Major adverse events in youth-onset type 1 and type 2 diabetes: The SEARCH and TODAY studies.

AIMS: To determine contemporary incidence rates and risk factors for major adverse events in youth-onset T1D and T2D. METHODS: Participant interviews were conducted once during in-person visits from 2018 to 2019 in SEARCH (T1D: N = 564; T2D: N = 149) and semi-annually from 2014 to 2020 in TODAY (T2D: N = 495). Outcomes were adjudicated using harmonized, predetermined, standardized criteria. RESULTS: Incidence rates (events per 10,000 person-years) among T1D participants were: 10.9 ophthalmologic; 0 kidney; 11.1 nerve, 3.1 cardiac; 3.1 peripheral vascular; 1.6 cerebrovascular; and 15.6 gastrointestinal events. Among T2D participants, rates were: 40.0 ophthalmologic; 6.2 kidney; 21.2 nerve; 21.2 cardiac; 10.0 peripheral vascular; 5.0 cerebrovascular and 42.8 gastrointestinal events. Despite similar mean diabetes duration, complications were higher in youth with T2D than T1D: 2.5-fold higher for microvascular, 4.0-fold higher for macrovascular, and 2.7-fold higher for gastrointestinal disease. Univariate logistic regression analyses in T1D associated age at diagnosis, female sex, HbA1c and mean arterial pressure (MAP) with microvascular events. In youth-onset T2D, composite microvascular events associated positively with MAP and negatively with BMI, however composite macrovascular events associated solely with MAP. CONCLUSIONS: In youth-onset diabetes, end-organ events were infrequent but did occur before 15 years diabetes duration. Rates were higher and had different risk factors in T2D versus T1D.

Cystic fibrosis screening, evaluation, and management of hepatobiliary disease consensus recommendations.

Cystic fibrosis (CF) may cause a spectrum of hepatobiliary complications, including portal hypertension, multilobular cirrhosis, and liver failure. Current guidelines on the detection and monitoring of hepatobiliary complications in CF were published in 1999. The CF Foundation assembled a committee to evaluate research advances and formulate revised guidelines for CF-associated liver disease. A committee of hepatologists, gastroenterologists, pulmonologists, pharmacists, nurses, dietitians, individuals with CF, and the parents of a child with CF devised "population, intervention, comparison, and outcome" questions regarding hepatobiliary disease in CF. PubMed literature searches were performed for each population, intervention, comparison, and outcome question. Recommendations were voted on with 80% agreement required to approve a recommendation. Public comment on initial recommendations was solicited prior to the formulation of final recommendations. Thirty-one population, intervention, comparison, and outcome questions were assembled, 6401 manuscripts were title screened for relevance, with 1053 manuscripts undergoing detailed full-text review. Seven recommendations were approved for screening, 13 for monitoring of existing disease, and 14 for treatment of CF-associated hepatobiliary involvement or advanced liver disease. One recommendation on liver biopsy did not meet the 80% threshold. One recommendation on screening ultrasound was revised and re-voted on. Through a multidisciplinary committee and public engagement, we have assembled updated recommendations and guidance on screening, monitoring, and treatment of CF-associated hepatobiliary involvement and advanced liver disease. While research gaps remain, we anticipate that these recommendations will lead to improvements in CF outcomes through earlier detection and increased evidence-based approaches to monitoring and treatment.

Clinician perspectives and practices related to sexual and reproductive care provision for males with cystic fibrosis.

BACKGROUND: Males with cystic fibrosis (MwCF) have unique sexual and reproductive health (SRH) concerns. This study investigates multidisciplinary CF clinician perspectives related to SRH for MwCF in the current era of CF care. METHODS: We surveyed multidisciplinary clinicians exploring attitudes, practices, and preferences toward male CF SRH care. We compared responses across groups by population served (pediatric vs. adult vs. both pediatric and adult MwCF) using chi square/Fisher's exact tests. RESULTS: A total of 297 clinicians completed the survey (41 % pediatric, 36 % adult, 23 % both; 27 % physicians, 24 % social workers, 11 % nurses, 41 % other). Nearly all (98 %) believed the CF team had a role in SRH care with 75 % believing they should be primarily responsible. Pediatric clinicians were less likely to deem SRH topics important and less likely to report annual discussions compared to adult colleagues (all p<0.05). Pediatric clinicians reported less comfort in their SRH knowledge than adult colleagues (p<0.001) and in their ability to provide SRH care (p<0.05). Common barriers endorsed by respondents included lack of SRH knowledge (75 %) and presence of family/partners in exam room (64 %). A majority rated SRH screening tools (91 %), partnerships with SRH specialists (90 %), clinician training (83 %), and management algorithms (83 %) as potential facilitators. CONCLUSION: Multidisciplinary CF clinicians perceive SRH for MwCF as important but report suboptimal SRH discussions. Pediatric clinicians report significantly less comfort and skill in discussing and managing male SRH. Identified barriers and facilitators should be used to improve SRH care for MwCF.

Factors associated with pubertal growth outcomes in cystic fibrosis: Early Growth and Puberty in CF.

BACKGROUND: Pubertal delays in children with cystic fibrosis (CF) have historically been common. It is unclear to what degree puberty is affected in the new era of CF care or the role of early nutritional status. We hypothesized that more favorable early growth trajectories are associated with improved pubertal growth outcomes. METHODS: We used data from the United States CF Foundation Patient Registry to analyze associations between early weight-for-length/body mass index (WFL-BMI) growth trajectories and pubertal outcomes, using peak height velocity (PHV) and age at PHV (APHV) as proxy measures for puberty in addition to adult height (defined as height at age 18 years). Our analysis consisted of shape invariant mixed modeling and multivariable linear regression. RESULTS: Our sample consisted of 9,186 people with CF aged 18 to 21 years between 2010-2019. APHV was earliest and PHV/adult height were highest in those with WFL-BMI always >50th percentile from 0-6 years. However, there was no difference after adjusting for key covariates. Receiving CF transmembrane conductance regulator (CFTR) modulator therapy in childhood was associated with being taller at 18 years, by 0.92 cm in males (p=0.048) and 1.02 cm in females (p=0.010) in adjusted models. Higher height z-score at 2 years was associated with improved APHV and PHV for males and improved adult height for both males and females (p<0.001) in adjusted models. CONCLUSIONS: Early height, but not early WFL-BMI trajectories, may be associated with pubertal growth outcomes. CFTR modulator therapy shows the potential to improve pubertal growth outcomes, but further research is necessary.

Trajectories of eGFR and risk of albuminuria in youth with type 2 diabetes: results from the TODAY cohort study.

BACKGROUND: We conducted exploratory analyses to identify distinct trajectories of estimated glomerular filtration rate (eGFR) and their relationship with hyperfiltration, subsequent rapid eGFR decline, and albuminuria in participants with youth-onset type 2 diabetes enrolled in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. METHODS: Annual serum creatinine, cystatin C, urine albumin, and creatinine measurements were obtained from 377 participants followed for ≥ 10 years. Albuminuria and eGFR were calculated. Hyperfiltration peak is the greatest eGFR inflection point during follow-up. Latent class modeling was applied to identify distinct eGFR trajectories. RESULTS: At baseline, participants' mean age was 14 years, type 2 diabetes duration was 6 months, mean HbA1c was 6%, and mean eGFR was 120 ml/min/1.73 m2. Five eGFR trajectories associated with different rates of albuminuria were identified, including a "progressive increasing eGFR" group (10%), three "stable eGFR" groups with varying starting mean eGFR, and an "eGFR steady decline" group (1%). Participants who exhibited the greatest peak eGFR also had the highest levels of elevated albuminuria at year 10. This group membership was characterized by a greater proportion of female and Hispanic participants. CONCLUSIONS: Distinct eGFR trajectories that associate with albuminuria risk were identified, with the eGFR trajectory characterized by increasing eGFR over time associating with the highest level of albuminuria. These descriptive data support the current recommendations to estimate GFR annually in young persons with type 2 diabetes and provide insight into eGFR-related factors which may contribute to predictive risk strategies for kidney disease therapies in youth with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00081328, date registered 2002. A higher resolution version of the Graphical abstract is available as Supplementary information.

Characterization of glucose metabolism in youth with vs. without cystic fibrosis liver disease: A pilot study.

Background: Diabetes and liver disease are life-threatening complications of cystic fibrosis (CF). CF-liver disease is a risk factor for CF related diabetes (CFRD) development, but the underlying mechanisms linking the two co-morbidities are not known. The objective of this pilot study was to characterize glucose metabolism in youth with CF with and without liver disease. Methods: In this two-center cross-sectional study, 20 youth with CF with and without liver disease underwent a 3-hour oral glucose tolerance test. Subjects were categorized by liver disease (LD) status [no LD, mild LD, severe LD] and diabetes status. Measures of glucose excursion, islet cell secretory responses, insulin sensitivity and clearance were obtained. Results: Participants with severe LD had the highest fasting, peak, and glucose area under the curve over 3 h (AUC3h) among individuals with CFRD (interaction p < 0.05). In parallel with glycemic changes, prandial ß-cell secretory response (AUC C-peptide 3h) was lower in those with severe LD compared to mild or no LD (p < 0.01). There was a trend of higher HOMA-IR in those with severe LD (p = 0.1) as well as lower fasting insulin clearance in those with mild and severe LD compared to no LD (p = 0.06) and lower prandial insulin clearance in severe LD among those with CFRD (interaction p = 0.1). Conclusion: In this small cohort, subjects with severe LD tended to have more impaired glycemia, insulin secretion, insulin sensitivity and clearance. Larger studies are imperative to define the pathogenesis to inform clinical care guidelines in terms of CFRD screening, diagnosis, and treatment options.

Cardiovascular risk factor progression in adolescents and young adults with youth-onset type 2 diabetes.

AIMS: Youth-onset type 2 diabetes (T2D) confers a high risk of early adverse cardiovascular morbidity. We describe the cumulative incidence and prevalence of cardiovascular risk factors over time and examine relationships with diabetes progression in young adults with youth-onset T2D from the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. METHODS: Longitudinal data was used to evaluate the relationships between hypertension, LDL-C dyslipidemia, hypertriglyceridemia, and smoking with risk factors in 677 participants. RESULTS: Baseline mean age was 14 ± 2 years and mean follow-up 10.2 ± 4.5 years. The 14-year cumulative incidence of hypertension, LDL-C dyslipidemia, and hypertriglyceridemia was 59%, 33%, and 37% respectively. Average prevalence of reported smoking was 23%. Male sex, non-Hispanic white race/ethnicity, obesity, poor glycemic control, lower insulin sensitivity, and reduced beta-cell function were significantly associated with an unfavorable risk profile. At end of follow-up, 54% had ≥2 cardiovascular risk factors in addition to T2D. CONCLUSIONS: Cardiovascular risk factor incidence and prevalence was high over a decade of follow-up in young adults with youth-onset T2D. Glucose control and management of cardiovascular risk factors is critical in youth with T2D for prevention of cardiovascular morbidity and mortality.

Men's sexual and reproductive health in cystic fibrosis in the era of highly effective modulator therapies-A qualitative study.

BACKGROUND: As people with cystic fibrosis (CF) are living longer, men with CF increasingly face both general and disease-specific sexual and reproductive health (SRH) concerns. This study explored the SRH experiences and preferences of men with CF in health care in the era of widespread use of highly effective CF modulator therapies. METHODS: We recruited men with CF aged 18 years and older to participate in a qualitative descriptive study using semi-structured telephone interviews to explore experiences and preferences related to CF SRH care. Two independent researchers coded interview transcripts and conducted content and thematic analysis using an inductive approach. FINDINGS: We interviewed 24 participants (mean age 33.7 ± 11.8 years, range 19-60) and identified five major themes: 1) CF SRH concerns, specifically infertility, can have negative impacts on men's perceptions of masculinity, relationships, and mental health; 2) As life expectancy increases, addressing male SRH is increasingly important in CF care; 3) Men with CF experience lack of SRH counseling and care; 4) Conversations about SRH should begin in early adolescence and be addressed regularly by CF providers in a stepwise fashion; 5) Men with CF value peer support and SRH information featuring the experiences of other men with CF. CONCLUSIONS: Men with CF acknowledge the need for comprehensive CF care that includes SRH and value early, stepwise, provider-initiated SRH conversations. Future work should seek a broader understanding of the impact of SRH on the mental health of men with CF as these concerns can have significant effects on the lives and self-identities of men with CF.

Cystic fibrosis related liver disease and endocrine considerations.

Cystic fibrosis-liver disease (CFLD) is one of the most common non-pulmonary complications in the CF population, is associated with significant morbidity and represents the third leading cause of mortality in those with CF. CFLD encompasses a broad spectrum of hepatobiliary manifestations ranging from mild transaminitis, biliary disease, hepatic steatosis, focal biliary cirrhosis and multilobular biliary cirrhosis. The diagnosis of CFLD and prediction of disease progression remains a clinical challenge. The identification of novel CFLD biomarkers as well as the role of newer imaging techniques such as elastography to allow for early detection and intervention are active areas of research focus. Biliary cirrhosis with portal hypertension represents the most severe spectrum of CFLD, almost exclusively develops in the pediatric population, and is associated with a decline in pulmonary function, poor nutritional status, and greater risk of hospitalization. Furthermore, those with CFLD are at increased risk for vitamin deficiencies and endocrinopathies including CF-related diabetes, CF-related bone disease and hypogonadism, which can have further implications on disease outcomes and management. Effective treatment for CFLD remains limited and current interventions focus on optimization of nutritional status, identification and treatment of comorbid conditions, as well as early detection and management of CFLD specific sequelae such as portal hypertension or variceal bleeding. The extent to which highly effective modulator therapies may prevent the development or modify the progression of CFLD remains an active area of research. In this review, we discuss the challenges with defining and evaluating CFLD and the endocrine considerations and current management of CFLD.

Exploring provider attitudes and perspectives related to men's health in cystic fibrosis.

BACKGROUND: New modulator therapies have markedly improved the health of people with cystic fibrosis (CF), allowing an increased focus on quality-of-life improvements for men with CF, including those related to sexual and reproductive health (SRH). This study explored CF providers' attitudes and experiences with addressing men's health in CF. METHODS: We interviewed geographically diverse adult and pediatric United States (U.S.) CF program directors via semi-structured telephone interviews exploring their perspectives and practices related to men's SRH in CF. Two coders analyzed transcribed interviews and created a codebook to identify key themes. RESULTS: We interviewed 20 providers and identified the following themes: 1) Men's SRH is important to address within CF care, but there is no standardization around this aspect of care; 2) There is no consensus about the recommendation or utilization of semen analysis to assess men's infertility; 3) There are many barriers to men's SRH care provision in CF centers, including the low priority of SRH concerns and provider discomfort and lack of expertise in SRH; 4) Providers desire clear evidence-based guidelines and patient resources related to men's SRH in CF; and 5) Providers believe future research should focus on testosterone and the impact of modulators on men's SRH. CONCLUSIONS: CF center directors acknowledge the importance of addressing SRH with men with CF, but there is a lack of standardization and research in this aspect of care. Existing barriers to optimal SRH care and identified facilitators in this study can serve as targets for interventions in the CF care model.

Longitudinal changes in vascular stiffness and heart rate variability among young adults with youth-onset type 2 diabetes: results from the follow-up observational treatment options for type 2 diabetes in adolescents and youth (TODAY) study.

AIMS: (1) To describe changes in arterial stiffness and heart rate variability (HRV) over a 5-year interval, (2) examine changes by sex and race-ethnicity, and (3) evaluate the risk factors associated with the longitudinal changes in arterial stiffness and HRV. METHODS: Participants with youth-onset type 2 diabetes enrolled in the observational follow-up phase of the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) clinical trial had arterial stiffness [(pulse wave velocity, augmentation index, brachial distensibility] and six indices of HRV measured 5 years apart. Multivariable linear regression models assessed risk factors associated with changes in the outcomes over time. RESULTS: At initial vascular assessment, the 304 participants were a mean age of 21 years, 34% male, and had a mean diabetes duration of 8 years. In more than half the cohort pulse wave velocity, augmentation index and HRV increased over 5 years (p<0.01). Brachial distensibility did not change. There were no differences in the 5-year change by race/ethnicity except for a single HRV measure, where non-Hispanic Blacks had greater worsening of parasympathetic function compared to non-Hispanic Whites, p = 0.008. Blood pressure was related to greater worsening in augmentation index and pulse wave velocity. Higher hemoglobin A1c over time was related to worsening pulse wave velocity and HRV. CONCLUSIONS: Arterial stiffness and HRV worsened over 5 years. Blood pressure and glycemic control may be potential targets to influence adverse changes in arterial stiffness and HRV in young adults with youth-onset type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT00081328.

Gynecologic health care for females with cystic fibrosis.

As females with cystic fibrosis (CF) increasingly reach their reproductive years, gynecologic issues have become an important area of clinical care and research. First, females with CF may have disease-specific gynecologic problems, including cyclic pulmonary symptoms, vaginal yeast infections, and urinary incontinence. Next, contraceptive methods are thought to be overall safe and effective, however further research is needed to confirm this and to understand the lower rates of uptake among females with CF compared to the general population. Further, females with CF have reduced fertility, although the etiology of this is unknown and under investigation. While assisted reproductive technologies may help achieve pregnancy, decision-making around parenthood remains complex. Finally, while patients and providers agree on the importance of sexual and reproductive health care, females with CF underutilize basic preventive services such as cervical cancer screening, and better approaches are needed to bridge the gap with gynecology. In this review, we discuss the current state of gynecologic care for females with CF, as well as clinical and research opportunities for improvement.

Effects of Oral Sodium Nitrite on Blood Pressure, Insulin Sensitivity, and Intima-Media Arterial Thickening in Adults With Hypertension and Metabolic Syndrome.

The nitrate-nitrite-NO pathway regulates NO synthase-independent vasodilation and NO signaling. Ingestion of inorganic nitrite has vasodilatory and blood pressure-lowering effects. Preclinical studies in rodent models suggest there may be a benefit of nitrite in lowering serum triglyceride levels and improving the metabolic syndrome. In a phase 2 study, we evaluated the safety and efficacy of chronic oral nitrite therapy in patients with hypertension and the metabolic syndrome. Twenty adult subjects with stage 1 or 2 hypertension and the metabolic syndrome were enrolled in an open-label safety and efficacy study. The primary efficacy end point was blood pressure reduction; secondary end points included insulin-dependent glucose disposal and endothelial function measured by flow-mediated dilation of the brachial artery and intima-media diameter of the carotid artery. Chronic oral nitrite therapy (40 mg/3× daily) was well tolerated. Oral nitrite significantly lowered systolic, diastolic, and mean arterial pressures, but tolerance was observed after 10 to 12 weeks of therapy. There was significant improvement in the intima-media thickness of the carotid artery and trends toward improvements in flow-mediated dilation of the brachial artery and insulin sensitivity. Chronic oral nitrite therapy is safe in patients with hypertension and the metabolic syndrome. Despite an apparent lack of enzymatic tolerance to nitrite, we observed tolerance after 10 weeks of chronic therapy, which requires additional mechanistic studies and possible therapeutic dose titration in clinical trials. Nitrite may be a safe therapy to concominantly improve multiple features of the metabolic syndrome including hypertension, insulin resistance, and endothelial dysfunction. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT01681810.

Effects of exercise modality on body composition and cardiovascular disease risk factors in adolescents with obesity: a randomized clinical trial.

We compared the effects of aerobic exercise, resistance exercise, and combined aerobic and resistance exercise on total, regional subcutaneous adipose tissue (SAT) and visceral AT (VAT), skeletal muscle (SM), and biomarkers of cardiovascular disease in adolescents. Adolescents with overweight/obesity (N = 118; body mass index ≥ 85th percentile; age, 12-17 years) were randomized to 1 of the following groups for 6 months (3 days/week, 180 min/week): aerobic exercise (n = 38), resistance exercise (n = 40), or combined aerobic and resistance exercise (n = 40). After accounting for age, sex, and baseline value, there was a greater (P < 0.05) reduction in body weight in the aerobic exercise group compared with the resistance exercise group and the combined groups. There were reductions (P < 0.05) in total and regional SAT within the aerobic exercise group only, and the reductions in lower-body SAT were greater (P = 0.02) than the combined group. All groups had reductions (P < 0.01) in VAT, with no group differences. There were significant increases in total and regional SM mass in the resistance exercise and combined group, and not in the aerobic exercise group. Although all exercise modalities are effective in reducing VAT, aerobic exercise is superior at reducing total and regional SAT, but inferior for increasing SM in adolescents with obesity. Despite reductions in VAT, carotid-femoral pulse wave velocity and carotid intima-media thickness did not improve with either exercise. Clinicaltrials.gov identifier: NCT01938950. Novelty Regular exercise (180 min/week) is associated with reductions in visceral fat independent of exercise modality. Resistance exercise alone and combined resistance and aerobic exercise are similarly effective in increasing SM mass.

Glycemic control and FEV1 recovery during pulmonary exacerbations in pediatric cystic fibrosis-related diabetes.

RATIONALE: Whether short-term glucose control in cystic fibrosis-related diabetes (CFRD) is associated with FEV1 recovery during acute pulmonary exacerbations is unclear. METHODS: Data from all patients with CFRD ages 6-21 years hospitalized in 2010-2016 for pulmonary exacerbations at our CF Center were analyzed, including CFRD status at each encounter, all FEV1 recorded during each exacerbation, and relevant clinical covariates. Glucose control was analyzed using meter blood glucose area under the curve (AUC) indices. The primary outcome was FEV1 recovery. RESULTS: Patients with CFRD who finished IV antibiotics at home were treated for longer than those fully treated in the hospital (22.2 vs. 13.8 days). In those who finished treatment at home, poor inpatient glycemic control was associated with lower lung function improvement: when comparing the 75th to the 25th percentile of each glycemic index (i.e., "poorer" vs. "better" glycemic control), FEV1 recovery at discharge was 20.1% lower for glucose AUC (95%CI -0.4%, -39.9%); 20.9% lower for 48-h AUC (95%CI -2.7%, -39.1%); and 28.2% lower for AUC/day (95%CI -7.1%, -49.3%). Similar results were found at the end of IV antibiotics and at clinic follow-up. Likewise, patients with poor glycemic control had a lower slope of inpatient FEV1 recovery. Analysis in patients with normal glucose tolerance was largely non-significant. No associations were found between hemoglobin A1c and FEV1 recovery. CONCLUSIONS: In patients with CFRD who complete IV antibiotic treatment at home, poor inpatient glycemic control is associated with worse FEV1 recovery despite longer duration of treatment.

Adrenal function in cystic fibrosis.

Cystic fibrosis (CF) is not known to directly affect the adrenal gland, but commonly used CF therapies do impact the function of the hypothalamic-pituitary-adrenal (HPA) axis. By binding to the glucocorticoid receptor, medications such as inhaled and oral corticosteroids can enhance the systemic effects of cortisol and result in iatrogenic Cushing syndrome. Prolonged use suppresses the body's ability to make cortisol, resulting in iatrogenic adrenal insufficiency upon medication discontinuation. Chronic use of inhaled and oral corticosteroids can negatively affect bone health, growth, and glucose metabolism. This chapter provides practical guidelines regarding the screening, diagnosis, and treatment of iatrogenic adrenal insufficiency. As the guidelines are mainly derived from the asthma literature, this chapter also highlights the need for studies to evaluate the impact of CF therapies on adrenal function and other CF-endocrinopathies.

Female reproductive health in cystic fibrosis.

Women with cystic fibrosis (CF) are living longer and healthier lives, and opportunities for childbearing are increasingly promising. However, this population can also face sexual and reproductive health concerns, including menstrual irregularities, unplanned pregnancies, infertility and pregnancy complications. Additionally, more women are entering menopause and are at risk for the consequences of estrogen deficiency. The exact mechanisms involved in female reproductive health conditions in CF are not clearly understood, but are thought to include cystic fibrosis transmembrane regulator (CFTR)-mediated abnormalities, changes in female sex hormones, and other CF health-related factors. In the era of CFTR modulator therapy, new data are necessary to understand the impact of CFTR modulation on contraceptive effectiveness, fertility, and pregnancy outcomes to help guide future clinical care. This article reviews the current scientific knowledge of major reproductive health issues for women with CF.

Conjugated Linoleic Acid Modulates Clinical Responses to Oral Nitrite and Nitrate.

Dietary NO3- (nitrate) and NO2- (nitrite) support ˙NO (nitric oxide) generation and downstream vascular signaling responses. These nitrogen oxides also generate secondary nitrosating and nitrating species that react with low molecular weight thiols, heme centers, proteins, and unsaturated fatty acids. To explore the kinetics of NO3-and NO2-metabolism and the impact of dietary lipid on nitrogen oxide metabolism and cardiovascular responses, the stable isotopes Na15NO3 and Na15NO2 were orally administered in the presence or absence of conjugated linoleic acid (cLA). The reduction of 15NO2- to 15NO was indicated by electron paramagnetic resonance spectroscopy detection of hyperfine splitting patterns reflecting 15NO-deoxyhemoglobin complexes. This formation of 15NO also translated to decreased systolic and mean arterial blood pressures and inhibition of platelet function. Upon concurrent administration of cLA, there was a significant increase in plasma cLA nitration products 9- and 12-15NO2-cLA. Coadministration of cLA with 15NO2- also impacted the pharmacokinetics and physiological effects of 15NO2-, with cLA administration suppressing plasma NO3-and NO2-levels, decreasing 15NO-deoxyhemoglobin formation, NO2-inhibition of platelet activation, and the vasodilatory actions of NO2-, while enhancing the formation of 9- and 12-15NO2-cLA. These results indicate that the biochemical reactions and physiological responses to oral 15NO3-and 15NO2-are significantly impacted by dietary constituents, such as unsaturated lipids. This can explain the variable responses to NO3-and NO2-supplementation in clinical trials and reveals dietary strategies for promoting the generation of pleiotropic nitrogen oxide-derived lipid signaling mediators. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT01681836.

The Shape of the Glucose Response Curve During an Oral Glucose Tolerance Test Heralds Biomarkers of Type 2 Diabetes Risk in Obese Youth.

OBJECTIVE: The shape of the glucose response curve during an oral glucose tolerance test (OGTT), monophasic versus biphasic, identifies physiologically distinct groups of individuals with differences in insulin secretion and sensitivity. We aimed to verify the value of the OGTT-glucose response curve against more sensitive clamp-measured biomarkers of type 2 diabetes risk, and to examine incretin/pancreatic hormones and free fatty acid associations in these curve phenotypes in obese adolescents without diabetes. RESEARCH DESIGN AND METHODS: A total of 277 obese adolescents without diabetes completed a 2-h OGTT and were categorized to either a monophasic or a biphasic group. Body composition, abdominal adipose tissue, OGTT-based metabolic parameters, and incretin/pancreatic hormone levels were examined. A subset of 106 participants had both hyperinsulinemic-euglycemic and hyperglycemic clamps to measure in vivo insulin sensitivity, insulin secretion, and ß-cell function relative to insulin sensitivity. RESULTS: Despite similar fasting and 2-h glucose and insulin concentrations, the monophasic group had significantly higher glucose, insulin, C-peptide, and free fatty acid OGTT areas under the curve compared with the biphasic group, with no differences in levels of glucagon, total glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide, and pancreatic polypeptide. Furthermore, the monophasic group had significantly lower in vivo hepatic and peripheral insulin sensitivity, lack of compensatory first and second phase insulin secretion, and impaired ß-cell function relative to insulin sensitivity. CONCLUSIONS: In obese youth without diabetes, the risk imparted by the monophasic glucose curve compared with biphasic glucose curve, independent of fasting and 2-h glucose and insulin concentrations, is reflected in lower insulin sensitivity and poorer ß-cell function, which are two major pathophysiological biomarkers of type 2 diabetes in youth.

SIRT3-AMP-Activated Protein Kinase Activation by Nitrite and Metformin Improves Hyperglycemia and Normalizes Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Pulmonary hypertension associated with heart failure with preserved ejection fraction (PH-HFpEF) is an increasingly recognized clinical complication of metabolic syndrome. No adequate animal model of PH-HFpEF is available, and no effective therapies have been identified to date. A recent study suggested that dietary nitrate improves insulin resistance in endothelial nitric oxide synthase null mice, and multiple studies have reported that both nitrate and its active metabolite, nitrite, have therapeutic activity in preclinical models of pulmonary hypertension. METHODS AND RESULTS: To evaluate the efficacy and mechanism of nitrite in metabolic syndrome associated with PH-HFpEF, we developed a 2-hit PH-HFpEF model in rats with multiple features of metabolic syndrome attributable to double-leptin receptor defect (obese ZSF1) with the combined treatment of vascular endothelial growth factor receptor blocker SU5416. Chronic oral nitrite treatment improved hyperglycemia in obese ZSF1 rats by a process that requires skeletal muscle SIRT3-AMPK-GLUT4 signaling. The glucose-lowering effect of nitrite was abolished in SIRT3-deficient human skeletal muscle cells, and in SIRT3 knockout mice fed a high-fat diet, as well. Skeletal muscle biopsies from humans with metabolic syndrome after 12 weeks of oral sodium nitrite and nitrate treatment (IND#115926) displayed increased activation of SIRT3 and AMP-activated protein kinase. Finally, early treatments with nitrite and metformin at the time of SU5416 injection reduced pulmonary pressures and vascular remodeling in the PH-HFpEF model with robust activation of skeletal muscle SIRT3 and AMP-activated protein kinase. CONCLUSIONS: These studies validate a rodent model of metabolic syndrome and PH-HFpEF, suggesting a potential role of nitrite and metformin as a preventative treatment for this disease.