Comparison of the efficacy and safety of rapid-acting insulin analogs, lispro versus aspart, in the treatment of diabetes: a systematic review of randomized controlled trials.

INTRODUCTION: We evaluated a potential move from one rapid-acting insulin analog to another, or their biosimilars, to aid better and faster decisions for diabetes management. METHODS: A systematic literature review was performed according to PRISMA reporting guidelines. The MEDLINE/EMBASE/COCHRANE databases were searched for randomized control trials (RCTs) comparing aspart/lispro in type-1 (T1D) and type-2 (T2D) diabetes. The methodological quality of the included studies was assessed using the Cochrane Collaboration's risk of bias assessment criteria. RESULTS: Of the 753 records retrieved, the six selected efficacy/safety RCTs and the additional three hand-searched pharmacokinetics/pharmacodynamics RCTs showed some heterogeneity in the presentation of the continuous variables; however, collectively, the outcomes demonstrated that lispro and aspart had comparable efficacy and safety in adult patients with T1D and T2D. Both treatments yielded a similar decrease in glycated hemoglobin (HbA1c) and had similar dosing and weight changes, with similar treatment-emergent adverse events (TEAE) and serious adverse event (SAE) reporting, similar hypoglycemic episodes in both T1D and T2D populations, and no clinically significant differences for hyperglycemia, occlusions or other infusion site/set complications. CONCLUSIONS: Aspart and lispro demonstrate comparative safety and efficacy in patients with T1D/T2D. Since both are deemed equally suitable for controlling prandial glycemic excursions and both have similar safety attributes, they may be used interchangeably in clinical practice. PROSPERO REGISTRATION NUMBER: CRD42023376793.

Comparative clinical efficacy and safety of insulin glargine 300 U/ml (Toujeo) versus insulin glargine 100 U/ml in type 2 diabetes and type 1 diabetes: A systematic literature review and meta-analysis.

AIM: To compare the clinical efficacy and safety of glargine-U100 (Lantus/Gla-100) with glargine-U300 (Toujeo/Gla-300) in adult patients with type 2 diabetes (T2D) and type 1 diabetes (T1D). MATERIALS AND METHODS: A literature search on Gla-300/Gla-100 in diabetes management was conducted using the MEDLINE/Embase/Cochrane databases from inception to 10 January 2021. Eligible studies considered for inclusion were parallel-design, randomized controlled trials (RCTs). The Cochrane risk-of-bias tool was used to evaluate the quality of the included studies. The random-effects model was applied for interpretation of the results. RESULTS: Of 5348 records screened, 592 were assessed for eligibility and 15 RCTs were considered for data extraction and meta-analysis (T2D [N = 10; n = 7082]; T1D [N = 5; n = 2222]). In patients with T1D, all safety parameters were comparable between Gla-100 and Gla-300. In T2D, statistically significant differences were observed in favour of Gla-300 over Gla-100 for nocturnal and total hypoglycaemia. For efficacy parameters, a statistically and clinically significant difference favouring Gla-100 in basal insulin dose requirement was observed for both T2D and T1D. Change in HbA1c showed a statistically but not clinically significant reduction with Gla-100 compared with Gla-300 in T1D. Statistically significant but clinically less relevant differences favoured Gla-300 for control of body weight in T1D and T2D and Gla-100 for fasting blood glucose in T2D. CONCLUSIONS: Gla-100 and Gla-300 had comparable efficacy and safety profiles in both T1D and T2D populations. Gla-300 showed a lower risk of nocturnal and total hypoglycaemia, significant in insulin-experienced/exposed patients with T2D. Patients on Gla-300 required significantly more units of insulin daily than the Gla-100 group to achieve equivalent efficacy.

Biosimilars and interchangeable biosimilars: facts every prescriber, payor, and patient should know. Insulins perspective.

INTRODUCTION: For many of the 537 million adults living now with diabetes, the cost of insulin is becoming prohibitive as the insulin prices have tripled between 2002-2013. Globally, the direct annual cost of healthcare expenditure due to diabetes will soon be US$1 Trillion. Biosimilars provide access to high-quality, affordable biologic therapy that is otherwise inaccessible due to the high costs of original biologics. AREAS COVERED: A primer to the development of biosimilars shows comparable structural and analytical characterization to the original biologics (e.g. insulins), with no clinically significant or meaningful differences in efficacy and safety. 'Interchangeability' status, a regulatory designation by the US FDA, bestowed to some biosimilars, enables confidence in high-quality, bio-equivalent biosimilar of insulin with key global approvals. This can allow rapid uptake of biosimilars by the prescribers, formulary decision-makers, and payors. Biocon-Viatris's biosimilar Insulin Glargine (Semglee®) is the first interchangeable biosimilar insulin approved by the US FDA. EXPERT OPINION: The 'interchangeable' status can prompt faster and wider uptake of insulin biosimilars and keep the insulin expenditure under control, especially for patients who otherwise practice non-adherence or rationing of life-saving insulin. Education, support, and awareness can ensure that interchangeable biosimilars gain wider acceptance.

Biological evaluation of RBx-0128, a potent and selective dipeptidyl peptidase-IV inhibitor in type 2 diabetes genetic model.

AIM: Dipeptidyl peptidase IV (DPP-IV) inhibition to modulate the incretin effect is a proven strategy to treat type 2 diabetes mellitus. The present study describes the pharmacological profile of a novel DPP-IV inhibitor RBx-0128, as an antidiabetic agent. MATERIAL AND METHODS: DPP-IV assay was carried out to evaluate in vitro potency of RBx-0128 using human, mouse, and rat plasma as an enzyme source. Selectivity was assessed with various serine proteases. In vivo efficacy was assessed in ob/ob mice. The pharmacokinetic (PK) profile was performed in Wistar rats. RESULTS: RBx-0128 inhibited human, mouse, and rat plasma DPP-IV activity with IC50 values of 10.6, 18.1, and 56.0 nM respectively, selective over various serine proteases (900-9000-fold). The inhibition was reversible and competitive in nature. In ob/ob mice, RBx-0128 significantly (P<0.05) inhibited plasma DPP-IV and stimulated GLP-1 and insulin at 10 mg/kg. In the oral glucose tolerance test (OGTT), glucose lowering effect was better than sitagliptin (23 vs. 17%) at 10 mg/kg. The effect was sustained till 8 hours (30-35%) at 10 mg/kg with favorable PK profile (plasma clearance: 39.3 ml/min/kg; Cmax 790 ng/ml; t1/2 1.6 hours; tmax 4.8 hours, Vss 3.24 l/kg and Foral 55%) in Wistar rats. CONCLUSIONS: The present study showed that RBx-0128 is a novel, DPP-IV inhibitor with an antihyperglycemic effect. It can be a promising candidate for the treatment of type 2 diabetes mellitus.

Antihyperglycemic effect of Annona squamosa hexane extract in type 2 diabetes animal model: PTP1B inhibition, a possible mechanism of action?

AIM: The mechanism of action of Annona squamosa hexane extract in mediating antihyperglycemic and antitriglyceridimic effect were investigated in this study. MATERIALS AND METHODS: The effects of extract on glucose uptake, insulin receptor-ß (IR-ß), insulin receptor substrate-1 (IRS-1) phosphorylation and glucose transporter type 4 (GLUT4) and phosphoinositide 3-kinase (PI3 kinase) mRNA expression were studied in L6 myotubes. The in vitro mechanism of action was tested in protein-tyrosine phosphatase 1B (PTP1B), G-protein-coupled receptor 40 (GPR40), silent mating type information regulation 2 homolog 1 (SIRT1) and dipeptidyl peptidase-IV (DPP-IV) assays. The in vivo efficacy was characterized in ob/ob mice after an oral administration of the extract for 21 days. RESULTS: The effect of extract promoted glucose uptake, IR-ß and IRS-1 phosphorylation and GLUT4 and PI3 kinase mRNA upregulation in L6 myotubes. The extract inhibited PTP1B with an IC(50) 17.4 µg/ml and did not modulate GPR40, SIRT1 or DPP-IV activities. An oral administration of extract in ob/ob mice for 21 days improved random blood glucose, triglyceride and oral glucose tolerance. Further, the extract did not result in body weight gain before and after treatment (29.3 vs. 33.6 g) compared to rosiglitazone where significant body weight gain was observed (28.4 vs. 44.5 g; *P<0.05 after treatment compared to before treatment). CONCLUSION: The results suggest that Annona squamosa hexane extract exerts its action by modulating insulin signaling through inhibition of PTP1B.

RBx-0597, a potent, selective and slow-binding inhibitor of dipeptidyl peptidase-IV for the treatment of type 2 diabetes.

Dipeptidyl peptidase IV (DPP-IV) inhibiton is a well recognized approach to treat Type 2 diabetes. RBx-0597 is a novel DPP-IV inhibitor discovered in our laboratory. The aim of the present study was to characterize the pharmacological profiles of RBx-0597 in vitro and in vivo as an anti-diabetic agent. RBx-0597 inhibited human, mouse and rat plasma DPP-IV activity with IC(50) values of 32, 31 and 39nM respectively. RBx-0597 exhibited significant selectivity over dipeptidyl peptidase8 (DPP-8), dipeptidyl peptidase9 (DPP-9) (150-300 fold) and other proline-specific proteases (>200-2000 fold). Kinetic analysis revealed that RBx-0597 is a competitive and slow binding DPP-IV inhibitor. In ob/ob mice, RBx-0597 (10mg/kg) inhibited plasma DPP-IV activity upto 50% 8h post-dose and showed a dose-dependent glucose excursion. RBx-0597 (10mg/kg) showed a significant glucose lowering effect (∼25% AUC of △ blood glucose) which was sustained till 12h, significantly increased the active glucagon-like peptide-1(GLP-1) and insulin levels. It showed a favourable pharmacokinetic profile (plasma clearance:174ml/min/kg; C(max) 292ng/ml; T(1/2) 0.28h; T(max) 0.75h and V(ss) 4.13L/kg) in Wistar rats with the oral bioavailability (F(oral)) of 65%. In summary, the present studies indicate that RBx-0597 is a novel DPP-IV inhibitor with anti-hyperglycemic effect and a promising candidate for further development as a drug for the treatment of type 2 diabetes.

Nature of action of Sitagliptin, the dipeptidyl peptidase-IV inhibitor in diabetic animals.

OBJECTIVE: The aim of this study was to evaluate the dipeptidyl peptidase-IV (DPP-IV) inhibitor sitagliptin with respect to mode of inhibition and its in vivo duration of inhibition and efficacy in type 2 diabetes animal model. MATERIALS AND METHODS: DPP-IV enzyme assay was carried out in human plasma (10 µL) or human recombinant enzyme (10 ng) using H-Gly-Pro-AMC as a substrate. The competitive nature was estimated by plotting IC(50) values measured at different substrate concentrations on the Y axis and substrate concentration on the X axis. The tight binding nature was estimated by plotting IC(50) values measured at different plasma volumes on the Y axis and plasma volumes on the X axis. Fast binding kinetics was assessed by progressive curves at different inhibitor concentrations in the DPP-IV assay. The reversibility of the inhibitor was assessed by a dissociation study of the DPP-IV-sitagliptin complex. Durations of DPP-IV inhibition and efficacy were shown in ob/ob mice dosed at 10 mg/kg, p.o. RESULTS: Sitagliptin is a competitive, reversible, fast and tight binding DPP-IV inhibitor. In ob/ob mice, 10 mg/kg, (p.o.) showed a long duration of inhibition of > 70% at 8 h. The duration was translated into long duration of efficacy (~ 35% glucose excursion at 8 h) in the same model and the effect was comparable to vildagliptin. CONCLUSION: The DPP-IV inhibitor sitagliptin behaves as a competitive, tight, and fast binding inhibitor. Sitagliptin differs mechanistically from vildagliptin and exhibits comparable efficacy to that of latter. The finding may give an understanding to develop-second generation DPP-IV inhibitors with desired kinetic profiles.

From a glucocentric to a lipocentric approach towards metabolic syndrome.

Insulin resistance, the essential component of metabolic syndrome, has traditionally been defined from a glucocentric viewpoint, with glucotoxicity playing a lead role. However, as overabundant circulating fatty acids are now known to be overt contributors, there is a paradigm shift in the understanding of metabolic syndrome acknowledging the importance of lipotoxicity as a major perpetuator of insulin resistance. Ectopic accumulation of fat in liver, adipose, muscle and pancreatic islets, provokes insulin resistance through various mechanisms. Chronic inflammation/adipocytokine generation, endoplasmic reticulum stress and mitochondrial dysfunction/oxidative stress also contribute significantly towards insulin resistance. Targets that can act as counter regulators/master switches at the converging point of all these metabolic pathways are currently under intense development.

Topiramate and type 2 diabetes: an old wine in a new bottle.

Topiramate, a marketed antiepileptic drug, has been used to treat seizures and allied neurological problems since 1999. Recently, a series of newer findings for the use of topiramate have cropped up, which include Type 2 diabetes and obesity. In a series of clinical studies, a subset of neurological patients with Type 2 diabetes mellitus (T2DM) serendipitously showed better glycaemic control when treated with topiramate. It has since been demonstrated that topiramate can act both as an insulin secretagogue and sensitiser in T2DM animal models. Pathogenesis of Type 2 diabetes involves both beta-cell dysfunction and insulin resistance. Therefore, an agent that has dual action (insulin secretagougue and sensitisation) is preferred for T2DM. Topiramate seems to act through multiple mechanisms to ameliorate diabetic symptoms, some of them unknown. Hence, it becomes imperative to discuss its probable modes of action. Topiramate raises new hope as an antidiabetic agent or a potential new chemotype with a better safety profile for the treatment of T2DM.

Combination of dipeptidylpeptidase IV inhibitor and low dose thiazolidinedione: preclinical efficacy and safety in db/db mice.

Thiazolidinediones (TZDs) are currently the most efficacious class of oral antidiabetics. However, they carry the burden of weight gain and haemodilution, which may lead to cardiovascular complications. The present study was designed to ascertain whether a combination of dipeptidyl peptidase IV (DPP IV) inhibitor with low dose of a thiazolidinedione absolves TZD associated weight gain and oedema without compromising its efficacy. In this study, we examined the efficacy and safety of lower dose (1 mg/kg/day) of rosiglitazone, a thiazolidinedione, in combination with 5 mg/kg/day dose of LAF-237 (vildagliptin), a known DPP IV inhibitor, in aged db/db mice after 14 days of treatment and compared the combination with therapeutic dose (10 mg/kg) of rosiglitazone. The combination therapy showed similar efficacy as that of 10 mg/kg/day rosiglitazone in lowering random blood glucose (53.8%, p<0.001 and 54.3%, p<0.001 respectively), AUC ((0-120) min) during oral glucose tolerance test (OGTT) (38.6 %, p<0.01; 38.3%, p<0.01 respectively) and triglyceride levels (63.9% and 61% respectively; p<0.01). Plasma active glucagon like peptide-1 (GLP-1) and insulin levels were found to be elevated significantly (p<0.01 and p<0.05 respectively) in both LAF-237 and combination treated groups following oral glucose load. LAF-237 alone had no effect on random glucose and glucose excursion during OGTT in severely diabetic db/db mice. Interestingly, the combination treatment showed no significant increase in body weight as compared to the robust weight gain by therapeutic dose of rosiglitazone. Rosiglitazone at 10 mg/kg/day showed significant reduction (p<0.05) in haematocrit, RBC count, haemoglobin pointing towards haemodilution associated with increased mRNA expression of Na(+), K(+)-ATPase-alpha and epithelial sodium channel gamma (ENaCgamma) in kidney. The combination therapy escaped these adverse effects. The results suggest that combination of DPP IV inhibitor with low dose of thiazolidinedione can interact synergistically to represent a therapeutic advantage for the clinical treatment of type 2 diabetes without the adverse effects of haemodilution and weight gain associated with thiazolidinediones.

Role of peripheral 5-HT1A receptors in detrusor over activity associated with partial bladder outlet obstruction in female rats.

We have investigated the role of peripheral 5-hydroxytryptamine 1A (5-HT(1A)) receptors and their probable up-regulation in rat model of partial bladder outlet obstruction. Bladder outlet obstruction was induced in adult female rats, hypertropic bladders were harvested after 6 weeks and isometric contractions of bladder strips were recorded. A marked spontaneous activity of the bladder was observed in obstructed bladder strips compared to control strips. The effect of alpha(1A/1D)-adrenergic antagonist, tamsulosin, was observed to be inhibitory on the spontaneous contractions albeit at higher doses (10, 30 and 100 nM). As tamsulosin at higher doses also has high affinity for 5-HT(1A) receptors, the role of peripheral 5-HT(1A) receptors in overactive bladder was hypothesized. 8-hydroxy-2-(di-n-propylamino) tetralin [8-OH-DPAT], a selective 5-HT(1A) receptor agonist, dose-dependently induced significant contractions in the obstructed bladder strips, compared to control bladders. N-[2-[4-(2-methoxyphenyl) piperazin-1-yl]ethyl]-N-pyridin-2-yl-cyclohexanecarboxamide dihydrochloride (WAY-100635), a selective 5-HT(1A) receptor antagonist, competitively antagonized the contractile response to 8-OH-DPAT in obstructed bladder strips in a dose-dependent manner. Tamsulosin at a higher dose was also observed to antagonize the responses to 8-OH-DPAT. Taken together, these observations suggest the involvement of peripheral 5-HT(1A) receptors in detrusor over activity associated with bladder outlet obstruction in female rats.

Intermittent claudication: an overview.

Intermittent claudication (IC) is defined by leg muscle pain, cramping and fatigue brought on by ambulation/exercise; relieved on rest; and caused by inadequate blood supply and is the primary symptom of peripheral arterial disease (PAD). PAD has a detrimental effect on the quality of life. PAD is a debilitating atherosclerotic disease of the lower limbs and is associated with an increased risk of cardiovascular morbidity and mortality. IC is an extremely important marker of atheroma. Up to 60% patients with IC have significant underlying coronary and/or carotid disease and 40% of all patients suffering from IC die or suffer a stroke within 5 years of presentation. The therapeutic intervention of IC essentially aims at providing symptomatic relief and reducing the systemic cardiovascular complications. Although exercise therapy is one of the most efficacious conservative treatments for claudication, the pharmacotherapeutic goals can be best achieved through an increase in the walking capacity to improve quality of life and a decrease in rates of amputation. In the development of treatment for IC, an aggressive non-pharmacological intervention and pharmacological treatment of the risk factors associated with IC are considered. In the next 2 years, the results of major trials of drugs that stabilize and regress atherosclerosis such as statins and angiotensin converting enzyme inhibitors, and anti-platelet agents, recombinant growth factors and immune modulators will be available for IC. Levocarnitine (l-carnitine) and a derivative, propionyl levocarnitine, are emerging agents that increase the pain-free walking and improve the quality of life in IC patients by working at the metabolism and exercise performance of ischemic muscles. This article provides a comprehensive review of the pathophysiology involved, diagnosis of IC and existing and emerging pharmacotherapies with rationale for their use in its treatment.

Gs and Gi coupling of adrenomedullin in adult rat ventricular myocytes.

Adrenomedullin (ADM) acts as an autocrine or a paracrine factor in the regulation of cardiac function. The intracellular mechanisms involved in the direct effect of ADM on adult rat ventricular myocytes (ARVMs) are still to be elucidated. In ARVMs from normal rats, ADM produced an initial (< 30 min) increase in cell shortening and Ca2+ transients and a marked decrease in both on prolonged incubation (> 1 h). Both effects were sensitive to ADM antagonist ADM-(22-52). Treatment with SQ-22536, an inhibitor of adenylate cyclase, blocked the positive inotropic effect of ADM and potentiated its negative inotropic effect. The negative inotropic effect was sensitive to inhibition by pertussis toxin (PTX), an inhibitor of Gi proteins and KT-5720, an inhibitor of PKA. The observations suggest a switch from Gs-coupled to PTX-sensitive, PKA-dependent Gi coupling by ADM in ARVMs. The ADM-mediated Gi-signaling system involves cAMP-dependent pathways because SQ-22536 further increased the negative inotropic actions of ADM. Also, because ADM is overproduced by ARVMs in our rat model of septic shock, ARVMs from LPS-treated rats were subjected to treatment with ADM-(22-52) and PTX. The decrease in cell shortening and Ca2+ transients in LPS-treated ARVMs could be reversed back with ADM-(22-52) and PTX. This indicates that ADM plays a role in mediating the negative inotropic effect in LPS-treated ARVM through the activation of Gi signaling. This study delineates the intracellular pathways involved in ADM-mediated direct inotropic effects on ARVMs and also suggests a role of ADM in sepsis.

Role of cyclooxygenase in ventricular effects of adrenomedullin: is adrenomedullin a double-edged sword in sepsis?

Adrenomedullin (ADM) is upregulated in cardiac tissue under various pathophysiological conditions. However, the direct inotropic effect of ADM on normal and compromised cardiomyocytes is not clear. In rat ventricular myocytes, ADM produced an initial (<30 min) increase in cell shortening and Ca(2+) transient and, on prolonged incubation (>1 h), a marked decrease in cell shortening and Ca(2+) transient. Both effects were sensitive to inhibition by the ADM antagonist ADM-(22-52). The increase and decrease in cell shortening and Ca(2+) transient were attenuated by pretreatment with indomethacin [a nonspecific cyclooxygenase (COX) inhibitor], nimesulide and SC-236 (specific COX-2 inhibitors), and tranylcypromine (a prostacyclin synthase inhibitor); SQ-29548 (a thromboxane receptor antagonist) was without effect. Cells isolated from LPS-treated rats that were in the late, hypodynamic phase of septic shock also showed a marked decrease in cell shortening and Ca(2+) transient. Because ADM is overexpressed in sepsis, we repeated the above protocol in cells isolated from LPS-treated rats. At 4 h after LPS injection, ADM levels markedly increased in plasma, ventricles, and freshly isolated ventricular myocytes. Decreases in cell shortening and Ca(2+) transient in LPS-treated cells were reversed by pretreatment with ADM-(22-52). Anti-ADM (rat) IgG also reversed the decrease in cell shortening and other parameters of cell kinetics. Indomethacin, SC-236, and tranylcypromine restored cell contractility and the decrease in Ca(2+) transient, whereas SQ-29548 had no effect, implying that prostacyclin played a role in both effects. However, with regard to cell-shortening kinetics, indomethacin and SQ-29548 decreased the amount of time taken by the cells to return to baseline, whereas SC-236 and tranylcypromine did not, implying that not only prostacyclin, but also thromboxane, is involved. The results indicate that ADM interacts with COX to yield prostanoids, which mediate its negative inotropic effect in LPS-treated rat ventricular myocytes.