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Metformin hydrochloride (Met) is the first-line drug to treat type 2 diabetes and has shown high efficiency in reducing Alzheimer's disease in recent studies. Herein, a borneol W/O/W composite submicron emulsion containing Met (B-Met-W/O/W SE) was prepared, expecting longer in-vivo circulation time, better bioavailability and brain targeting of Met drug. In the optimized formulation, the mean droplets size, polydispersity index and encapsulation efficiency of the composite were 386.5 nm, 0.219 and 87.26%, respectively. FTIR analysis confirmed that Met interacted with carriers in B-Met-W/O/W SE. Compared with Met free drug, in-vitro release of Met in B-Met-W/O/W SE delivery system was much slower. In pharmacokinetic studies in rats, the AUC, MRT and t of the B-Met-W/O/W SE system were respectively 1.27, 2.49 and 4.02-fold higher than Met free drug system. The drug-targeting index of B-Met-W/O/W SE system to the brain tissue was also higher than that of Met free drug system and Met-W/O/W SE system. These results indicated that B-Met-W/O/W SE drug delivery system is a promising candidate in treating clinical Alzheimer's disease.
Copyright © 2019 Elsevier B.V. All rights reserved.
PURPOSE - Several observational studies suggest that metformin reduces incidence cancer risk; however, many of these studies suffer from time-related biases and several cancer outcomes have not been investigated due to small sample sizes.
METHODS - We constructed a propensity score-matched retrospective cohort of 84,434 veterans newly prescribed metformin or a sulfonylurea as monotherapy. We used Cox proportional hazard regression to assess the association between metformin use compared to sulfonylurea use and incidence cancer risk for 10 solid tumors. We adjusted for clinical covariates including hemoglobin A1C, antihypertensive and lipid-lowering medications, and body mass index. Incidence cancers were defined by ICD-9-CM codes.
RESULTS - Among 42,217 new metformin users and 42,217 matched-new sulfonylurea users, we identified 2,575 incidence cancers. Metformin was inversely associated with liver cancer (adjusted hazard ratio [aHR] = 0.44, 95% CI 0.31, 0.64) compared to sulfonylurea. We found no association between metformin use and risk of incidence bladder, breast, colorectal, esophageal, gastric, lung, pancreatic, prostate, or renal cancer when compared to sulfonylurea use.
CONCLUSIONS - In this large cohort study that accounted for time-related biases, we observed no association between the use of metformin and most cancers; however, we found a strong inverse association between metformin and liver cancer. Randomized trials of metformin for prevention of liver cancer would be useful to verify these observations.
Previous studies by us and others have indicated that renal epidermal growth factor receptors (EGFR) are activated in models of diabetic nephropathy (DN) and that inhibition of EGFR activity protects against progressive DN in type 1 diabetes. In this study we examined whether inhibition of EGFR activation would affect the development of DN in a mouse model of accelerated type 2 diabetes (BKS with endothelial nitric oxide knockout [eNOS]). eNOS mice received vehicle or erlotinib, an inhibitor of EGFR tyrosine kinase activity, beginning at 8 weeks of age and were sacrificed at 20 weeks of age. In addition, genetic models inhibiting EGFR activity () and transforming growth factor-α () were studied in this model of DN in type 2 diabetes. Compared with vehicle-treated mice, erlotinib-treated animals had less albuminuria and glomerulosclerosis, less podocyte loss, and smaller amounts of renal profibrotic and fibrotic components. Erlotinib treatment decreased renal oxidative stress, macrophage and T-lymphocyte infiltration, and the production of proinflammatory cytokines. Erlotinib treatment also preserved pancreas function, and these mice had higher blood insulin levels at 20 weeks, decreased basal blood glucose levels, increased glucose tolerance and insulin sensitivity, and increased blood levels of adiponectin compared with vehicle-treated mice. Similar to the aforementioned results, both and diabetic mice also had attenuated DN, preserved pancreas function, and decreased basal blood glucose levels. In this mouse model of accelerated DN, inhibition of EGFR signaling led to increased longevity.
© 2018 by the American Diabetes Association.
Adherence to diabetes management is a challenge for adolescents with type 1 diabetes (T1D). Positive psychology interventions have improved adherence to treatment recommendations in adults with chronic health conditions but have not been widely tested in pediatric populations. We hypothesized that higher engagement with a text-messaging intervention to promote positive affect would increase the effects on diabetes management among adolescents with T1D. Adolescents with T1D (n = 48) and their caregivers were randomized to either an attention control condition or a novel positive psychology intervention delivered through personalized automated text messaging. We examined rates of engagement (percent response to text messages) in relation to demographic factors, and we explored the effect of engagement in relation to adherence and glycemic control. Adolescent engagement was good (mean response rate of 76%) over the 8-week intervention. Engagement was related to adolescents' gender, race, baseline glycemic control, and blood glucose monitoring, but not to treatment type (pump vs. injection), diabetes duration, age, or household income. There was a significant effect of level of engagement on better caregiver-reported adherence, but adolescents' engagement was not related to self-reported adherence or glycemic control. These results indicate feasibility and initial efficacy of using automated text-messaging to deliver an intervention aimed at promoting adherence in adolescents with T1D.
Islet β cells from newborn mammals exhibit high basal insulin secretion and poor glucose-stimulated insulin secretion (GSIS). Here we show that β cells of newborns secrete more insulin than adults in response to similar intracellular Ca concentrations, suggesting differences in the Ca sensitivity of insulin secretion. Synaptotagmin 4 (Syt4), a non-Ca binding paralog of the β cell Ca sensor Syt7, increased by ∼8-fold during β cell maturation. Syt4 ablation increased basal insulin secretion and compromised GSIS. Precocious Syt4 expression repressed basal insulin secretion but also impaired islet morphogenesis and GSIS. Syt4 was localized on insulin granules and Syt4 levels inversely related to the number of readily releasable vesicles. Thus, transcriptional regulation of Syt4 affects insulin secretion; Syt4 expression is regulated in part by Myt transcription factors, which repress Syt4 transcription. Finally, human SYT4 regulated GSIS in EndoC-βH1 cells, a human β cell line. These findings reveal the role that altered Ca sensing plays in regulating β cell maturation.
Copyright © 2018 Elsevier Inc. All rights reserved.
The frequency of prediabetes is increasing as the prevalence of obesity rises worldwide. In prediabetes, hyperglycemia, insulin resistance, and inflammation and metabolic derangements associated with concomitant obesity cause endothelial vasodilator and fibrinolytic dysfunction, leading to increased risk of cardiovascular and renal disease. Importantly, the microvasculature affects insulin sensitivity by affecting the delivery of insulin and glucose to skeletal muscle; thus, endothelial dysfunction and extracellular matrix remodeling promote the progression from prediabetes to diabetes mellitus. Weight loss is the mainstay of treatment in prediabetes, but therapies that improved endothelial function and vasodilation may not only prevent cardiovascular disease but also slow progression to diabetes mellitus.
© 2018 American Heart Association, Inc.
Purpose - The current study compares the relative strength of associations of different adherence measures with glycemic control in adolescents with type 1 diabetes, while highlighting the challenges in using more objective measures (i.e., glucometer data).
Methods - Adolescents with type 1 diabetes ( = 149) and their caregivers completed a questionnaire measure assessing adolescents' adherence (Self-Care Inventory (SCI)) to the diabetes regimen. Adolescents' glucometers were downloaded to determine average blood glucose checks per day, as an objective measure of adherence. A measure of glycemic control (hemoglobin A1c (HbA1c)) was obtained as part of adolescents' regular clinic visits.
Results - Adolescents' self-reported adherence to the treatment regimen was more strongly correlated with HbA1c than caregivers' reports of adherence. In multivariate analyses, both adolescents' self-report of adherence and average blood glucose checks per day (obtained via a glucometer) were significant predictors of HbA1c. Challenges to obtaining glucometer data were identified.
Conclusions - The findings highlight adolescents' self-report of adherence using the SCI as a brief and meaningful measure to understand and improve adolescents' glycemic control, particularly when glucometer data is difficult to obtain.
The purpose of this study is to examine timing of meal insulin and further determine whether an association exists between timing of meal insulin and missed meal insulin doses. The cohort included 4768 T1D Exchange clinic registry participants <26 years with type 1 diabetes ≥1 year. Chi-square tests, t-tests, and regression were used to assess the relationship between participant characteristics and timing of meal insulin and missed meal doses, respectively. Timing of meal insulin and association with missed meal doses was analyzed using logistic regression. In all, 21% reported administering insulin several minutes before, 44% immediately before, 10% during, and 24% after meal. Participants who gave insulin prior to a meal had significantly lower HbA1c than those who gave insulin during or after meal (8.4% ± 1.5% vs 8.8% ± 1.6%, adjusted P < .001), but no significant association was observed regarding DKA events. Those who reported missing ≥1 insulin dose per week had higher HbA1c (9.8% ± 1.9% vs 8.3% ± 1.3%, adjusted P < .001) and were more likely to experience at least one DKA event (9% vs 5%, adjusted P = .001) compared with those who rarely missed a meal insulin dose. Participants who reported administering insulin during or after a meal were more likely to report missing ≥1 meal insulin dose per week compared with those who administered insulin before a meal (28% vs 14%, adjusted P < .001). Premeal insulin was associated with lower HbA1c and fewer missed meal insulin doses. Providers may use this information to discuss the benefits of premeal insulin on glycemic control and adherence to therapy.
The contribution of hormone-independent counterregulatory signals in defense of insulin-induced hypoglycemia was determined in adrenalectomized, overnight-fasted conscious dogs receiving hepatic portal vein insulin infusions at a rate 20-fold basal. Either euglycemia was maintained () or hypoglycemia (≈45 mg/dl) was allowed to occur. There were three hypoglycemic groups: one in which hepatic autoregulation against hypoglycemia occurred in the absence of sympathetic nervous system input (), one in which autoregulation occurred in the presence of norepinephrine (NE) signaling to fat and muscle (), and one in which autoregulation occurred in the presence of NE signaling to fat, muscle, and liver (). Average net hepatic glucose balance (NHGB) during the last hour for was -0.7 ± 0.1, 0.3 ± 0.1 ( < 0.01 vs. ), 0.7 ± 0.1 ( = 0.01 vs. ), and 0.8 ± 0.1 ( = 0.7 vs. ) mg·kg·min, respectively. Hypoglycemia per se () increased NHGB by causing an inhibition of net hepatic glycogen synthesis. NE signaling to fat and muscle () increased NHGB further by mobilizing gluconeogenic precursors resulting in a rise in gluconeogenesis. Lowering glucose per se decreased nonhepatic glucose uptake by 8.9 mg·kg·min, and the addition of increased neural efferent signaling to muscle and fat blocked glucose uptake further by 3.2 mg·kg·min The addition of increased neural efferent input to liver did not affect NHGB or nonhepatic glucose uptake significantly. In conclusion, even in the absence of increases in counterregulatory hormones, the body can defend itself against hypoglycemia using glucose autoregulation and increased neural efferent signaling, both of which stimulate hepatic glucose production and limit glucose utilization.
Copyright © 2017 the American Physiological Society.
BACKGROUND - Medications that impact insulin sensitivity or cause weight gain may increase heart failure risk. Our aim was to compare heart failure and cardiovascular death outcomes among patients initiating sulfonylureas for diabetes mellitus treatment versus metformin.
METHODS AND RESULTS - National Veterans Health Administration databases were linked to Medicare, Medicaid, and National Death Index data. Veterans aged ≥18 years who initiated metformin or sulfonylureas between 2001 and 2011 and whose creatinine was <1.4 (females) or 1.5 mg/dL (males) were included. Each metformin patient was propensity score-matched to a sulfonylurea initiator. The outcome was hospitalization for acute decompensated heart failure as the primary reason for admission or a cardiovascular death. There were 126 867 and 79 192 new users of metformin and sulfonylurea, respectively. Propensity score matching yielded 65 986 per group. Median age was 66 years, and 97% of patients were male; hemoglobin A 6.9% (6.3, 7.7); body mass index 30.7 kg/m (27.4, 34.6); and 6% had heart failure history. There were 1236 events (1184 heart failure hospitalizations and 52 cardiovascular deaths) among sulfonylurea initiators and 1078 events (1043 heart failure hospitalizations and 35 cardiovascular deaths) among metformin initiators. There were 12.4 versus 8.9 events per 1000 person-years of use (adjusted hazard ratio 1.32, 95%CI 1.21, 1.43). The rate difference was 4 heart failure hospitalizations or cardiovascular deaths per 1000 users of sulfonylureas versus metformin annually.
CONCLUSIONS - Predominantly male patients initiating treatment for diabetes mellitus with sulfonylurea had a higher risk of heart failure and cardiovascular death compared to similar patients initiating metformin.
© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.