Effects of Dapagliflozin on 24-Hour Glycemic Control in Patients with Type 2 Diabetes: A Randomized Controlled Trial.

BACKGROUND: Glycated hemoglobin (HbA1c) and measures of short-term glycemia do not fully capture daily patterns in plasma glucose dynamics. This study evaluated 24-h glycemic profiles in patients with type 2 diabetes (T2D) initiated on dapagliflozin treatment using continuous glucose monitoring (CGM). METHODS: This randomized double-blind placebo-controlled multicenter parallel-design 4-week study compared dapagliflozin (10 mg/d; n = 50) with placebo (n = 50) in adult patients with T2D uncontrolled (HbA1c 7.5%-10.5%) on either stable doses of metformin monotherapy (≥1500 mg/d) or insulin (≥30 U/d with or without up to two oral antidiabetes drugs). CGM was used to measure 24-h glycemic profiles for 7 days pretreatment and during week 4 of treatment. The primary outcome was change from baseline in 24-h mean glucose (MG) at week 4. RESULTS: The 24-h MG decreased 18.2 mg/dL with dapagliflozin and increased 5.8 mg/dL with placebo (P < 0.001). The proportion of time spent in the target glucose range (70-180 mg/dL) increased significantly with dapagliflozin versus placebo (69.6% vs. 52.9%; P < 0.001), with a small (0.3%) increase in time spent in the hypoglycemic range (<70 mg/dL), driven by those on background insulin therapy. Dapagliflozin reduced postprandial glucose and significantly decreased overall glucose variability. Few events of symptomatic hypoglycemia occurred. The most common adverse event was urinary tract infection (6% in each treatment arm). CONCLUSIONS: Compared with placebo, dapagliflozin improved measures of glycemic control and variability as assessed by CGM. Glycemic improvements were more pronounced in the group on background metformin than those receiving basal insulin.

Exenatide once weekly improved 24-hour glucose control and reduced glycaemic variability in metformin-treated participants with type 2 diabetes: a randomized, placebo-controlled trial.

AIM: To assess the effects of once-weekly exenatide on 24-hour glucose control and variability. MATERIALS AND METHODS: This double-blind, placebo-controlled trial randomized metformin-treated adults with type 2 diabetes to once-weekly exenatide 2.0 mg or placebo. Continuous glucose monitoring (CGM) was performed at baseline and weeks 4 and 10. The primary outcome was change in CGM-measured 24-hour mean glucose level. RESULTS: In the once-weekly exenatide (n = 60) and placebo (n = 56) groups (modified intention-to-treat population), the baseline glycated haemoglobin (HbA1c) concentrations were 8.2% and 8.0%, respectively, and the fasting plasma glucose (FPG) concentration was 9.86 and 9.32 mmol/L, respectively. Once-weekly exenatide significantly (p < 0.001) reduced 24-hour mean glucose level versus placebo (week 4, -1.44 vs -0.29 mmol/L; week 10, -1.71 vs -0.17 mmol/L), with consistent control throughout the week. Once-weekly exenatide significantly reduced FPG and 2-hour postprandial glucose (PPG) levels versus placebo at week 4 (FPG, -1.65 vs -0.11 mmol/L; PPG, -1.79 vs -0.11 mmol/L) and week 10 (FPG, -2.32 vs -0.28 mmol/L; PPG, -2.46 vs -0.33 mmol/L). At week 10, once-weekly exenatide reduced the mean amplitude of glucose excursions (MAGE; -0.84 vs 0.16 mmol/L) and standard deviation (s.d.) of mean glucose (-0.35 vs 0.04 mmol/L). By week 10, once-weekly exenatide-treated participants spent more time in euglycaemia (once-weekly exenatide, 77% vs placebo, 58%), less time in hyperglycaemia (22% vs 42%), and a similar time in hypoglycaemia (0.7% vs 0.3%). Common adverse events were injection-site nodule (once-weekly exenatide, 10.0% vs placebo, 0.0%), urinary tract infection (6.7% vs 8.9%) and nausea (6.7% vs 0.0%). CONCLUSIONS: In metformin-treated participants with type 2 diabetes, once-weekly exenatide significantly improved daily glucose control and reduced glycaemic variability at weeks 4 and 10, as shown by reductions in 24-hour glucose, FPG and PPG levels, MAGE and s.d., and increased time spent in euglycaemia.

The nuclear matrix shell proteome of human epidermis.

BACKGROUND: Proteomic approaches have identified cancer specific biomarker proteins in the nuclear matrix fraction of cancer cells. We wanted to determine whether a similar approach could be used to investigate melanoma biomarkers. OBJECTIVE: Since it was not clear that a nuclear matrix fraction could be isolated from the intact human epidermis, we first wanted to determine whether a nuclear matrix fraction could be isolated from the intact epidermis of human skin. If this was possible, we secondarily wanted to compare the proteome of cultured melanoma and carcinoma cells to that of the intact epidermis. METHODS: We applied two-dimensional electrophoresis (2DGE) and LC/MS/MS to identify proteins isolated in the nuclear matrix shell protein fraction isolated from the human epidermis and from cultured primary skin and cancer cells. RESULTS: A subcellular fractionation of intact epidermis succeeded in yielding a nuclear matrix shell which made up approximately 40% of total tissue protein. Only 5-10% of total cell protein was fractionated in the nuclear matrix shell of cultured skin cells. The nuclear matrix shell of the intact epidermis was distinguishable from cultured keratinocytes or HaCaT cells by expression of keratin 1. The nuclear matrix of the epidermis was distinguishable from melanocytes and melanoma cells by expression of vimentin in melanocyte-derived cells and by expression of desmoplakin in the intact epidermis. CONCLUSION: The nuclear matrix-intermediate filament system can be isolated from the intact human epidermis. A careful examination of the protein composition of this subcellular fraction from the epidermis and skin cancers may identify useful cancer specific biomarkers.

Protein phosphorylation in irradiated human melanoma cells.

In the present study, we examined the response of confluent, primary human fibroblasts and cells of a melanoma (YUSAC2) cell line to ionizing radiation mediated through post-translational protein phosphorylation. Since the purpose of our study was to identify novel radiation-induced phosphoproteins in the DNA damage stress response of melanoma cells, we were primarily interested in changes in protein phosphoserine expression at early times after irradiation. Our rationale was that by examining the overall protein phosphorylation profile (the phosphoproteome) in irradiated cells, we might discover novel radiation-induced phosphoproteins that distinguish fibroblasts from melanoma cells. Cell proteins were separated by gel electrophoresis and phosphoproteins were identified by Western blot analysis using nonspecific anti-phosphoamino acid antibodies. This approach was not pursued previously since adequate antibodies for examining global protein phosphoserine expression were unavailable. While some radiation-induced phosphoprotein changes in high-abundance proteins were identified, in general the sensitivity of this approach was not sufficient to detect changes in low-abundance, regulatory proteins. Characterization of these phosphoproteins will require greater enrichment of low-abundance proteins.

Mechanism of dipyridamole's action in inhibition of venous and arterial smooth muscle cell proliferation.

Dipyridamole is a potential pharmacological agent to prevent vascular stenosis because of its antiproliferative properties. The mechanisms by which dipyridamole inhibits the growth of vascular smooth muscle cells, especially venous smooth muscle cells, are unclear. In the present study, dipyridamole transiently but significantly increased cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels in human venous and arterial smooth muscle cells in a time- and dose-dependent manner. Peak concentrations of both cyclic nucleotides were achieved at 15-30 min. and correlated with inhibition of proliferation in both cell types. The antiproliferative effects of dipyridamole observed at 48 hr were similar whether drug exposure was only 15 min. or sustained for 48 hr. Specific competitive inhibitors of protein kinases A and G attenuated the antiproliferative effects of subsaturating concentrations of dipyridamole, with the effects of protein kinase inhibition being particularly pronounced in venous smooth muscle cells. Flow cytometry analysis showed that dipyridamole caused an enrichment of cells in G(0)/G(1) and a corresponding reduction of cells in S phase. These data indicate that a transient increase in cGMP and cAMP is sufficient to induce downstream kinase activation and subsequent cell cycle arrest, and that protein kinase G may be more important than protein kinase A in mediating the growth inhibitory effect of dipyridamole in venous protein kinase.

Inhibition of neointimal hyperplasia in vascular grafts by sustained perivascular delivery of paclitaxel.

BACKGROUND: Neointimal hyperplasia occurs commonly at the anastomoses of arteriovenous grafts for chronic hemodialysis, causing stenosis and occlusion. Antiproliferative drugs may be effective in inhibiting hyperplasia, but local drug delivery would be required to minimize systemic side effects. We examined the feasibility of local drug delivery to inhibit neointimal hyperplasia at dialysis grafts in a canine model. METHODS: Bilateral polytetrafluoroethylene loop grafts (10-cm length and 6-mm internal diameter) were placed between the femoral artery and ipsilateral femoral vein of five mongrel dogs. At the time of surgery or 1 to 5 weeks later, 2 mL of a thermosensitive biodegradable copolymer (ReGel) mixed with 0.26 mg or 0.65 mg paclitaxel were applied to the external surface of one graft around the anastomoses to provide a depot for sustained release of the drug. ReGel alone without paclitaxel was applied to the contralateral graft as a control. The grafts and the connecting vessels were explanted at eight or nine weeks, and the cross-sections were examined histologically. The degree of hyperplasia at the anastomoses was graded by five blinded independent reviewers, with scores ranging from 0 to 5. RESULTS: The median (25th-75th percentile) hyperplasia score of both arterial and venous anastomoses was 1.80 (0.90-3.05) in the grafts treated with ReGel alone, and 0.95 (0.70-1.50) in the grafts treated with ReGel/paclitaxel (N= 8; P < 0.05 by Wilcoxon signed rank test). There were no noticeable localized or systemic complications attributed to the treatments in these animals. Paclitaxel levels in the plasma obtained from forelimb veins were undetectable (<10 ng/mL). CONCLUSION: These results suggest that the local delivery of antiproliferative agents using a thermosensitive, injectable biodegradable copolymer (ReGel) for sustained delivery is a promising strategy to inhibit neointimal hyperplasia of arteriovenous hemodialysis grafts.