Negative Selection by an Endogenous Retrovirus Promotes a Higher-Avidity CD4+ T Cell Response to Retroviral Infection

Effective T cell responses can decisively influence the outcome of retroviral infection. However, what constitutes protective T cell responses or determines the ability of the host to mount such responses is incompletely understood. Here we studied the requirements for development and induction of CD4+ T cells that were essential for immunity to Friend virus (FV) infection of mice, according to their TCR avidity for an FV-derived epitope. We showed that a self peptide, encoded by an endogenous retrovirus, negatively selected a significant fraction of polyclonal FV-specific CD4+ T cells and diminished the response to FV infection. Surprisingly, however, CD4+ T cell-mediated antiviral activity was fully preserved. Detailed repertoire analysis revealed that clones with low avidity for FV-derived peptides were more cross-reactive with self peptides and were consequently preferentially deleted. Negative selection of low-avidity FV-reactive CD4+ T cells was responsible for the dominance of high-avidity clones in the response to FV infection, suggesting that protection against the primary infecting virus was mediated exclusively by high-avidity CD4+ T cells. Thus, although negative selection reduced the size and cross-reactivity of the available FV-reactive naïve CD4+ T cell repertoire, it increased the overall avidity of the repertoire that responded to infection. These findings demonstrate that self proteins expressed by replication-defective endogenous retroviruses can heavily influence the formation of the TCR repertoire reactive with exogenous retroviruses and determine the avidity of the response to retroviral infection. Given the overabundance of endogenous retroviruses in the human genome, these findings also suggest that endogenous retroviral proteins, presented by products of highly polymorphic HLA alleles, may shape the human TCR repertoire that reacts with exogenous retroviruses or other infecting pathogens, leading to interindividual heterogeneity

Oral Health Knowledge and Behaviors among Adolescents with Type 1 Diabetes

Early onset and more advanced periodontal disease has been reported for children with diabetes. We surveyed oral health knowledge, attitudes, and behaviors among adolescents with diabetes in order to inform potential intervention strategies. Study subjects were youth (ages 12–19 years) with type 1 diabetes (N = 90) participating in a cohort study investigating determinants of periodontal disease at a regional pediatric diabetes specialty clinic. Over 90% of the youth had been instructed on how to brush and floss and had preventive dental care in the past year. However, 44% knew that periodontal disease is associated with diabetes and 32% knew that it can start in childhood with bleeding gums. Despite being at high risk for developing periodontal disease, the mean toothbrushing frequency was once per day and 42% did not floss. Significant opportunity exists for improving periodontal disease knowledge and adoption of preventive oral hygiene behaviors in adolescents with diabetes

Lower objectively measured physical activity is linked with perceived risk of hypoglycemia in type 1 diabetes

Aims Compare physical activity (PA) levels in adults with and without type 1 diabetes and identify diabetes-specific barriers to PA. Methods Forty-four individuals with type 1 diabetes and 77 non-diabetic controls in the Coronary Artery Calcification in Type 1 Diabetes study wore an accelerometer for 2 weeks. Moderate-to-vigorous physical activity (MVPA) was compared by diabetes status using multiple linear regression. The Barriers to Physical Activity in Type 1 Diabetes questionnaire measured diabetes-specific barriers to PA, and the Clarke hypoglycemia awareness questionnaire measured hypoglycemia frequency. Results Individuals with type 1 diabetes engaged in less MVPA, fewer bouts of MVPA, and spent less time in MVPA bouts per week than individuals without diabetes (all p  0.05). The most common diabetes-specific barrier to PA was risk of hypoglycemia. Individuals with diabetes reporting barriers spent less time in MVPA bouts per week than those not reporting barriers (p = 0.047). Conclusions Individuals with type 1 diabetes engage in less MVPA than those without diabetes despite similar self-reported levels, with the main barrier being perceived risk of hypoglycemia. Adults with type 1 diabetes require guidance to meet current PA guidelines and reduce cardiovascular risk

Lipid and Lipoprotein Profiles in Youth With and Without Type 1 Diabetes: The SEARCH for Diabetes in Youth Case-Control Study

OBJECTIVE—The purpose of this study was to compare the lipid profile and the prevalence of lipid abnormalities in youth with and without type 1 diabetes and explore the role of glycemic control on the hypothesized altered lipid profile in youth with type 1 diabetes

A cross‐sectional view of the current state of treatment of youth with type 2 diabetes in the USA: enrollment data from the Pediatric Diabetes Consortium Type 2 Diabetes Registry

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136377/1/pedi12377_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136377/2/pedi12377.pd

Lipid and Lipoprotein Profiles in Youth With and Without Type 1 Diabetes: The SEARCH for Diabetes in Youth Case-Control Study

OBJECTIVE The purpose of this study was to compare the lipid profile and the prevalence of lipid abnormalities in youth with and without type 1 diabetes and explore the role of glycemic control on the hypothesized altered lipid profile in youth with type 1 diabetes. RESEARCH DESIGN AND METHODS - We conducted a cross-sectional analysis of 512 youth with type 1 diabetes (mean duration 4.22 years) and 188 healthy control subjects aged 10-22 years in Colorado and South Carolina. SEARCH for Diabetes in Youth (SEARCH) participants with type 1 diabetes and healthy control subjects recruited from primary care offices in the same geographic regions were invited to attend a research visit. Fasting lipid profiles were compared between youth with type 1 diabetes (stratified according to categories of optimal [AlC <7.5%] and suboptimal [AlC ≥7.5%] glycemic control) and healthy nondiabetic youth, using multiple linear and logistic regression. RESULTS - Youth with type 1 diabetes and optimal AlC had lipid concentrations that were similar (total cholesterol, LDL cholesterol, and LDL particle size) or even less atherogenic (HDL cholesterol, non-HDL cholesterol, triglyceride, and triglyceride-to-HDL cholesterol ratio) than those observed in nondiabetic youth, whereas youth with suboptimal glycemic control had elevated standard lipid levels (total cholesterol, LDL cholesterol, and non-HDL cholesterol). Youth with type 1 diabetes also had significantly elevated apolipoprotein B levels and more small, dense LDL particles than nondiabetic youth, regardless of glycemic control. CONCLUSIONS Youth with type 1 diabetes have abnormal lipid levels and atherogenic changes in lipoprotein composition, even after a relatively short disease duration. As in adults, glycemic control is an important mediator of these abnormalities

Burden of Cardiovascular Risk Factors Over Time and Arterial Stiffness in Youth With Type 1 Diabetes Mellitus: The SEARCH for Diabetes in Youth Study

Background: The incidence of type 1 diabetes mellitus (T1DM) in children is increasing, resulting in higher burden of cardiovascular diseases due to diabetes mellitus–related vascular dysfunction. Methods and Results: We examined cardiovascular risk factors (CVRFs) and arterial parameters in 1809 youth with T1DM. Demographics, anthropometrics, blood pressure, and laboratory data were collected at T1DM onset and 5 years later. Pulse wave velocity and augmentation index were collected with tonometry. ANOVA or chi�square tests were used to test for differences in measures of arterial parameters by CVRF. Area under the curve of CVRFs was entered in general linear models to explore determinants of accelerate vascular aging. Participants at the time of arterial measurement were 17.6±4.5 years old, 50% female, 76% non�Hispanic white, and duration of T1DM was 7.8±1.9 years. Glycemic control was poor (glycated hemoglobin, 9.1±1.8%). All arterial parameters were higher in participants with glycated hemoglobin ≥9% and pulse wave velocity was higher with lower insulin sensitivity or longer duration of diabetes mellitus. Differences in arterial parameters were found by sex, age, and presence of obesity, hypertension, or dyslipidemia. In multivariable models, higher glycated hemoglobin, lower insulin sensitivity, body mass index, blood pressure, and lipid areas under the curve were associated with accelerated vascular aging. Conclusions: In young people with T1DM, persistent poor glycemic control and higher levels of traditional CVRFs are independently associated with arterial aging. Improving glycemic control and interventions to lower CVRFs may prevent future cardiovascular events in young individuals with T1DM

Design and Psychometrics for New Measures of Health-Related Quality of Life in Adults with Type 1 Diabetes: Type 1 Diabetes and Life (T1DAL)

AIMS: To use a three-phase process to develop and validate new self-report measures of diabetes-specific health-related quality of life (HRQOL) for adults with type 1 diabetes. We report on four versions of the Type 1 Diabetes and Life (T1DAL) measure for people age 18-25, 26-45, 46-60, and over 60 years. METHODS: We first conducted qualitative interviews to guide measure creation, then piloted the draft measures. We evaluated psychometric properties at six T1D Exchange Clinic Network sites via completion of T1DAL and validated measures of related constructs. Participants completed the T1DAL again in 4-6 weeks. We used psychometric data to reduce each measure to 23-27 items in length. Finally, we obtained participant feedback on the final measures. RESULTS: The T1DAL-Adult measures demonstrated good internal consistency (α=0.85-0.88) and test-retest reliability (r=0.77-0.87). Significant correlations with measures of general quality of life, generic and diabetes-specific HRQOL, diabetes burden, self-management, and glycemic control demonstrated validity. Factor analyses yielded 4-5 subscales per measure. Participants were satisfied with the final measures and reported they took 5-10 minutes to complete. CONCLUSIONS: The strong psychometric properties of the newly developed self-report T1DAL measures for adults with type 1 diabetes make them appropriate for use in clinical research and care