Pharmacology, Efficacy, and Safety of Linagliptin for the Treatment of Type 2 Diabetes Mellitus

Dipeptidyl peptidase-4 inhibitor linagliptin reduces inflammatory response, ameliorates tissue edema formation, and improves survival in severe sepsis

BACKGROUND

Excessive inflammation in sepsis causes microvascular dysfunction associated with organ dysfunction and high mortality. The present studies aimed to examine the therapeutic potential of linagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor in a clinically relevant polymicrobial sepsis model in mice.

METHODS

Sepsis was induced by cecal ligation and puncture (CLP). Mice were grouped into: Sham control+vehicle; Group 2: CLP+vehicle; Group 3: CLP+dexamethasone (10 mg/kg, s.c.) given 6 h after CLP; Group 4: CLP+linagliptin (1 mg/kg, s.c.) given 6 h after CLP. The experiment was terminated 24 hours after CLP in two experimental sets. Seven-day survival following CLP was determined in a third experimental set.

RESULTS

Treatment with linagliptin inhibited DPP-4 activity, increased the levels of active forms of endogenous gastric inhibitory polypeptide and glucagon-like peptide-1, without affecting the blood glucose levels in CLP mice. Compared to vehicle treatment, administration of linagliptin reduced sepsis-induced tissue hyper permeability as evidenced by a reduction in vascular Evans blue leakage, prevented edema formation in the lung, heart, liver and kidney. Furthermore, linagliptin or dexamethasone reduced sepsis-induced proinflammatory cytokine and chemokine production, such as IL-1β, IL-2, IL-10, IL-23, IL-27, VCAM-1, eotaxin, MDC, MCSF1, GCP-2, and NGAL. Importantly, administration of linagliptin improved the 7-day survival rate following CLP in mice. RNA sequencing in lung and heart revealed that linagliptin attenuated key inflammatory pathways including TNF alpha (via NFκB) and IL6/JAK/STAT3 signaling and activated interferon signaling in the heart.

CONCLUSIONS

Linagliptin treatment can attenuate the inflammatory response, protect against severe sepsis-induced vascular hyperpermeability, reduce multiorgan injury, and most importantly, improve the survival.

DPP-4 inhibitors for treating T2DM - hype or hope? an analysis based on the current literature

DPP-4 inhibition is an interesting line of therapy for treating Type 2 Diabetes Mellitus (T2DM) and is based on promoting the incretin effect. Here, the authors have presented a brief appraisal of DPP-4 inhibitors, their modes of action, and the clinical efficiency of currently available drugs based on DPP-4 inhibitors. The safety profiles as well as future directions including their potential application in improving COVID-19 patient outcomes have also been discussed in detail. This review also highlights the existing queries and evidence gaps in DPP-4 inhibitor research. Authors have concluded that the excitement surrounding DPP-4 inhibitors is justified because in addition to controlling blood glucose level, they are good at managing risk factors associated with diabetes.

Neuroprotective Role of DPP-4 Inhibitor Linagliptin Against Neurodegeneration, Neuronal Insulin Resistance and Neuroinflammation Induced by Intracerebroventricular Streptozotocin in Rat Model of Alzheimer's Disease

Alzheimer's disease (AD) is an age-related, multifactorial progressive neurodegenerative disorder manifested by cognitive impairment and neuronal death in the brain areas like hippocampus, yet the precise neuropathology of AD is still unclear. Continuous failure of various clinical trial studies demands the utmost need to explore more therapeutic targets against AD. Type 2 Diabetes Mellitus and neuronal insulin resistance due to serine phosphorylation of Insulin Receptor Substrate-1 at 307 exhibits correlation with AD. Dipeptidyl Peptidase-4 inhibitors (DPP-4i) have also indicated therapeutic effects in AD by increasing the level of Glucagon-like peptide-1 in the brain after crossing Blood Brain Barrier. The present study is hypothesized to examine Linagliptin, a DPP-4i in intracerebroventricular streptozotocin induced neurodegeneration, and neuroinflammation and hippocampal insulin resistance in rat model of AD. Following infusion on 1st and 3rd day, animals were treated orally with Linagliptin (0.513 mg/kg, 3 mg/kg, and 5 mg/kg) and donepezil (5 mg/kg) as a standard for 8 weeks. Neurobehavioral, biochemical and histopathological analysis was done at the end of treatment. Dose-dependently Linagliptin significantly reversed behavioral alterations done through locomotor activity (LA) and morris water maze (MWM) test. Moreover, Linagliptin augmented hippocampal GLP-1 and Akt-ser473 level and mitigated soluble Aβ (1-42), IRS-1 (s307), GSK-3β, TNF-α, IL-1β, IL-6, AchE and oxidative/nitrosative stress level. Histopathological analysis also exhibited neuroprotective and anti-amylodogenic effect in Hematoxylin and eosin and Congo red staining respectively. The findings of our study concludes remarkable dose-dependent therapeutic potential of Linagliptin against neuronal insulin resistance via IRS-1 and AD-related complication. Thus, demonstrates unique molecular mechanism that underlie AD.

Linagliptin, a DPP-4 inhibitor, ameliorates Aβ (1-42) peptides induced neurodegeneration and brain insulin resistance (BIR) via insulin receptor substrate-1 (IRS-1) in rat model of Alzheimer's disease

Alzheimer's disease (AD) is the most devastating neurodegenerative disorder, accounting over 46 million cases of dementia globally. Evidence supports that Brain Insulin Resistance (BIR) due to serine phosphorylation of Insulin Receptor Substrate-1 (IRS-1) has an association with AD. GLP-1 an incretin hormone, rapidly degraded by Dipeptidyl Peptidase-4 (DPP-4) has also confirmed its efficacious role in AD. Linagliptin, a DPP-4 inhibitor is hypothesized to increase GLP-1 level, which then crosses Blood Brain Barrier (BBB), decreases Amyloid-beta (Aβ) and insulin resistance in hippocampus. Thus, the present study was designed to evaluate Linagliptin in Aβ (1-42) peptides induced rat model of AD. Following 1 week of induction, rats were administered with Linagliptin (0.513 mg/kg, 3 mg/kg, and 5 mg/kg) orally for 8 weeks and donepezil (5 mg/kg) as a reference standard. At the end of scheduled treatment neurobehavioral parameters were assessed. After this, rats were sacrificed, hippocampus was isolated from the whole brain for histopathological analysis and biochemical parameters estimation. Linagliptin dose-dependently and significantly reversed motor and cognitive impairment, assessed through locomotor activity (LA) and Morris water maze (MWM) test respectively. Moreover, Linagliptin augmented GLP-1 level and attenuated soluble Aβ (1-42), IRS-1 (s307), GSK-3β, TNF-α, IL-1β, IL-6, AchE and oxidative/nitrosative stress level in hippocampus. H&E and Congo red staining also exhibited neuroprotective and anti-amylodogenic effect respectively. Our study findings implies the significant effect of Linagliptin in reversing the behavioural and biochemical deficits by altering Aβ (1-42) and BIR via IRS-1 confirming one of the mechanism underlying the pathophysiology of AD.

DPP-4 inhibitor attenuates toxic effects of indoxyl sulfate on kidney tubular cells

Diabetic nephropathy is a common causative factor of chronic kidney disease (CKD). DPP-4 inhibitor has the ability to improve kidney function and renal microvasculature. In the present study, we investigate the deleterious effects of IS on proximal tubular cells and the protective role of DPP-4 inhibitor. Human kidney 2 (HK-2) cells were exposed to IS in the presence or absence of DPP-4 inhibitor. Effects of DPP-4 inhibitor on viability of HK-2 cells were determined by MTT assay. Reactive oxygen species (ROS) production was examined using fluorescent microscopy. Levels of cleaved caspase-3, transforming growth factor-beta (TGF-β), α-smooth muscle actin (α-SMA) and NF-kappaB p65 and phosphorylation of AKT and extracellular signal-regulated kinase (ERK) were detected by immunoblotting. Production of ROS and level of cleaved caspase-3 were increased by IS in a dose-dependent manner. The phosphorylation of AKT and ERK p65 were decreased alongside activation of NF-κB. Expression of TGF-β and α-SMA, were upregulated in IS-treated HK-2 cells. Treatment with DPP-4 inhibitor resulted in a significant increase in cell viability and a decrease of ROS production in IS-treated HK-2 cells. DPP-4 inhibitor restored IS-induced deactivations of AKT and ERK and inhibited activation of NF-κB in IS-treated HK-2 cells. Moreover, DPP-4 inhibitor could also attenuate IS-induced up-regulation of TGF-β and α-SMA expression. These findings suggest that DPP-4 inhibitor possesses anti-apoptotic activity to ameliorate the IS-induced renal damage, which may be partly attributed to regulating ROS/p38MAPK/ERK and PI3K-AKT pathways as well as downstream NF-κB signaling pathway.

Probable linagliptin-induced liver toxicity: a case report

AIM

Unlike other dipeptidyl peptidase 4 (DPP-4) inhibitors, the excretion of linagliptin is mainly through a biliary route. Despite this fact, liver injury with linagliptin has thus far not been reported in the literature. However, this report describes the first case of probable linagliptin-induced liver toxicity.

METHODS

The clinical history, diagnosis, investigations and drug treatment of the patient are reviewed here.

RESULTS

A 58-year-old Japanese woman presented with fatigue, nausea, jaundice and marked elevations of hepatic enzymes 4weeks after starting linagliptin 5mg/day as monotherapy. No other medications were taken, and imaging studies revealed no other obvious causes of hepatic injury. Tests for viral serology and antinuclear antigen were negative. Symptoms disappeared and the levels of hepatic parameters (serum aminotransferases and biliary enzymes) slowly recovered after discontinuation of linagliptin. The slow recovery process may have been due to the very long half-life of the drug. The patient's Naranjo scale score was 6 and RUCAM score was 7.

CONCLUSION

Although linagliptin currently carries no liver warnings, it may be necessary to monitor hepatic function in some patients upon administration of this drug until further evidence is obtained.

Antidiabetic agents: past, present and future

Treatment of diabetes mellitus requires, at a certain stage of its course, drug intervention. This article reviews the properties of available antidiabetic medications and highlights potential targets for developing newer and safer drugs. Antidiabetic agents are grouped in the article as parts I, II and III according to the history of development. Part I groups early developed drugs, during the 20th century, including insulin, sulfonylureas, the metiglinides, insulin sensitizers, biguanides and α-glucosidase inhibitors. Part II groups newer drugs developed during the early part of the 21st century, the past decade, including GLP-1 analogs, DPP-VI inhibitors, amylin analogs and SGLT2 inhibitors. Part III groups potential targets for future design of newer antidiabetic agents with less adverse effects than the currently available antidiabetic drugs.