Impact of Polymorphism in the ß2-Receptor Gene on Metabolic Responses to Repeated Hypoglycemia in Healthy Humans.

CONTEXT: The Arg16 variant in the ß2-receptor gene is associated with increased risk of severe hypoglycemia in subjects with type 1 diabetes mellitus. OBJECTIVE: We hypothesized that the Arg16 variant is associated with decreased metabolic and symptomatic responses to recurrent hypoglycemia. METHODS: Twenty-five healthy male subjects selected according to ADRB2 genotype and being homozygous for either Arg16 (AA; n = 13) or Gly16 (GG; n = 12) participated in 2 consecutive trial days with 3 periods of hypoglycemia (H1-H3) induced by a hyperinsulinemic hypoglycemic clamp. The main outcome measure was mean glucose infusion rate (GIR) during H1-H3. RESULTS: During H1-H3, there was no difference between AA or GG subjects in GIR, counter-regulatory hormones (glucagon, epinephrine, cortisol, growth hormone), or substrate levels of lactate, glycerol, and free fatty acids (FFAs), and no differences in symptom response score or cognitive performance (trail making test, Stroop test). At H3, lactate response was reduced in both genotype groups, but AA subjects had decreased response (mean ±â€…standard error of the mean of area under the curve) of glycerol (-13.1 ±â€…3.8 µmol L-1 hours; P = .0052), FFA (-30.2 ±â€…11.1 µmol L-1 hours; P = .021), and ß-hydroxybutyrate (-0.008 ±â€…0.003 mmol L-1 hour; P = .027), while in GG subjects alanine response was increased (negative response values) (-53.9 ±â€…20.6 µmol L-1 hour; P = .024). CONCLUSION: There was no difference in GIR between genotype groups, but secondary outcomes suggest a downregulation of the lipolytic and ß-hydroxybutyrate responses to recurrent hypoglycemia in AA subjects, in contrast to the responses in GG subjects.

A systematic review of trial registry entries for randomized clinical trials investigating COVID-19 medical prevention and treatment.

AIM: To identify investigated interventions for COVID-19 prevention or treatment via trial registry entries on planned or ongoing randomised clinical trials. To assess these registry entries for recruitment status, planned trial size, blinding and reporting of mortality. METHODS: We identified trial registry entries systematically via the WHO International Clinical Trials Registry Platform and 33 trial registries up to June 23, 2020. We included relevant trial registry entries for randomized clinical trials investigating medical preventive, adjunct or supportive therapies and therapeutics for treatment of COVID-19. Studies with non-random and single-arm design were excluded. Trial registry entries were screened by two authors independently and data were systematically extracted. RESULTS: We included 1303 trial registry entries from 71 countries investigating 381 different single interventions. Blinding was planned in 47% of trials. Sample size was >200 participants in 40% of trials and a total of 611,364 participants were planned for inclusion. Mortality was listed as an outcome in 57% of trials. Recruitment was ongoing in 54% of trials and completed in 8%. Thirty-five percent were multicenter trials. The five most frequent investigational categories were immune modulating drugs (266 trials (20%)), unconventional medicine (167 trials (13%)), antimalarial drugs (118 trials (9%)), antiviral drugs (100 trials (8%)) and respiratory adjuncts (78 trials (6%)). The five most frequently tested uni-modal interventions were: chloroquine/hydroxychloroquine (113 trials with 199,841 participants); convalescent plasma (64 trials with 11,840 participants); stem cells (51 trials with 3,370 participants); tocilizumab (19 trials with 4,139 participants) and favipiravir (19 trials with 3,210 participants). CONCLUSION: An extraordinary number of randomized clinical trials investigating COVID-19 management have been initiated with a multitude of medical preventive, adjunctive and treatment modalities. Blinding will be used in only 47% of trials, which may have influence on future reported treatment effects. Fifty-seven percent of all trials will assess mortality as an outcome facilitating future meta-analyses.

Impact of Genetic Polymorphism in the ß2-Receptor Gene on Risk of Severe Hypoglycemia in Patients With Type 1 Diabetes.

Context: Severe hypoglycemic events are unevenly distributed in people with type 1 diabetes, making a genetic influence probable. Of the common adrenoceptor ß-2 receptor gene (ADRB2) polymorphisms, the Arg16 allele is associated with receptor downregulation and reduced agonist-mediated endogenous glucose production. Objective: We tested the hypothesis that the Arg16 variant is associated with severe hypoglycemia. Method: A cohort of 311 patients with type 1 diabetes reported severe hypoglycemic events retrospectively in a validated questionnaire. The patients were characterized by diabetes history, state of hypoglycemia awareness, C-peptide status, HbA1c, and ADRB2 genotype. Results: The ADRB2 Gly16Arg genotype distribution was in Hardy-Weinberg equilibrium. The rate of severe hypoglycemia differed among all genotypes (P = 0.01). Patients homozygous for the Arg16 genotype (AA; n = 60) had a relative rate (RR) of severe hypoglycemia of 2.2 (95% CI, 1.3 to 3.6) compared with patients homozygous for the Gly16 genotype (GG; n = 116; P = 0.002). Among patients with impaired awareness or unawareness (n = 175), those with the AA genotype (n = 33) had an RR of severe hypoglycemia of 3.2 (95% CI, 1.7 to 6.0) compared with patients with the GG genotype (n = 58; P < 0.000). Genotype was not associated with state of hypoglycemia awareness per se, as assessed by any of three classification methods. The difference was not explained by other risk factors. Conclusion: Genetic polymorphism in ADRB2 is associated with risk of severe hypoglycemia in individuals with type 1 diabetes, especially in those with impaired hypoglycemia awareness.

ADRB2 gly16gly Genotype, Cardiac Output, and Cerebral Oxygenation in Patients Undergoing Anesthesia for Abdominal Aortic Aneurysm Surgery.

BACKGROUND: Gly16arg polymorphism of the adrenergic ß2-receptor is associated with the elevated cardiac output (Q) in healthy gly16-homozygotic subjects. We questioned whether this polymorphism also affects Q and regional cerebral oxygen saturation (SCO2) during anesthesia in vascular surgical patients. METHODS: One hundred sixty-eight patients (age 71 ± 6 years) admitted for elective surgery were included. Cardiovascular variables were determined before and during anesthesia by intravascular pulse contour analysis (Nexfin) and SCO2 by cerebral oximetry (INVOS 5100C). Genotyping was performed with the TaqMan assay. RESULTS: Before anesthesia, Q and SCO2 were 4.7 ± 1.2 L/min and 66% ± 8%, respectively, and linearly correlated (r = 0.35, P < .0001). In patients with the gly16gly genotype baseline, Q was approximately 0.4 L/min greater than in arg16 carriers (CI95: 0.0-0.8, Pt test = .03), but during anesthesia, the difference was 0.3 L/min (Pmixed-model = .07). Post hoc analysis revealed the change in SCO2 from baseline to the induction of anesthesia to be on average 2% greater in gly16gly homozygotes than in arg16 patients when adjusted for the change in Q (P = .03; CI95: 0.2-4.0%). CONCLUSIONS: This study suggests that the ß2-adrenoceptor gly16gly genotype is associated with the elevated resting Q. An interesting trend to greater frontal lobe oxygenation at induction of anesthesia in patients with gly16gly genotype was found, but because of insufficient sample size and lack of PCO2 control throughout the measurements, the presented data may only serve as the hypothesis generating for future studies. The confidence limits indicate that the magnitude of the effects may range from clinically insignificant to potentially important.