Recommendations for the primary prevention of atherosclerotic cardiovascular disease in primary care: study protocol for a systematic guideline review.

INTRODUCTION: Atherosclerotic cardiovascular disease (ASCVD) was the main cause of death in Germany in 2021, with major risk factors (ie, hypertension, diabetes, dyslipidaemia, obesity and certain lifestyle factors) being highly prevalent. Preventing ASCVD by assessment and modification of these risk factors is an important challenge for general practitioners. This study aims to systematically review and synthesise recent recommendations of national and international guidelines regarding the primary prevention of ASCVD in adults in primary care. METHODS AND ANALYSIS: We will conduct a systematic review of clinical practice guidelines (CPGs) to evaluate primary prevention strategies for ASCVD. CPGs will be retrieved from MEDLINE and the Turning Research Into Practice database, guideline-specific databases and websites of guidelines-producing societies, with searches limited to publications from 2016 onwards. We will include CPGs in English, Spanish, German or Dutch languages that provide evidence-based recommendations for ASCVD prevention. The study population will include adults without diagnosed ASCVD. Two independent reviewers will assess guideline eligibility and quality by means of the mini-checklist MiChe, and extract study characteristics and relevant recommendations for further consistency analysis. A third reviewer will resolve disagreements. Findings will be presented as a narrative synthesis and in tabular form. ETHICS AND DISSEMINATION: This review does not require ethical approval. Our systematic review will inform the CPG of the German College of General Practitioners and Family Physicians on the primary prevention of ASCVD. The review results will also be disseminated through publications in peer-reviewed journals and presentations at local, national and international conferences. PROSPERO REGISTRATION NUMBER: CRD42023394605.

Profiles of socially isolated community-dwelling older adults during the COVID-19 pandemic: A latent class analysis.

OBJECTIVE: To identify different profiles of socially isolated older adults during the first wave of COVID-19 in Quebec, Canada. STUDY DESIGN: Cross-sectional data were obtained through a telehealth socio-geriatric risk assessment tool, ESOGER, administered to adults aged 70 years or more between April and July 2020 in Montreal, Canada. MEASURES: Those living alone with no social contacts in the last few days were considered socially isolated. Latent class analysis was performed to identify profiles of socially isolated older adults based on: age, sex, polypharmacy, use of home care, use of a walking aid, recall of current year/month, anxiety level (scale 0-10), and need for follow-up from a healthcare provider. RESULTS: Three-hundred and eighty (380) older adults identified as socially isolated were analyzed, of whom 75.5 % were female and 56.6 % were over 85. Three classes were identified: Class 1 ("physically frail older females") had the highest proportion of polypharmacy, walking aid, and home care use. Class 2 ("anxious, relatively younger males") were predominantly males who used the least home care but had the highest anxiety levels. Class 3 ("seemingly well older females") had the highest proportion of females, lowest proportion of polypharmacy, lowest anxiety level, and none used a walking aid. Recall of current year/month was similar across the three classes. CONCLUSIONS: This study found heterogeneity among socially isolated older adults during the first wave of the COVID-19 pandemic with varying levels of physical and mental health. Our findings may contribute to the development of targeted interventions to support this vulnerable population during and after the pandemic.

Implementing a Telehealth Support Tool for Community-Dwelling Older Adults During the COVID-19 Pandemic: A Qualitative Investigation of Provider Experiences.

During the COVID-19 pandemic, policymakers had to quickly offer telehealth services to address older adults' needs. This study aimed to understand the experiences of providers who implemented a telephone-based telehealth tool named Socio-Geriatric Evaluation (ESOGER), which assessed health and social isolation risks in community-dwelling older adults in Quebec (Canada). This qualitative study used 20 semi-structured online/phone interviews with health and social service providers coming from publicly-funded healthcare facilities and community organizations. We included adopters and non-adopters of the telehealth tool. Interviews were audio-recorded and transcribed verbatim. We used reflexive thematic analysis to interpret the data. Three dimensions of providers' practice influenced the tool's implementation: service organization, working conditions, and interactions with older adults. Participants reported that the tool fostered continuity of care, provided guidance for their pandemic-related new tasks, and helped identify and support socially isolated older adults. Challenges to implementation included limited appropriateness of the telehealth tool for diverse services, feasibility barriers to adopting a new tool amid the health crisis, and acceptability challenges with some older adults. Despite relevance of the telehealth tool for providers, organizational, professional, and interactional barriers could hinder implementation success. Participatory approaches to telehealth may be promising avenues for future policies in this field.

Effectiveness of Interventions for Prevention of Common Infections Among Opioid Users: A Systematic Review of Systematic Reviews.

Background: The North American opioid crisis is marked by high opioid-related mortality and morbidity, including opioid use-associated infections (OUAIs). Users of pharmaceutical and non-pharmaceutical opioids are at an increased risk of acquiring hepatitis C (HCV), human immunodeficiency virus (HIV), and other infections. No high-level evidence, however, has been synthesized regarding effectiveness of interventions to prevent OUAIs in legal, and illegal/mixed opioid users. The aim of the study is to synthesize available systematic review (SR)-level evidence on the scope and effectiveness of interventions to prevent OUAIs among opioid users. Methods: A SR of SRs approach was applied. We searched PubMed, Embase, PsycINFO, Cochrane Database of Systematic Reviews, Epistemonikos and Google Scholar from inception to September 2020. Data selection and extraction were performed independently by three researchers. Risk of bias and quality of evidence were assessed using the AMSTAR2 tool. Results were narratively synthesized. Strength of evidence for each category was reported. Results: Eleven of twelve identified SRs included interventions to prevent HCV/HIV transmission in persons who inject drugs (PWID), including opioids. One SR evaluated interventions to prevent recurrent infectious endocarditis. There was sufficient and tentative SR of SRs-level evidence for the effectiveness of opioid substitution therapy (OST) in preventing HIV and HCV, respectively. We found tentative evidence to support effectiveness of needle/syringe exchange programs (NSP) in HIV prevention, and sufficient evidence to support effectiveness of the combined OST and NSP in HCV prevention. There was insufficient SR-level evidence to support or discount effectiveness of other interventions to prevent OUAIs. No SR focused on non-PWID populations. Conclusion: SR-level evidence supports the use of OST, NSP, and combined interventions for the reduction of HCV and HIV transmission in PWID. More research on prevention of other OUAIs and on prevention of OUAIs in non-PWID populations is urgently needed. Systematic Review Registration: Registered in PROSPERO on July 30, 2020. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=195929, identifier: #195929.

Effectiveness of interventions for prevention of common infections in people who use opioids: a protocol for a systematic review of systematic reviews.

BACKGROUND: The North American opioid crisis is driven by opioid-related mortality and morbidity, including opioid use-associated infections (OUAIs), resulting in a substantial burden for society. Users of legal and illegal opioids are at an increased risk of OUAIs compared to individuals not using opioids. As reported for hepatitis C virus (HCV), human immunodeficiency virus (HIV), bacterial, fungal, and other infections, OUAIs transmission and acquisition risks may be modifiable. Several systematic reviews (SRs) synthetized data regarding interventions to prevent infections in persons using drugs (e.g., opioid substitution therapy, needle and syringes exchange programs, psycho-social interventions); however, their conclusions varied. Therefore, SR of published SRs is needed to synthesize the highest level of evidence on the scope and effectiveness of interventions to prevent OUAIs in people using opioids legally or illegally. METHODS: We will comprehensively search for SRs in the PubMed, Embase, PsycINFO, Cochrane Database of Systematic Reviews, Epistemonikos, and Google Scholar databases from inception to November 2020. Data selection and extraction for each SR will be performed independently by two researchers, with disagreements resolved by consensus. All SRs regarding interventions with evaluated effectiveness to prevent OUAI in legal and/or illegal opioid users will be eligible. Risk of bias assessment will be performed using the AMSTAR2 tool. The results will be qualitatively synthesized, and a typology of interventions' effectiveness with a statement on the strength of evidence for each category will be created. DISCUSSION: Our pilot search of PubMed resulted in 379 SRs analyzing the effectiveness of interventions to prevent HCV and HIV in persons who inject different types of drugs, including opioids. Of these 379 SRs, 8 evaluated primary studies where participants used opioids and would therefore be eligible for inclusion. The search results thus justify the application of SR of SRs approach. Comprehensive data on the scope and effectiveness of existing interventions to prevent OUAIs will help policy-makers to plan and implement preventive interventions and will assist clinicians in the guidance for their patients using opioids. SYSTEMATIC REVIEW REGISTRATION: Registered in PROSPERO on 30 July 2020 ( #195929 ).

Evaluating Prevalence and Patterns of Prescribing Medications for Depression for Patients With Obesity Using Large Primary Care Data (Canadian Primary Care Sentinel Surveillance Network).

Introduction: Depression is a serious disorder that brings a tremendous health and economic burden. Many antidepressants (AD) have obesogenic effects, increasing the population of obese patients at increased risk for a more severe disease course and poor treatment response. In addition, obese patients with depression may not be receiving the recommended standard of care due to "obesity bias." It is important to evaluate prescribing pharmacological treatment of depression in patients with obesity. Objectives: To describe the prevalence and patterns of AD prescribing for patients with depression and comorbid obesity compared with normal weight patients, and to examine the association of prescribing prevalence with obesity class. Methods: Study sample of adult patients (>18 years old) with depression was extracted from the national Canadian Primary Care Sentinel Surveillance Network (CPCSSN) Electronic Medical Records database for 2011-2016. Measures were prescribing of at least one AD (outcome) and body mass index (BMI) to categorize patients into weight categories (exposure). Data were analyzed cross-sectionally using descriptive statistics and mixed effects logistic regression model with clustering on CPCSSN networks and adjusting for age, sex, and the comorbidities. Results: Of 120,381 patients with depression, 63,830 patients had complete data on studied variables (complete cases analysis). Compared with normal weight patients, obese patients were more likely to receive an AD prescription (adjusted Odds Ratio [aOR] = 1.17; 95% Confidence Interval [CI]: 1.12-1.22). Patients with obesity classes II and III were 8% (95% CI: 1.00, 1.16) and 6% (95% CI: 0.98, 1.16) more likely, respectively, to receive AD. After imputing missing data using Multiple Imputations by Chained Equations, the results remained unchanged. The prevalence of prescribing >3 AD types was higher in obese category (7.27%, [95% CI: 6.84, 7.73]) than in normal weight category (5.6%; [95% CI: 5.24, 5.99]). Conclusion: The association between obesity and high prevalence of AD prescribing and prescribing high number of different AD to obese patients, consistent across geographical regions, raises a public health concern. Study results warrant qualitative studies to explore reasons behind the difference in prescribing, and quantitative longitudinal studies evaluating the association of AD prescribing patterns for obese patients with health outcomes.

Excess body weight as a predictor of response to treatment with antidepressants in patients with depressive disorder.

BACKGROUND: Depression and obesity are debilitating conditions representing an enormous health and economic burden worldwide. Depression is common among patients with excess weight, but more importantly, these patients may be at risk for poor response when treated with antidepressant medications (AD). METHODS: We conducted a comprehensive scoping review to summarize the evidence regarding the difference in response to treatment of depression with AD among patients with excess weight as compared to normal weight patients and to identify knowledge gaps. RESULTS: The search of the Medline and PsycINFO (2004-2019) identified twelve relevant studies. Tabulation and frequency analysis of the charted data along with a narrative synthesis were performed. Nine studies (75%) reported clinically relevant negative association between patients' high BMI or obesity and treatment response to either nortriptyline, fluoxetine, or various AD; one study (8.3%) reported no difference in response to various AD combinations between BMI groups. One study showed benefits of bupropion and escitalopram combination in patients with morbid obesity (BMI > 35 kg/m2) as compared with escitalopram monotherapy. Another study reported benefits when using venlafaxine-XR in patients with morbid obesity. We also acknowledge the possible role of sex and genetic factors predicting AD treatment response. LIMITATIONS: The search was restricted to two most relevant sources, publications in four languages and adult population. CONCLUSION: The synthesized data may be useful to physicians in their decision regarding the choice of AD in patients with excess weight. Researchers need to address causality of association between obesity and treatment response to individual AD types.

In Their Words: Children's Perspectives on an El Sistema Music Program's Effects on their Well-Being.

BACKGROUND: The El Sistema movement uses music as a promising tool to promote healthy childhood development and well-being, particularly in children facing socioeconomic challenges. Recognizing the need to better support underprivileged children in their neighborhood, the community-based organization Share the Warmth (STW) created an El Sistema-inspired music program named STW El Sistema. Owing to their program's recent rise in popularity and corresponding costs, STW El Sistema coordinators partnered with McGill University researchers to formally evaluate and better understand the program's effects on participating children. We sought to understand participating children's lived experiences in STW El Sistema, and their perspectives on the program's impact in their lives and on their well-being. METHODS: Community-based participatory research (CBPR), where STW partners were actively involved in the identification of the research question and in the interpretation and dissemination of research findings. This qualitative descriptive study included eight children aged 7-12 years stratified by age into two semistructured focus groups for thematic analysis. RESULTS: Children described STW El Sistema as associated with their well-being: 1) emotionally, by learning to cope with stress, and learning patience and confidence; 2) socially, by fostering a sense of community and relationships with peers and family; and 3) personally and educationally, by promoting scholarly motivation and career ambition. CONCLUSIONS: Children expressed that STW El Sistema music program improved aspects of their well-being. Study results warrant longitudinal studies to further assess El Sistema's impact on quality-of-life indicators.

Health professionals' perspectives on breast cancer risk stratification: understanding evaluation of risk versus screening for disease.

BACKGROUND: Younger women at higher-than-population-average risk for breast cancer may benefit from starting screening earlier than presently recommended by the guidelines. The Personalized Risk Stratification for Prevention and Early Detection of Breast Cancer (PERSPECTIVE) approach aims to improve the prevention of breast cancer through differential screening recommendations based on a personal risk estimate. In our study, we used deliberative stakeholder consultations to engage health professionals in an in-depth dialog to explore the feasibility of the proposed implementation strategies for this new personalized breast cancer screening approach. METHODS: Deliberative stakeholder consultation is a qualitative descriptive study design used to engage health professionals in the discussion, while the mediators play a more passive role. A purposeful sample of 11 health professionals (family physicians and genetic counselors) working in Montreal was used. The deliberations were organized in two phases, including small group deliberations according to the deliberants' health profession and a mixed group deliberation combining participants from the small groups. Inductive thematic content analysis was performed on the transcripts by two coders to create the deliberative and analytic outputs. Quality of deliberations was assessed quantitatively using the de Vries method and qualitatively using participant observation. RESULTS: One of our key findings was that health professionals lacked understanding of the two steps of the screening approach: risk stratification "screening," which is an evaluation for the level of risk and screening for disease. As part of this confusion, the main topic of concern was a justification of program implementation as a population-wide screening, based on their uncertainty that it will be beneficial for women with near-population risks. Despite the noted difficulties concerning implementation, health professionals acknowledged the substantial benefits of the proposed PERSPECTIVE program. CONCLUSIONS: Our study was the first to evaluate the perspectives of health professionals on the implementation and benefits of a new program for breast cancer risk stratification with the purpose of personalizing screening for disease. This new multi-step approach to screening requires more clarity in communication with health professionals. To implement and maintain effective screening, engagement of family physicians with other health professionals or even development of a centralized public health system may be needed.

Frenotomy in Infants with Tongue-Tie and Breastfeeding Problems.

BACKGROUND: Infant tongue-tie can cause breastfeeding problems, which may be improved by frenotomy. However, controversy exists among the medical community. RESEARCH AIM: To examine the influence of frenotomy on infants with posterior ankyloglossia, by quantifying the changes in breastfeeding and maternal nipple pain using standardized tools. METHODS: Newborns (N = 30) below 12 weeks of age were recruited from the Herzl-Goldfarb Breastfeeding Clinic between April 2014 and April 2015. Diagnosis of posterior ankyloglossia was made clinically. Frenotomy was performed. Mothers received breastfeeding counseling before and after the procedure. Pain and breastfeeding were assessed before the procedure, immediately after the procedure, and after 2 days, 7 days and 14 days. Breastfeeding was assessed using the LATCH Tool and by subjective questioning. Maternal nipple pain was assessed using the Numeric Rating System. RESULTS: No complications were reported with frenotomy. There was a significant improvement in LATCH score immediately post-frenotomy, with an increase in median scores from 7.5 to 8.5 (p < .0001, Wilcoxon signed rank test). There was a significant decrease in median pain score immediately post-frenotomy, from 3.0 on the left nipple and 3.25 on the right nipple, to 0 bilaterally (p < .0001, Wilcoxon signed rank test). Subjective improvement in breastfeeding was reported by 90% of mothers immediately after frenotomy and 83% of mothers at Day 14. CONCLUSION: Frenotomy for posterior ankyloglossia may improve breastfeeding and nipple pain.

High hepatitis C incidence in relation to prescription opioid injection and poly-drug use: Assessing barriers to hepatitis C prevention.

BACKGROUND: Prescription opioid (PO) injection and poly-drug use have been associated with hepatitis C virus (HCV) infection among people who inject drugs (PWID). Poly-drug use is often a barrier to key HCV preventive programmes including opioid agonist treatment. The contribution of specific drug combinations to high HCV incidence in poly-drug users has not been assessed previously. Addressing this knowledge gap could enhance HCV treatment and prevention efforts. We examined the association between specific drugs and number of drugs used in addition to injected POs, and HCV seroconversion. METHODS: PWID participating in a cohort study in Montréal (HEPCO), HCV-seronegative at baseline and followed between 2004 and 2013, were included. Data were collected by interview-administered questionnaires. Blood samples were tested for HCV new infections at each 3-6 month follow-up visit. Time-varying Cox regression models were utilized. RESULTS: Of 356 participants (81.5% males; mean age: 34.7 years), 123 (34.6%) reported injected POs in the past month at baseline. In univariate analyses, recent use of the following drugs was associated with HCV seroconversion: injected POs, injected cocaine, injected heroin, non-injected tranquilisers, and smoked crack/cocaine. The relative excess risk of HCV seroconversion due to interaction (RER1HR) was the highest for co-use of injected POs with the following substances: injected cocaine (RER1HR=3.44), smoked crack/cocaine (RER1HR=1.27), and non-injected tranquilisers (RER1HR=0.8). In addition, a significant linear trend (p<0.001) towards higher risk was observed with increasing the number of these three drugs used in combination with injected POs. CONCLUSION: Specific drugs and number of drugs used in addition to injected POs play a modulating role in the risk of HCV primary infection. Poly-drug use among people who inject POs has to be addressed in order to improve harm reduction programmes and reduce HCV transmission in this high-risk population.

Short-term injection drug use changes following hepatitis C virus (HCV) assessment and treatment among persons who inject drugs with acute HCV infection.

BACKGROUND: It is unclear whether treatment and care for hepatitis C virus (HCV) infection can help people who inject drugs (PWID) modify their injection drug use behaviours. This study examined changes in injection drug use among PWID with acute HCV systematically referred for HCV clinical assessment and treatment and offered targeted health care services, over the course of one year. METHODS: The study sample included PWID with documented acute HCV infection recruited and followed-up semi-annually at least twice in IMPACT (2007-2015), a longitudinal community-based prospective study in Montréal, Canada. Following enrolment, participants with contra-indications to treatment due to severe co-morbidity were offered targeted health care services. Pegylated interferon-alpha (12-24 weeks) was offered to all other participants who did not spontaneously resolve their infection. At each study visit, data were collected on socio-demographic factors and drug use patterns. Logistic regression was used to assess changes in injection drug use at one-year follow-up. RESULTS: Of the 87 eligible participants (mean age: 35.6; 78.2% male), 21.8% received treatment [(RT), Sustained virological response: 84.2%], 25.3% spontaneously resolved their infection (SR), 14.9% had contra-indication(s) (CI) and 37.9% chose not to engage in HCV care post-diagnosis (NE). In multivariate analyses adjusting for age, gender and injection drug use at baseline, the RT [Adjusted odds ratio (AOR): 0.18; 95% Confidence interval (CI): 0.04-0.76], SR (AOR: 0.34; 95% CI: 0.08-1.40), and CI (AOR: 0.24; 95% CI: 0.05-1.22) groups were less likely to report injection drug use at follow-up relative to the NE group. CONCLUSION: PWID who received treatment, spontaneously resolved their infection or presented with treatment contra-indication(s) reported reduced injection drug use at one-year follow-up relative to those who did not engage in therapy. Findings suggest that the benefits of HCV assessment and treatment may extent to helping PWID modify their injection drug use patterns.

Hepatitis C Virus seroconversion among persons who inject drugs in relation to primary care physician visiting: The potential role of primary healthcare in a combined approach to Hepatitis C prevention.

BACKGROUND: Meaningful reductions in Hepatitis C Virus (HCV) transmission rates among persons who inject drugs (PWID) require a comprehensive prevention approach, including access to harm reduction measures and to healthcare-related interventions, such as HCV screening, testing and antiviral treatment. Little is known, however, about the role of visiting a primary care physician (PCP) in relation to HCV infection risk among PWID, when integrated within a combined prevention approach. This study assessed the association between PCP visiting and HCV seroconversion among PWID attending needle exchange programs (NEP). METHODS: A prospective cohort study, HEPCO, was conducted among active PWID in Montréal (2004-2013). Interviews scheduled at 3- or 6-month intervals included completion of an interviewer-administered questionnaire, and collection of blood samples for HCV antibody testing. HCV-seronegative participants who reported NEP attendance at baseline and had at least one follow-up visit were eligible for this study. HCV incidence was calculated using the person-time method. Time-varying Cox regression modeling was conducted to evaluate the relationship between self-reported recent PCP visiting and HCV incidence. RESULTS: At baseline assessment, of 226 participants (80.5% male; median age: 30.6 years), 37.2% reported having recently visited a PCP. During 449.6 person-years of follow-up, 79 participants seroconverted to HCV [incidence rate: 17.6 per 100 person-years, 95% confidence interval (CI): 14.0-21.8]. Covariate-adjusted analyses indicated that visiting a PCP was associated with a lower risk of HCV infection [Adjusted Hazard Ratio: 0.54, 95% CI: 0.31-0.93]. Other independent predictors of HCV infection included unstable housing, cocaine injection and prescription opioid injection. CONCLUSION: Among PWID attending NEP, visiting a PCP was associated with a lower risk of HCV infection. Yet, only a minority of participants reported PCP visiting. Efforts to intensify engagement with PCP among PWID could potentially contribute to lower HCV transmission when integrated within a combined approach to prevention.

[Exploration of potential mechanisms underlying substance use disorders in individuals with personality disorders]. / Exploration des mécanismes potentiels sous-jacents aux troubles liés à l'utilisation d'une substance chez les personnes atteintes d'un trouble de la personnalité

Background Cluster-B personality disorders (DSM-V), particularly borderline and antisocial personality disorders, are associated with high rates of substance use disorder. However, the mechanisms underlying this relationship have yet to be fully understood. Craving has recently been identified as an important component of substance use disorder. The purpose of this article is therefore to review the current literature and explore whether craving could be implicated as an underlying mechanism of comorbid substance use disorder in antisocial and borderline personality disorders.Method Critical review of the literature.Results Emerging evidence indicates that there is in fact an association between craving and personality disorders. Patients afflicted with the latter, incidentally, respond differently to anti-craving medication when compared to normal subjects. While a limited number of studies have directly assessed craving in patients with personality disorders, a growing number have looked at the association between craving and specific personality traits. The correlation between impulsivity, negative affect and craving seems like a plausible explanation for the high prevalence and severity of substance use disorder in subjects with antisocial or borderline personality disorders.Conclusion These findings suggest that specific personality traits are related to craving and could represent promising targets for the prevention, assessment and management of comorbid substance use disorders.

Parathyroid hormone signaling via Gαs is selectively inhibited by an NH(2)-terminally truncated Gαs: implications for pseudohypoparathyroidism.

Pseudohypoparathyroid patients have resistance predominantly to parathyroid hormone (PTH), and here we have examined the ability of an alternative Gαs-related protein to inhibit Gαs activity in a hormone-selective manner. We tested whether the GNAS exon A/B-derived NH(2)-terminally truncated (Tr) αs protein alters stimulation of adenylate cyclase by the PTH receptor (PTHR1), the thyroid-stimulating hormone (TSH) receptor (TSHR), the ß(2)-adrenergic receptor (ß(2)AR), or the AVP receptor (V2R). HEK293 cells cotransfected with receptor and full-length (FL) Gαs ± Tr αs protein expression vectors were stimulated with agonists (PTH [10(-7) to 10(-9) M], TSH [1 to 100 mU], isoproterenol [10(-6) to 10(-8) M], or AVP [10(-6) to 10(-8) M]). Following PTH stimulation, HEK293 cells cotransfected with PTHR1 + FL Gαs + Tr αs had a significantly lower cAMP response than those transfected with only PTHR1 + FL Gαs. Tr αs also exerted an inhibitory effect on the cAMP levels stimulated by TSH via the TSHR but had little or no effect on isoproterenol or AVP acting via ß(2)AR or V2R, respectively. These differences mimic the spectrum of hormone resistance in pseudohypoparathyroidism type 1a (PHP-1a) and type 1b (PHP-1b) patients. In opossum kidney (OK) cells, endogenously expressing the PTHR1 and ß(2)AR, the exogenous expression of Tr αs at a level similar to endogenous FL Gαs resulted in blunting of the cAMP response to PTH, whereas that to isoproterenol was unaltered. A pseudopseudohypoparathyroid patient with Albright hereditary osteodystrophy harbored a de novo paternally inherited M1I Gαs mutation. Similar maternally inherited mutations at the initiation codon have been identified previously in PHP-1a patients. The M1I αs mutant (lacking the first 59 amino acids of Gαs) blunted the increase in cAMP levels stimulated via the PTHR1 in both HEK293 and OK cells similar to the Tr αs protein. Thus NH(2)-terminally truncated forms of Gαs may contribute to the pathogenesis of pseudohypoparathyroidism by inhibiting the activity of Gαs itself in a GPCR selective manner.

Human growth hormone receptor gene expression is regulated by Gfi-1/1b and GAGA cis-elements.

Human growth hormone receptor (hGHR) gene regulation is complex: mRNAs are transcribed from multiple variant (V) 5'UTR exons, several ubiquitously while others only in the postnatal hepatocyte. The liver-specific V1 exon promoter contains Gfi-1/1b repressor sites adjacent to a GAGA box, a GH response element (GHRE) in several mammalian genes. GAGA boxes are also present in the ubiquitously expressing V3 exon promoter. Heterologous sites in bovine, ovine and murine GHR genes suggest conserved roles. GAGA factor stimulated V1 and V3 promoters while Gfi-1/1b repressed basal and GAF-stimulated V1 transcription. HGH treatment of HepG2 cells resulted in a new complex forming with V3 GAGA elements, suggesting a functional GHRE. Data suggest liver-specific V1 transcription is regulated by inhibitory Gfi-1/1b and stimulatory GAGA cis-elements and Gfi-1/1b may control the lack of V1 expression in fetal liver, hepatic tumours and non-hepatic tissues. In addition, hGH may regulate hGHR expression through V3 GAGA boxes.

Transcriptional regulation of the human growth hormone receptor (hGHR) gene V2 promoter by transcriptional activators and repressor.

The V2 transcript is the major ubiquitously expressed human GH receptor (hGHR) mRNA in all tissues examined to date. In a previous investigation, we defined the V2 promoter as TATA-less and exhibiting many characteristics of a housekeeping gene promoter. We also demonstrated that its basal activity is determined by several different cis-regulatory regions within both the promoter and the V2 exon. In the present study, we used luciferase-reporter, site-directed mutagenesis, gel shift, chromatin immunoprecipitation, and quantitative RT-PCR assays to investigate the ability of certain transcription factors to regulate hGHR V2 transcription through these regions in mammalian cells, including human adipocytes. Ets1 was found to transactivate the V2 proximal promoter through specific Ets sites. Two CCAAT/enhancer-binding protein (C/EBP) family members [C/EBP-homologous protein (CHOP) and C/EBPbeta] enhanced V2 transcription via different pathways: indirectly, by association with a V2 exon region (CHOP), and directly, using a V2 proximal promoter noncanonical binding site (C/EBPbeta). The Notch signaling mediator, Hes1, potently suppressed V2 promoter activity through interaction with two Hes sites within the V2 exon. We propose that these transcriptional factors regulate hGHR V2 expression by acting as downstream nuclear effectors, linking specific signaling cascades (e.g. MAPK and Notch) triggered by different growth factor-, development-, and nutrition- as well as stress-related stimuli. Our data also suggest that these factors are likely to be important in the differentiation-induced increase in V2 mRNA expression in adipocytes, with Ets1 and CHOP functioning at the preadipocyte stage to prepare the cells for differentiation and increasing C/EBPs and decreasing Hes1 levels contributing during adipocyte maturation.

Structure and activity of the human growth hormone receptor (hGHR) gene V2 promoter.

Human GH (hGH) has important effects on growth as well as carbohydrate, fat, and protein metabolism. These actions require the presence of normal levels of a functional hGH receptor (hGHR) on the surface of target cells. hGHR gene expression is characterized by the use of several 5'-noncoding exons and alternative splicing, resulting in the generation of multiple mRNA isoforms. The hGHR V2 transcript is predominant in most tissues, including human fat. However, factors regulating its ubiquitous expression have remained unidentified. The present study was aimed at characterizing the mechanisms regulating hGHR V2 transcription. Two major V2 transcriptional start sites were identified by primer extension assays. The V2 proximal promoter is TATA-less, with several characteristics of a housekeeping gene promoter. Transient transfection analyses of 2.6 kb of the 5'-flanking region of V2 confirmed its promoter activity in multiple primate cell lines. Similar promoter activity patterns were observed in human SGBS preadipocytes and mature adipocytes but with much higher V2 promoter activity in mature adipocytes, suggesting that changes in the availability of specific factors during adipocyte differentiation play a role in V2 promoter regulation. Serial deletion and mutation analyses revealed that transcription of hGHR V2 in different cell types, including adipocytes, is determined by a core promoter and distinct inhibitory and activation domains in the 5'-promoter region as well as within the V2 exon. Our data suggest that V2 transcription is the result of a complex interplay involving multiple factors, to ensure appropriate expression of hGHR in different hGH target cells.