Perhexiline Therapy in Patients with Type 2 Diabetes: Dissociation Between Potentiation of Nitric Oxide Signalling and Changes in Insulin Resistance

Purpose: Perhexiline (Px) has previously been utilized primarily in the treatment of otherwise refractory angina pectoris and/or systolic heart failure. In recent years, Px has also shown increasing promise as a potential chemotherapeutic agent. Px inhibits carnitine palmitoyltransferases 1 and 2 (CPT1, CPT2), which control uptake of long-chain fatty acids into mitochondria and thus represent the rate-limiting steps in their metabolism. However, occasional cases of hypoglycaemia have been reported in Px-treated patients, raising the possibility that Px may also increase sensitivity to insulin. Furthermore, Px increases anti-aggregatory responses to nitric oxide (NO), an effect which may parallel insulin sensitization. No previous studies have examined either the effect of Px on insulin sensitivity, or the relationship of such putative changes with effects on NO signalling. We therefore sought to examine these relationships in patients with stable T2D and cardiovascular disease.Methods: In 30 patients with concomitant T2D and cardiovascular disease, Px was initiated, and dosage was titrated to reach therapeutic range and to prevent toxicity. Investigations were performed before and after 2 weeks, to examine changes in insulin sensitivity, platelet responsiveness to the anti-aggregatory effects of the NO donor sodium nitroprusside (SNP), as well as other markers of inflammation and modulators of NO signaling.Results: Px substantially potentiated inhibition of ADP-induced platelet aggregation by SNP (from 16.7±3.0 to 27.3±3.7%; p=0.005). Px did not change fasting blood glucose concentrations and reduced insulin sensitivity (HOMA-IR score increased from median of 4.47 to 6.08; p=0.028), via increasing fasting plasma insulin concentrations (median 16.5 to 19.0 mU/L: p=0.014). Increases in SNP responses tended (r=-0.30; p=0.11) to be reciprocally related to increases in HOMA-IR. No patient developed symptomatic hypoglycaemia, nor was there any other short-term toxicity of Px.Conclusions: In patients with stable T2D and cardiovascular disease, Px is not an insulin sensitizer, and does not normally induce hypoglycaemia. These results effectively dissociate the NO-sensitizing effect of Px from variability in insulin signaling.

The Insulin-Sensitizer Pioglitazone Remodels Adipose Tissue Phospholipids in Humans

The insulin-sensitizer pioglitazone exerts its cardiometabolic benefits in type 2 diabetes (T2D) through a redistribution of body fat, from ectopic and visceral areas to subcutaneous adipose depots. Whereas excessive weight gain and lipid storage in obesity promotes insulin resistance and chronic inflammation, the expansion of subcutaneous adipose by pioglitazone is associated with a reversal of these immunometabolic deficits. The precise events driving this beneficial remodeling of adipose tissue with pioglitazone remain unclear, and whether insulin-sensitizers alter the lipidomic composition of human adipose has not previously been investigated. Using shotgun lipidomics, we explored the molecular lipid responses in subcutaneous adipose tissue following 6months of pioglitazone treatment (45mg/day) in obese humans with T2D. Despite an expected increase in body weight following pioglitazone treatment, no robust effects were observed on the composition of storage lipids (i.e., triglycerides) or the content of lipotoxic lipid species (e.g., ceramides and diacylglycerides) in adipose tissue. Instead, pioglitazone caused a selective remodeling of the glycerophospholipid pool, characterized by a decrease in lipids enriched for arachidonic acid, such as plasmanylethanolamines and phosphatidylinositols. This contributed to a greater overall saturation and shortened chain length of fatty acyl groups within cell membrane lipids, changes that are consistent with the purported induction of adipogenesis by pioglitazone. The mechanism through which pioglitazone lowered adipose tissue arachidonic acid, a major modulator of inflammatory pathways, did not involve alterations in phospholipase gene expression but was associated with a reduction in its precursor linoleic acid, an effect that was also observed in skeletal muscle samples from the same subjects. These findings offer important insights into the biological mechanisms through which pioglitazone protects the immunometabolic health of adipocytes in the face of increased lipid storage.

MLR-1023 Treatment in Mice and Humans Induces a Thermogenic Program, and Menthol Potentiates the Effect

A glucose-lowering medication that acts by a different mechanism than metformin, or other approved diabetes medications, can supplement monotherapies when patients fail to meet blood glucose goals. We examined the actions underlying the effects of an insulin sensitizer, tolimidone (MLR-1023) and investigated its effects on body weight. Diet-induced obesity (CD1/ICR) and type 2 diabetes (db/db) mouse models were used to study the effect of MLR-1023 on metabolic outcomes and to explore its synergy with menthol. We also examined the efficacy of MLR-1023 alone in a clinical trial (NCT02317796), as well as in combination with menthol in human adipocytes. MLR-1023 produced weight loss in humans in four weeks, and in mice fed a high-fat diet it reduced weight gain and fat mass without affecting food intake. In human adipocytes from obese donors, the upregulation of Uncoupling Protein 1, Glucose (UCP)1, adiponectin, Glucose Transporter Type 4 (GLUT4), Adipose Triglyceride Lipase (ATGL), Carnitine palmitoyltransferase 1 beta (CPT1β), and Transient Receptor Potential Melastin (TRPM8) mRNA expression suggested the induction of thermogenesis. The TRPM8 agonist, menthol, potentiated the effect of MLR-1023 on the upregulation of genes for energy expenditure and insulin sensitivity in human adipocytes, and reduced fasting blood glucose in mice. The amplification of the thermogenic program by MLR-1023 and menthol in the absence of adrenergic activation will likely be well-tolerated, and bears investigation in a clinical trial.

Astragalus hamosus Acts as an Insulin Sensitizer Through the Treatment of Polycystic Ovary Syndrome Rat Models by Affecting IRS1 Expression

Background: Polycystic ovary syndrome (PCOS) is the most common endocrine abnormality among women of reproductive age. Insulin resistance is known as the hallmark of PCOS that leads to hyperinsulinemia and type 2 diabetes in PCOS patients. Objective: This study aimed to evaluate the expression pattern of IRS1 as a candidate gene in insulin resistance development in the PCOS Rat models. Methods: In this study, estradiol valerate was used for PCOS induction. Then, all of the rats were divided into five experimental groups and treated with Astragalus hamosus extract. Ethanol was used for extraction by Soxhlet, and extracts were analyzed by GC-MS. Ovarian morphology was analyzed using histological experiments. Finally, the expression of IRS1 and hormonal titration of testosterone and insulin were evaluated using qRT-PCR and ELISA assays, respectively. Results: Induction of PCOS led to an increase in body weight, which decreased after treatment with the extract. Histological assessment declared an increased number of corpus luteums in treated groups and reduced cystic follicles compared with the PCOS group. Astragalus hamosus extract-treated groups exhibited decreased levels of insulin and testosterone compared to the PCOS group. qRT-PCR results showed an increase in the expression levels of IRS1 in the treated groups compared to the PCOS group. Conclusions: This study indicated the impact of Astragalus hamosus extract on PCOS by clarifying the increased levels of IRS1 expression in the treated groups compared to the PCOS group.

Berberine Phospholipid Is an Effective Insulin Sensitizer and Improves Metabolic and Hormonal Disorders in Women with Polycystic Ovary Syndrome: A One-Group Pretest–Post-Test Explanatory Study

Polycystic Ovary Syndrome (PCOS) is the most frequent endocrine disease in females of reproductive age and is characterized by multifactorial unhealthy conditions related to hormonal unbalance and also to dysmetabolism and inflammation. Recently, increasing evidence has shown that natural plant-based products may play a role in PCOS management. The aim of this one-group pretest–post-test explanatory study was to evaluate, in normal–overweight PCOS women with normal menses, the effectiveness of berberine on: Insulin resistance (IR) by Homeostasis Model Assessment (HOMA); Inflammation by C-Reactive Protein (CRP), Tumor Necrosis Factor α (TNF-α); Lipid metabolism; Sex hormone profile and symptoms correlated to hyperandrogenism, such as acne, by Global Acne Grading System (GAGS) and Cardiff Acne Disability Index (CADI); Body composition by DXA. Finally, adverse effects were assessed by liver and kidney functions and creatine phosphokinase (CPK). All these parameters were collected at baseline and 60 days after supplementation with a new bioavailable and safe berberine formulation. Twelve females (aged 26.6 ± 4.9, BMI 25.3 ± 3.6) were supplied for 60 days with two tablets/day (550 mg/table) of the bioavailable berberine. Results showed a statistically significant decrease in HOMA, CRP, TNF-α, Triglycerides, testosterone, Body Mass Index (BMI), Visceral Adipose Tissue (VAT), fat mass, GAGS and CADI scores, and a statistically significant increase in sex hormone-binding globulin (SHBG). Liver and kidney functions and CPK are not statistically significantly different. Therefore, berberine can represent a safe novel dietary supplement, helpful in treatment strategy for PCOS.

In-silico discovery of antidiabetic drug potential of Balanites aegyptiaca leaf’s phenolic compounds

<i>Balanites aegyptiaca</i> leaf is very effective in managing diabetes and rich in phenolic compounds. However, the modes of action of the phytochemicals are mainly unknown. Thus, the present in silico drug discovery study on some phenolic compounds was designed to evaluate potential mechanisms of action of the antihyperglycemic phytochemicals of <i>B. aegyptiaca</i> leaf extract. The study deployed in silico drug-like studying techniques such as; predicted activity spectra of substances (PASS), molecular docking, prediction of adsorption, distribution, metabolism, excretion, and toxicity (ADMET), Lipinski’s rule of 5 (PLOP). The study reveals six compounds with good drug-like properties: cLogp, hydrogen bond donor/acceptor (<5/ < 10), and molar refractivity. In addition, ADMET and drug properties like kinase inhibitors, ion channel modulators, and nuclear receptors were positive for the compounds. Each phenolic compound showed one or more antidiabetic activities like insulin promoter, insulin sensitizer and inhibitors of α-amylase and α-glucosidase. Docking result predicted that the phenolic compounds inhibited either α-amylase or α-glucosidase while one of the compounds; 2-methoxy-4-(1-propenyl)-phenol inhibited both α-amylase and α-glucosidase with binding energies of -4.4 and -4.2 kcal/mol against -3.8 and -4.8 kcal/mol by Acarbose. The study revealed that phenolic compounds from <i>B. aegyptiaca</i> leaf possessed drug-like properties, including the ability to interact with α-amylase and α-glucosidase, a vital target protein in the management of diabetes mellitus. The data from the in silico study is a step toward the pharmaceutical discovery of the antidiabetic drug potential of <i>B. aegyptiaca</i> leaf.

NM101 Phase III study of NE3107 in Alzheimer’s: rationale, design and therapeutic modulation of neuroinflammation and insulin resistance

Recently, the roles of inflammation and insulin resistance in neurodegeneration have become better appreciated. NE3107, an oral small molecule, blood-brain permeable anti-inflammatory insulin sensitizer that binds extracellular signal-regulated kinase, has been shown to selectively inhibit inflammation-driven ERK- and NFκB-stimulated inflammatory mediators, including TNFα, without inhibiting their homeostatic functions. We describe the rationale and design of NM101, the first randomized, multicenter Phase III clinical study to examine the safety and efficacy of 30 week treatment with NE3107 versus placebo in elderly adults with mild to moderate Alzheimer’s disease. Patients (316) will be randomized in a 1:1 ratio. The co-primary end points measure cognitive function (ADAS Cog12), and functional and behavioral characteristics (ADCS CGIC). Trial registration number: NCT04669028 (Clinicaltrials.gov)