overweight and obesity among children. Members of the steering committees were asked to complete a retrospective social network questionnaire using a roster of other committee members and free recall. Each participant was asked to recall the people with whom they discussed issues related to childhood obesity throughout the intervention period, along with providing the closeness and level of influence of each relationship. RESULTS: Networks were reported by 13 participants from the SUS steering committee and 8 participants from the R&C steering committee. On average, participants nominated 16 contacts with whom they discussed issues related to childhood obesity through the intervention, with approximately half of the relationships described as 'close' and 30% as 'influential'. The 'discussion' and 'close' networks had high clustering and reciprocity, with ties directed to other steering committee members, and to individuals external to the committee. In contrast, influential ties were more prominently directed internal to the steering committee, with higher network centralization, lower reciprocity and lower clustering. DISCUSSION AND CONCLUSION: Social network analysis provides a method to evaluate the ties within steering committees of community-based obesity prevention interventions. In this study, the network characteristics between a sub-set of stakeholders appeared to be supportive of diffused communication. Future work should prospectively examine stakeholder network structures in a heterogeneous sample of community-based interventions to identify elements most strongly associated with intervention effectiveness.

School-based systems change for obesity prevention in adolescents: outcomes of the Australian Capital Territory 'It's Your Move!'

OBJECTIVE: The Australian Capital Territory 'It's Your Move!' (ACT-IYM) was a three-year (2012-2014) systems intervention to prevent obesity among adolescents. METHODS: The ACT-IYM project involved three intervention schools and three comparison schools and targeted secondary students aged 12-16 years. The intervention consisted of multiple initiatives at individual, community, and school policy level to support healthier nutrition and physical activity. Intervention school-specific objectives related to increasing active transport, increasing time spent physically active at school, and supporting mental wellbeing. Data were collected in 2012 and 2014 from 656 students. Anthropometric data were objectively measured and behavioural data self-reported. RESULTS: Proportions of overweight or obesity were similar over time within the intervention (24.5% baseline and 22.8% follow-up) and comparison groups (31.8% baseline and 30.6% follow-up). Within schools, two of three the intervention schools showed a significant decrease in the prevalence of overweight and obesity (p<0.05). CONCLUSIONS: There was some evidence of effectiveness of the systems approach to preventing obesity among adolescents. Implications for public health: The incorporation of systems thinking has been touted as the next stage in obesity prevention and public health more broadly. These findings demonstrate that the use of systems methods can be effective on a small scale.

MicroRNAs in a hypertrophic heart: from foetal life to adulthood.

The heart is the first organ to form and undergoes adaptive remodelling with age. Ventricular hypertrophy is one such adaptation, which allows the heart to cope with an increase in cardiac demand. This adaptation is necessary as part of natural growth from foetal life to adulthood. It may also occur in response to resistance in blood flow due to various insults on the heart and vessels that accumulate with age. The heart can only compensate to this increase in workload to a certain extent without losing its functional architecture, ultimately resulting in heart failure. Many genes have been implicated in cardiac hypertrophy, however none have been shown conclusively to be responsible for pathological cardiac hypertrophy. MicroRNAs offer an alternative mechanism for cellular regulation by altering gene expression. Since 1993 when the function of a non-coding DNA sequence was first discovered in the model organism Caenorhabditis elegans, many microRNAs have been implicated in having a central role in numerous physiological and pathological cellular processes. The level of control these antisense oligonucleotides offer can often be exploited to manipulate the expression of target genes. Moreover, altered levels of microRNAs can serve as diagnostic biomarkers, with the prospect of diagnosing a disease process as early as during foetal life. Therefore, it is vital to ascertain and investigate the function of microRNAs that are involved in heart development and subsequent ventricular remodelling. Here we present an overview of the complicated network of microRNAs and their target genes that have previously been implicated in cardiogenesis and hypertrophy. It is interesting to note that microRNAs in both of these growth processes can be of possible remedial value to counter a similar disease pathophysiology.

Disruption of the Class IIa HDAC Corepressor Complex Increases Energy Expenditure and Lipid Oxidation.

Drugs that recapitulate aspects of the exercise adaptive response have the potential to provide better treatment for diseases associated with physical inactivity. We previously observed reduced skeletal muscle class IIa HDAC (histone deacetylase) transcriptional repressive activity during exercise. Here, we find that exercise-like adaptations are induced by skeletal muscle expression of class IIa HDAC mutants that cannot form a corepressor complex. Adaptations include increased metabolic gene expression, mitochondrial capacity, and lipid oxidation. An existing HDAC inhibitor, Scriptaid, had similar phenotypic effects through disruption of the class IIa HDAC corepressor complex. Acute Scriptaid administration to mice increased the expression of metabolic genes, which required an intact class IIa HDAC corepressor complex. Chronic Scriptaid administration increased exercise capacity, whole-body energy expenditure and lipid oxidation, and reduced fasting blood lipids and glucose. Therefore, compounds that disrupt class IIa HDAC function could be used to enhance metabolic health in chronic diseases driven by physical inactivity.

Zebrafish Embryonic Lipidomic Analysis Reveals that the Yolk Cell Is Metabolically Active in Processing Lipid.

The role of lipids in providing energy and structural cellular components during vertebrate development is poorly understood. To elucidate these roles further, we visualized lipid deposition and examined expression of key lipid-regulating genes during zebrafish embryogenesis. We also conducted a semiquantitative analysis of lipidomic composition using liquid chromatography (LC)-mass spectrometry. Finally, we analyzed processing of boron-dipyrromethene (BODIPY) lipid analogs injected into the yolk using thin layer chromatography. Our data reveal that the most abundant lipids in the embryo are cholesterol, phosphatidylcholine, and triglyceride. Moreover, we demonstrate that lipids are processed within the yolk prior to mobilization to the embryonic body. Our data identify a metabolically active yolk and body resulting in a dynamic lipid composition. This provides a foundation for studying lipid biology during normal or pharmacologically compromised embryogenesis.

A gene expression signature for insulin resistance.

Insulin resistance is a heterogeneous disorder caused by a range of genetic and environmental factors, and we hypothesize that its etiology varies considerably between individuals. This heterogeneity provides significant challenges to the development of effective therapeutic regimes for long-term management of type 2 diabetes. We describe a novel strategy, using large-scale gene expression profiling, to develop a gene expression signature (GES) that reflects the overall state of insulin resistance in cells and patients. The GES was developed from 3T3-L1 adipocytes that were made "insulin resistant" by treatment with tumor necrosis factor-α (TNF-α) and then reversed with aspirin and troglitazone ("resensitized"). The GES consisted of five genes whose expression levels best discriminated between the insulin-resistant and insulin-resensitized states. We then used this GES to screen a compound library for agents that affected the GES genes in 3T3-L1 adipocytes in a way that most closely resembled the changes seen when insulin resistance was successfully reversed with aspirin and troglitazone. This screen identified both known and new insulin-sensitizing compounds including nonsteroidal anti-inflammatory agents, ß-adrenergic antagonists, ß-lactams, and sodium channel blockers. We tested the biological relevance of this GES in participants in the San Antonio Family Heart Study (n = 1,240) and showed that patients with the lowest GES scores were more insulin resistant (according to HOMA_IR and fasting plasma insulin levels; P < 0.001). These findings show that GES technology can be used for both the discovery of insulin-sensitizing compounds and the characterization of patients into subtypes of insulin resistance according to GES scores, opening the possibility of developing a personalized medicine approach to type 2 diabetes.

Identification of novel genes expressed during rhabdomyosarcoma differentiation using cDNA microarrays.

Rhabdomyosarcomas (RMS) are highly aggressive tumors that are thought to arise as a consequence of the regulatory disruption of the growth and differentiation of skeletal muscle progenitor cells. Normal myogenesis is characterized by the expression of the myogenic regulatory factor gene family but, despite their expression in RMS, these tumor cells fail to complete the latter stages of myogenesis. The RMS cell line RD-A was treated with 12-O-tetradecanoylphorbol-13-acetate to induce differentiation and cultured for 10 days. RNA was extracted on days 1, 3, 6, 8 and 10. A human skeletal muscle cDNA microarray was developed and used to analyze the global gene expression of RMS tumors over the time-course of differentiation. As a comparison, the genes identified were subsequently examined during the differentiated primary human skeletal muscle cultures. Prothymosin alpha (PTMA), and translocase of inner mitochondrial membrane 10 (Tim10), two genes not previously implicated in RMS, showed reduced expression during differentiation. Marked differences in the expression of PTMA and Tim10 were observed during the differentiation of human primary skeletal muscle cells. These results identify several new genes with potential roles in the myogenic arrest present in rhabdomyosarcoma. PTMA expression in RMS biopsy samples might prove to be an effective diagnostic marker for this disease.