The mechanisms of insulin secretion and calcium signaling in pancreatic β-cells exposed to fluoroquinolones

Effects of Varied Sulfamethazine Dosage and Exposure Durations on Offspring Mice

The development of antibiotics was a turning point in the history of medicine; however, their misuse and overuse have contributed to the current global epidemic of antibiotic resistance. According to epidemiological studies, early antibiotic exposure increases the risk of immunological and metabolic disorders. This study investigated the effects of exposure to different doses of sulfamethazine (SMZ) on offspring mice and compared the effects of exposure to SMZ on offspring mice in prenatal and early postnatal periods and continuous periods. Furthermore, the effects of SMZ exposure on the gut microbiota of offspring mice were analyzed using metagenome. According to the results, continuous exposure to high-dose SMZ caused weight gain in mice. IL-6, IL-17A, and IL-10 levels in the female offspring significantly increased after high-dose SMZ exposure. In addition, there was a significant gender difference in the impact of SMZ exposure on the gut microbiota of offspring: Continuous high-dose SMZ exposure significantly decreased the relative abundance of Ligilactobacillus murinus, Limosilactobacillus reuteri, Lactobacillus johnsonii, and Bifidobacterium pseudolongum (p < 0.05) in female offspring mice; however, these significant changes were not observed in male offspring mice.

Pharmacodynamic Studies of Pravastatin Sodium Nanoemulsion Loaded Transdermal Patch for Treatment of Hyperlipidemia

Pravastatin sodium (PVS) is a hypolipidemic drug with poor oral bioavailability due to the first-pass effect. Therefore, this study aims to formulate and evaluate transdermal patches containing PVS-loaded nanoemulsions (PVS-NEs) to increase PVS's hypolipidemic and hepatoprotective activities. PVS-NEs were prepared using the aqueous titration method, where oleic acid was chosen as an oil phase, and span 80 and tween 80 were used as surfactant and cosurfactant respectively. Droplet size (DS), polydispersity index (PDI), zeta potential (ZP), clarity, and thermodynamic stability of NEs were all characterized. Also, PVS-NEs (NE2) with 50% oil phase, 40% SC mix 2:1, and 10% water were selected as an optimum formula based on the results of DS (251 ± 16), PDI (0.4 ± 0.16), and ZP (-70 ± 10.4) to be incorporated into a transdermal patch, and PVS-NE2 loaded transdermal patches (PVS-NE2-TDPs) were prepared by solvent evaporation method. F1 patch with HPMC E15 and PVP K30 in a ratio of 3:1 represented satisfactory patch properties with good drug-excipients compatibility. Thus, it was selected as an optimum patch formula. The optimized F1 patch was characterized for thickness, moisture content, weight variation, and drug-excipients incompatibility. Therefore, it was subjected to ex vivo skin permeation and finally pharmacodynamic studies. Ex vivo permeation studies of F1 revealed that the cumulative amount of PVS permeated across rat skin was 271.66 ± 19 µg/cm2 in 72 h, and the pharmacodynamic studies demonstrated that the F1 patch was more effective in treating hyperlipidemia than PVS-TDP (control patch) based on both blood analysis and histopathological examination. .

Hypoglycemia and anxiolysis mediated by levofloxacin treatment in diabetic rats

Purpose

The present study was designed to determine the effect of levofloxacin (LVX) treatment on the blood glucose level, insulin sensitivity, anxiety level, nitrite and MDA level of STZ induced diabetic rats.

Methods

Wistar rats were used in the present study. The rats were made diabetic by the administration of single dose of STZ (45 mg/kg, i.p.) and NAD (50 mg/kg, i.p.). The rats with the blood glucose level greater than 200 mg/dl were considered as diabetic (confirmed at day-3 of STZ-NAD administration). The non-diabetic rats were considered as control and received saline.Diabetic rats received metformin (50 mg/kg, p.o.) and LVX (20, 25, 30 and 35 mg/kg, i.p.) daily for 14 days (starting from the day at which STZ was injected). Following administration on 14th day,the blood sample was collected and the rats were subjected to behavioral assays for the determination of locomotor activity and anxiety level. Plasma was separated and used for the estimation ofnitrite and malondialdehyde (MDA)level. On 15th day OGTT was performed in the overnight fasted rats for the assessment of insulin sensitivity.

Results

The results obtained suggested that the administration of STZ-NAD induced the hyperglycemia at day-3 of administration. Diabetic rats displayed the significant increase in blood glucose, anxiety related behavior, MDA level while significant decrease in the insulin sensitivity and plasma nitrite level. Daily administration of metformin to the diabetic rats decreased the blood glucose level, increased the time spent at the center of open field, reversed the anxiety related behavior in LDT and EPM, did not affect the plasma nitrite level, decreased the plasma MDA level, decreased the fasting glucose level and AUC in OGTT assay. LVX (30 and 35 mg/kg) treatment significantly decreased the blood glucose level of diabetic rats. LVX (20, 25 and 30 mg/kg) treatment significantly decreased the number of square crossing while LVX (20, 25, 30 and 35) treatment significantly increased the time spent at the center of the field by the diabetic rats. LVX (20 and 35 mg/kg) treatment significantly reversed the STZ induced anxiety in LDT while LVX (20, 30 and 35 mg/kg) treatment significantly reversed the STZ induced anxiety in EPM test. LVX (20, 25 and 35 mg/kg) treatment significantly increased the plasma nitrite level and LVX (20-35 mg/kg) treatment significantly decreased the MDA level of diabetic rats. Further only LVX (35 mg/kg) treatment significantly decreased the fasting glucose level and increased the AUC of diabetic rats.

Conclusion

In conclusion, STZ-NAD administration increased the blood glucose level, anxiety related behavior, decreased the plasma nitrite and increased the MDA level. LVX administration potentiated the diabetogenic effects of STZ-NAD in rats. Daily administration of LVX decreased the blood glucose level of diabetic rats. LVX administration alleviated the STZ induced anxiety in OFT, LDT and EPM test. LVX administration increased the plasma nitrite level and decreased the lipid peroxidation in diabetic rats.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01234-0.

Mas-related G protein-coupled receptor MRGPRX2 in human basophils: Expression and functional studies

Background

Occupancy of MRGPRX2 heralds a new era in our understandings of immediate drug hypersensitivity reactions (IDHRs), but a constitutive expression of this receptor by basophils is debated.

Objective

To explore the expression and functionality of MRGPRX2 in and on basophils.

Methods

Basophils from patients with birch pollen allergy, IDHRs to moxifloxacin, and healthy controls were studied in different conditions, that is, in rest, after stimulation with anti-IgE, recombinant major birch pollen allergen (rBet v 1), moxifloxacin, fMLP, substance P (SP), or other potential basophil secretagogues. In a separate set of experiments, basophils were studied after purification and resuspension in different media.

Results

Resting whole blood basophils barely express MRGPRX2 on their surface and are unresponsive to SP or moxifloxacin. However, surface MRGPRX2 is quickly upregulated upon incubation with anti-IgE or fMLP. Pre-stimulation with anti-IgE can induce a synergic effect on basophil degranulation in IgE-responsive subjects after incubation with SP or moxifloxacin, provided that basophils have been obtained from patients who experienced an IDHR to moxifloxacin. Cell purification can trigger a "spontaneous" and functional upregulation of MRGPRX2 on basophils, not seen in whole blood cells, and its surface density can be influenced by distinct culture media.

Conclusion

Basophils barely express MRGPRX2 in resting conditions. However, the receptor can be quickly upregulated after stimulation with anti-IgE, fMLP, or after purification, making cells responsive to MRGPRX2 occupation. We anticipate that such "conditioned" basophils constitute a model to explore MRGPRX2 agonism or antagonism, including IDHRs originating from the occupation of this receptor.

Conformational adaptability determining antibody recognition to distomer: structure analysis of enantioselective antibody against chiral drug gatifloxacin

Enantioselective antibodies have great potential to separate and detect chiral compounds. However, cross-reactivity of enantioselective antibodies to the distomer may limit the application. An in-depth understanding of interactions between antibodies and chiral drugs could be helpful to investigate antibody recognition to the distomer. In this study, a monoclonal antibody against chiral quinolone S-(−)-gatifloxacin (S-GAT) was produced and its Fab fragment was prepared by proteolysis. The S-GAT Fab exhibited 10% cross-reactivity against the R-enantiomer compared to that of the S-enantiomer in an indirect competitive enzyme-linked immunosorbent assay (icELISA). The crystal structures of the S-GAT Fab apo form and complex with S-GAT were analyzed, and molecular docking of the R-enantiomer was carried out. The ligand conformation was further studied using molecular dynamics simulations. The results showed that the distomer R-enantiomer could enter the chiral center recognition region of the antibody by adjusting the piperazine ring conformation. Meanwhile, the antibody binding cavity had obvious conformational adaptability during ligand binding. It demonstrated that conformational change of both ligand and antibody was the key reason why antibodies recognize the distomer. Restricting conformational adaptability could improve the enantioselective recognition ability of antibodies. This study provided a new explanation for the cross-reactivity of enantioselective antibodies to the distomer, and could help to modulate antibody enantioselectivity for immunoassay of chiral drugs.

The conformational adaptability of both antibody and ligand could determine the antibody enantioselectivity in chiral drug immunoassay.

Hypoglycemia Associated with Antibiotics Alone and in Combination with Sulfonylureas and Meglitinides: An Epidemiologic Surveillance Study of the FDA Adverse Event Reporting System (FAERS)

INTRODUCTION

Fluoroquinolones, clarithromycin, linezolid, tigecycline, cefditoren, doxycycline, and trimethoprim-sulfamethoxazole are known to be associated with hypoglycemia, but few studies have considered concomitant glucose-lowering medications.

OBJECTIVE

The objective of this study was to evaluate the association between hypoglycemia and antibiotics using the US Food and Drug Administration Adverse Event Reporting System (FAERS), while accounting for concomitant glucose-lowering medications including sulfonylureas and meglitinides.

METHODS

FAERS reports from 1 January 2004 to 31 December 2017 were included in the study. Reporting odds ratios (RORs) and corresponding 95% confidence intervals (CIs) for the association between antibiotics and hypoglycemia were calculated. An association was considered to be statistically significant when the lower limit of the 95% CI was > 1.0.

RESULTS

A total of 2,334,959 reports (including 18,466 hypoglycemia reports) were considered, after inclusion criteria were applied. Statistically significant hypoglycemia RORs (95% CI) for antibiotics were: cefditoren 14.03 (8.93-22.03), tigecycline 3.32 (1.95-5.65), clarithromycin 2.41 (1.89-3.08), ertapenem 2.07 (1.14-3.75), moxifloxacin 2.06 (1.59-2.65), levofloxacin 1.66 (1.37-2.01), and linezolid 1.54 (1.07-2.20). After adjusting for concomitant sulfonylureas and meglitinides, the following antibiotics were still significantly associated with hypoglycemia: cefditoren 14.25 (9.08-22.39), tigecycline 3.34 (1.96-5.68), ertapenem 1.93 (1.03-3.60), and clarithromycin 1.56 (1.15-2.11).

CONCLUSION

In many patients, antibiotics, including fluoroquinolones, are associated with hypoglycemia when they are also taking sulfonylureas or meglitinides. Cefditoren, tigecycline, ertapenem, and clarithromycin are associated with hypoglycemia even if not taken with sulfonylureas or meglitinides. The association between ertapenem and hypoglycemia has not been previously reported.

Blockade of multiple monoamines receptors reduce insulin secretion from pancreatic β-cells

Clinical use of olanzapine frequently causes severe hyperglycemia as an adverse effect. In this study, we elucidated mechanisms by which olanzapine reduced insulin secretion using the hamster pancreatic β-cell line HIT-T15. Reverse transcriptional-PCR analysis revealed expression of dopamine (D₂, D₃ and D₄), serotonin (5-HT_2A, 5-HT_2B, 5-HT_2C, and 5-HT₆), and histamine (H₁ and H₂) receptors in HIT-T15 cells. Olanzapine decreased insulin secretion from HIT-T15 cells at clinically relevant concentrations (64–160 nM). A dopamine D₂ agonist, D₃ antagonist, and D₄ antagonist suppressed insulin secretion, whereas a D₂ antagonist and D₃ agonist increased it. A serotonin 5-HT_2B agonist slightly increased insulin secretion, while a 5-HT_2C antagonist slightly decreased it. Other agonists and antagonists for serotonin receptors did not affect insulin secretion. A histamine H₁ agonist increased insulin secretion, whereas an H₁ antagonist and H₂ agonist suppressed it. Our results suggest that dopamine (D₂, D₃ and D₄), serotonin (5-HT_2B and 5-HT_2C), and histamine (H₁ and H₂) receptors, which are expressed on pancreatic β-cells, directly modulate insulin secretion from pancreatic β-cells. Thus, olanzapine may induce hyperglycemia in clinical settings by suppressing insulin secretion from pancreatic β-cells through inhibition of dopamine D₃, serotonin 5-HT_2B and 5-HT_2C, and histamine H₁ receptors.

A multicentre study of patients with Timothy syndrome

Aims

Timothy syndrome (TS) is an extremely rare multisystem disorder characterized by marked QT prolongation, syndactyly, seizures, behavioural abnormalities, immunodeficiency, and hypoglycaemia. The aim of this study was to categorize the phenotypes and examine the outcomes of patients with TS.

Methods and results

All patients diagnosed with TS in the United Kingdom over a 24-year period were reviewed. Fifteen centres in the British Congenital Arrhythmia Group network were contacted to partake in the study. Six patients with TS were identified over a 24-year period (4 boys and 2 girls). Five out of the six patients were confirmed to have a CACNA1C mutation (p.Gly406Arg) and the other patient was diagnosed clinically. Early presentation with heart block, due to QT prolongation was frequently seen. Four are still alive, two of these have a pacemaker and two have undergone defibrillator implantation. Five out of six patients have had a documented cardiac arrest with three occurring under general anaesthesia. Two patients suffered a cardiac arrest while in hospital and resuscitation was unsuccessful, despite immediate access to a defibrillator. Surviving patients seem to have mild developmental delay and learning difficulties.

Conclusion

Timothy syndrome is a rare disorder with a high attrition rate if undiagnosed. Perioperative cardiac arrests are common and not always amenable to resuscitation. Longer-term survival is possible, however, patients invariably require pacemaker or defibrillator implantation.

[Research on Insufficient Information for Pharmaceutical Products]

 Several issues concerning medicines remain unclear, including the availability of known, but not easily recognizable information. This review evaluates the mechanisms of side effects and the various risk indications included in package inserts. The results can be summarized as follows. 1) Short-term exposure to gatifloxacin significantly induced insulin secretion and increased the cytosolic Ca²⁺ concentration of islet cells by augmenting extracellular Ca²⁺ influx and its release from the endoplasmic reticulum. Alternatively, there was a decline in the cellular insulin level and reactivity to sulfonylurea after prolonged exposure. The insulin depletion was greater than that produced by other fluoroquinolones. 2) The elution of di(2-ethylhexyl)phthalate (DEHP) from the infusion set could be associated with the solubilizers in the injection medicines. The package inserts of several products containing polysorbate or ethanol had no warning about DEHP. Although there was a slight correlation between polysorbate content and descriptions on package inserts, the use of DEHP-containing devices was prohibited for some products, even with limited amounts of polysorbate. Therefore, the package insert statements should be reviewed to reflect appropriately the extent of DEHP elution. 3) Risk management plan consists of strategies to minimize the potential risks of medicines. One approach could be to introduce reminders on package inserts; however, of 268 potential risks associated with 81 products, 56 were not mentioned in package inserts. Because most postmarketing pharmacovigilance plans depend on spontaneous reporting by healthcare personnel, the descriptions on package inserts should be reexamined.

Novel members of quinoline compound family enhance insulin secretion in RIN-5AH beta cells and in rat pancreatic islet microtissue

According to clinical data, some tyrosine kinase inhibitors (TKIs) possess antidiabetic effects. Several proposed mechanisms were assigned to them, however their mode of action is not clear. Our hypothesis was that they directly stimulate insulin release in beta cells. In our screening approach we demonstrated that some commercially available TKIs and many novel synthesized analogues were able to induce insulin secretion in RIN-5AH beta cells. Our aim was to find efficient, more selective and less toxic compounds. Out of several hits, we chose members from a compound family with quinoline core structure for further investigation. Here we present the studies done with these novel compounds and reveal structure activity relationships and mechanism of action. One of the most potent compounds (compound 9) lost its affinity to kinases, but efficiently increased calcium influx. In the presence of calcium channel inhibitors, the insulinotropic effect was attenuated or completely abrogated. While the quinoline TKI, bosutinib substantially inhibited tyrosine phosphorylation, compound 9 had no such effect. Molecular docking studies further supported our data. We confirmed that some TKIs possess antidiabetic effects, moreover, we present a novel compound family developed from the TKI, bosutinib and optimized for the modulation of insulin secretion.

Regulation of L-type Ca2+ Channel Activity and Insulin Secretion by Huntingtin-associated Protein 1

Huntingtin-associated protein 1 (Hap1) was originally identified as a protein that binds to the Huntington disease protein, huntingtin. Growing evidence has shown that Hap1 participates in intracellular trafficking via its association with various microtubule-dependent transporters and organelles. Recent studies also revealed that Hap1 is involved in exocytosis such as insulin release from pancreatic β-cells. However, the mechanism underlying the action of Hap1 on insulin release remains to be investigated. We found that Hap1 knock-out mice had a lower plasma basal insulin level than control mice. Using cultured pancreatic β-cell lines, INS-1 cells, we confirmed that decreasing Hap1 reduces the number of secreted vesicles and inhibits vesicle exocytosis. Electrophysiology and imaging of intracellular Ca²⁺ measurements demonstrated that Hap1 depletion significantly reduces the influx of Ca²⁺ mediated by L-type Ca²⁺ channels (Cav). This decrease is not due to reduced expression of Cav1.2 channel mRNA but results from the decreased distribution of Cav1.2 on the plasma membrane of INS-1 cells. Fluorescence recovery after photobleaching showed a defective movement of Cav1.2 in Hap1 silencing INS-1 cells. Our findings suggest that Hap1 is important for insulin secretion of pancreatic β-cells via regulating the intracellular trafficking and plasma membrane localization of Cav1.2, providing new insight into the mechanisms that regulate insulin release from pancreatic β-cells.

Drug Management in the Elderly IBD Patient

OPINION STATEMENT

Managing inflammatory bowel disease (IBD) in a world of immunomodulators and biologics is complex enough, but managing the elderly IBD patient is further confounded by multiple comorbidities, polypharmacy with drug-drug interactions, and cognitive mobility/motility disturbances. Social and insurance coverage issues also always lurk in the background. All of these factors summate into a daunting challenge for the clinician. In this review, we aim to describe important considerations when prescribing to an elderly patient with IBD, taking into account costs of medications, drug interactions, the aging body's effect on pharmacokinetics, and the effect of aging on the immune system. Adverse effects and drug-drug interactions are expounded upon in detail specific for the aging adult with IBD in an effort to assist the clinician in the decision-making process.