Effect of bromocriptine-QR (a quick-release formulation of bromocriptine mesylate) on major adverse cardiovascular events in type 2 diabetes subjects

DCRM 2.0: Multispecialty practice recommendations for the management of diabetes, cardiorenal, and metabolic diseases

The spectrum of cardiorenal and metabolic diseases comprises many disorders, including obesity, type 2 diabetes (T2D), chronic kidney disease (CKD), atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), dyslipidemias, hypertension, and associated comorbidities such as pulmonary diseases and metabolism dysfunction-associated steatotic liver disease and metabolism dysfunction-associated steatohepatitis (MASLD and MASH, respectively, formerly known as nonalcoholic fatty liver disease and nonalcoholic steatohepatitis [NAFLD and NASH]). Because cardiorenal and metabolic diseases share pathophysiologic pathways, two or more are often present in the same individual. Findings from recent outcome trials have demonstrated benefits of various treatments across a range of conditions, suggesting a need for practice recommendations that will guide clinicians to better manage complex conditions involving diabetes, cardiorenal, and/or metabolic (DCRM) diseases. To meet this need, we formed an international volunteer task force comprising leading cardiologists, nephrologists, endocrinologists, and primary care physicians to develop the DCRM 2.0 Practice Recommendations, an updated and expanded revision of a previously published multispecialty consensus on the comprehensive management of persons living with DCRM. The recommendations are presented as 22 separate graphics covering the essentials of management to improve general health, control cardiorenal risk factors, and manage cardiorenal and metabolic comorbidities, leading to improved patient outcomes.

Efficacy and Safety of Bromocriptine-QR as an Adjunctive Therapy on Glycemic Control in Subjects with Uncontrolled Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis

Introduction

There has been an increasing awareness of the effects of combining bromocriptine-QR with other medications for diabetes mellitus type 2. This study aimed to assess the efficacy and safety of bromocriptine-QR as an adjunctive therapy for patients with uncontrolled type 2 diabetes mellitus.

Methodology

This systematic review is registered at the International Prospective Register of Systematic Reviews (CRD42022360326). Literature search was done via MEDLINE, NCBI, Google Scholar, Science Direct, Europe PMC and Cochrane Library databases. We included randomized controlled trials with participants 18 years old and above with uncontrolled type 2 diabetes mellitus. The primary outcome of interest is the efficacy and safety of bromocriptine-QR as an adjunctive therapy for glycemic control. Case reports, case series, reviews and animal studies were excluded. The risk of bias was reviewed using the Cochrane Risk of Bias tool. Meta-analysis was performed using Review Manager 5.4 and presented as a weighted mean difference and 95% confidence interval for changes from the baseline level.

Results

Nine studies were included in the systematic review with a total of 2709 participants. The baseline HbA1c in the bromocriptine-QR group was 7.42% and 7.51% in the control group. The bromocriptine-QR group was favoured, outperforming the control group in terms of reducing hemoglobin A1c(HbA1c), with a statistically significant difference (weighted mean difference -0.6%; 95% CI [-0.83,-0.36]; p<0.00001). The most common side effects were nausea (33.75% vs 6.92%), fatigue (13.11% vs 5.94%), and headache (11.17% vs 6.87%).

Conclusion

Administration of bromocriptine-QR at a dose range of 1.6 to 4.8 mg/day as an adjunctive therapy reduced HbA1c and FBG in patients with uncontrolled type 2 diabetes mellitus (T2DM). However, there were also statistically greater odds of the occurrence of adverse events such as nausea, vomiting, and headache compared to controls.

Bromocriptine: does this drug of Parkinson's disease have a role in managing cardiovascular diseases?

Cardiovascular disease (CVD) is the most common cause of morbidity and mortality worldwide. Bromocriptine is a partial antagonist for D1 dopamine receptors while also serving as a selective agonist on D2 dopamine receptors as a dopamine receptor agonist. Apart from prolactin inhibiting action, bromocriptine has some beneficial effects on the blood pressure, plasma norepinephrine levels and vascular resistance. Dopamine D2 receptor activation of bromocriptine is associated with the antihypertensive effect, which lowers blood pressure via inhibiting sympathetic nerve activity and Na/K ATPase activity. Plasma levels of the pro-inflammatory cytokines such as interleukin (IL)-1B and IL-18, chemokine CCL2/ MCP-1/, and the pro-inflammatory hormone prolactin, all of which are elevated and linked to accelerated cardiometabolic illness, were decreased because of bromocriptine therapy. The most common side effects of Bromocriptine use are dizziness, nausea, headache, vomiting and hypotension. Bromocriptine is mainly contraindicated in patients with syncope with hypotension, psychosis, and type I diabetes mellitus. The authors suggest that developing therapies directed to increase D2 receptor expression and function by drugs like Bromocriptine can provide practical and novelistic approaches to prevent and manage myocardial and renal injury in the cardiovascular disease patients.

Brain Dopamine-Clock Interactions Regulate Cardiometabolic Physiology: Mechanisms of the Observed Cardioprotective Effects of Circadian-Timed Bromocriptine-QR Therapy in Type 2 Diabetes Subjects

Despite enormous global efforts within clinical research and medical practice to reduce cardiovascular disease(s) (CVD), it still remains the leading cause of death worldwide. While genetic factors clearly contribute to CVD etiology, the preponderance of epidemiological data indicate that a major common denominator among diverse ethnic populations from around the world contributing to CVD is the composite of Western lifestyle cofactors, particularly Western diets (high saturated fat/simple sugar [particularly high fructose and sucrose and to a lesser extent glucose] diets), psychosocial stress, depression, and altered sleep/wake architecture. Such Western lifestyle cofactors are potent drivers for the increased risk of metabolic syndrome and its attendant downstream CVD. The central nervous system (CNS) evolved to respond to and anticipate changes in the external (and internal) environment to adapt survival mechanisms to perceived stresses (challenges to normal biological function), including the aforementioned Western lifestyle cofactors. Within the CNS of vertebrates in the wild, the biological clock circuitry surveils the environment and has evolved mechanisms for the induction of the obese, insulin-resistant state as a survival mechanism against an anticipated ensuing season of low/no food availability. The peripheral tissues utilize fat as an energy source under muscle insulin resistance, while increased hepatic insulin resistance more readily supplies glucose to the brain. This neural clock function also orchestrates the reversal of the obese, insulin-resistant condition when the low food availability season ends. The circadian neural network that produces these seasonal shifts in metabolism is also responsive to Western lifestyle stressors that drive the CNS clock into survival mode. A major component of this natural or Western lifestyle stressor-induced CNS clock neurophysiological shift potentiating the obese, insulin-resistant state is a diminution of the circadian peak of dopaminergic input activity to the pacemaker clock center, suprachiasmatic nucleus. Pharmacologically preventing this loss of circadian peak dopaminergic activity both prevents and reverses existing metabolic syndrome in a wide variety of animal models of the disorder, including high fat-fed animals. Clinically, across a variety of different study designs, circadian-timed bromocriptine-QR (quick release) (a unique formulation of micronized bromocriptine-a dopamine D2 receptor agonist) therapy of type 2 diabetes subjects improved hyperglycemia, hyperlipidemia, hypertension, immune sterile inflammation, and/or adverse cardiovascular event rate. The present review details the seminal circadian science investigations delineating important roles for CNS circadian peak dopaminergic activity in the regulation of peripheral fuel metabolism and cardiovascular biology and also summarizes the clinical study findings of bromocriptine-QR therapy on cardiometabolic outcomes in type 2 diabetes subjects.

Effect of bromocriptine on glycemic control, risk of cardiovascular diseases and weight in patients with type 2 diabetes: a systematic review

BACKGROUND

Type 2 diabetes (T2DM) patients, including those in good glycemic control, have an increased risk of cardiovascular disease (CVD). Maintaining good glycemic control with drugs may reduce long-term CVD risk. Bromocriptine has been in clinical use for over 30 years, but the utility of bromocriptine in the treatment of diabetes patients has been proposed more recently.

OBJECTIVE

To summarize the available data regarding the effect of bromocriptine in T2DM management.

METHOD

A systematic literature search was conducted in the electronic databases, including Google Scholar, PubMed, Medline, and Science Direct, to locate studies that meet the objectives of this systematic review. Additional articles were included by conducting direct Google searches of the references cited by eligible articles located by the database search. The following search terms were used on PubMed "bromocriptine OR dopamine agonist AND diabetes mellitus OR hyperglycemia OR obese".

RESULT

Eight studies were included in the final analysis. 6210 of the 9391 study participants received bromocriptine treatment, while 3183 received a placebo. The studies demonstrated that patients who took bromocriptine treatment had significantly reduced blood glucose and BMI, which is the main cardiovascular risk factor in T2DM patients.

CONCLUSION

Based on this systematic review, bromocriptine may be used for T2DM treatment for its cardiovascular risk reduction effect, especially body weight reduction. However, advanced study designs might be warranted.

Anti-Diabetic Therapy and Heart Failure: Recent Advances in Clinical Evidence and Molecular Mechanism

Diabetic patients have a two- to four-fold increase in the risk of heart failure (HF), and the co-existence of diabetes and HF is associated with poor prognosis. In randomized clinical trials (RCTs), compelling evidence has demonstrated the beneficial effects of sodium-glucose co-transporter-2 inhibitors on HF. The mechanism includes increased glucosuria, restored tubular glomerular feedback with attenuated renin-angiotensin II-aldosterone activation, improved energy utilization, decreased sympathetic tone, improved mitochondria calcium homeostasis, enhanced autophagy, and reduced cardiac inflammation, oxidative stress, and fibrosis. The RCTs demonstrated a neutral effect of the glucagon-like peptide receptor agonist on HF despite its weight-reducing effect, probably due to it possibly increasing the heart rate via increasing cyclic adenosine monophosphate (cAMP). Observational studies supported the markedly beneficial effects of bariatric and metabolic surgery on HF despite no current supporting evidence from RCTs. Bromocriptine can be used to treat peripartum cardiomyopathy by reducing the harmful cleaved prolactin fragments during late pregnancy. Preclinical studies suggest the possible beneficial effect of imeglimin on HF through improving mitochondrial function, but further clinical evidence is needed. Although abundant preclinical and observational studies support the beneficial effects of metformin on HF, there is limited evidence from RCTs. Thiazolidinediones increase the risk of hospitalized HF through increasing renal tubular sodium reabsorption mediated via both the genomic and non-genomic action of PPARγ. RCTs suggest that dipeptidyl peptidase-4 inhibitors, including saxagliptin and possibly alogliptin, may increase the risk of hospitalized HF, probably owing to increased circulating vasoactive peptides, which impair endothelial function, activate sympathetic tones, and cause cardiac remodeling. Observational studies and RCTs have demonstrated the neutral effects of insulin, sulfonylureas, an alpha-glucosidase inhibitor, and lifestyle interventions on HF in diabetic patients.

Bromocriptine Improves Central Aortic Stiffness in Adolescents With Type 1 Diabetes: Arterial Health Results From the BCQR-T1D Study

BACKGROUND

The presence of vascular dysfunction is a well-recognized feature in youth with type 1 diabetes (T1D), accentuating their lifetime risk of cardiovascular events. Therapeutic strategies to mitigate vascular dysfunction are a high clinical priority. In the bromocriptine quick release T1D study (BCQR-T1D), we tested the hypothesis that BCQR would improve vascular health in youth with T1D.

METHODS

BCQR-T1D was a placebo-controlled, random-order, double-blinded, cross-over study investigating the cardiovascular and metabolic impact of BCQR in T1D. Adolescents in the BCQR-T1D study were randomized 1:1 to phase-1: 4 weeks of BCQR or placebo after which blood pressure and central aortic stiffness measurements by pulse wave velocity, relative area change, and distensibility from phase-contrast magnetic resonance imaging were performed. Following a 4-week washout period, phase 2 was performed in identical fashion with the alternate treatment.

RESULTS

Thirty-four adolescents (mean age 15.9±2.6 years, hemoglobin A1c 8.6±1.1%, body mass index percentile 71.4±26.1, median T1D duration 5.8 years) with T1D were enrolled and had magnetic resonance imaging data available. Compared with placebo, BCQR therapy decreased systolic (∆=-5 mmHg [95% CI, -3 to -7]; P<0.001) and diastolic blood pressure (∆=-2 mmHg [95% CI, -4 to 0]; P=0.039). BCQR reduced ascending aortic pulse wave velocity (∆=-0.4 m/s; P=0.018) and increased relative area change (∆=-2.6%, P=0.083) and distensibility (∆=0.08%/mmHg; P=0.017). In the thoraco-abdominal aorta, BCQR decreased pulse wave velocity (∆=-0.2 m/s; P=0.007) and increased distensibility (∆=0.05 %/mmHg; P=0.013).

CONCLUSIONS

BCQR improved blood pressure and central and peripheral aortic stiffness and pressure hemodynamics in adolescents with T1D over 4 weeks versus placebo. BCQR may improve aortic stiffness in youth with T1D, supporting future longer-term studies.

Bromocriptine quick-release as adjunct therapy in youth and adults with type 1 diabetes: A randomized, placebo-controlled crossover study

AIM

To evaluate the potential for glycaemic, renal and vascular benefits of bromocriptine quick release (BCQR) in adolescents and adults with type 1 diabetes.

MATERIALS AND METHODS

Forty adolescents and 40 adults with type 1 diabetes aged 12-60 years old were enrolled in a double-blind, placebo-controlled, random order crossover study of 4 weeks of treatment in the morning with BCQR (titrated weekly from 0.8 mg to 1.6 mg to 3.2 mg, minimum dose 1.6 mg). Study assessments after each phase included blood pressure (BP), lipids, peripheral arterial stiffness and autonomic function, mixed meal tolerance test, continuous glucose monitoring (CGM), creatinine, estimated glomerular filtration rate, estimated insulin sensitivity, insulin dose and indirect calorimetry.

RESULTS

Adolescents displayed baseline hyperglycaemia, insulin resistance, metabolic dysfunction and increased renal filtration compared with adults. In both age groups, continuous glucose monitoring measures, estimated insulin sensitivity and insulin dose did not differ with BCQR treatment. In adolescents, BCQR decreased systolic BP, diastolic BP and triangular index and increased serum creatinine. In adults, systolic BP, mean arterial pressure, systemic vascular resistance, and mixed meal tolerance test glucose and glucagon-like peptide 1 areas under the curve were lower, and the orthostatic drop in systolic BP was greater with BCQR.

CONCLUSIONS

Greater hyperglycaemia, insulin resistance, metabolic dysfunction and renal hyperfiltration in adolescents argues for increased attention during this high-risk age period. Although BCQR had little impact on glycaemia or insulin sensitivity, initial vascular and renal responses suggest potential benefits of BCQR in adolescents and adults with type 1 diabetes requiring further study.

Bromocriptine-QR Therapy Reduces Sympathetic Tone and Ameliorates a Pro-Oxidative/Pro-Inflammatory Phenotype in Peripheral Blood Mononuclear Cells and Plasma of Type 2 Diabetes Subjects

Bromocriptine-QR is a sympatholytic dopamine D2 agonist for the treatment of type 2 diabetes that has demonstrated rapid (within 1 year) substantial reductions in adverse cardiovascular events in this population by as yet incompletely delineated mechanisms. However, a chronic state of elevated sympathetic nervous system activity and central hypodopaminergic function has been demonstrated to potentiate an immune system pro-oxidative/pro-inflammatory condition and this immune phenotype is known to contribute significantly to the advancement of cardiovascular disease (CVD). Therefore, the possibility exists that bromocriptine-QR therapy may reduce adverse cardiovascular events in type 2 diabetes subjects via attenuation of this underlying chronic pro-oxidative/pro-inflammatory state. The present study was undertaken to assess the impact of bromocriptine-QR on a wide range of immune pro-oxidative/pro-inflammatory biochemical pathways and genes known to be operative in the genesis and progression of CVD. Inflammatory peripheral blood mononuclear cell biology is both a significant contributor to cardiovascular disease and also a marker of the body’s systemic pro-inflammatory status. Therefore, this study investigated the effects of 4-month circadian-timed (within 2 h of waking in the morning) bromocriptine-QR therapy (3.2 mg/day) in type 2 diabetes subjects whose glycemia was not optimally controlled on the glucagon-like peptide 1 receptor agonist on (i) gene expression status (via qPCR) of a wide array of mononuclear cell pro-oxidative/pro-inflammatory genes known to participate in the genesis and progression of CVD (OXR1, NRF2, NQO1, SOD1, SOD2, CAT, GSR, GPX1, GPX4, GCH1, HMOX1, BiP, EIF2α, ATF4, PERK, XBP1, ATF6, CHOP, GSK3β, NFkB, TXNIP, PIN1, BECN1, TLR2, TLR4, TLR10, MAPK8, NLRP3, CCR2, GCR, L-selectin, VCAM1, ICAM1) and (ii) humoral measures of sympathetic tone (norepinephrine and normetanephrine), whole-body oxidative stress (nitrotyrosine, TBARS), and pro-inflammatory factors (IL-1β, IL-6, IL-18, MCP-1, prolactin, C-reactive protein [CRP]). Relative to pre-treatment status, 4 months of bromocriptine-QR therapy resulted in significant reductions of mRNA levels in PBMC endoplasmic reticulum stress-unfolded protein response effectors [GRP78/BiP (34%), EIF2α (32%), ATF4 (29%), XBP1 (25%), PIN1 (14%), BECN1 (23%)], oxidative stress response proteins [OXR1 (31%), NRF2 (32%), NQO1 (39%), SOD1 (52%), CAT (26%), GPX1 (33%), GPX4 (31%), GCH1 (30%), HMOX1 (40%)], mRNA levels of TLR pro-inflammatory pathway proteins [TLR2 (46%), TLR4 (20%), GSK3β (19%), NFkB (33%), TXNIP (18%), NLRP3 (32%), CCR2 (24%), GCR (28%)], mRNA levels of pro-inflammatory cellular receptor proteins CCR2 and GCR by 24% and 28%, and adhesion molecule proteins L-selectin (35%) and VCAM1 (24%). Relative to baseline, bromocriptine-QR therapy also significantly reduced plasma levels of norepinephrine and normetanephrine by 33% and 22%, respectively, plasma pro-oxidative markers nitrotyrosine and TBARS by 13% and 10%, respectively, and pro-inflammatory factors IL-18, MCP1, IL-1β, prolactin, and CRP by 21%,13%, 12%, 42%, and 45%, respectively. These findings suggest a unique role for circadian-timed bromocriptine-QR sympatholytic dopamine agonist therapy in reducing systemic low-grade sterile inflammation to thereby reduce cardiovascular disease risk.

Therapeutic potential of dopamine agonists in the treatment of type 2 diabetes mellitus

Diabetes is a global health concern that has affected almost 415 million people globally. Bromocriptine is a dopamine D2 agonist, which is a Food and Drug Administration (FDA)-approved drug to treat type 2 diabetes mellitus (T2DM) patients. However, it is considered that a novel treatment therapy is required which can be used in the treatment of diabetes with or without other antidiabetic agents. Dopamine agonists are usually used in neurological disorders like Parkinson's disease (PD), restless leg syndrome, and hyperprolactinemia. However, dopamine agonists including bromocriptine and cabergoline are also effective in reducing the glycemic level in T2DM patients. Bromocriptine was formerly used for the treatment of PD, hyperprolactinemia, and restless leg syndrome, but now it is used for improving glycemic levels as well as reducing free fatty acids and triglycerides. In addition, cabergoline has been found to be effective in glycemic control, but this drug is yet to be approved by the FDA due to its limitations and lack of study. Findings of the clinical trials of bromocriptine have suggested that it reduces almost 0.4-0.8% glycated hemoglobin and cardiovascular risk by 40% in insulin-resistant patients. Moreover, the safe use of bromocriptine in obese T2DM patients makes it a more attractive option as it causes weight loss. Indeed, bromocriptine is a novel therapy for T2DM patients, as its mechanism of action is unique in T2DM patients with minimal adverse effects. This review summarizes the potential of dopamine agonists in the treatment of T2DM.

Comparative effectiveness of cardiovascular, renal and safety outcomes of second-line antidiabetic drugs use in people with type 2 diabetes: A systematic review and network meta-analysis of randomised controlled trials

AIMS

To compare the cardiovascular, renal and safety outcomes of second-line glucose-lowering agents used in the management of people with type 2 diabetes.

METHODS

MEDLINE, EMBASE and CENTRAL were searched from inception to 13 July 2021 for randomised controlled trials comparing second-line glucose lowering therapies with placebo, standard care or one another. Primary outcomes included cardiovascular and renal outcomes. Secondary outcomes were non-cardiovascular adverse events. Risk ratios (RRs) and corresponding confidence intervals (CI) or credible intervals (CrI) were reported within pairwise and network meta-analysis. The quality of evidence was evaluated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) criteria. Number needed to treat (NNT) and number needed (NNH) to harm were calculated at 5 years using incidence rates and RRs. PROSPERO (CRD42020168322).

RESULTS

We included 38 trials from seven classes of glucose-lowering therapies. Both sodium-glucose co-transporter-2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP1RA) showed moderate to high certainty in reducing risk of 3-point major adverse cardiovascular events, 3P-MACE (network estimates: SGLT2i [RR 0.90; 95% CrI 0.84-0.96; NNT, 59], GLP1RA [RR 0.88; 95% CrI 0.83-0.93; NNT, 50]), cardiovascular death, all-cause mortality, renal composite outcome and macroalbuminuria. SGLT2i also showed high certainty in reducing risk of hospitalization for heart failure (hHF), ESRD, acute kidney injury, doubling in serum creatinine and decline in eGFR. GLP1RA were associated with lower risk of stroke (high certainty) while glitazone use was associated with an increased risk of hHF (very low certainty). The risk of developing ESRD was lower with the use of sulphonylureas (low certainty). For adverse events, sulphonylureas and insulin were associated with increased hypoglycaemic events (very low to low certainty), while GLP1RA increased the risk of gastrointestinal side effects leading to treatment discontinuation (low certainty). DPP-4i increased risk of acute pancreatitis (low certainty). SGLT2i were associated with increased risk of genital infection, volume depletion (high certainty), amputation and ketoacidosis (moderate certainty). Risk of fracture was increased with the use of glitazones (moderate certainty).

CONCLUSIONS

SGLT2i and GLP1RA were associated with lower risk for different cardiorenal end points, when used as an adjunct to metformin in people with type 2 diabetes. Additionally, SGLT2i demonstrated benefits in reducing risk for surrogate end points in kidney disease progression. Safety outcomes differ among the available pharmacotherapies.

DCRM Multispecialty Practice Recommendations for the management of diabetes, cardiorenal, and metabolic diseases

Type 2 diabetes (T2D), chronic kidney disease (CKD), atherosclerotic cardiovascular disease (ASCVD), and heart failure (HF)-along with their associated risk factors-have overlapping etiologies, and two or more of these conditions frequently occur in the same patient. Many recent cardiovascular outcome trials (CVOTs) have demonstrated the benefits of agents originally developed to control T2D, ASCVD, or CKD risk factors, and these agents have transcended their primary indications to confer benefits across a range of conditions. This evolution in CVOT evidence calls for practice recommendations that are not constrained by a single discipline to help clinicians manage patients with complex conditions involving diabetes, cardiorenal, and/or metabolic (DCRM) diseases. The ultimate goal for these recommendations is to be comprehensive yet succinct and easy to follow by the nonexpert-whether a specialist or a primary care clinician. To meet this need, we formed a volunteer task force comprising leading cardiologists, nephrologists, endocrinologists, and primary care physicians to develop the DCRM Practice Recommendations, a multispecialty consensus on the comprehensive management of the patient with complicated metabolic disease. The task force recommendations are based on strong evidence and incorporate practical guidance that is clinically relevant and simple to implement, with the aim of improving outcomes in patients with DCRM. The recommendations are presented as 18 separate graphics covering lifestyle therapy, patient self-management education, technology for DCRM management, prediabetes, cognitive dysfunction, vaccinations, clinical tests, lipids, hypertension, anticoagulation and antiplatelet therapy, antihyperglycemic therapy, hypoglycemia, nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), ASCVD, HF, CKD, and comorbid HF and CKD, as well as a graphical summary of medications used for DCRM.

The interplay between prolactin and cardiovascular disease

Hyperprolactinemia can be caused by several conditions and its effects on the hypothalamic-pituitary-gonadal axis are understood in more detail. Nevertheless, in recent decades, other metabolic effects have been studied and data pointed to a potential increased cardiovascular disease (CVD) risk. A recent study showed a decrease in total and LDL- cholesterol only in men with prolactinoma treated with dopamine agonists (DA) supporting the previous results of a population study with increased CVD risk in men harboring prolactinoma. However, other population studies did not find a correlation between prolactin (PRL) levels and CVD risk or mortality. There is also data pointing to an increase in high-density lipoprotein levels, and decreases in triglycerides, carotid-intima-media thickness, C-reactive protein, and homocysteine levels in patients with prolactinoma on DA treatment. PRL was also implicated in endothelial dysfunction in pre and postmenopausal women. Withdrawal of DA resulted in negative changes in vascular parameters and an increase in plasma fibrinogen. It has been shown that PRL levels were positively correlated with blood pressure and inversely correlated with dilatation of the brachial artery and insulin sensitivity, increased homocysteine levels, and elevated D-dimer levels. Regarding possible mechanisms for the association between hyperprolactinemia and CVD risk, they include a possible direct effect of PRL, hypogonadism, and even effects of DA treatment, independently of changes in PRL levels. In conclusion, hyperprolactinemia seems to be associated with impaired endothelial function and DA treatment could improve CVD risk. More studies evaluating CVD risk in hyperprolactinemic patients are important to define a potential indication of treatment beyond hypogonadism.

Time-of-Day-Dependent Effects of Bromocriptine to Ameliorate Vascular Pathology and Metabolic Syndrome in SHR Rats Held on High Fat Diet

The treatment of type 2 diabetes patients with bromocriptine-QR, a unique, quick release micronized formulation of bromocriptine, improves glycemic control and reduces adverse cardiovascular events. While the improvement of glycemic control is largely the result of improved postprandial hepatic glucose metabolism and insulin action, the mechanisms underlying the drug's cardioprotective effects are less well defined. Bromocriptine is a sympatholytic dopamine agonist and reduces the elevated sympathetic tone, characteristic of metabolic syndrome and type 2 diabetes, which potentiates elevations of vascular oxidative/nitrosative stress, known to precipitate cardiovascular disease. Therefore, this study investigated the impact of bromocriptine treatment upon biomarkers of vascular oxidative/nitrosative stress (including the pro-oxidative/nitrosative stress enzymes of NADPH oxidase 4, inducible nitric oxide (iNOS), uncoupled endothelial nitric oxide synthase (eNOS), the pro-inflammatory/pro-oxidative marker GTP cyclohydrolase 1 (GTPCH 1), and the pro-vascular health enzyme, soluble guanylate cyclase (sGC) as well as the plasma level of thiobarbituric acid reactive substances (TBARS), a circulating marker of systemic oxidative stress), in hypertensive SHR rats held on a high fat diet to induce metabolic syndrome. Inasmuch as the central nervous system (CNS) dopaminergic activities both regulate and are regulated by CNS circadian pacemaker circuitry, this study also investigated the time-of-day-dependent effects of bromocriptine treatment (10 mg/kg/day at either 13 or 19 h after the onset of light (at the natural waking time or late during the activity period, respectively) among animals held on 14 h daily photoperiods for 16 days upon such vascular biomarkers of vascular redox state, several metabolic syndrome parameters, and mediobasal hypothalamic (MBH) mRNA expression levels of neuropeptides neuropeptide Y (NPY) and agouti-related protein (AgRP) which regulate the peripheral fuel metabolism and of mRNA expression of other MBH glial and neuronal cell genes that support such metabolism regulating neurons in this model system. Such bromocriptine treatment at ZT 13 improved (reduced) biomarkers of vascular oxidative/nitrosative stress including plasma TBARS level, aortic NADPH oxidase 4, iNOS and GTPCH 1 levels, and improved other markers of coupled eNOS function, including increased sGC protein level, relative to controls. However, bromocriptine treatment at ZT 19 produced no improvement in either coupled eNOS function or sGC protein level. Moreover, such ZT 13 bromocriptine treatment reduced several metabolic syndrome parameters including fasting insulin and leptin levels, as well as elevated systolic and diastolic blood pressure, insulin resistance, body fat store levels and liver fat content, however, such effects of ZT 19 bromocriptine treatment were largely absent versus control. Finally, ZT 13 bromocriptine treatment reduced MBH NPY and AgRP mRNA levels and mRNA levels of several MBH glial cell/neuronal genes that code for neuronal support/plasticity proteins (suggesting a shift in neuronal structure/function to a new metabolic control state) while ZT 19 treatment reduced only AgRP, not NPY, and was with very little effect on such MBH glial cell genes expression. These findings indicate that circadian-timed bromocriptine administration at the natural circadian peak of CNS dopaminergic activity (that is diminished in insulin resistant states), but not outside this daily time window when such CNS dopaminergic activity is naturally low, produces widespread improvements in biomarkers of vascular oxidative stress that are associated with the amelioration of metabolic syndrome and reductions in MBH neuropeptides and gene expressions known to facilitate metabolic syndrome. These results of such circadian-timed bromocriptine treatment upon vascular pathology provide potential mechanisms for the observed marked reductions in adverse cardiovascular events with circadian-timed bromocriptine-QR therapy (similarly timed to the onset of daily waking as in this study) of type 2 diabetes subjects and warrant further investigations into related mechanisms and the potential application of such intervention to prediabetes and metabolic syndrome patients as well.

The Diabetes Syndrome - A Collection of Conditions with Common, Interrelated Pathophysiologic Mechanisms

The four basic pathophysiologic mechanisms which damage the β-cell within diabetes (ie, genetic and epigenetic changes, inflammation, an abnormal environment, and insulin resistance [IR]) also contribute to cell and tissue damage and elevate the risk of developing all typical diabetes-related complications. Genetic susceptibility to damage from abnormal external and internal environmental factors has been described including inflammation and IR. All these mechanisms can promote epigenetic changes, and in total, these pathophysiologic mechanisms interact and react with each other to cause damage to cells and tissues ultimately leading to disease. Importantly, these pathophysiologic mechanisms also serve to link other common conditions including cancer, dementia, psoriasis, atherosclerotic cardiovascular disease (ASCVD), nonalcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH). The “Diabetes Syndrome”, an overarching group of interrelated conditions linked by these overlapping mechanisms, can be viewed as a conceptual framework that can facilitate understanding of the inter-relationships of superficially disparate conditions. Recognizing the association of the conditions within the Diabetes Syndrome due to common pathophysiologies has the potential to provide both benefit to the patient (eg, prevention, early detection, precision medicine) and to the advancement of medicine (eg, driving education, research, and dynamic decision-based medical practice).

Pharmacological treatment of hyperglycemia in type 2 diabetes

Diabetes mellitus is a major public health problem, affecting about 10% of the population. Pharmacotherapy aims to protect against microvascular complications, including blindness, end-stage kidney disease, and amputations. Landmark clinical trials have demonstrated that intensive glycemic control slows progression of microvascular complications (retinopathy, nephropathy, and neuropathy). Long-term follow-up has demonstrated that intensive glycemic control also decreases risk of macrovascular disease, albeit rigorous evidence of macrovascular benefit did not emerge for over a decade. The US FDA's recent requirement for dedicated cardiovascular outcome trials ushered in a golden age for understanding the clinical profiles of new type 2 diabetes drugs. Some clinical trials with sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP1) receptor agonists reported data demonstrating cardiovascular benefit (decreased risk of major adverse cardiovascular events and hospitalization for heart failure) and slower progression of diabetic kidney disease. This Review discusses current guidelines for use of the 12 classes of drugs approved to promote glycemic control in patients with type 2 diabetes. The Review also anticipates future developments with potential to improve the standard of care: availability of generic dipeptidylpeptidase-4 (DPP4) inhibitors and SGLT2 inhibitors; precision medicine to identify the best drugs for individual patients; and new therapies to protect against chronic complications of diabetes.

The effect of dopamine agonists on metabolic variables in adults with type 2 diabetes: A systematic review with meta analysis and trial sequential analysis of randomized clinical trials

AIM

To assess the metabolic effects of dopamine agonists compared with placebo in randomized controlled trials (RCTs) including adults with type 2 diabetes.

MATERIALS AND METHODS

Eligible trials were identified by searching PubMed, Embase and CENTRAL. The primary outcomes were HbA1c and serious adverse events (SAEs) assessed at longest available follow-up. Secondary outcomes were fasting plasma glucose, adverse events, body weight, hypoglycaemia and triglycerides. We assessed risk of bias and evaluated the certainty of the evidence with the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Nine RCTs enrolling 3456 participants were included, six of which assessed the effect of bromocriptine, and the other three the effect of cabergoline. Dopamine agonists reduced HbA1c with 0.69 standardized mean difference (95% CI = 0.28 to 1.09; P = .0008; I² = 80%; GRADE: low) compared with placebo. There was no difference in the effect between bromocriptine and cabergoline. Heterogeneity was partly explained by dosage and study duration, both of which were inversely associated with effect size. Only one large trial reported SAEs and no difference was reported for the risk of an SAE (RR = 0.89; 95% CI = 0.70 to 1.12; P = .32) between active intervention and placebo. Secondary outcomes suggested a decrease in fasting plasma glucose and triglycerides and no effect on the remaining outcomes.

CONCLUSION

Dopamine agonists reduce HbA1c as well as fasting plasma glucose and triglycerides in patients with type 2 diabetes without causing SAEs. These data are based on moderate to low quality evidence thus our confidence in the effect estimates is limited.

Late phase completed clinical trials investigating bromocriptine mesylate quick release as treatment of type 2 diabetes mellitus

INTRODUCTION

Bromocriptine mesylate quick release (QR) is a dopamine D2 receptor agonist and is the only oral, primarily centrally acting drug that can be used for the treatment of adults with type 2 diabetes.

AREAS COVERED

The authors describe current recommendations on the use of bromocriptine mesylate QR. Major efficacy and safety parameters of the late phase trials, including The Cycloset Safety Trial, have been identified and presented.

EXPERT OPINION

Efficacy of bromocriptine mesylate QR monotherapy appears to be low but is compensated by favorable safety profile: low risk of hypoglycemia and no weight gain. The latter makes the drug an acceptable choice for obese individuals with type 2 diabetes. As a valuable additional benefit, bromocriptine is associated with significant cardiovascular risk reduction. Current recommendations include bromocriptine mesylate QR as part of dual or triple antihyperglycemic therapy especially in individuals with type 2 diabetes who are hesitant to add injectable treatment options and/or have cardiovascular disease.

Dopamine metabolite levels in the vitreous of diabetic and non-diabetic humans

Animal studies suggest that the retinal dysfunction in diabetic subjects that precedes overt clinical vasculopathy may be due to a retinal dopamine deficit. We analyzed levels of dopamine (DA) and its primary metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), in the vitreous of diabetic and non-diabetic human subjects. Adult patients undergoing pars plana vitrectomy for non-hemorrhagic indications were prospectively recruited from the Emory Eye Center in Atlanta, GA. Vitreous samples were analyzed using high performance liquid chromatography (HPLC) to measure levels of DOPAC and DA in the vitreous specimens. Vitreous samples from 9 diabetic patients and 20 from non-diabetic patients were analyzed. No eyes had apparent diabetic retinopathy. Mean normalized DA concentration in vitreous of diabetic subjects was 0.76 ± 0.12 pg/μL vs. 0.73 ± 0.08 pg/μL in non-diabetic vitreous (p = 0.849). DOPAC concentration was 8.84 ± 0.74 pg/μL in vitreous of diabetic subjects vs. 9.22 ± 0.56 pg/μL in vitreous of non-diabetic subjects (p = 0.691). No difference was observed in the concentrations of DA and DOPAC in the vitreous of people without diabetes compared to those with diabetes without retinopathy.

Dopamine D2 receptor signaling modulates pancreatic beta cell circadian rhythms

Antipsychotic drugs (APD) have clinically important, adverse effects on metabolism that limit their therapeutic utility. Pancreatic beta cells produce dopamine and express the D₂ dopamine receptor (D2R). As D2R antagonists, APDs alter glucose-stimulated insulin secretion, indicating that dopamine likely plays a role in APD-induced metabolic dysfunction. Insulin secretion from beta cells is also modulated by the circadian clock. Disturbed circadian rhythms cause metabolic disturbances similar to those observed in APD-treated subjects. Given the importance of dopamine and circadian rhythms for beta cells, we hypothesized that the beta cell dopamine system and circadian clock interact and dually regulate insulin secretion, and that circadian manipulations may alter the metabolic impact of APDs. We measured circadian rhythms, insulin release, and the impact of dopamine upon these processes in beta cells using bioluminescent reporters. We then assessed the impact of circadian timing on weight gain and metabolic outcomes in mice treated with the APD sulpiride at the onset of light or dark. We found that molecular components of the dopamine system were rhythmically expressed in beta cells. D2R stimulation by endogenous dopamine or the agonist bromocriptine reduced circadian rhythm amplitude, and altered the temporal profile of insulin secretion. Sulpiride caused greater weight gain and hyperinsulinemia in mice when given in the dark phase compared to the light phase. D2R-acting drugs affect circadian-dopamine interactions and modulate beta cell metabolic function. These findings identify circadian timing as a novel and important mechanism underlying APD-induced metabolic dysfunction, offering new possibilities for therapeutic interventions.

Association of glucose-lowering medications with cardiovascular outcomes: an umbrella review and evidence map

BACKGROUND

Considering the global burden of diabetes and associated cardiovascular disease, an urgent need exists for the best treatment, which should be based on the best available evidence. We examined the association between glucose-lowering medications and a broad range of cardiovascular outcomes, and assessed the strength of evidence for these associations.

METHODS

For this umbrella review we searched PubMed, Embase, and the Cochrane Library to identify systematic reviews and meta-analyses of randomised controlled trials examining the cardiovascular safety of glucose-lowering medications. Cardiovascular outcomes examined included major adverse cardiovascular events, cardiovascular death, myocardial infarction, stroke, heart failure, unstable angina, and atrial fibrillation. For each meta-analysis, we estimated the relative risk (RR) and 95% CI. We also created an evidence map showing the plausible benefits or harms of each intervention and the certainty of the evidence.

FINDINGS

We examined 232 meta-analyses evaluating ten classes of diabetes drugs. We identified six risk and 38 protective associations showing a high strength of evidence. Six associations increased the risk of cardiovascular disease, including glimepiride (stroke [RR 2·01; 95% CI 1·02-3·98]), rosiglitazone (myocardial infarction [1·28; 1·02-1·62] and heart failure [1·72, 1·31-2·27]), and pioglitazone (heart failure [1·40; 1·16-1·69]). 38 associations decreased the risk of cardiovascular disease, including glucagon-like peptide-1 receptor agonists as a class (major adverse cardiovascular events [RR 0·88; 95% CI 0·84-0·92], death from cardiovascular disease [0·87; 0·81-0·94], myocardial infarction [0·92; 0·86-0·99], stroke [0·84; 0·77-0·93], and heart failure [0·90; 0·83-0·99]), albiglutide (major adverse cardiovascular events [0·81; 0·68-0·96], myocardial infarction [0·77; 0·64-0·92], and heart failure [0·71; 0·55-0·93]), dulaglutide (stroke [0·78; 0·64-0·96]), exenatide (major adverse cardiovascular events [0·91; 0·83-1·00]), liraglutide (major adverse cardiovascular events [0·86; 0·77-0·96]), semaglutide (major adverse cardiovascular events [0·76; 0·62-0·92] and stroke [0·67; 0·45-1·00]), sodium-glucose co-transporter-2 inhibitors as a class (major adverse cardiovascular events [0·87; 0·82-0·93], death from cardiovascular disease [0·82; 0·75-0·90], myocardial infarction [0·86; 0·78-0·94], and heart failure [0·68; 0·63-0·73]), canagliflozin (major adverse cardiovascular events [0·84; 0·75-0·93], death from cardiovascular disease [0·82; 0·71-0·96], and heart failure [0·65; 0·54-0·78]), dapagliflozin (heart failure [0·70; 0·60-0·82]), empagliflozin (major adverse cardiovascular events [0·85; 0·77-0·94], death from cardiovascular disease [0·62; 0·50-0·78], and heart failure [0·64; 0·53-0·77]), and pioglitazone (major adverse cardiovascular events [0·84; 0·74-0·96], myocardial infarction [0·80; 0·67-0·95], and stroke [0·79; 0·65-0·95]).

INTERPRETATION

We found varied levels of evidence for the associations between diabetes drugs and cardiovascular outcomes; some drugs raised the risk of cardiovascular disease, whereas others showed benefit.

FUNDING

None.

Circadian-timed quick-release bromocriptine lowers elevated resting heart rate in patients with type 2 diabetes mellitus

OBJECTIVE

Sympathetic nervous system (SNS) overactivity is a risk factor for insulin resistance and cardiovascular disease (CVD). We evaluated the impact of bromocriptine-QR, a dopamine-agonist antidiabetes medication, on elevated resting heart rate (RHR) (a marker of SNS overactivity in metabolic syndrome), blood pressure (BP) and the relationship between bromocriptine-QR's effects on RHR and HbA1c in type 2 diabetes subjects.

DESIGN AND SUBJECTS

RHR and BP changes were evaluated in this post hoc analysis of data from a randomized controlled trial in 1014 type 2 diabetes subjects randomized to bromocriptine-QR vs placebo added to standard therapy (diet ± ≤2 oral antidiabetes medications) for 24 weeks without concomitant antihypertensive or antidiabetes medication changes, stratified by baseline RHR (bRHR).

RESULTS

In subjects with bRHR ≥70 beats/min, bromocriptine-QR vs placebo reduced RHR by -3.4 beats/min and reduced BP (baseline 130/79; systolic, diastolic, mean arterial BP reductions [mm Hg]: -3.6 [P = .02], -1.9 [P = .05], -2.5 [P = .02]). RHR reductions increased with higher baseline HbA1c (bHbA1c) (-2.7 [P = .03], -5 [P = .002], -6.1 [P = .002] with bHbA1c ≤7, >7, ≥7.5%, respectively] in the bRHR ≥70 group and more so with bRHR ≥80 (-4.5 [P = .07], -7.8 [P = .015], -9.9 [P = .005]). Subjects with bRHR <70 had no significant change in RHR or BP. With bHbA1c ≥7.5%, %HbA1c reductions with bromocriptine-QR vs placebo were -0.50 (P = .04), -0.73 (P = .005) and -1.22 (P = .008) with bRHR <70, ≥70 and ≥80, respectively. With bRHR ≥70, the magnitude of bromocriptine-QR-induced RHR reduction was an independent predictor of bromocriptine-QR's HbA1c lowering effect.

CONCLUSION

Bromocriptine-QR lowers elevated RHR with concurrent decrease in BP and hyperglycaemia. These findings suggest a potential sympatholytic mechanism contributing to bromocriptine-QR's antidiabetes effect and potentially its previously demonstrated effect to reduce CVD events.

Analysis of the Relationship between Type II Diabetes Mellitus and Parkinson's Disease: A Systematic Review

In the early sixties, a discussion started regarding the association between Parkinson's disease (PD) and type II diabetes mellitus (T2DM). Today, this potential relationship is still a matter of debate. This review aims to analyze both diseases concerning causal relationships and treatments. A total of 104 articles were found, and studies on animal and “in vitro” models showed that T2DM causes neurological alterations that may be associated with PD, such as deregulation of the dopaminergic system, a decrease in the expression of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), an increase in the expression of phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes 15 (PED/PEA-15), and neuroinflammation, as well as acceleration of the formation of alpha-synuclein amyloid fibrils. In addition, clinical studies described that Parkinson's symptoms were notably worse after the onset of T2DM, and seven deregulated genes were identified in the DNA of T2DM and PD patients. Regarding treatment, the action of antidiabetic drugs, especially incretin mimetic agents, seems to confer certain degree of neuroprotection to PD patients. In conclusion, the available evidence on the interaction between T2DM and PD justifies more robust clinical trials exploring this interaction especially the clinical management of patients with both conditions.

Second-line Glucose-Lowering Therapy in Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

There is consensus that metformin should be the first-line pharmacological therapy for type 2 diabetes. Although new evidence on effective treatments for type 2 diabetes is rapidly evolving, there is uncertainty regarding the optimal choice of second-line therapy. Our aim was to review the current major guidelines for second-line therapy in type 2 diabetes, along with findings from the recent cardiovascular outcome trials, focusing on two particularly promising classes of glucose-lowering drugs, sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 receptor agonists (GLP1 RAs).

RECENT FINDINGS

In the recent randomized controlled trials, two SGLT2 inhibitors (i.e., empagliflozin and canagliflozin) and two GLP1 RAs (i.e., liraglutide and albiglutide) reduced cardiovascular events in patients with type 2 diabetes, of whom most had established atherosclerotic cardiovascular disease. Some clinical guidelines have changed their recommendations for second-line therapy based on these findings. The first choice for a second-line therapy by the new American Diabetes Association/European Association for the Study of Diabetes (ADA/EASD) guidelines is SGLT2 inhibitors or GLP1 RAs for patients with atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease. For patients without these conditions, the ADA/EASD lists five options of noninsulin second-line therapy without a suggested hierarchy of use. On the other hand, the 2019 consensus statement from the American Association of Clinical Endocrinologists/American College of Endocrinology lists nine hierarchical options, with GLP1 RAs as the first recommended therapy, followed by SGLT2 inhibitors and dipeptidyl peptidase 4 (DPP4) inhibitors, and sulfonylurea as the last option. The American College of Physicians recommends four oral treatment options, which do not include GLP1 RAs. The International Diabetes Federation recommends sulfonylureas, DPP4 inhibitors, or SGLT2 inhibitors as preferred second-line drugs with GLP1 RAs as an alternative in obese patients. The World Health Organization strongly recommends sulfonylureas in low-resource settings. The National Institute for Health and Care Excellence in the UK recommends DPP4 inhibitors, thiazolidinediones, or sulfonylureas, with use of SGLT2 inhibitors only under special circumstances. Clinical guidelines for the choice of second-line therapy in type 2 diabetes are inconsistent. A comprehensive assessment of the risks and benefits of second-line therapy is needed to address knowledge gaps that underlie core clinical practice.

Current Views on Dopaminergic Drugs Affecting Glucose Homeostasis

BACKGROUND

For more than three decades, it has been known that manipulation of dopaminergic system could affect glucose homesotasis in experimental animals. The notion that glucose homeostasis in human might be influenced by dopaminergic drugs has attracted a great deal of attention in the past two decades. In spite of rapid advancements in revealing involvement of dopaminergic neurotransmission in insulin release, glucose up-take and pancreatic beta cell function in general through centrally and peripherally controlled mechanisms, there are discrepancies among observations on experimental animals and human subjects.

CONCLUSION

With the expansion of pharmacotherapy in psychotic conditions, depression and endocrine abnormalities along with a sharp increase in prevalence of type two diabetes and disturbances of glucose homeostasis as a major risk factor for many cardiovascular complications and associated mortalities; it seems a critical analysis of recent investigations on drugs which act as agonists or antagonists of dopaminergic receptors in various tissues and organs may provide better insight into how safe and efficient these medicines could be prescribed. Furthermore, the other main objective of present review is to compare clinical data on significance of changes in blood glucose and insulin levels during short term and after long term treatment with these agents. This in turn would be beneficial for determining adequate strategies to combat or to avoid adverse effects associated with dopaminergic drug therapy.

Glucose lowering and vascular protective effects of cycloset added to GLP-1 receptor agonists in patients with type 2 diabetes

OBJECTIVE

To determine the glucose-lowering mechanism of action and the effects of a quick-release bromocriptine-QR, a D2-dopamine agonist (Cycloset) on vascular function in patients with type 2 diabetes (T2D).

STUDY DESIGN AND METHODS

Fifteen poorly controlled T2D treated with metformin plus glucagon-like peptide-1 receptor agonists (GLP-1RA) were studied after 4 months of Cycloset, 3.2 mg/d. Subjects received a 5-hour double-tracer (iv 3-3H-glucose and oral 14C-glucose) mixed meal test (MMT) to quantitate rates of endogenous glucose production (EGP), oral glucose appearance (RaO) and disappearance (Rd) pre- and post-Cycloset. Vascular assessments included 2-day continuous BP monitoring, reactive hyperaemia index (RHI) and arterial stiffness (AS).

RESULTS

HbA1c decreased from 8.3 ± 0.3% to 7.7 ± 0.2% (P < 0.05), fasting plasma glucose did not change (143 ± 4 vs 147 ± 5) and mean plasma glucose during MTT decreased from 223 ± 3 to 210 ± 4 mg/dL (P < 0.05) after Cycloset. Basal EGP (2.2 ± 0.2 vs 2.1 ± 0.2 mg/kg min) was unchanged, but there was greater MMT suppression (1.1 ± 0.1 vs 0.7 ± 0.1, P < 0.05). After Cycloset, RaO declined from 2.0 ± 0.1 to 1.7 ± 0.2 mg/kg min and peripheral oral glucose appearance from 53.1 ± 3.2 to 44.4 ± 3.1 g (P < 0.01). There were no changes in plasma insulin or glucagon concentration. Systolic (134 ± 4 vs 126 ± 6), diastolic (78 ± 3 vs 73 ± 4), mean BP (97 ± 5 vs 90 ± 4) and pulse pressure (54 ± 2 vs 51 ± 2 mm Hg) were reduced; RHI increased from 1.4 ± 0.1 to 1.9 ± 0.3 au and AS decreased modestly (19.8 ± 4.1 to 16.2 ± 3.7 au, P = NS).

CONCLUSIONS

Addition of Cycloset to GLP-1 RA improved vascular indices and postprandial hyperglycaemia in T2DM primarily by lowering oral glucose appearance, suggesting that hepatic glucose uptake was enhanced. Improved vascular indices may explain the reduction in cardiovascular events observed with Cycloset therapy in patients with T2DM.

Cardiac Autonomic Neuropathy in Diabetes: A Predictor of Cardiometabolic Events

Autonomic nervous system (ANS) imbalance manifesting as cardiac autonomic neuropathy in the diabetic population is an important predictor of cardiovascular events. Symptoms and signs of ANS dysfunction, such as resting heart rate elevations, diminished blood pressure responses to standing, and altered time and frequency domain measures of heart rate variability in response to deep breathing, standing, and the Valsalva maneuver, should be elicited from all patients with diabetes and prediabetes. With the recognition of the presence of ANS imbalance or for its prevention, a rigorous regime should be implemented with lifestyle modification, physical activity, and cautious use of medications that lower blood glucose. Rather than intensifying diabetes control, a regimen tailored to the individual risk of autonomic imbalance should be implemented. New agents that may improve autonomic function, such as SGLT2 inhibitors, should be considered and the use of incretins monitored. One of the central mechanisms of dysfunction is disturbance of the hypothalamic cardiac clock, a consequence of dopamine deficiency that leads to sympathetic dominance, insulin resistance, and features of the metabolic syndrome. An improvement in ANS balance may be critical to reducing cardiovascular events, cardiac failure, and early mortality in the diabetic population.

Insulin therapy for type 2 diabetes - are we there yet? The d-Nav® story

Insulin replacement therapy is mostly used by patients with type 2 diabetes who become insulin deficient and have failed other therapeutic options. They comprise about a quarter of those with diabetes, endures the majority of the complications and consumes the majority of the resources. Adequate insulin replacement therapy can prevent complications and reduce expenses, as long as therapy goals are achieved and maintained. Sadly, these therapy goals are seldom achieved and outcomes have not improved for decades despite advances in pharmacotherapy and technology.

There is a growing recognition that the low success rate of insulin therapy results from intra-individual and inter-individual variations in insulin requirements. Total insulin requirements per day vary considerably between patients and constantly change without achieving a steady state. Thus, the key element in effective insulin therapy is unremitting and frequent dosage adjustments that can overcome those dynamics. In practice, insulin adjustments are done sporadically during outpatient clinic. Due to time constraints, providers are not able to deliver appropriate insulin dosage optimization.

The d-Nav® Insulin Guidance Service has been developed to provide appropriate insulinization in insulin users without increasing the burden on healthcare systems. It relies on dedicated clinicians and a spectrum of technological solutions. Patients are provided with a handheld device called d-Nav® which advises them what dose of insulin to administer during each injection and automatically adjust insulin dosage when needed. The d-Nav care specialists periodically follow-up with users through telephone calls and in-person consultations to bestow user confidence, correct usage errors, triage, and identify uncharacteristic clinical courses.

The following review provide details about the service and its clinical outcomes.

Select medications that unexpectedly lower HbA1c levels

WHAT IS KNOWN AND OBJECTIVE

A variety of medication classes are available for diabetes; however, treatment options become limited due to adverse effect profiles and cost. Current diabetes guidelines include agents not originally developed for diabetes treatment, bromocriptine and colesevelam.

COMMENT

Other non-diabetes medications demonstrating haemoglobin A1c lowering, including agents for weight loss, depression, anaemia and coronary artery disease, are described in this review article.

WHAT IS NEW AND CONCLUSION

More research looking into the impact of non-diabetes medications on blood glucose may offer additional diabetes treatment strategies.

Influence of Bromocriptine Plus Metformin Treatment on Glycaemia and Blood Pressure in Patients with Type 2 Diabetes Mellitus

Background and aims: Bromocriptine is a dopaminergic (D2) agonist that has shown hypoglycemic and normotensive activity in preclinical and clinical studies. The main objective of this study was to investigate the effect of bromocriptine plus metformin on glycaemia and blood pressure in patients with type 2 diabetes mellitus (T2DM).

Material and methods: An open-label randomised controlled trial was conducted for three months. It involved two groups (n=10), each containing 2 women and 8 men with an average age of 50 years. One group was given monotherapy (MT) with metformin (850 mg every 12 h) and the other combined therapy (CT) with the same dose of metformin plus an increasing dose of bromocriptine (from 1.25 mg per day to 2.5 mg per day). The parameters monitored were glycaemia, glycated hemoglobin (HbA1c), serum creatinine, blood pressure, and the body mass index.

Results: CT was able to significantly decrease the level of glycaemia, HbA1c and diastolic blood pressure, whereas MT had no effect on any of the measured variables.

Conclusions: The ability of CT with bromocriptine and metformin to control glycaemia and produce a normotensive effect reaffirms its advantages for controlling T2DM. Further research is needed to improve this therapeutic strategy.

Heart Failure: Epidemiology, Pathophysiology, and Management of Heart Failure in Diabetes Mellitus

This article briefly discusses the epidemiology of heart failure and diabetes and summarizes the key findings from the recent cardiovascular outcome trials in patients with type 2 diabetes, with a focus on heart failure as an endpoint.

A Unified Pathophysiological Construct of Diabetes and its Complications

Advances in understanding diabetes mellitus (DM) through basic and clinical research have helped clarify and reunify a disease state fragmented into numerous etiologies and subtypes. It is now understood that a common pathophysiology drives the diabetic state throughout its natural history and across its varied clinical presentations, a pathophysiology involving metabolic insults, oxidative damage, and vicious cycles that aggravate and intensify organ dysfunction and damage. This new understanding of the disease requires that we revisit existing diagnostics and treatment approaches, which were built upon outmoded assumptions. 'The Common Pathophysiologic Origins of Diabetes Mellitus and its Complications Construct' is presented as a more accurate, foundational, and translatable construct of DM that helps make sense of the hitherto ambiguous findings of long-term outcome studies.

Pharmacologic Management of Type 2 Diabetes Mellitus: Available Therapies

Choices for the treatment of type 2 diabetes mellitus (T2DM) have multiplied as our understanding of the underlying pathophysiologic defects has evolved. Treatment should target multiple defects in T2DM and follow a patient-centered approach that considers factors beyond glycemic control, including cardiovascular risk reduction. The American Association of Clinical Endocrinologists/American College of Endocrinology and the American Diabetes Association recommend an initial approach consisting of lifestyle changes and monotherapy, preferably with metformin. Therapy choices are guided by glycemic efficacy, safety profiles, particularly effects on weight and hypoglycemia risk, tolerability, patient comorbidities, route of administration, patient preference, and cost. Balancing management of hyperglycemia with the risk of hypoglycemia and consideration of the effects of pharmacotherapy on weight figure prominently in US-based T2DM recommendations, whereas less emphasis has been placed on the ability of specific medications to affect cardiovascular outcomes. This is likely because, until recently, specific glucose-lowering agents have not been shown to affect cardiorenal outcomes. The Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME), the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial, and the Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide in Subjects with Type 2 Diabetes 6 (SUSTAIN-6) recently showed a reduction in overall cardiovascular risk with empagliflozin, liraglutide, and semaglutide treatment, respectively. Moreover, empagliflozin has become the first glucose-lowering agent indicated to reduce the risk of cardiovascular death in adults with T2DM and established cardiovascular disease. Results from cardiovascular outcomes trials have prompted an update to the 2017 American Diabetes Association standards of care, which now recommend consideration of empagliflozin or liraglutide for patients with suboptimally controlled long-standing T2DM and established atherosclerotic cardiovascular disease because these agents have been shown to reduce cardiovascular and all-cause mortality when added to standard care.

Impact of bromocriptine-QR therapy on cardiovascular outcomes in type 2 diabetes mellitus subjects on metformin

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is associated with a substantially increased risk of cardiovascular disease (CVD). Bromocriptine-QR (B-QR), a quick release sympatholytic dopamine D₂ receptor agonist, is a FDA-approved therapy for T2DM which may provide CVD risk reduction. Metformin is considered to be an agent with a potential cardioprotective benefit. This large placebo controlled clinical study assessed the impact of B-QR addition to existing metformin therapy on CVD outcomes in T2DM subjects.

METHODS

1791 subjects (1208 B-QR; 583 placebo) on metformin ± another anti-diabetes therapy at baseline derived from the Cycloset Safety Trial, a 12-month, randomized, multicenter, placebo-controlled, double-blind study in T2DM, were included in this study. The primary CVD endpoint evaluated was treatment impact on CVD event rate, prespecified as a composite of time to first myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina/congestive heart failure. Impact on glycemic control was evaluated as a secondary analysis.

RESULTS

The composite CVD end point occurred in 16/1208 B-QR treated (1.3%) and 18/583 placebo treated (3.1%) subjects resulting in a 55% CVD hazard risk reduction (intention-to-treat, Cox regression analysis; HR: 0.45 [0.23-0.88], p = 0.028). Kaplan-Meier curves demonstrated a significantly lower cumulative incidence rate of the CVD endpoint in the B-QR treatment group (Log-Rank p = 0.017). In subjects with poor glycemic control (HbA1c ≥ 7.5) at baseline, B-QR therapy relative to placebo resulted in a significant mean %HbA1c reduction of -0.59 at week 12 and -0.51 at week 52 respectively (p < 0.001 for both) and a 10 fold higher percent of subjects achieving HbA1c goal of ≤7% by week 52 (B-QR 30%, placebo 3%; p = 0.003).

CONCLUSION

These findings suggest that in T2DM subjects on metformin, BQR therapy may represent an effective strategy for reducing CVD risk. Cycloset Safety Trial registration: ClinicalTrials.gov Identifier: NCT00377676.

What Are We Learning from the FDA-Mandated Cardiovascular Outcome Studies for New Pharmacological Antidiabetic Agents?

Cardiovascular disease (CVD) is common in patients with diabetes. For these patients, clinicians should seek diabetes treatment that is beneficial rather than harmful in relation to CVD. Until recently, there have been many treatments for hyperglycemia, whose impact on CVD has been controversial. The aims of this review are to evaluate the effectiveness of antihyperglycemic medications on risk factors for CVD and to examine the impact of these drugs on CVD in cardiovascular (CV) outcome trials. In this article, we summarize current knowledge about the impacts of these drugs on various risk factors as well as CV outcomes. We identify the recent emergence of trials with antihyperglycemic agents showing newly discovered CV benefits as well as past trials with antihyperglycemic agents not showing much benefit on CV events. Rather than focusing on treatment strategies, we review the effects of individual drug classes on CV outcomes. We also briefly review goal-driven glycemia reduction and its impact on CVD. We conclude that antihyperglycemic agents are associated with improvement in CV risk factors in patients with diabetes and insulin resistance; in fact, a few drugs reduced CV events in randomized CV outcome trials. Therefore, the use of these drugs is appropriate for reducing glucose and decreasing CV event risk in a select subpopulation.

Evidence-based practice use of quick-release bromocriptine across the natural history of type 2 diabetes mellitus

OBJECTIVES

To provide an evidence-based practice overview on the clinical use of bromocriptine-quick release (QR) across the natural history of type 2 diabetes mellitus (T2DM).

METHODS

Articles for inclusion were selected after a comprehensive literature search of English-language PubMed articles and identification of other relevant references through other sources. Inclusion criteria were animal studies examining the mechanism of action and efficacy of bromocriptine, and clinical studies examining the safety and efficacy of bromocriptine-QR in patients with T2DM, without a time limitation.

RESULTS

The brain plays a key role in total body metabolism, in particular ensuring that sufficient levels of glucose are available for proper neural functioning. The hypothalamic suprachiasmatic nucleus (SCN), the body's biological clock, plays a key role in the regulation of seasonal and diurnal variations of insulin sensitivity. A daily surge of dopaminergic activity in the SCN upon waking enables insulin sensitivity throughout the day. When this is disrupted (e.g. by a high fat/sugar diet, stress, altered [diminished] exercise, altered sleep/wake cycle, diabetes), insulin resistance persists throughout the day and overnight. Improving the morning surge in dopaminergic activity with the short-acting dopamine D2 receptor agonist bromocriptine-QR can safely and effectively improve glycemic control, while improving cardiovascular disease risk factors and related adverse events, and reducing sympathetic tone, as demonstrated by 5 reports of the Cycloset Safety Trial and 3 additional clinical studies of bromocriptine-QR.

CONCLUSIONS

In patients with T2DM, the dopamine D2 receptor agonist bromocriptine-QR has been shown to be well tolerated, efficacious, and a logical treatment option.

Combination therapy for the improvement of long-term macrovascular and microvascular outcomes in type 2 diabetes: Rationale and evidence for early initiation

Diabetes is a leading cause of macrovascular and microvascular complications that can increase the risk of mortality if not properly managed. Proper glucose control can reduce the incidence of these complications, in particular those of the microvasculature. Over the last~10years, the cardiovascular safety of glucose-lowering drugs has come to the forefront of diabetes management and clinical trial design. While early combination therapy improves glycemic control, its impact on long-term outcomes, is not as clearly understood. The objective of this review is to examine the evidence of early combination therapy for the treatment of type 2 diabetes mellitus as it relates to studies of long-term microvascular and macrovascular outcomes.

Common medications used by patients with type 2 diabetes mellitus: what are their effects on the lipid profile?

Dyslipidemia is the most fundamental risk factor for atherosclerotic cardiovascular disease (ASCVD). In clinical practice, many commonly prescribed medications can alter the patient's lipid profile and, potentially, the risk for ASCVD-either favorably or unfavorably. The dyslipidemia observed in type 2 diabetes mellitus (T2DM) can be characterized as both ominous and cryptic, in terms of unrecognized, disproportionately elevated atherogenic cholesterol particle concentrations, in spite of deceptively and relatively lower levels of low-density lipoprotein cholesterol (LDL-C). Several factors, most notably insulin resistance, associated with the unfavorable discordance of elevated triglyceride (TG) levels and low levels of high-density lipoprotein cholesterol (HDL-C), have been shown to correlate with an increased risk/number of ASCVD events in patients with T2DM. This review focuses on known changes in the routine lipid profile (LDL-C, TGs, and HDL-C) observed with commonly prescribed medications for patients with T2DM, including antihyperglycemic agents, antihypertensive agents, weight loss medications, antibiotics, analgesics, oral contraceptives, and hormone replacement therapies. Given that the risk of ASCVD is already elevated for patients with T2DM, the use of polypharmacy may warrant close observation of overall alterations through ongoing lipid-panel monitoring. Ultimately, the goal is to reduce levels of atherogenic cholesterol particles and thus the patient's absolute risk.

Cardiovascular effects of anti-diabetes drugs

INTRODUCTION

Cardiovascular disease remains the major contributor to morbidity and mortality in diabetes. From the need to reduce cardiovascular risk in diabetes and to ensure that such risk is not exacerbated by drug treatments, governmental regulators and drug manufacturers have focused on clinical trials evaluating cardiovascular outcomes.

AREAS COVERED

Findings from mechanistic and clinical trials of biguanides, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, and sodium-glucose co-transporter 2 (SGLT-2) inhibitors will be reviewed. These drug classes will be compared within the context of available cardiovascular outcomes data. Clinical implications of new study regulations will be examined.

EXPERT OPINION

Recent cardiovascular studies provide a more comprehensive evaluation of specific anti-diabetes therapy in individuals with high cardiovascular risk. Long-term effects of anti-hyperglycemic agents in patients with lower cardiovascular risk are still speculative. Historical data supports continued use of metformin as a first-line agent. DPP-4 inhibitors and GLP-1 receptor agonists appear to have neutral effects on cardiovascular outcomes. The significantly decreased cardiovascular risk associated with empagliflozin SGLT-2 inhibitor therapy is impressive and may change how practitioners prescribe add-on therapy to metformin.

Clinical Update: Cardiovascular Disease in Diabetes Mellitus: Atherosclerotic Cardiovascular Disease and Heart Failure in Type 2 Diabetes Mellitus - Mechanisms, Management, and Clinical Considerations

Cardiovascular disease remains the principal cause of death and disability among patients with diabetes mellitus. Diabetes mellitus exacerbates mechanisms underlying atherosclerosis and heart failure. Unfortunately, these mechanisms are not adequately modulated by therapeutic strategies focusing solely on optimal glycemic control with currently available drugs or approaches. In the setting of multifactorial risk reduction with statins and other lipid-lowering agents, antihypertensive therapies, and antihyperglycemic treatment strategies, cardiovascular complication rates are falling, yet remain higher for patients with diabetes mellitus than for those without. This review considers the mechanisms, history, controversies, new pharmacological agents, and recent evidence for current guidelines for cardiovascular management in the patient with diabetes mellitus to support evidence-based care in the patient with diabetes mellitus and heart disease outside of the acute care setting.

Effects of bromocriptine mesylate on homocysteine and high-sensitivity C-reactive protein levels in patients with type-2 diabetes mellitus

Introduction: Quick release bromocriptine (BROM-QR), currently approved for glycemic control, reduces the risk of cardiovascular events in adults with type-2 diabetes mellitus (T2DM). This study evaluates the effect of BROM-QR on homocysteine (HOMC) and high sensitive C-reactive protein (hs-CRP), the biochemical markers of coronary atherosclerosis/inflammation, in patients with uncontrolled T2DM.

Methods: In this non-randomized, before-and-after clinical trial, patients with uncontrolled T2DM on stable doses of two oral hypoglycemic agents received BROM-QR for 6 months. The change in serum concentrations of HOMC was the primary endpoint. Anthropometric measurements such as body mass index (BMI) and waist circumference were measured at the baseline and at the completion of treatment along with fasting plasma glucose (FPG), HbA1c, total cholesterol, triglyceride, creatinine and hs-CRP. Multivariate regression analysis was performed to identify factors associated with changes in the levels of HOMC.

Results: In 64 patients (46 completed 6 months of treatment), age was 55±7 years and the duration of T2DM was 8.0 ± 4.4 years. On enrollment, mean HbA1c, FPG, hs-CRP and HOMC levels were 9.0± 1.3 percent, 184 ± 42 mg/dL, 3.8± 3.4 mg/dl and 10.8 ± 6.2 micromole/L; respectively. Mean decrease of 0.7 ± 1.1 percent for HbA1c (P = 0.001) and 22 ± 44 mg/dL for FPG was observed (P = 0.002). HOMC levels decreased to 8.5 ± 5.2 micromole/L (P = 0.011) while hs-CRP levels remained unchanged at 3.7 ± 2.9 mg/dL (P = 0.835).

Conclusion: While HOMC and HbA1c levels decreased significantly after 6 months of treatment with BROM-QR in patients with T2DM, serum levels of hs-CRP, total cholesterol and triglyceride did not significantly change.