Assessing the Impact of Growth Hormone Deficiency (GHD) in Adults: Interpreting Change of the Treatment-Related Impact Measure-Adult Growth Hormone Deficiency (TRIM-AGHD).

BACKGROUND: This study's purpose was to assess the minimal important difference (MID) for the Treatment-Related Impact Measure-Adult Growth Hormone Deficiency (TRIM-AGHD), a patient-reported outcome measure assessing growth hormone deficiency (GHD) impacts. The measure was demonstrated to have adequate psychometric measurement properties, and be reliable and valid. For scores to be interpretable, the TRIM-AGHD must be responsive to treatment benefit and the MID in scores quantified. METHODS: A prospective, non-interventional, observational, clinic-based survey study of naïve-to-treatment adult GHD patients (N = 98) was conducted. Key assessments were at baseline and follow-up (between 4 and approximately 8 weeks), with weekly telephone monitoring post-baseline (last n = 34 patients). Responsiveness was evaluated using the effect size of change scores from baseline to follow-up. MID estimates were derived from distribution-based (half standard deviation [0.5 SD], standard error of measurement [SEm]) and anchor-based methods (patient global rating of change [PGRC]) using change scores from baseline to initial report of minimal improvement in GHD severity. Findings from each method were converged to establish an acceptable MID. RESULTS: Patients were mean age 49.7 years, 65.6% female, and 76.0% Caucasian. The TRIM-AGHD was highly responsive to treatment with the total score effect size being 1.38. For the total score, the 0.5 SD was 8.09 and the SEm was 2.66. The difference found using the PGRC was 20.43. The converged MID value for the total score was 10 points. CONCLUSIONS: The TRIM-AGHD is a highly responsive measure assessing AGHD treatment impacts. A 10-point change score is considered a clinically meaningful improvement.

Understanding Treatment Burden for Children Treated for Growth Hormone Deficiency.

OBJECTIVE: Growth hormone deficiency (GHD) treatment for children requires growth hormone injections, typically administered daily until the child reaches adult height. Child GHD treatment burden is not well understood and no disease-specific measures exist to assess this burden. The purpose of the study was to explore GHD treatment burden for children and their parents by conducting concept elicitation interviews supporting a theoretical model of the impact of GHD treatment. METHODS: Four focus groups (in Germany) and 52 telephone interviews (in the UK and USA) were conducted with children/adolescents with GHD aged 8 to <13 years and parents of children with GHD aged ≥4 to <13 years. The purpose of the interviews was to understand the experience of GHD treatment from the child's perspective, and for parents, the impact of their child's treatment on themselves. Interview transcripts were analyzed thematically based on modified grounded theory principles. RESULTS: Interviews with 70 respondents who produced descriptions (n = 73) of patients experiences with GHD treatment (three parents spoke for two children each) were conducted. Analysis identified three major areas of GHD treatment burden for children: physical; emotional well-being; and interference. Parent burdens identified were: emotional well-being and interference. Modifiers such as treatment efficacy and duration, which may impact the degree of treatment burden severity, were identified. CONCLUSIONS: Overall treatment burden of child GHD is considerable for children and their parents. The concept elicitation and theoretical model can be used to develop a disease-specific outcome measure, which adequately reflects the burden of GHD treatment for children and their parents.

Understanding burden of illness for child growth hormone deficiency.

PURPOSE: Research demonstrates that children and adolescents with growth hormone deficiency (GHD) are impacted in multiple ways beyond their short stature; however, there are no disease-specific measures to assess these impacts. The purpose of this study was to examine the burden of GHD on children and adolescents, and to conduct concept elicitation to develop a model of the impact of GHD to support a disease-specific outcome measure. METHODS: Four focus groups and 52 telephone interviews were conducted with children with GHD and parents/guardians of children with GHD to understand the experience and impacts from the child's perspective, reported by children or parent-observers about the impact on the child. The interviews and focus groups were conducted in Germany, the United Kingdom, and the United States. Interview transcripts were analyzed thematically based on modified grounded theory principles. RESULTS: There were 73 descriptions of patient's experiences elicited from 70 respondents, as three respondents spoke for two children each. A majority of GHD descriptive narratives refer to boy children (n = 51, 69.9%) and a majority of children had taken GHD treatment (n = 64, 89%). Analysis identified four major areas of GHD impact: Signs and Symptoms (beyond short stature), Physical Aspects of Daily Life, Social Well-Being, and Emotional Well-Being. CONCLUSIONS: The burden of GHD in children and adolescents is considerable and not limited to short stature. The severity of GHD impact on children and adolescents appears to be variable and individualized, but these data indicate that early identification and growth hormone treatment may lead to fewer impacts.

Development of the Weight-Related Sign and Symptom Measure.

BACKGROUND: Overweight and obesity have been associated with physical and emotional signs & symptoms. Research has shown that modest weight loss can mitigate some symptoms in individuals with overweight or obesity. This study's purpose was to conduct concept elicitation (CE) interviews to provide documented qualitative support for the development of the Weight-Related Sign and Symptom Measure (WRSSM) to assess weight-related signs/symptoms in U.S. adults with overweight or obesity, with or without type 2 diabetes (T2DM).Eight focus groups were conducted in the U.S. with adults with overweight or obesity to understand weight-related sign/symptom impact from the patient perspective. Individual interviews were conducted with clinical experts to understand the impact of overweight or obesity on patient signs and symptoms. Transcripts were analyzed to identify symptoms and observable signs. A clinical challenge was conducted with clinical experts to confirm the signs/symptoms were clinically relevant, important to patients, and would improve with modest weight loss. Cognitive debriefing (CD) was conducted with individuals with overweight or obesity to confirm readability and symptom relevance. RESULTS: CE interviews were conducted with four clinical experts, and 61 people, 32% of whom had T2DM, participated in the focus groups. Analyses identified two major areas of obesity impacts: weight-related physical signs/symptoms, and emotional impacts. The most frequently reported physical signs/symptoms were feeling tired (74%), shortness of breath (69%), and joint pain (64%). The most often reported emotional impacts included poor self-image (72%) and depression (51%). Twelve signs/symptoms were identified during item generation and included on the preliminary measure. Twelve adults with overweight/obesity, who were not part of the focus groups, participated in CD. After the CD, a validation-ready, 10-item WRSSM measure was generated. CONCLUSIONS: Findings provide evidence of content validity for the validation-ready WRSSM in U.S. adults with overweight or obesity, including people with and without T2DM.

Assessing the impact of non-severe hypoglycemic events and treatment in adults: development of the Treatment-Related Impact Measure-Non-severe Hypoglycemic Events (TRIM-HYPO).

PURPOSE: Non-severe hypoglycemic events (NSHEs) are commonly experienced by diabetes patients, particularly among insulin users, and can have serious impacts on daily functioning, emotional well-being, sleep, work productivity, and treatment adherence. Currently, no PRO measures are available to assess the impacts of non-severe hypoglycemia. To address this gap, the Treatment-Related Impact Measure-Non-severe Hypoglycemic Events (TRIM-HYPO) was developed. This paper describes the TRIM-HYPO development and validation. METHODS: The creation of the TRIM-HYPO followed FDA's guideline for PRO development. Concept elicitation data were gathered from literature review, clinical expert interviews, and focus groups of patients with Type 1 or 2 diabetes in four countries. Based on the qualitative analysis, draft items were generated and cognitively debriefed. Psychometric validation included factor analysis, item response theory analysis, and assessment of psychometric characteristics for the TRIM-HYPO. RESULTS: Eight clinical experts and 167 patients participated in concept elicitation. The validation study included 407 patients. Thirteen of the 46 items from the preliminary measure were dropped due to ceiling/floor effects and high correlations between conceptually similar items. Factor analysis confirmed five domains in the TRIM-HYPO: daily function, emotional well-being, diabetes management, sleep disruption, and work productivity. All scores were internally consistent (0.86-0.95) and reproducible with a test-retest range of 0.75-0.98. All but one a priori hypothesized associations for validity were confirmed. CONCLUSIONS: Study findings demonstrate that the final, 33-item TRIM-HYPO is reliable and valid and may be useful for assessing impacts related to NSHEs in research and clinical practice.

Development of a conceptual model evaluating the humanistic and economic burden of Crohn's disease: implications for patient-reported outcomes measurement and economic evaluation.

The primary objective of this review is to develop a conceptual model for Crohn's disease (CD) outlining the disease burden for patients, healthcare systems and wider society, as reported in the scientific literature. A search was conducted using MEDLINE, PsycINFO, EconLit, Health Economic Evaluation Database and Centre for Reviews and Dissemination databases. Patient-reported outcome (PRO) measures widely used in CD were reviewed according to the US FDA PRO Guidance for Industry. The resulting conceptual model highlights the characterization of CD by gastrointestinal disturbances, extra-intestinal and systemic symptoms. These symptoms impact physical functioning, ability to complete daily activities, emotional wellbeing, social functioning, sexual functioning and ability to work. Gaps in conceptual coverage and evidence of reliability and validity for some PRO measures were noted. Review findings also highlight the substantial direct and indirect costs associated with CD. Evidence from the literature confirms the substantial burden of CD to patients and wider society; however, future research is still needed to further understand burden from the perspective of patients and to accurately understand the economic burden of disease. Challenges with existing PRO measures also suggest the need for future research to refine or develop new measures.

Impact of adult growth hormone deficiency on daily functioning and well-being.

BACKGROUND: Adult Growth Hormone Deficiency (AGHD) is a debilitating condition resulting from tumors, pituitary surgery, radiation of the head, head injury, or hypothalamic-pituitary disease. This qualitative study was conducted to better understand the multi-faceted impacts and treatment effects of GHD on adult patients' daily lives.Seven focus groups and four telephone interviews were conducted in three countries. Eligible AGHD patients were age 22 or older who had started and stopped growth hormone treatment at least once as an adult. Transcripts were analyzed thematically. RESULTS: Thirty-nine patients were interviewed; majority etiology was pituitary disease or tumor (62%). Thirty-four patients (87%) were currently on growth hormone replacement therapy; therapy initiation mean age was 43 years. Analysis identified five domains of disease impact: 1) Psychological Health--changed body or self-image and negative emotional impacts; 2) Physical Health--problems with sleep/fatigue, sex drive, weight gain, hair, skin, muscle/bone loss; 3) Cognition--concentration or memory trouble; 4) Energy Loss and its negative impacts (productivity, exercise, chores, socialization, or motivation); and 5) Treatment Effect--treatment enhances quality of life, enabling patients to increase effort (exercise, chores, or work improvements). Energy and sleep are improved. Saturation of themes was reached after the sixth focus group. A conceptual model of GHD disease impacts was developed. CONCLUSIONS: Untreated AGHD has significant negative impacts for patients, which treatment often improves. It is important for clinicians and researchers to understand these multiple impacts so that they can address them in individualized treatment plans and incorporate them when assessing treatment outcomes.

Patient-reported outcome measures for systemic lupus erythematosus clinical trials: a review of content validity, face validity and psychometric performance.

BACKGROUND: Despite overall progress in treatment of autoimmune diseases, patients with systemic lupus erythematosus (SLE) experience many inflammatory symptoms representing an unmet medical need. This study aimed to create a conceptual model of the humanistic and economic burden of SLE, and review the patient-reported outcomes (PROs) used to measure such concepts in SLE clinical trials. METHODS: A conceptual model for SLE was developed from structured review of published articles from 2007 to August 2013 identified from literature databases (MEDLINE, EMBASE, PsycINFO, EconLit) plus other sources (PROLabels, FDA/EMA websites, Clinicaltrials.gov). PROs targeting key symptoms/impacts were identified from the literature. They were reviewed in the context of available guidance and assessed for face and content validity and psychometric properties to determine appropriateness for use in SLE trials. RESULTS: The conceptual model identified fatigue, pain, cognition, daily activities, emotional well-being, physical/social functioning and work productivity as key SLE concepts. Of the 68 articles reviewed, 38 reported PRO data. From these and the other sources, 15 PROs were selected for review, including SLE-specific health-related quality of life (HRQoL) measures (n = 5), work productivity (n = 1), and generic measures of fatigue (n = 3), pain (n = 2), depression (n = 2) and HRQoL (n = 2). The Functional Assessment of Chronic Illness Therapy - Fatigue Scale (FACIT-Fatigue), Brief Pain Inventory (BPI-SF) and LupusQoL demonstrated the strongest face validity, conceptual coverage and psychometric properties measuring key concepts in the conceptual model. All PROs reviewed, except for three Lupus-specific measures, lacked qualitative SLE patient involvement during development. The Hospital Anxiety and Depression Scale (HADS), Short Form [36 item] Health Survey version 2 (SF-36v2), EuroQoL 5-dimensions (EQ-5D-3L and EQ-5D-5L) and Work Productivity and Activity Impairment Questionnaire: Lupus (WPAI:Lupus) showed suitability for SLE economic models. CONCLUSIONS: Based on the identification of key symptoms and impacts of SLE using a scientifically sound conceptual model, we conclude that SLE is a condition associated with high unmet need and considerable burden to patients. This review highlights the availability and need for disease-specific and generic patient-reported measures of relevant domains of disease signs and symptoms, HRQoL and work productivity, providing useful insight for SLE clinical trial design.

Linguistic validation into 20 languages and content validity of the rheumatoid arthritis-specific Work Productivity and Activity Impairment questionnaire.

BACKGROUND: Impairments in work productivity and daily activities contribute to the burden of rheumatoid arthritis (RA). It is thus essential to use an instrument assessing both work and daily activity impairments when studying the full impact of RA on individuals. The Work Productivity and Activity Impairment (WPAI) questionnaire is such an instrument. OBJECTIVE: This study aims to linguistically validate the RA-specific WPAI (WPAI:RA) instrument in 20 new languages and to assess its content validity for individuals with RA. METHODS: The linguistic validation of the questionnaire followed a standard methodology that included comprehension test interviews (n = 5 individuals with RA per language) to assess the relevance, understanding and acceptability of the WPAI:RA. Content validity of the instrument was simultaneously investigated. RESULTS: Comprehension testing showed that the WPAI:RA questionnaire was well understood similarly across countries; minor changes were made to ensure fidelity to the original concepts and for ease of comprehension. The majority of interviewees (66/93) considered its content comprehensive and appropriate to measure their ability to work and perform daily activities. CONCLUSION: The WPAI:RA questionnaire is now linguistically validated in 20 new languages [Czech (Czech Republic), Dutch (Belgium), English (Canada and UK), French (Belgium, Canada and France), German (Germany), Hungarian (Hungary), Italian (Italy), Polish (Poland), Portuguese (Brazil), Romanian (Romania), Russian (Russia and Ukraine), Spanish (Argentina, Mexico, Spain and US) and Ukrainian (Ukraine)]. The WPAI:RA questionnaire shows good content validity. It can thus be used in multi-country clinical trials to assess RA-related impact on the patients' ability to work and perform daily activities.

Assessing the impact of growth hormone deficiency and treatment in adults: development of a new disease-specific measure.

CONTEXT: Approximately 50 000 adults in the United States are diagnosed with GH deficiency, which has negative impacts on cognitive functioning, psychological well-being, and quality of life. OBJECTIVE: This paper presents development and validation of a patient-reported outcome measure (PRO), the Treatment-Related Impact Measure-Adult Growth Hormone Deficiency (TRIM-AGHD). The TRIM-AGHD was developed to measure the impact of GH deficiency and its treatment. DESIGN AND SETTINGS: The development and validation of the TRIM-AGHD was conducted according to the Food and Drug Administration guidance on the development of PROs. Concept elicitation, conducted in three countries included interviews with patients, clinical experts, and literature review. Qualitative data were analyzed based on grounded theory principles, and draft items were cognitively debriefed. The measure underwent psychometric validation in a US clinic-based population. An a priori statistical analysis plan included assessment of the measurement model, reliability, and validity. Item functioning was reviewed using item response theory analyses. PATIENTS OR OTHER PARTICIPANTS: Forty-eight patients and six clinical experts participated in concept elicitation and 169 patients completed the validation study. MAIN OUTCOME MEASURE: TRIM-AGHD was measured. RESULTS: Factor analysis resulted in four domains: energy level, physical health, emotional health, and cognitive ability. The item response theory confirmed adequate item fit and placement within their domain. Internal consistency ranged from 0.82 to 0.95 and test-retest ranged from 0.80 to 0.92. All prespecified hypotheses for convergent validity and all but two for discriminant validity were met. CONCLUSIONS: The final 26-item TRIM-AGHD can be considered a reliable and valid PRO of the impact of disease and treatment for adult GH deficiency.

Physical inactivity affects skeletal muscle insulin signaling in a birth weight-dependent manner.

AIMS: We investigated whether physical inactivity could unmask defects in insulin and AMPK signaling in low birth weight (LBW) subjects. METHODS: Twenty LBW and 20 normal birth weight (NBW) subjects were investigated using the euglycemic-hyperinsulinemic clamp with excision of skeletal muscle biopsies pre and post 9days of bed rest. Employing Western blotting, we investigated skeletal muscle Akt, AS160, GLUT4, and AMPK signaling. RESULTS: Peripheral insulin action was similar in the two groups and was decreased to the same extent post bed rest. Insulin and AMPK signaling was unaffected by bed rest in NBW individuals. LBW subjects showed decreased insulin-stimulated Akt phosphorylation and increased AMPK α1 and γ3 protein expression post bed rest. Insulin response of AS160 phosphorylation was lower in LBW subjects both pre and post bed rest. CONCLUSIONS: Bed rest-induced insulin resistance is not explained by impaired muscle insulin or AMPK signaling in subjects with or without LBW. Lower muscle insulin signaling in LBW subjects post bed rest despite similar degree of insulin resistance as seen in controls may to some extent support the idea that LBW subjects are at higher risk of developing type 2 diabetes when being physically inactive.

Muscle inflammatory signaling in response to 9 days of physical inactivity in young men with low compared with normal birth weight.

OBJECTIVE: The molecular mechanisms linking physical inactivity and muscle insulin resistance in humans have been suggested to include increased muscle inflammation, possibly associated with impaired oxidative metabolism. We employed a human bed rest study including 20 young males with normal birth weight (NBW) and 20 with low birth weight (LBW) and increased risk of diabetes. METHODOLOGY: The subjects were studied before and after 9 days of bed rest using the euglycemic-hyperinsulinemic clamp and muscle biopsy excision. Muscle inflammatory status was assessed as nuclear factor-κB (NF-κB) activity and mRNA expression of the pro-inflammatory MCP1 (CCL2) and IL6 and the macrophage marker CD68. Furthermore, mRNA expression of genes central to oxidative phosphorylation (OXPHOS) was measured including ATP5O, COX7A1, NDUFB6, and UQCRB. RESULTS: At baseline, muscle inflammatory status was similar in NBW and LBW individuals. After bed rest, CD68 expression was increased in LBW (P=0.03) but not in NBW individuals. Furthermore, expression levels of all OXPHOS genes were reduced after bed rest in LBW (P ≤ 0.05) but not in NBW subjects and were negatively correlated with CD68 expression in LBW subjects (P ≤ 0.03 for all correlations). MCP1 expression and NF-κB activity were unaffected by bed rest, and IL6 expression was too low for accurate measurements. None of the inflammatory markers correlated with insulin sensitivity. CONCLUSIONS: Although LBW subjects exhibit disproportionately elevated CD68 mRNA expression suggesting macrophage infiltration and reduced OXPHOS gene expression when exposed to bed rest, our data altogether do not support the notion that bed rest-induced (9 days) insulin resistance is caused by increased muscle inflammation.

Increased lipolysis but diminished gene expression of lipases in subcutaneous adipose tissue of healthy young males with intrauterine growth retardation.

Intrauterine growth retardation (IUGR) is associated with a central fat distribution and risk of developing type 2 diabetes in adults when exposed to a sedentary Western lifestyle. Increased lipolysis is an early defect of metabolism in IUGR subjects, but the sites and molecular mechanisms involved are unknown. Twenty IUGR and 20 control (CON) subjects, aged 20-30 years, were studied before and after 10 days of bed rest using the glucose clamp technique combined with measurements of in vivo metabolism by microdialysis technique and blood flow by (133)Xe washout technique in subcutaneous abdominal (SCAAT) and femoral (SCFAT) adipose tissue. Additionally, mRNA expression of lipases was evaluated in biopsies from SCAAT. Lipolysis in SCAAT was substantially higher in IUGR than in CON subjects despite markedly lower mRNA expression of lipases. Blood flow was higher in IUGR compared with CON in both SCAAT and SCFAT. Whole body insulin sensitivity did not differ between groups and decreased after bed rest. After bed rest, SCAAT lipolysis remained higher in IUGR compared with CON, and SCFAT lipolysis decreased in CON but not in IUGR. Prior to the development of whole body insulin resistance, young men with IUGR are characterized by increased in vivo adipose tissue lipolysis and blood flow with a paradoxically decreased expression of lipases compared with CON, and 10 days of physical inactivity underlined the baseline findings. Subjects with IUGR exhibit primary defects in adipose tissue metabolism.

Impact of physical inactivity on adipose tissue low-grade inflammation in first-degree relatives of type 2 diabetic patients.

OBJECTIVE: First-degree relatives (FDRs) of patients with type 2 diabetes may exhibit a disproportionately elevated risk of developing insulin resistance, obesity, and type 2 diabetes when exposed to physical inactivity, which to some unknown extent may involve low-grade inflammation. We investigated whether subjects who are nonobese FDRs show signs of low-grade inflammation before or after exposure to short-term physical inactivity. RESEARCH DESIGN AND METHODS: We studied 13 healthy FDR subjects and 20 control (CON) subjects matched for age, sex, and BMI before and after 10 days of bed rest (BR). Insulin sensitivity was measured by the hyperinsulinemic euglycemic clamp. Key low-grade inflammation mediators were measured in arterial blood and microdialysate from subcutaneous abdominal (SCAAT) and femoral adipose tissue. Adipokine mRNA expression was determined in SCAAT. RESULTS: Before BR, FDR subjects displayed insulin resistance, elevated plasma C-reactive protein, leptin, and monocyte chemoattractant protein (MCP)-1, high interleukin (IL)-6, and MCP-1 expressions, as well as low adiponectin and leptin expressions. FDR subjects responded to BR by decreasing plasma adiponectin and IL-10 expression and increasing plasma expression of IL-10 and tumor necrosis factor-α. In contrast, CON subjects responded to BR by increasing plasma adiponectin and adiponectin expression and by decreasing SCAAT microdialysate leptin. CONCLUSIONS: Young and nonobese FDR of patients with type 2 diabetes exhibit low-grade inflammation, which is further and disproportionately aggravated when exposed to physical inactivity. The study provides support for the notion that people at increased risk of type 2 diabetes should avoid even short periods of physical inactivity.

Endothelial function after 10 days of bed rest in individuals at risk for type 2 diabetes and cardiovascular disease.

Physical inactivity is considered to be deleterious to vascular health, and in particular in first-degree relatives to patients with type 2 diabetes (FDR) and persons born with low birth weight (LBW), who may later in life develop cardiovascular disease. A period of imposed physical inactivity could unmask this risk. We hypothesized that the impact of physical inactivity on endothelial function would be more marked in subjects at increased risk for type 2 diabetes and cardiovascular disease (LBW and FDR) compared with a matched control group (CON), all of whom were recruited via advertisements and via the Danish Birth Registry. Twenty LBW, 20 CON and 13 FDR were studied before and after 10 days of bed rest. Forearm blood flow (FBF) was measured by venous occlusion plethysmography during brachial intra-arterial infusion of acetylcholine or adenosine at baseline and with superimposed hyperinsulinaemia. Markers of endothelial activation and inflammation were measured in plasma. Bed rest did not change the vasodilator responses to adenosine or acetylcholine alone in any group, but reduced vasodilator responses to adenosine or acetylcholine during hyperinsulinaemia in LBW. Bed rest impaired insulin-mediated vasodilatation in CON and LBW and increased endothelial activation markers in FDR and LBW but not in CON. Vasodilator responses were very low in FDR prior to bed rest, and did not decrease further during bed rest. Physical inactivity does not impair endothelium-dependent vasodilatation per se, but the vascular vasodilator effect of insulin diminished in CON and LBW after bed rest. In FDR, a further deterioration of FBF with inactivity is not possible.

Impact of physical inactivity on subcutaneous adipose tissue metabolism in healthy young male offspring of patients with type 2 diabetes.

OBJECTIVE: Physical inactivity is a risk factor for type 2 diabetes and may be more detrimental in first-degree relative (FDR) subjects, unmasking underlying defects of metabolism. Using a positive family history of type 2 diabetes as a marker of increased genetic risk, the aim of this study was to investigate the impact of physical inactivity on adipose tissue (AT) metabolism in FDR subjects. RESEARCH DESIGN AND METHODS: A total of 13 FDR and 20 control (CON) subjects participated in the study. All were studied before and after 10 days of bed rest using the glucose clamp technique combined with measurements of glucose uptake, lipolysis, and lactate release from subcutaneous abdominal (SCAAT) and femoral (SCFAT) adipose tissue by the microdialysis technique. Additionally, mRNA expression of lipases was determined in biopsies from SCAAT. RESULTS: Before bed rest, the FDR subjects revealed significantly increased glucose uptake in SCAAT. Furthermore, mRNA expression of lipases was significantly decreased in the SCAAT of FDR subjects. Bed rest significantly decreased lipolysis and tended to increase glucose uptake in the SCFAT of both CON and FDR subjects. In response to bed rest, SCAAT glucose uptake significantly increased in CON subjects but not in FDR subjects. CONCLUSIONS: FDR subjects exhibit an abnormal AT metabolism including increased glucose uptake prior to bed rest. However, the differences between FDR and CON subjects in AT metabolism were attenuated during bed rest due to relatively more adverse changes in CON subjects compared with FDR subjects. Physical inactivity per se is not more deleterious in FDR subjects as compared with CON subjects with respect to derangements in AT metabolism.

Effect of 10 days of bedrest on metabolic and vascular insulin action: a study in individuals at risk for type 2 diabetes.

Physical inactivity is a known risk factor for type 2 diabetes. We studied whole body and forearm insulin sensitivity in subjects at increased risk for type 2 diabetes [persons with low birth weight (LBW group; n = 20) and first-degree relatives to type 2 diabetic patients (FDR group; n = 13)] as well as a control (CON) group (n = 20) matched for body mass index, age, and physical activity levels before and after 10 days of bedrest. Subjects were studied by hyperinsulinemic isoglycemic clamp combined with arterial and deep venous catheterization of the forearm. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. All groups responded with a decrease in whole body insulin sensitivity in response to bedrest [CON group: 6.8 +/- 0.5 to 4.3 +/- 0.3 mg x min(-1) x kg(-1) (P < 0.0001), LBW group: 6.2 +/- 0.5 to 4.3 +/- 0.3 mg x min(-1) x kg(-1) (P < 0.0001), and FDR group: 4.3 +/- 0.7 to 3.1 +/- 0.3 mg x min(-1) x kg(-1) (P = 0.068)]. The percent decrease was significantly greater in the CON group compared with the FDR group (CON group: 34 +/- 4%, LBW group: 27 +/- 4%, and FDR group: 10 +/- 13%). Forearm insulin-stimulated glucose clearance decreased significantly in the CON and LBW groups in response to bedrest; in the FDR group, clearance was very low before bedrest and no change was observed. Before bedrest, the CON and LBW groups demonstrated a significant increase in FBF during hyperinsulinemia; after bedrest, an increase in FBF was observed only in the CON group. In conclusion, bedrest induced a pronounced reduction in whole body, skeletal muscle, and vascular insulin sensitivity in the CON and LBW groups. The changes were most pronounced in the CON group. In the FDR group, insulin resistance was already present before bedrest, but even this group displayed a high sensitivity to changes in daily physical activity.

The T-allele of TCF7L2 rs7903146 associates with a reduced compensation of insulin secretion for insulin resistance induced by 9 days of bed rest.

OBJECTIVE: The aim of this study was to determine whether the type 2 diabetes-associated T-allele of transcription factor 7-like 2 (TCF7L2) rs7903146 associates with impaired insulin secretion to compensate for insulin resistance induced by bed rest. RESEARCH DESIGN AND METHODS: A total of 38 healthy young Caucasian men were studied before and after bed rest using the hyperinsulinemic-euglycemic clamp technique combined with indirect calorimetry preceded by an intravenous glucose tolerance test. The TCF7L2 rs7903146 was genotyped using allelic discrimination performed with an ABI 7900 system. The genetic analyses were done assuming a dominant model of inheritance. RESULTS: The first-phase insulin response (FPIR) was significantly lower in carriers of the T-allele compared with carriers of the CC genotype before bed rest, with and without correction for insulin resistance. The incremental rise of FPIR in response to insulin resistance induced by bed rest was lower in carriers of the T-allele (P < 0.001). Fasting plasma glucagon levels were significantly lower in carriers of the T-allele before and after bed rest. While carriers of the CC genotype developed increased hepatic insulin resistance, the TCF7L2 rs7903146 did not influence peripheral insulin action or the rate of lipolysis before or after bed rest. CONCLUSIONS: Healthy carriers of the T-allele of TCF7L2 rs7903146 exhibit a diminished increase of insulin secretion in response to intravenous glucose to compensate for insulin resistance as induced by bed rest. Reduced paracrine glucagon stimulation may contribute to the impairment of beta-cell function in the carriers TCF7L2 rs7903146 T-allele associated with increased risk of type 2 diabetes.

Impact of 9 days of bed rest on hepatic and peripheral insulin action, insulin secretion, and whole-body lipolysis in healthy young male offspring of patients with type 2 diabetes.

OBJECTIVE: The aim of this study was to investigate the impact of 9 days of bed rest on insulin secretion, insulin action, and whole-body glucose and fat metabolism in first-degree relative (FDR) and matched control (CON) subjects. RESEARCH DESIGN AND METHODS: A total of 13 FDR and 20 CON subjects participated in the study. All were studied before and after 9 days of bed rest using the clamp technique combined with indirect calorimetry preceded by an intravenous glucose tolerance test. Glucose and glycerol turnover rates were studied using stable isotope kinetics. RESULTS: Bed rest caused a significant decrease in whole-body insulin sensitivity in both groups. Hepatic insulin resistance was elevated in FDR subjects prior to bed rest and was significantly augmented by bed rest in FDR (P < 0.01) but not in CON (P = NS) subjects. The rate of whole-body lipolysis decreased during bed rest in both FDR and CON subjects, with no significant differences between the groups. Insulin resistance induced by bed rest was fully accounted for by the impairment of nonoxidative glucose metabolism in both groups (overall P < 0.001). CONCLUSIONS: Whole-body insulin action in both insulin-resistant FDR and healthy CON subjects deteriorates with 9 days of bed rest, converging toward similar degrees of whole-body insulin resistance. FDR subjects exhibit hepatic insulin resistance (HIR), which, in contrast to CON subjects, deteriorates in response to physical inactivity. FDR subjects exhibit reduced insulin secretion when seen in relation to their degree of HIR but not peripheral insulin resistance.

Effect of steel and teflon infusion catheters on subcutaneous adipose tissue blood flow and infusion counter pressure in humans.

BACKGROUND: Subcutaneous tissue is an important target for drug deposition or infusion. A local trauma may induce alterations in local microcirculation and diffusion barriers with consequences for drug bioavailability. We examined the influence of infusion catheters' wear time on local microcirculation and infusion counter pressure. METHODS: One steel catheter and one Teflon (Dupont, Wilmington, DE) catheter were inserted in subcutaneous, abdominal adipose tissue (SCAAT) in 10 healthy, lean men. The catheters were infused with isotonic saline at a rate of 10 microL/h for 48 h. Another steel catheter and a Teflon catheter were inserted contralateral to the previous catheters after 48 h. The infusion counter pressure was measured during a basal infusion rate followed by a bolus infusion. The measurements during a basal rate infusion were repeated after the bolus infusion. Adipose tissue blood flow (ATBF) was measured in SCAAT continuously. RESULTS: A significant increase in ATBF was observed with wear time for Teflon but not for steel catheters. Mean infusion pressure during the bolus phase increased significantly from 0 to 48 h for Teflon but not for steel catheters. ATBF and infusion counter pressure was similar between Teflon and steel catheters after acute catheter implantation and after wear time of 48 h. The maximum value of pressure during the bolus phase increased with wear time of a catheter. CONCLUSIONS: ATBF and bolus mean infusion pressure increased significantly with a wear time of 48 h in Teflon but not in steel catheters. The maximal pressure required to deliver a bolus infusion increased with wear time of a catheter. A higher maximal pressure was required to deliver a bolus infusion through a Teflon than through a steel catheter. We propose that the difference in infusion counter pressure and ATBF between Teflon and steel catheters with wear time may be explained by better biocompatibility of steel than Teflon.