Glucose variability is associated with an adverse vascular profile but only in the presence of insulin resistance in individuals with type 1 diabetes: An observational study

Glucose Variability in People with Type 1 Diabetes: Associations with Body Weight, Body Composition, and Insulin Sensitivity

The prevalence of overweight and obesity increases in people with type 1 diabetes (T1D). However, the impact of fat accumulation on glucose dynamics in T1D is poorly understood. We assessed continuous glucose monitoring (CGM) parameters in patients with T1D depending on their body weight, body composition, and insulin sensitivity. In 547 patients, including 238 overweight/obese individuals, CGM-derived time in range (TIR) and glucose variability (GV) were estimated. Body composition was assessed by DXA. Estimated glucose disposal rate (eGDR) was used as an indicator of insulin sensitivity. Overweight/obese patients, when compared to normal-weight ones, have a lower time below range (TBR) (<3 mmol/L), GV, and experienced fewer episodes of low glucose. In men, lower TIR, higher time above range (TAR), and GV reduction were associated with central adiposity assessed by total, trunk, and android fat mass. In women, gynoid fat mass only was associated with a lower TIR and higher TAR. The eGDR was a positive predictor of TIR and a negative predictor of TAR, TBR, and GV in men and women. In conclusion, adiposity in people with T1D is associated with a lower risk of CGM-confirmed hypoglycemia, higher TAR, and reduced GV. These features of daily glucose dynamics may be mediated by insulin resistance.

Short, frequent, light-intensity walking activity improves postprandial vascular-inflammatory biomarkers in people with type 1 diabetes: The SIT-LESS randomized controlled trial

AIM

To examine the effect of interrupting prolonged sitting with short, frequent, light-intensity activity on postprandial cardiovascular markers in people with type 1 diabetes (T1D).

MATERIALS AND METHODS

In a randomized crossover trial, 32 adults with T1D (mean ± SD age 28 ± 5 years, glycated haemoglobin 67.9 ± 12.6 mmol/mol, 17 women) completed two 7-h laboratory visits separated by >7 days. Participants either remained seated for 7 h (SIT) or interrupted sitting with 3-min bouts of self-paced walking at 30-min intervals commencing 1 h after each meal (SIT-LESS). Physical activity, insulin regimen, experimental start times, and meal consumption were standardized during each arm. Plasma levels of interleukin (IL)-1β, tumour necrosis factor (TNF)-α, plasminogen activator inhibitor (PAI)-1 and fibrinogen were sampled at baseline, 3.5 and 7 h, and assessed for within- and between-group effects using a repeated measures ANOVA. The estimated glucose disposal rate was used to determine the insulin resistance status.

RESULTS

Vascular-inflammatory parameters were comparable between SIT and SIT-LESS at baseline (p > .05). TNF-α, IL-1β, PAI-1 and fibrinogen increased over time under SIT, whereas these rises were attenuated under SIT-LESS (p < .001). Specifically, over the 7 h under SIT, postprandial increases were detected in TNF-α, IL-1β, PAI-1 and fibrinogen (+67%, +49%, +49% and +62%, respectively; p < .001 for all). Conversely, the SIT-LESS group showed no change in IL-1β (-9%; p > .50), whereas reductions were observed in TNF-α, PAI-1 and fibrinogen (-22%, -42% and -44%, respectively; p < .001 for all). The intervention showed enhanced effects in insulin-resistant individuals with T1D.

CONCLUSIONS

Interrupting prolonged sitting with light-intensity activity ameliorates postprandial increases in vascular-inflammatory markers in T1D.

TRIAL REGISTRATION

The trial was prospectively registered (ISRCTN13641847).

Rapid Improvement in Weight, Body Composition, and Glucose Variability With Semaglutide in Type 1 Diabetes

The efficacy of glucagon-like peptide-1 receptor agonists (GLP1-RA) in type 2 diabetes mellitus is well-established. GLP1-RAs are not approved for use in type 1 diabetes mellitus (T1DM). A 34-year-old woman with a 23-year history of T1DM presented for review for weight gain (weight 63 kg, BMI 26.9 kg/m2) and increased HbA1c (8.3%) and glycemic variability. Subcutaneous semaglutide (1 mg weekly) was commenced. After two months, there was decrease in weight by 12 kg, body fat percent by 15%, visceral fat by 7%, and a reduction in insulin dose, glycemic variability, and HbA1c. Semaglutide could be an important adjunct to insulin treatment in T1DM.

Mechanisms of endothelial activation, hypercoagulation and thrombosis in COVID-19: a link with diabetes mellitus

Early since the onset of the COVID-19 pandemic, the medical and scientific community were aware of extra respiratory actions of SARS-CoV-2 infection. Endothelitis, hypercoagulation, and hypofibrinolysis were identified in COVID-19 patients as subsequent responses of endothelial dysfunction. Activation of the endothelial barrier may increase the severity of the disease and contribute to long-COVID syndrome and post-COVID sequelae. Besides, it may cause alterations in primary, secondary, and tertiary hemostasis. Importantly, these responses have been highly decisive in the evolution of infected patients also diagnosed with diabetes mellitus (DM), who showed previous endothelial dysfunction. In this review, we provide an overview of the potential triggers of endothelial activation related to COVID-19 and COVID-19 under diabetic milieu. Several mechanisms are induced by both the viral particle itself and by the subsequent immune-defensive response (i.e., NF-κB/NLRP3 inflammasome pathway, vasoactive peptides, cytokine storm, NETosis, activation of the complement system). Alterations in coagulation mediators such as factor VIII, fibrin, tissue factor, the von Willebrand factor: ADAMST-13 ratio, and the kallikrein-kinin or plasminogen-plasmin systems have been reported. Moreover, an imbalance of thrombotic and thrombolytic (tPA, PAI-I, fibrinogen) factors favors hypercoagulation and hypofibrinolysis. In the context of DM, these mechanisms can be exacerbated leading to higher loss of hemostasis. However, a series of therapeutic strategies targeting the activated endothelium such as specific antibodies or inhibitors against thrombin, key cytokines, factor X, complement system, the kallikrein-kinin system or NETosis, might represent new opportunities to address this hypercoagulable state present in COVID-19 and DM. Antidiabetics may also ameliorate endothelial dysfunction, inflammation, and platelet aggregation. By improving the microvascular pathology in COVID-19 and post-COVID subjects, the associated comorbidities and the risk of mortality could be reduced.

Plasma levels of mannan-binding lectin-associated serine proteases are increased in type 1 diabetes patients with insulin resistance

Activation of the lectin pathway of the complement system, as demonstrated by elevated levels of mannan-binding lectin proteins (MBL), contributes to vascular pathology in type 1 diabetes (T1D). Vascular complications are greatest in T1D individuals with concomitant insulin resistance (IR), however, whether IR amplifies activiation of the lectin pathway in T1D is unknown. We pooled pretreatment data from two RCTs and performed a cross-sectional analysis on 46 T1D individuals. We employed estimated glucose disposal rate (eGDR), a validated IR surrogate with cut-points of: <5.1, 5.1-8.7, and > 8.7 mg/kg/min to determine IR status, with lower eGDR values conferring higher degrees of IR. Plasma levels of MBL-associated proteases (MASP-1, MASP-2, and MASP-3) and their regulatory protein MAp44 were compared among eGDR classifications. In a subset of 14 individuals, we assessed change in MASPs and MAp44 following improvement in IR. We found that MASP-1, MASP-2, MASP-3, and MAp44 levels increased in a stepwise fashion across eGDR thresholds with elevated MASPs and MAp44 levels conferring greater degrees of IR. In a subset of 14 patients, improvement in IR was associated with significant reductions in MASPs, but not MAp44, levels. In conclusion, IR in T1D amplifies levels of MASP-1/2/3 and their regulator MAp44, and improvement of IR normalizes MASP-1/2/3 levels. Given that elevated levels of these proteins contribute to vascular pathology, amplification of the lectin pathway of the complement system may offer mechanistic insight into the relationship between IR and vascular complications in T1D.

Barriers to Exercise in Adults With Type 1 Diabetes and Insulin Resistance

OBJECTIVE

Our aim in this study was to assess attitudes toward exercise and quality of life (QoL) in adults with type 1 diabetes (T1D) with and without insulin resistance (IR).

METHODS

We pooled baseline pretreatment data from a subset of individuals with T1D from 2 randomized controlled trials. Estimated glucose disposal rate (eGDR), a validated surrogate marker of IR, was calculated using an established formula to classify individuals according to IR status with a cutpoint of <6 mg/kg/min for the determination of IR. Self-reported barriers to exercise were obtained using a validated questionnaire, the Barriers to Physical Activity in T1D (BAPAD-1). In addition, QoL was determined using the 36-item Short Form (SF-36) questionnaire. Differences between dichotomized variables were assessed using the independent t test, Mann-Whitney U test, or Fisher exact test. Linear regression was employed to explore the association of eGDR with BAPAD-1 and QoL scores, with sequential adjustment for potential confounders.

RESULTS

Of the 85 individuals included in our study, 39 were classified as having IR. The mean BAPAD-1 total score was higher for individuals with IR (IR: 3.87±0.61; non-IR: 2.83±0.55; p<0.001). The highest exercise barrier scores for individuals with IR were risk of hypoglycemia (5.67±1.26) and risk of hyperglycemia (5.23±1.20), whereas the highest scoring exercise barrier scores for non-IR individuals were not diabetes-related, with low level of fitness (3.91±1.26) and physical health status, excluding diabetes (3.67±1.48), ranked highest. QoL scores were comparable between groups (p>0.05).

CONCLUSIONS

Risk of hypoglycemia was the greatest barrier to exercise in individuals with T1D with IR, whereas non-diabetes-related barriers to exercise were more salient in individuals with T1D without IR.

Reducing Sitting Time in Type 1 Diabetes: Considerations and Implications

Sedentary behaviours are ubiquitous in modern society with Western populations spending approximately ∼50% of their waking hours in low levels of energy expenditure. This behaviour is associated with cardiometabolic derangements and increased morbidity and mortality. In individuals living with or at risk of developing type 2 diabetes (T2D), "breaking up" sedentariness, by interrupting prolonged periods of sitting has been shown to acutely improve glucose control and cardiometabolic risk factors related to diabetes complications. As such, current guidelines recommend interrupting prolonged periods of sitting with short, frequent activity breaks. However, the evidence underpinning these recommendations remain preliminary and are focussed on those with or at risk of developing T2D, with little information regarding whether and how reducing sedentariness may be effective and safe in those living with type 1 diabetes (T1D). In this review, we discuss the potential application of interventions that target prolonged sitting time in T2D within the context of T1D.