The Efficacy and Safety of Rebamipide Ophthalmic Suspension (OPC-12759) in Patients with Dry Eye Disease: A Systematic Review of Randomized Controlled Trials

The aim of this paper is to evaluate the efficacy and safety of Rebamipide (REB) ophthalmic suspension in dry eye disease (DED). A systematic review that only included full-length randomized controlled studies (RCTs) reporting the effects of REB ophthalmic suspension in three databases, PubMed, Scopus and Web of Science, was performed according to the PRISMA statement. The Cochrane risk of bias tool was used to analyze the quality of the studies selected. A total of seven studies were included in this systematic review. Although the overall risk of bias was low, most studies were sponsored by the manufacturer. REB ophthalmic suspension treatment achieved higher improvement than the control group in all reported variables. The mean differences between both groups were in favor of the REB group and were as follows: dry eye-related quality of life score (DEQS) -3.5 ± 2.9 points, tear film break-up time (TBUT) of 0.7 ± 0.6 s, Schirmer test (ST) without anesthesia of 0.3 ± 0.6 mm and total corneal fluorescein staining (tCFS) of -1.2 ± 0.7 points. Adverse events (AEs) were 5.2 ± 7.6% superior in the REB group, with an overall compliance > 95%. Therefore, REB ophthalmic suspension is a safe and effective treatment that could be recommended in patients with DED.

An Uncommon Case of Recurrent Hypoglycemic Episodes in a Healthy Non-diabetic Male: Insulin Autoimmune Syndrome

Insulin autoimmune syndrome is a rare cause of recurrent hypoglycemic episodes that can mimic various other pathological problems leading to unnecessary diagnostic assessments and interventions. Here, we report a case of a healthy non-diabetic male in his 50s presenting with recurrent episodes of hypoglycemia with no prior exposure to exogenous insulin. During a 72-hour fasting test, his glucose levels reached 22 mg/dl within less than three hours. The lab tests showed insulin of 1000 μIU/mL and C-peptide of 4.99 ng/ml. On further evaluation, high titers of insulin autoantibodies (IAA) >100 U/ml (normal = <10 U/ml) were consistent with insulin autoimmune syndrome diagnosis. This case thus highlights the importance of including IAA titers in first-line investigations for hypoglycemia in a non-diabetic patient with strikingly high blood insulin levels.

Short-term Efficacy and Safety of Biological Tear Substitutes and Topical Secretagogues for Dry Eye Disease: A Systematic Review and Network Meta-analysis

PURPOSE

The purpose of this study was to assess short-term efficacy and safety of tear promotion eye drops (biological tear substitutes and topical secretagogues) for treating dry eye disease.

METHODS

Randomized controlled trials comparing short-term effects of biological tear substitutes or topical secretagogues versus placebo or other topical dry eye treatments in adults with dry eye disease were identified from the MEDLINE, Embase, Scopus, ClinicalTrials.gov , and World Health Organization International Clinical Trials Registry Platform databases. Pairwise meta-analysis and network meta-analysis were performed. Outcomes were ocular symptoms, ocular surface staining, tear break-up time, Schirmer test, and adverse events. The certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Thirty-nine randomized controlled trials (3693 patients) were eligible. Using artificial tears as a reference, autologous platelet lysate was the most effective treatment for lowering ocular surface disease index (unstandardized mean difference [USMD] -31.85; 95% confidence interval [CI]: -43.19 to -20.51) and platelet rich plasma showed the most reduction in corneal fluorescein staining scores (standardized mean difference -2.52; 95% CI: -3.23 to -1.82). Cord blood serum was the most effective treatment for increasing tear break-up time (USMD 2.67; 95% CI: 0.53-4.82), and eledoisin was superior to others in improving Schirmer scores (USMD 2.28; 95% CI: 0.14-4.42). Most interventions did not significantly increase ocular adverse events compared with artificial tears.

CONCLUSIONS

Biological tear substitutes, including autologous serum, autologous platelet lysate, platelet rich plasma, and cord blood serum, might be the most effective treatment among tear promotion eye drops in relieving dry eye symptoms without increasing adverse events. However, there remains uncertainty around these findings because of low/very low certainty of evidence.

Novel luciferase-based GLP-1 reporter assay reveals naturally-occurring secretagogues

BACKGROUND AND PURPOSE

Glucagon-like peptide 1 (GLP-1) is a hormone derived from preproglucagon. It is secreted by enteroendocrine cells in response to feeding, and, in turn, acts as a critical regulator of insulin release. Modulating GLP-1 secretion thus holds promise as a strategy for controlling blood glucose levels.

EXPERIMENTAL APPROACH

To dissect GLP-1 regulation and to discover specific secretagogues, we engineered a reporter cell line introducing a luciferase within proglucagon sequence in GLUTag cells. The assay was validated using western blotting and ELISA. A focused natural compounds library was screened. We measured luminescence, glucose uptake and ATP to investigate the mechanism by which newly found secretagogues potentiate GLP-1 secretion.

KEY RESULTS

The newly created reporter cell line is ideal for the rapid, sensitive and quantitative assessment of GLP-1 secretion. The small molecule screen identified non-toxic GLP-1 modulators. Quercetin is the most potent newly found GLP-1 secretagogue, while other flavonoids also potentiate GLP-1 secretion. Quercetin requires glucose and extracellular calcium to act as GLP-1 secretagogue. Our results support a mechanism whereby flavonoids cause GLUTag cells to utilize glucose more efficiently, leading to elevated ATP levels, followed by K_ATP channel blockade and GLP-1 exocytosis.

CONCLUSION AND IMPLICATIONS

Our methodology enables finding of new GLP-1 secretagogues. Quercetin is a potent, naturally occuring GLP-1 secretagogue. Mechanistic studies of newly found secretagogues are possible in newly created reporter cell line. Further validation in more physiological systems, such as primary L-cells or whole organisms is needed. GLP-1 secretagogues might serve as leads for developing alternative glucose-lowering therapies.

Chronic Idiopathic Constipation in Adults: A Review on Current Guidelines and Emerging Treatment Options

Chronic idiopathic constipation (CIC) is a common functional bowel disorder characterized by difficult, infrequent, and/or incomplete defecation. It has a great impact on the quality of life and on health care system and represents a heavy economic burden. The diagnosis is based on symptoms, classified by the Rome IV criteria. The aim of this review was to evaluate the current therapeutic guidelines for adult CIC and highlight new emerging treatments. In detail, European, French, Spanish and Korean guidelines have been identified and compared. Osmotic laxatives, and in particular polyethylene glycol, represent the first-line therapeutic approach. Stimulant laxatives are recommended as a second-line therapy. Pelvic floor rehabilitation is recommended in patients with ano-rectal dyssynergia. In patients who fail to improve with pharmacological therapies sacral nerve stimulation is considered as last chance before surgery. Surgical approach has however limited indications in selected cases. Inertia coli refractory to any approach and obstructed defecation are two subtypes which can benefit from surgery. Among emerging agents, prucalopride, a prokinetic agent, is recommended as a second-line treatment in refractory CIC patients. In addition, the secretagogues linaclotide and plecanatide and the bile acid transported inhibitor elobixibat can be effective in patients not responsive to a second-line therapeutic regimen, although they are not worldwide commercially available.

Development of a Predictive Enrichment Marker for the Oral GH Secretagogue LUM-201 in Pediatric Growth Hormone Deficiency

Context

We hypothesize, based on the degree of residual hypothalamic-pituitary function, that some, but not all, children with growth hormone deficiency (GHD) may have beneficial growth responses to the orally administered growth hormone (GH) secretagogue LUM-201.

Objective

To determine if pretreatment testing can identify predictive enrichment markers (PEM) for subjects with adequate residual function who are responsive to LUM-201.

Methods

We performed an analysis of a completed, randomized, placebo-controlled trial of LUM-201, a GH secretagogue receptor agonist, in which all randomized subjects had pretreatment testing.

This international multicenter study conducted in pediatric endocrinology clinics included 68 naïve-to-treatment, prepubertal children with established diagnoses of GHD. Outcome measures included the sensitivity, specificity, and predictive accuracy of potential markers to predict 6-month growth responses to oral LUM-201 and daily rhGH.

Results

Two PEM were identified for use in defining PEM-positive status: (1) baseline insulin-like growth factor I (IGF-I) concentration >30 ng/mL and (2) peak GH response of ≥5 ng/mL upon administration of single-dose LUM-201. PEM-positive status enriches a population for better growth responses to LUM-201. PEM-negative status enriches a population for better growth responses to rhGH.

Conclusion

Combined, the peak GH response to single-dose LUM-201 and the baseline IGF-I concentration are effective PEMs for 6-month growth responses to LUM-201 and rhGH in prepubertal children with GHD.

Beyond the Sick Role: The Many Roles of Adults With Type 1 and Type 2 Diabetes in the Management of Hypoglycemia-The InHypo-DM Study, Canada

OBJECTIVES

Hypoglycemia is a common adverse event for people with type 1 and type 2 diabetes mellitus. In this article, we explore the specific roles that individuals assume to prevent or treat hypoglycemia.

METHODS

A descriptive qualitative study from the UnderstandINg the impact of HYPOglycemia on Diabetes Management Study (InHypo-DM) research program. A purposive sample of people with type 1 and type 2 diabetes were recruited for semistructured interviews. There were 16 participants (women and men), who were, on average, 53 years old. Average time since diagnosis was 15 (type 1) and 21 (type 2) years; all patients had at least 1 hypoglycemic event in the past year. Individual and team analysis of interviews were conducted to identify overarching themes.

RESULTS

Participants articulated 4 roles in preventing or treating hypoglycemia. The first role was being a manager by assuming ownership and accountability for their own glycemic control. The second role, being a technician, used both subjective and objective information and employed specific strategies to respond to hypoglycemic events. The third role, educator, extended beyond self-management to increase others' awareness of hypoglycemia. The fourth role, advocate, involved championing one's own needs during a hypoglycemic event. These 4 roles were, in turn, influenced by the contexts of work, social settings, exercise and travel.

CONCLUSIONS

These findings demonstrate that strategies that individuals use to avoid or reduce the severity of a hypoglycemic event extend beyond merely making impromptu decisions during events. Instead, these 4 roles of manager, technician, educator and advocate, embedded in specific contexts, enhanced their mastery in managing hypoglycemia in daily life.

Differences in efficacy and safety of lubiprostone used for idiopathic vs opioid-induced constipation: meta-analysis of East Asian and Western populations

Several secretagogues, such as lubiprostone, have been developed for the treatment of constipation in the last 10 years. It is unclear whether the efficacy of lubiprostone for spontaneous bowel movement (SBM) and the adverse events are similar between idiopathic and opioid-induced constipation and between East-Asian and Western populations. We conducted a meta-analysis to compare efficacy and safety of lubiprostone in two populations with idiopathic vs opioid-induced constipation. The PubMed and Cochrane databases were searched for relevant randomized control trials (RCTs) investigating the efficacy and safety that were published in English up to March 2019. Compared with the placebo groups in idiopathic and opioid-induced constipation, the lubiprostone groups significantly improved in 24-h SBM frequency [relative risk: 1.28, 95% confidence interval, 1.11-1.49, and 1.23, 1.14-1.32] and weekly frequency >3 SBM/week (1.68, 1.41-2.01, and 1.43, 1.01-2.04), respectively. Although the incidence of adverse events was similar between idiopathic and opioid-induced constipation, the incidence of nausea in Western populations with idiopathic constipation was significantly higher (29.2%) than that in East-Asian populations (10.0%, p<0.001). In conclusion, lubiprostone effectively improved SBM frequency, irrespective of the etiology of constipation and population. The incidence of nausea was significantly higher in Western populations.

Analysis of Mrgprb2 Receptor-Evoked Ca 2+ Signaling in Bone Marrow Derived (BMMC) and Peritoneal (PMC) Mast Cells of TRPC-Deficient Mice

Mast cells are a heterogeneous group of immune cells. The simplest and commonly accepted classification divides them in two groups according to their protease content. We have compared the action of diverse secretagogues on bone marrow derived (BMMC) and peritoneal (PMC) mast cells which represent classical models of mucosal and connective tissue type mast cells in mice. Whereas, antigen stimulation of the FcεRI receptors was similarly effective in triggering elevations of free intracellular Ca²⁺ concentration ([Ca²⁺]_i) in both BMMC and PMC, robust [Ca²⁺]_i rise following Endothelin-1 stimulation was observed only in a fraction of BMMC. Leukotriene C4 activating cysteinyl leukotriene type I receptors failed to evoke [Ca²⁺]_i rise in either mast cell model. Stimulation of the recently identified target of many small-molecule drugs associated with systemic pseudo-allergic reactions, Mrgprb2, with compound 48/80, a mast cell activator with unknown receptor studied for many years, triggered Ca²⁺ oscillations in BMMC and robust [Ca²⁺]_i rise in PMCs similarly to that evoked by FcεRI stimulation. [Ca²⁺]_i rise in PMC could also be evoked by other Mrgprb2 agonists such as Tubocurarine, LL-37, and Substance P. The extent of [Ca²⁺]_i rise correlated with mast cell degranulation. Expression analysis of TRPC channels as potential candidates mediating agonist evoked Ca²⁺ entry revealed the presence of transcripts of all members of the TRPC subfamily of TRP channels in PMCs. The amplitude and AUC of compound 48/80-evoked [Ca²⁺]_i rise was reduced by ~20% in PMC from Trpc1/4/6^−/− mice compared to Trpc1/4^−/− littermatched control mice, whereas FcεRI-evoked [Ca²⁺]_i rise was unaltered. Whole-cell patch clamp recordings showed that the reduction in compound 48/80-evoked [Ca²⁺]_i rise in Trpc1/4/6^−/− PMC was accompanied by a reduced amplitude of Compound 48/80-induced cation currents which exhibited typical features of TRPC currents. Together, this study demonstrates that PMC are an appropriate mast cell model to study mechanisms of Mrgprb2 receptor-mediated mast cell activation, and it reveals that TRPC channels contribute at least partially to Mrgprb2-mediated mast cellactivation but not following FcεRI stimulation. However, the channels conducting most of the Ca²⁺ entry in mast cells triggered by Mrgprb2 receptor stimulation remains to be identified.

Chloroquine-Inducible Par-4 Secretion Is Essential for Tumor Cell Apoptosis and Inhibition of Metastasis

The induction of tumor suppressor proteins capable of cancer cell apoptosis represents an attractive option for the re-purposing of existing drugs. We report that the anti-malarial drug, chloroquine (CQ), is a robust inducer of Par-4 secretion from normal cells in mice and cancer patients in a clinical trial. CQ-inducible Par-4 secretion triggers paracrine apoptosis of cancer cells and also inhibits metastatic tumor growth. CQ induces Par-4 secretion via the classical secretory pathway that requires the activation of p53. Mechanistically, p53 directly induces Rab8b, a GTPase essential for vesicle transport of Par-4 to the plasma membrane prior to secretion. Our findings indicate that CQ induces p53- and Rab8b-dependent Par-4 secretion from normal cells for Par-4-dependent inhibition of metastatic tumor growth.

Therapeutic inhibitors for the treatment of dry eye syndrome

INTRODUCTION

Dry eye disease (DED), defined as a multifactorial disease of tears and ocular surface, results in symptoms of discomfort, ocular irritation, visual disturbance and tear film instability. This syndrome is accompanied of ocular surface inflammation and it is produced by a deficient activity of the lacrimal functional unit. In addition, it is associated with systemic autoimmune diseases such as Sjögren´s Syndrome, rheumatoid arthritis, systemic lupus erythematosus and some drug administration. The treatment of dry eye disease is based on the typical signs and symptoms of dry eye, which are associated with hyperosmolarity, ocular surface inflammation, discomfort, visual disturbance, and tear film instability. Areas covered: This review is focused on synthetic drugs currently used in clinical practice, from phase III development onwards to treat the ocular surface signs and symptoms of dry eye disease. Expert opinion: The multifactorial disease and the lack of correlation between signs and symptoms imply that not all the pharmacological approaches will be successful for dry eye. The correct design of the clinical trials, with appropriate endpoints, and the type of dry eye under study are complicated but mandatory. The anti-inflammatory and secretagogues drugs are both the main compounds to currently treat the dry eye disease.

Diabetic Pharmacotherapy and Endometrial Cancer Risk Within a Publicly Funded Health Care System

OBJECTIVE

There is conflicting evidence regarding the association between metformin and endometrial cancer risk. The objective of this study was to evaluate the association between type of diabetic pharmacotherapy and endometrial cancer risk within a population-based study. The hypothesis was that metformin was associated with the lowest risk.

METHODS

This was a nested case-control study using data from the BC Cancer Registry (2000-2009) and from a province-wide prescription network (PharmaNet) since 1996. Patients were classified by drug exposure (metformin, thiazolidinediones, secretagogues, with or without insulin). The primary analysis was a conditional logistic regression to estimate the odds ratios for endometrial cancer in the drug exposure groups. Sensitivity analysis was carried out to account for uncertainty regarding various parameters. The secondary analysis evaluated the effect of dosage using a principal components analysis.

RESULTS

The study cohort comprised 492 cases and 4404 controls. The primary analysis revealed no difference in endometrial cancer risk between those using metformin and those prescribed other classes of medications (OR 1.5, 95% CI 0.9 to 2.4). Women receiving all classes of medications had almost a two-fold increase in risk (OR 1.9, 95% CI 1.1 to 3.3). The secondary analysis revealed an increased risk associated with a greater duration of treatment and number of prescriptions (OR 1.3, 95% CI 1.2 to 1.4).

CONCLUSION

In this population-based study, metformin was not associated with a decreased endometrial cancer risk. Women receiving multiple types of medications over a long time had the highest risk, implying that the extent of insulin resistance, rather than the effect of any specific medication, drives endometrial cancer risk.

A review of animal models of nonneoplastic pancreatic diseases

The nonneoplastic diseases of the human pancreas generally comprise the inflammatory and degenerative conditions that include acute and chronic pancreatitis, with cystic fibrosis being arguably one of the most important diseases that induce the condition. Both acute and chronic conditions vary in severity, but both can be life threatening; and because of this fact, the study of their progression, and their responsiveness to therapy, is largely conducted by indirect means using serum markers of damage and repair such as amylase and lipase activities that normally occur at very low levels in the circulation but can be significantly increased during inflammatory episodes. Progress in the understanding the pathogenesis of both conditions has therefore been largely due to time course studies in animal models of pancreatitis, and it is in this context that animal model development has been so significant. In general terms, the animal models can be divided into the invasive, surgical procedures, and those induced by the administration of chemical secretagogues that induce hypersecretion of the pancreatic enzymes. The former include ligation and/or cannulation of the biliopancreatic ducts with infusion of solutions of various kinds, or the formation of closed duodenal loops. Secretagogue administration includes administration of caerulein or l-arginine in various protocols. An additional model involves administration of dibutyltin dichloride, which induces a partial blockage of the pancreatic ducts to induce pancreatic disease through enzymic reflux into the gland. The models have been invaluable in generating testable hypotheses for the human diseases. These hypotheses for the production of cellular damage as the initiating events in the disease include (1) intracellular chemical activation, (2) pancreatic secretion reflux, (3) intracellular production of reactive oxygen species, and (4) intracellular production of free radicals.

New treatment options for chronic constipation: mechanisms, efficacy and safety

The present review has several objectives, the first of which is to review the pharmacology and selectivity of serotonergic agents to contrast the older serotonergic agents (which were withdrawn because of cardiac or vascular adverse effects) with the newer generation serotonin receptor subtype 4 agonists. Second, the chloride ion secretagogues that act through the guanylate cyclase C receptor are appraised and their pharmacology is compared with the approved medication, lubiprostone. Third, the efficacy and safety of the application of bile acid modulation to treat constipation are addressed. The long-term studies of surgically induced excess bile acid delivery to the colon are reviewed to ascertain the safety of this therapeutic approach. Finally, the new drugs for opiate-induced constipation are introduced. Assuming these drugs are approved, practitioners will have a choice; however, patient responsiveness will be based on trial and error. Nevertheless, the spectrum of mechanisms and demonstrated efficacy and safety augur well for satisfactory treatment outcomes.