Beyond Obesity and Overweight: the Clinical Assessment and Treatment of Excess Body Fat In Children : Part 2 - the Prescription of Low-Carbohydrate Eating as the First Approach.

PURPOSE OF REVIEW: Pediatric obesity and comorbidities related to insulin resistance continue to be a growing public health crisis. If lifestyle measures are unsuccessful, pharmacological and surgical interventions are offered. In this paper, we describe the driving force of the obesity crisis: hyperinsulinemia and the development of insulin resistance. We give historical background of key policy issues which have contributed to this pandemic as well as the physiologic mechanisms of insulin resistance. The prevalence of obesity will continue to rise unless the root cause of hyperinsulinemia is addressed. RECENT FINDINGS: Current research on insulin resistance demonstrates that a decreased consumption of carbohydrates is an effective first-line dietary intervention for the treatment of obesity and related metabolic diseases. Evidence shows it is safe and beneficial. A low-carbohydrate eating pattern can be helpful to address pediatric obesity. However, there must be policy guardrails in place to ensure that this is a sustainable and viable option for children and their families. There must be a change in the nutritional environment to help individuals battle the chronic disease of obesity.

Beyond Obesity and Overweight: The Clinical Assessment and Treatment of Excess Body Fat in Children : Part 1 - Insulin Resistance as the Root Cause of Pediatric Obesity.

PURPOSE OF REVIEW: Pediatric obesity and comorbidities related to insulin resistance continue to be a growing public health crisis. If lifestyle measures are unsuccessful, pharmacological and surgical interventions are offered. In this paper, we describe the driving force of the obesity crisis: hyperinsulinemia and the development of insulin resistance. We give historical background of key policy issues which have contributed to this pandemic as well as the physiologic mechanisms of insulin resistance. The prevalence of obesity will continue to rise unless the root cause of hyperinsulinemia is addressed. RECENT FINDINGS: Current research on insulin resistance demonstrates that a decreased consumption of carbohydrates is an effective first-line dietary intervention for the treatment of obesity and related metabolic diseases. Evidence shows it is safe and beneficial. A low-carbohydrate eating pattern can be helpful to address pediatric obesity. However, there must be policy guardrails in place to ensure that this is a sustainable and viable option for children and their families. There must be a change in the nutritional environment to help individuals battle the chronic disease of obesity.

Weight Loss Diets, Fads, and Trends.

PURPOSE OF REVIEW: To review popular dietary trends and provide recommendations regarding validated dietary approaches for weight loss in the pediatric population. RECENT FINDINGS: Like adults, children and adolescents trying to lose weight will succumb to diets promoted by the media. Many of these so-called "fad" diets tout unsupported claims for health but prove very difficult for long-term adherence. Since childhood is a pivotal time for establishing lifestyle habits, we need to provide practical dietary advice supported by scientific research. Studies suggest that emphasizing macronutrient balance while limiting both ultraprocessed foods and sugar-sweetened beverages can help our pediatric patients achieve and maintain a healthy weight. We review literature discouraging the use of restrictive dieting in the pediatric population and instead encourage a whole-foods-based, balanced dietary approach, along with regular physical activity. The goal is to support reasonable and sustainable lifestyle habits that ultimately allow children to establish lifelong health-promoting behaviors.

Metaflammation in obesity and its therapeutic targeting.

Obesity-associated inflammation is a systemic process that affects all metabolic organs. Prominent among these is adipose tissue, where cells of the innate and adaptive immune system are markedly changed in obesity, implicating these cells in a range of processes linking immune memory to metabolic regulation. Furthermore, weight loss and weight cycling have unexpected effects on adipose tissue immune populations. Here, we review the current literature on the roles of various immune cells in lean and obese adipose tissue. Within this context, we discuss pharmacological and nonpharmacological approaches to obesity treatment and their impact on systemic inflammation.

Effects of Opioids on Immune and Endocrine Function in Patients with Cancer Pain.

OPINION STATEMENT: Opioids are an important treatment in managing cancer pain. Uncontrolled pain can be detrimental to function and quality of life. Common adverse effects of opioids such as sedation, constipation and nausea are well recognised, but opioid effects on the endocrine and immune systems are less apparent. The evidence for the immunomodulatory effects of opioids suggest that some opioids might be immunosuppressive and that their use might be associated with reduced survival and increased rates of infection in patients with cancer. However, the quality of this evidence is limited. Opioid-induced endocrinopathies, in particular opioid-induced hypogonadism, may also impact cancer survival and impair quality of life. But again, evidence in patients with cancer is limited, especially with regard to their management. There are some data that different opioids influence immune and endocrine function with varying outcomes. For example, some opioids, such as tramadol and buprenorphine, demonstrate immune-sparing qualities when compared to others. However, most of this data is preclinical and without adequate clinical correlation; thus, no opioid can currently be recommended over another in this context. Higher opioid doses might have more effect on immune and endocrine function. Ultimately, it is prudent to use the lowest effective dose to control the cancer pain. Clinical presentations of opioid-induced endocrinopathies should be considered in patients with cancer and assessed for, particularly in long-term opioid users. Hormone replacement therapies may be considered where appropriate with support from endocrinology specialists.

The recovery of training and education post-COVID-19: the importance of supporting the consultant workforce.

BACKGROUND/AIMS: Since the COVID-19 pandemic began, training and education have been significantly disrupted, causing an incalculable effect on trainees. However, the consultant workforce is crucial to the success of training recovery. The motivation of the consultant workforce to assist in training recovery, in a context of significant workload and increasing pressures on resources, is currently unknown. METHODS: This survey gathered the consultant workforce's views on assisting training recovery at one site of a large NHS foundation trust. RESULTS: There was reduced motivation to engage in training and education when compared to pre-pandemic levels, widespread indicators of burnout, and changes in attitude towards reducing their working hours and early retirement. CONCLUSIONS: These findings demonstrate a worrying trend that is likely to be replicated nationwide, which highlights the need to support consultants to avoid further disruption to training recovery.

Case analyses of state-sponsored asthma quality improvement interventions - benefits and technical assistance efforts.

OBJECTIVE: A cross-case analysis was used to discover how two states benefited from expanded use of evaluation for asthma quality improvement initiatives. If an asthma quality improvement (QI) initiative is successfully evaluated, data can inform how to effectively integrate clinical practice guidelines and circumvent non-clinical reasons that interrupt QI projects such as low staff interest. This article addresses a gap in the literature on quality of evaluation support needed to improve and sustain asthma QI at local health care organizations by describing the similar discoveries observed at two independent QI statewide initiatives in Indiana and Montana. METHODS: As part of a larger review, two states funded through the National Asthma Control Program at the Centers for Disease Control and Prevention were identified based on similarities in evaluation approaches. Each state used an iterative stakeholder-driven evaluation approach, mixed methods, process evaluation indicators, and active use of evaluation findings. The asthma QI initiatives and evaluations in Indiana and Montana were coordinated independent of each other. RESULTS: Although both states found that asthma QI initiatives improved health outcomes, evaluation data were able to further pinpoint areas that would improve quality of technical support to health care organizations and identify markers of sustainability, such as nontraditional benefits to staff, and intervention sites. CONCLUSION: Findings suggest that when evaluation is used to guide implementation, data are available to develop site-specific assistance and identify sustainability markers to prevent interruption of positive health outcomes associated with an asthma QI initiative.

Clinical associations of an updated medication effect score for measuring diabetes treatment intensity.

OBJECTIVES: The medication effect score reflects overall intensity of a diabetes regimen by consolidating dosage and potency of agents used. Little is understood regarding how medication intensity relates to clinical factors. We updated the medication effect score to account for newer agents and explored associations between medication effect score and patient-level clinical factors. METHODS: Cross-sectional analysis of baseline data from a randomized controlled trial involving 263 Veterans with type 2 diabetes and hemoglobin A1c levels ≥8.0% (≥7.5% if under age 50). Medication effect score was calculated for all patients at baseline, alongside additional measures including demographics, comorbid illnesses, hemoglobin A1c, and self-reported psychosocial factors. We used multivariable regression to explore associations between baseline medication effect score and patient-level clinical factors. RESULTS: Our sample had a mean age of 60.7 (SD = 8.2) years, was 89.4% male, and 57.4% non-White. Older age and younger onset of diabetes were associated with a higher medication effect score, as was higher body mass index. Higher medication effect score was significantly associated with medication nonadherence, although not with hemoglobin A1c, self-reported hypoglycemia, diabetes-related distress, or depression. DISCUSSION: We observed several expected associations between an updated medication effect score and patient-level clinical factors. These associations support the medication effect score as an appropriate measure of diabetes regimen intensity in clinical and research contexts.

Alcohol and drug use disorders in patients with cancer and caregivers: effects on caregiver burden.

BACKGROUND: The estimated prevalence of alcohol use disorders in patients with advanced cancer is reported as 4%-38%. There are limited data regarding alcohol and drug use disorders in caregivers of patients with cancer and the effects on other issues. AIM: To establish the prevalence of alcohol and drug use disorders in a large cohort of patients with advanced cancer and their caregivers.To evaluate the relationship between alcohol and drug use disorders and patient symptoms and caregiver burden. DESIGN: The patient with cancer and caregiver completed the Alcohol Use Disorders Identification Tool, CAGE questionnaire and Drug Abuse Screening Test. The patient completed the Memorial Symptom Assessment Scale-Short Form, and the caregiver completed the Zarit Burden Questionnaire.Statistical analysis compared cases and non-cases of alcohol and drug use disorders with symptom and burden score. SETTING/PARTICIPANTS: Patients with cancer, and their caregivers, were recruited from 11 UK sites, 6 hospices and 5 hospitals. RESULTS: Five hundred and seven patients and their caregivers were recruited. Twenty-seven patients (5%) and 44 caregivers (9%) screened positively for alcohol use disorders on the Alcohol Use Disorders Identification Tool. Thirty patients (6%), and 16 caregivers (3%), screened positively for drug abuse problems on the Drug Abuse Screening Test.There was a significantly higher carer burden score in caregivers screening positively for alcohol and drug abuse problems. CONCLUSIONS: The prevalence of alcohol use disorders in patients with cancer and caregivers was lower than reported in previous studies. Caregiver burden scores were significantly higher in carers screening positively for alcohol and drug use disorders. TRIAL REGISTRATION NUMBER: Trial registered National Institute for Health Research Clinical Research Network Portfolio (CPMS ID 30723) IRAS ID 198753.

Comparison of Group Medical Visits Combined With Intensive Weight Management vs Group Medical Visits Alone for Glycemia in Patients With Type 2 Diabetes: A Noninferiority Randomized Clinical Trial.

Importance: Traditionally, group medical visits (GMVs) for persons with diabetes improved glycemia by intensifying medications, which infrequently led to weight loss. Incorporating GMVs with intensive dietary change could enable weight loss and improve glycemia while decreasing medication intensity. Objective: To examine whether a program of GMVs combined with intensive weight management (WM) is noninferior to GMVs alone for change in glycated hemoglobin (HbA1c) level at 48 weeks (prespecified margin of 0.5%) and superior to GMVs alone for hypoglycemic events, diabetes medication intensity, and weight loss. Design, Setting, and Participants: This randomized clinical trial identified via the electronic medical record 2814 outpatients with type 2 diabetes, uncontrolled HbA1c, and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 27 or higher from Veterans Affairs Medical Center clinics in Durham and Greenville, North Carolina. Between January 12, 2015, and May 30, 2017, 263 outpatients started the intervention. Interventions: Participants randomized to the GMV group (n = 136) received counseling about diabetes-related topics with medication optimization every 4 weeks for 16 weeks, then every 8 weeks (9 visits). Participants randomized to the WM/GMV group (n = 127) received low-carbohydrate diet counseling with baseline medication reduction and subsequent medication optimization every 2 weeks for 16 weeks followed by an abbreviated GMV intervention every 8 weeks (13 visits). Main Outcomes and Measures: Outcomes included HbA1c level, hypoglycemic events, diabetes medication effect score, and weight at 48 weeks analyzed using hierarchical generalized mixed models to account for clustering within group sessions. Results: Among 263 participants (mean [SD] age, 60.7 [8.2] years; 235 [89.4%] men; 143 [54.4%] black), baseline HbA1c level was 9.1% (1.3%) and BMI was 35.3 (5.1). At 48 weeks, HbA1c level was improved in both study arms (8.2% in the WM/GMV arm and 8.3% in the GMV arm; mean difference, -0.1%; 95% CI, -0.5% to 0.2%; upper 95% CI, <0.5% threshold; P = .44). The WM/GMV arm had lower diabetes medication use (mean difference in medication effect score, -0.5; 95% CI, -0.6 to -0.3; P < .001) and greater weight loss (mean difference, -3.7 kg; 95% CI, -5.5 to -1.9 kg; P < .001) than did the GMV arm at 48 weeks and approximately 50% fewer hypoglycemic events (incidence rate ratio, 0.49; 95% CI, 0.27 to 0.71; P < .001) during the 48-week period. Conclusions and Relevance: In GMVs for diabetes, addition of WM using a low-carbohydrate diet was noninferior for lowering HbA1c levels compared with conventional medication management and showed advantages in other clinically important outcomes. Trial Registration: ClinicalTrials.gov identifier: NCT01973972.

Impact of endothelial microparticles on coagulation, inflammation, and angiogenesis in age-related vascular diseases.

Endothelial microparticles (EMPs) are complex vesicular structures that originate from plasma membranes of activated or apoptotic endothelial cells. EMPs play a significant role in vascular function by altering the processes of inflammation, coagulation, and angiogenesis, and they are key players in the pathogenesis of several vascular diseases. Circulating EMPs are increased in many age-related vascular diseases such as coronary artery disease, peripheral vascular disease, cerebral ischemia, and congestive heart failure. Their elevation in plasma has been considered as both a biomarker and bioactive effector of vascular damage and a target for vascular diseases. This review focuses on the pleiotropic roles of EMPs and the mechanisms that trigger their formation, particularly the involvement of decreased estrogen levels, thrombin, and PAI-1 as major factors that induce EMPs in age-related vascular diseases.

Antiinflammatory and antifibrotic effects of the oral direct thrombin inhibitor dabigatran etexilate in a murine model of interstitial lung disease.

OBJECTIVE: Activation of the coagulation cascade leading to generation of thrombin has been documented extensively in various forms of lung injury, including that associated with systemic sclerosis. We previously demonstrated that the direct thrombin inhibitor dabigatran inhibits thrombin-induced profibrotic signaling in lung fibroblasts. This study was undertaken to test whether dabigatran etexilate attenuates lung injury in a murine model of interstitial lung disease. METHODS: Lung injury was induced in female C57BL/6 mice by a single intratracheal instillation of bleomycin. Dabigatran etexilate was given as supplemented chow beginning on day 1 of bleomycin instillation (early treatment, study of antiinflammatory effect) or on day 8 following bleomycin instillation (late treatment, study of antifibrotic effect). Mice were killed 2 weeks or 3 weeks after bleomycin instillation, and lung tissue, bronchoalveolar lavage (BAL) fluid, and plasma were investigated. RESULTS: Both early treatment and late treatment with dabigatran etexilate attenuated the development of bleomycin-induced pulmonary fibrosis. Dabigatran etexilate significantly reduced thrombin activity and levels of transforming growth factor ß1 in BAL fluid, while simultaneously reducing the number of inflammatory cells and protein concentrations. Histologically evident lung inflammation and fibrosis were significantly decreased in dabigatran etexilate-treated mice. Additionally, dabigatran etexilate reduced collagen, connective tissue growth factor, and α-smooth muscle actin expression in mice with bleomycin-induced lung fibrosis, whereas it had no effect on basal levels of these proteins. CONCLUSION: Inhibition of thrombin using the oral direct thrombin inhibitor dabigatran etexilate has marked antiinflammatory and antifibrotic effects in a bleomycin model of pulmonary fibrosis. Our data provide preclinical information about the feasibility and efficacy of dabigatran etexilate as a new therapeutic approach for the treatment of interstitial lung disease.

Coagulation and autoimmunity in scleroderma interstitial lung disease.

OBJECTIVES: Interstitial lung disease in systemic sclerosis (SSc-ILD) is often an irreversible and progressive fibrosing process that now is the leading cause of scleroderma-related deaths. In this review we present our current understanding of the role played by coagulation and particularly by thrombin in autoimmune-mediated tissue injury and fibrosis, mainly as it relates to SSc-ILD. METHODS: We used PubMed to search for articles published up to October 2010 for keywords referring to autoimmunity, coagulation, pulmonary fibrosis, and scleroderma. RESULTS: SSc-ILD is an autoimmune disease associated with lymphocyte activation and release of various cytokines and growth factors. The production of autoantibodies is a central feature in SSc. Activation of the coagulation cascade with release of thrombin is 1 of the earliest events following tissue injury. Thrombin contributes to autoimmune responses by activating of pathogenic Th2 lymphocyte profile in SSc. Thrombin also modulates tissue repair responses, stimulates transformation of epithelial cells, endothelial cells, and fibroblasts into myofibroblast phenotype, and induces secretion of several pro-immune and profibrotic factors, which serve as antigens for pathogenic autoantibodies production in SSc-ILD. CONCLUSIONS: The identification of links between autoimmunity and coagulation would provide new insights into the pathogenesis of pulmonary fibrosis associated with autoimmune diseases and further acknowledge the importance of thrombin in the development of SSc-ILD.

Dabigatran, a direct thrombin inhibitor, demonstrates antifibrotic effects on lung fibroblasts.

OBJECTIVE: Myofibroblasts are the principal mesenchymal cells responsible for tissue remodeling, collagen deposition, and the restrictive nature of lung parenchyma associated with pulmonary fibrosis. We previously reported that thrombin activates protease-activated receptor 1 (PAR-1) and induces a myofibroblast phenotype in normal lung fibroblasts resembling the phenotype of scleroderma lung myofibroblasts. We undertook this study to investigate whether a selective direct thrombin inhibitor, dabigatran, interferes with signal transduction in human lung fibroblasts induced by thrombin and mediated via PAR-1. METHODS: Lung fibroblast proliferation was analyzed using the Quick Cell Proliferation Assay. Expression and organization of alpha-smooth muscle actin (alpha-SMA) was studied by immunofluorescence staining and immunoblotting. Contractile activity of lung fibroblasts was measured by a collagen gel contraction assay. Connective tissue growth factor (CTGF) and type I collagen expression was analyzed on Western blots. RESULTS: Dabigatran, at concentrations of 50-1,000 ng/ml, inhibited thrombin-induced cell proliferation, alpha-SMA expression and organization, and the production of collagen and CTGF in normal lung fibroblasts. Moreover, when treated with dabigatran (1 microg/ml), scleroderma lung myofibroblasts produced 6-fold less alpha-SMA, 3-fold less CTGF, and 2-fold less type I collagen compared with untreated cells. CONCLUSION: Dabigatran restrains important profibrotic events in lung fibroblasts and warrants study as a potential antifibrotic drug for the treatment of fibrosing lung diseases such as scleroderma lung disease and idiopathic pulmonary fibrosis.

Surfactant protein D and KL-6 as serum biomarkers of interstitial lung disease in patients with scleroderma.

OBJECTIVE: To assess whether serum concentrations of surfactant protein D (SP-D) and Krebs von den Lungen-6 (KL-6), glycoproteins expressed by type II pneumocytes, correlate with the presence of "alveolitis" and measures of lung function in patients enrolled in the Scleroderma Lung Study (SLS). METHODS: Serum obtained at baseline screening of patients with systemic sclerosis (SSc, scleroderma) in the SLS was assayed. "Alveolitis" was defined by either bronchoalveolar lavage or thoracic high-resolution computed tomography (HRCT) by SLS criteria. SP-D and KL-6 levels were measured by ELISA in 66 SSc patients (44 with "alveolitis," 22 without "alveolitis") and in 10 healthy controls. These were compared to clinical measures of lung disease and "alveolitis" in the SLS patients. RESULTS: SP-D levels were 300+/-214 ng/ml (mean+/-SD) in the SSc patients compared to 40+/-51 ng/ml in controls (p<0.0001). KL-6 levels were 1225+/-984 U/ml in the SSc patients and 333+/-294 U/ml in controls (p<0.0001). SSc patients with "alveolitis" had higher levels of both SP-D and KL-6 than those without "alveolitis." The level of SP-D was 353+/-219 ng/ml in patients with "alveolitis" and 161+/-143 ng/ml without "alveolitis" (p=0.0002). The level of KL-6 was 1458+/-1070 U/ml in patients with "alveolitis" and 640+/-487 U/ml without "alveolitis" (p=0.0001). Receiver operator characteristic curve analysis demonstrated high sensitivity and specificity of both SP-D and KL-6 for the determination of "alveolitis." KL-6 and SP-D were positively correlated with maximum fibrosis scores, but not with maximum ground-glass opacities, on HRCT. CONCLUSION: Serum levels of SP-D and KL-6 appear to be indicative of "alveolitis" in SSc patients as defined by the SLS, and are significantly higher than in SSc patients without "alveolitis." Serum SP-D and KL-6 may serve as noninvasive serological means of assessing interstitial lung disease in patients with SSc.

Proteomic analysis of CTGF-activated lung fibroblasts: identification of IQGAP1 as a key player in lung fibroblast migration.

Connective tissue growth factor (CTGF, CCN2) is overexpressed in lung fibroblasts isolated from patients with interstitial lung disease (ILD) and systemic sclerosis (SSc, scleroderma) and is considered to be a molecular marker of fibrosis. To understand the significance of elevated CTGF, we investigated the changes in lung fibroblast proteome in response to CTGF overexpression. Using 2-dimensional gel electrophoresis followed by in-gel proteolytic digestion and mass spectrometric analysis, we identified 13 proteins affected by CTGF. Several of the CTGF-induced proteins, such as pro-alpha (I) collagen and cytoskeletal proteins vinculin, moesin, and ezrin, are known to be elevated in pulmonary fibrosis, whereas 9 of 13 proteins have not been studied in pulmonary fibrosis and are, therefore, novel CTGF-responsive molecules that may have important roles in ILD. Our study demonstrates that 1 of the novel CTGF-induced proteins, IQ motif containing GTPase activating protein (IQGAP) 1, is elevated in lung fibroblasts isolated from scleroderma patients with ILD. IQGAP1 is a scaffold protein that plays a pivotal role in regulating migration of endothelial and epithelial cells. Scleroderma lung fibroblasts and normal lung fibroblasts treated with CTGF demonstrated increased rate of migration in a wound healing assay. Depletion of IQGAP1 expression by small interfering RNA inhibited CTGF-induced migration and MAPK ERK1/2 phosphorylation in lung fibroblasts. MAPK inhibitor U0126 decreased CTGF-induced cell migration and did not interfere with CTGF-induced IQGAP1 expression, suggesting that MAPK pathway is downstream of IQGAP1. These findings further implicate the importance of CTGF in lung tissue repair and fibrosis and propose that CTGF-induced migration of lung fibroblasts to the damaged tissue is mediated via IQGAP1 and MAPK signaling pathways.

Down-regulation of collagen and connective tissue growth factor expression with hepatocyte growth factor in lung fibroblasts from white scleroderma patients via two signaling pathways.

OBJECTIVE: To study the mechanisms by which hepatocyte growth factor (HGF) down-regulates collagen and connective tissue growth factor (CTGF) in scleroderma (systemic sclerosis [SSc]) lung fibroblasts. METHODS: CTGF, type I collagen, and IkappaBalpha expression, together with MAPK phosphorylation, were studied by immunoblotting of lung fibroblasts derived from white SSc patients. Matrix metalloproteinase 1 (MMP-1) expression in cell culture medium samples was measured by enzyme-linked immunosorbent assay, MMP-1 activity was studied using an MMP-1 assay, and NF-kappaB DNA binding activity was determined using a transcription factor assay. RESULTS: In lung fibroblasts from white SSc patients, HGF activated MAPK (ERK-1/2) signaling pathways and MMP-1, while it inhibited NF-kappaB and significantly down-regulated CTGF and collagen in a time- and dose-dependent manner. Small interfering RNA (siRNA)-mediated depletion of Grb2 expression disrupted c-Met receptor downstream signaling, which resulted in diminished HGF-induced ERK-1/2 phosphorylation and the recovery of HGF-inhibited expression of MMP-1, NF-kappaB, collagen, and CTGF. The MAPK inhibitor, U0126, blocked MMP-1 activity and restored HGF-inhibited collagen and CTGF accumulation. Inhibition of MMP activity by MMP inhibitor GM1489 and inhibition of MMP-1 expression by siRNA did not prevent HGF-induced ERK-1/2 phosphorylation and NF-kappaB activity, but significantly restored HGF-inhibited collagen and CTGF accumulation. NF-kappaB inhibitor BAY 11-7082 did not interfere with MAPK phosphorylation or MMP-1 expression and activation, but significantly inhibited NF-kappaB DNA binding activity and acted synergistically with HGF to completely diminish the expression of CTGF. CONCLUSION: In lung fibroblasts from white SSc patients, HGF down-regulates the accumulation of CTGF via MAPK/MMP-1 and NF-kappaB signaling pathways, whereas collagen down-regulation is mediated mainly by a MAPK/MMP-1-dependent pathway.

Impairment of the antifibrotic effect of hepatocyte growth factor in lung fibroblasts from African Americans: possible role in systemic sclerosis.

OBJECTIVE: To compare the composition of cytokines in African American and Caucasian patients with systemic sclerosis (SSc; scleroderma) and in healthy individuals, particularly the expression and function of hepatocyte growth factor (HGF). METHODS: Bronchoalveolar lavage (BAL) fluid samples were analyzed using cytokine array techniques. HGF in plasma and cell culture medium samples was measured by enzyme-linked immunosorbent assay. Connective tissue growth factor (CTGF), type I collagen expression, and c-Met receptor phosphorylation were studied by immunoblotting. RESULTS: Overall greater expression of cytokines in BAL fluid from African American patients as compared with Caucasian patients was observed. Significant increases in HGF concentrations were detected in BAL fluid, plasma, and fibroblast culture medium from Caucasian SSc patients. In contrast, African American SSc patients did not demonstrate an increase in HGF. Recombinant HGF readily abolished CTGF expression and collagen accumulation in lung fibroblasts isolated from Caucasian SSc patients. Pretreatment of lung fibroblasts with neutralizing anti-c-Met antibody abolished the effects of HGF on CTGF expression and collagen accumulation, suggesting that the antifibrotic activity of HGF is mediated via c-Met receptor tyrosine kinase. Whereas recombinant HGF rapidly induced c-Met receptor phosphorylation in lung fibroblasts from Caucasian patients, c-Met receptor phosphorylation was significantly reduced in lung fibroblasts from African American subjects. Moreover, recombinant HGF failed to prevent CTGF expression and collagen accumulation in lung fibroblasts derived from African American subjects. CONCLUSION: Ethnic differences exist in terms of antifibrotic HGF expression in lung fibroblasts derived from Caucasian and African American subjects. Reduced levels of HGF as well as a deficiency in c-Met receptor function appear to be present in African American patients with SSc. These findings may explain in part the greater disease severity and worse prognosis observed in African Americans with SSc.

Distinct PKC isoforms mediate cell survival and DNA synthesis in thrombin-induced myofibroblasts.

Thrombin activates protease-activated receptor (PAR)-1 and induces a myofibroblast phenotype in normal lung fibroblasts that resembles the phenotype of scleroderma lung fibroblasts. We now demonstrate that PAR-1 expression is dramatically increased in lung tissue from scleroderma patients, where it is associated with inflammatory and fibroproliferative foci. We also observe that thrombin induces resistance to apoptosis in normal lung fibroblasts, and this process is regulated by protein kinase C (PKC)-epsilon but not by PKC-alpha. Overexpression of a constitutively active (c-a) form of PAR-1 or PKC-epsilon significantly inhibits Fas ligand-induced apoptosis in lung fibroblasts, whereas scleroderma lung fibroblasts are resistant to apoptosis de novo. Thrombin translocates p21Cip1/WAF1, a signaling molecule downstream of PKC, from the nucleus to cytoplasm in normal lung fibroblasts mimicking the localization of p21Cip1/WAF1 in scleroderma lung fibroblasts. Overexpression of c-a PKC-alpha or PKC-epsilon results in accumulation of p21Cip1/WAF1 in the cytoplasm. Depletion of PKC-alpha or inhibition of mitogen-activated protein kinase (MAPK) blocks thrombin-induced DNA synthesis in lung fibroblasts. Inhibition of PKC by calphostin or PKC-alpha, but not PKC-epsilon, by antisense oligonucleotides prevents thrombin-induced MAPK phosphorylation and accumulation of G(1) phase regulatory protein cyclin D1, suggesting that PKC-alpha, MAPK, and cyclin D1 mediate lung fibroblast proliferation. These data demonstrate that two distinct PKC isoforms mediate thrombin-induced resistance to apoptosis and proliferation and suggest that p21Cip1/WAF1 promotes both phenomena.