A quantitative systems pharmacology model of colonic motility with applications in drug development

Computational insights into colonic motility: Mechanical role of mucus in homeostasis and inflammation

Colonic motility plays a vital role in maintaining proper digestive function. The rhythmic contractions and relaxations facilitate various types of motor functions that generate both propulsive and non-propulsive motility modes which in turn generate shear stresses on the epithelial surface. However, the interplay between colonic mucus, shear stress, and epithelium remains poorly characterized. Here, we present a colonic computational model that describes the potential roles of mucus and shear stress in both homeostasis and ulcerative colitis (UC). Our model integrates several key features, including the properties of the mucus bilayer and faeces, intraluminal pressure, and crypt characteristics to predict the time-space mosaic of shear stress. We show that the mucus thickness which could vary based on the severity of UC, may significantly reduce the amount of shear stress applied to the colonic crypts and effect faecal velocity. Our model also reveals an important spatial shear stress variance in homeostatic colonic crypts that suggests shear stress may have a modulatory role in epithelial cell migration, differentiation, apoptosis, and immune surveillance. Together, our study uncovers the rather neglected roles of mucus and shear stress in intestinal cellular processes during homeostasis and inflammation.

A Quantitative Systems Pharmacology Model Describing the Cellular Kinetic-Pharmacodynamic Relationship for a Live Biotherapeutic Product to Support Microbiome Drug Development

Live biotherapeutic products (LBPs) are human microbiome therapies showing promise in the clinic for a range of diseases and conditions. Describing the kinetics and behavior of LBPs poses a unique modeling challenge because, unlike traditional therapies, LBPs can expand, contract, and colonize the host digestive tract. Here, we present a novel cellular kinetic-pharmacodynamic quantitative systems pharmacology model of an LBP. The model describes bacterial growth and competition, vancomycin effects, binding and unbinding to the epithelial surface, and production and clearance of butyrate as a therapeutic metabolite. The model is calibrated and validated to published data from healthy volunteers. Using the model, we simulate the impact of treatment dose, frequency, and duration as well as vancomycin pretreatment on butyrate production. This model enables model-informed drug development and can be used for future microbiome therapies to inform decision making around antibiotic pretreatment, dose selection, loading dose, and dosing duration.

Research progress in the treatment of slow transit constipation by traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Slow transit constipation (STC) is a common gastrointestinal disorder seriously impacting patients' quality of life. At present, although conventional chemical drugs effectively control STC symptoms in the short term, the long-term effects are poor, and the side effects are significant. In this regard, traditional Chinese medicine (TCM) offers an opportunity for STC treatment. Many pharmacological and clinical studies have confirmed this efficacy of TCM with multiple targets and mechanisms.

AIM OF THE STUDY

This review attempted to summarize the characteristics of TCM (compound prescriptions, single Chinese herbs, and active ingredients) for STC treatment and discussed their efficacy based on analyzing the pathogenesis of STC.

MATERIALS AND METHODS

The information was acquired from different databases, including PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases. We then focused on the recent research progress in STC treatment by TCM. Finally, the future challenges and trends are proposed.

RESULTS

TCM has good clinical efficacy in the treatment of STC with multi-mechanisms. Based on the theory of syndrome differentiation, five kinds of dialectical treatment for STC by compound TCM prescriptions were introduced, namely: Nourishing Yin and moistening the intestines; Promoting blood circulation and removing blood stasis; Warming Yang and benefiting Qi; Soothing the liver and regulating Qi; and Benefiting Qi and strengthening the spleen. In addition, six single Chinese herbs and eight active ingredients also show good efficacy in STC treatment.

CONCLUSIONS

TCM, especially compound prescriptions, has bright prospects in treating STC attributed to its various holistic effects.

Systematic in silico analysis of clinically tested drugs for reducing amyloid-beta plaque accumulation in Alzheimer's disease

Introduction

Despite strong evidence linking amyloid beta (Aβ) to Alzheimer's disease, most clinical trials have shown no clinical efficacy for reasons that remain unclear. To understand why, we developed a quantitative systems pharmacology (QSP) model for seven therapeutics: aducanumab, crenezumab, solanezumab, bapineuzumab, elenbecestat, verubecestat, and semagacestat.

Methods

Ordinary differential equations were used to model the production, transport, and aggregation of Aβ; pharmacology of the drugs; and their impact on plaque.

Results

The calibrated model predicts that endogenous plaque turnover is slow, with an estimated half‐life of 2.75 years. This is likely why beta‐secretase inhibitors have a smaller effect on plaque reduction. Of the mechanisms tested, the model predicts binding to plaque and inducing antibody‐dependent cellular phagocytosis is the best approach for plaque reduction.

Discussion

A QSP model can provide novel insights to clinical results. Our model explains the results of clinical trials and provides guidance for future therapeutic development.

1907-2020: more than one century of colonic mass movements in humans

Motility of the large bowel may be grossly subdivided in two types of contractile activity: low-amplitude single or cyclic propagated waves and high-amplitude propagated activity. The latter is mainly apt to shift relatively large amounts of colonic contents, and it is related to defecation. The main component of this propagated activity is represented by the radiologically identified mass movements that have a manometric equivalent known as high-amplitude propagated contractions (HAPC). The present article reviews origins and characterization of HAPC in the time course of colonic motility investigations, and correlates it with technological advancements in recent years, putting into perspective the future possible options to better detect and investigate these important physiological events.