A revisit of rod microglia in preclinical studies

Microglial cells（or microglia）are the mononuclear phagocytes residing in the central nervous system（CNS）.In homeostasis,they showed ramified morphology with relative small cell bodies and long processes（Figure 1A）.They detect injury signals in the CNS and get activated.

Establishment of various biliary tract carcinoma cell lines and xenograft models for appropriate preclinical studies

We recently reported several driver genes of biliary tract carcinoma(BTC) that are known to play important roles in oncogenesis and disease progression. Although the need for developing novel therapeutic strategies is increasing, there are very few BTC cell lines and xenograft models currently available for conducting preclinical studies. Using a total of 88 surgical BTC specimens and 536 immunodeficient mice, 28 xenograft models and 13 new BTC cell lines, including subtypes, were established. Some of our cell lines were found to be resistant to gemcitabine, which is currently the first choice of treatment, thereby allowing highly practical preclinical studies to be conducted. Using the aforementioned cell lines and xenograft models and a clinical pathological database of patients undergoing BTC resection, we can establish a preclinical study system and appropriate parameters for drug efficacy studies to explore new biomarkers for practical applications in the future studies.

Type-B monoamine oxidase inhibitors in neurological diseases:clinical applications based on preclinical findings

Type-B monoamine oxidase inhibitors,encompassing selegiline,rasagiline,and safinamide,are available to treat Parkinson's disease.These drugs ameliorate motor symptoms and improve motor fluctuation in the advanced stages of the disease.There is also evidence suppo rting the benefit of type-B monoamine oxidase inhibitors on non-motor symptoms of Parkinson's disease,such as mood deflection,cognitive impairment,sleep disturbances,and fatigue.Preclinical studies indicate that type-B monoamine oxidase inhibitors hold a strong neuroprotective potential in Parkinson's disease and other neurodegenerative diseases for reducing oxidative stress and stimulating the production and release of neurotrophic factors,particularly glial cell line-derived neurotrophic factor,which suppo rt dopaminergic neurons.Besides,safinamide may interfere with neurodegenerative mechanisms,countera cting excessive glutamate overdrive in basal ganglia motor circuit and reducing death from excitotoxicity.Due to the dual mechanism of action,the new generation of type-B monoamine oxidase inhibitors,including safinamide,is gaining interest in other neurological pathologies,and many supporting preclinical studies are now available.The potential fields of application concern epilepsy,Duchenne muscular dystrophy,multiple scle rosis,and above all,ischemic brain injury.The purpose of this review is to investigate the preclinical and clinical pharmacology of selegiline,rasagiline,and safinamide in Parkinson's disease and beyond,focusing on possible future therapeutic applications.

Preclinical studies of the triazolo[1,5-a]pyrimidine derivative WS-716 as a highly potent,specific and orally active P-glycoprotein(P-gp)inhibitor

Multidrug resistance(MDR) is the main cause of clinical treatment failure and poor prognosis in cancer. Targeting P-glycoprotein(P-gp) has been regarded as an effective strategy to overcome MDR. In this work, we reported our preclinical studies of the triazolo[1,5-a]pyrimidine-based compound WS-716 as a highly potent, specific, and orally active P-gp inhibitor. Through direct binding to P-gp,WS-716 inhibited efflux function of P-gp and specifically reversed P-gp-mediated MDR to paclitaxel(PTX) in multiple resistant cell lines, without changing its expression or subcellular localization. WS-716 and PTX synergistically inhibited formation of colony and 3D spheroid, induced apoptosis and cell cycle arrest at G2/M phase in resistant SW620/Ad300 cells. In addition, WS-716 displayed minimal effect on the drug-metabolizing enzyme cytochrome P4503A4(CYP3A4). Importantly, WS-716 increased sensitivity of both pre-clinically and clinically derived MDR tumors to PTX in vivo with the T/C value of 29.7% in patient-derived xenograft(PDX) models. Relative to PTX treatment alone, combination of WS-716 and PTX caused no obvious adverse reactions. Taken together, our preclinical studies revealed therapeutic promise of WS-716 against MDR cancer, the promising data warrant its further development for cancer therapy.

Interplay between mesenchymal stromal cells and the immune system after transplantation: implications for advanced cell therapy in the retina

Advanced mesenchymal stromal cell-based therapies for neurodegenerative diseases are widely investigated in preclinical models.Mesenchymal stromal cells are well positioned as therapeutics because they address the underlying mechanisms of neurodegeneration,namely trophic factor deprivation and neuroinflammation.Most studies have focused on the beneficial effects of mesenchymal stromal cell transplantation on neuronal survival or functional improvement.However,little attention has been paid to the interaction between mesenchymal stromal cells and the host immune system due to the immunomodulatory properties of mesenchymal stromal cells and the long-held belief of the immunoprivileged status of the central nervous system.Here,we review the crosstalk between mesenchymal stromal cells and the immune system in general and in the context of the central nervous system,focusing on recent work in the retina and the importance of the type of transplantation.

Understanding the spectrum of non-motor symptoms in multiple sclerosis:insights from animal models

Multiple sclerosis is a chronic autoimmune disease of the central nervous system and is generally considered to be a non-traumatic,physically debilitating neurological disorder.In addition to experiencing motor disability,patients with multiple sclerosis also experience a variety of nonmotor symptoms,including cognitive deficits,anxiety,depression,sensory impairments,and pain.However,the pathogenesis and treatment of such non-motor symptoms in multiple scle rosis are still under research.Preclinical studies for multiple sclerosis benefit from the use of disease-appropriate animal models,including experimental autoimmune encephalomyelitis.Prior to understanding the pathophysiology and developing treatments for non-motor symptoms,it is critical to chara cterize the animal model in terms of its ability to replicate certain non-motor features of multiple sclerosis.As such,no single animal model can mimic the entire spectrum of symptoms.This review focuses on the non-motor symptoms that have been investigated in animal models of multiple sclerosis as well as possible underlying mechanisms.Further,we highlighted gaps in the literature to explain the nonmotor aspects of multiple sclerosis in expe rimental animal models,which will serve as the basis for future studies.

Transcatheter mitral valve implantation using a novel system:preclinical results

Background This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system(Mi-thos valve)composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.Methods The valve was implanted in 26 sheep using a transapical approach for short-and long-term evaluation.The technical feasibility,safety,durability,and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography,multisliced computed tomography,histological analysis,and electron microscopy.Results The success rate of valve implantation was 100%,and the immediate survival rate after surgery was 84%.Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction(n=2)and sudden intraoperative ventricular fibrillation(n=3).Twelve animals died within 1 month due to acute left heart dysfunction.Mild(n=5)and moderate(n=2)paravalvular leakage occurred in seven animals,and two moderate PVL animals died of chronic heart failure within three months.Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves,with no coronary artery obstruction,no left ventricular outflow tract obstruction,no severe transvalvular gradients and no paravalvular leakage.Macroscopic evaluation demonstrated stable,secure positioning of the valve,with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls.Histological and electron microscopic examinations at six months showed no obvious macro-or microcalcification in the leaflets.Conclusions Preclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible.The durability,functionality,and lack of leaflet calcification were all verified in animal experiments.The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.

Update on the preclinical and clinical assessment of Withania somnifera: from ancient Rasayana to modern perspectives

The Rasayana plant Withania somnifera(W.somnifera)Dunal,also known as“Ashwagandha”,has been mentioned in various classical Ayurvedic texts,such as Charaka Samhita,Sushruta Samhita,and Nighantus.This Ayurvedic drug has been referred to as a tonic that renews the body,provides physical and mental vigor in weakened states,and promotes endurance and longevity.W.somnifera possesses notable biological activity in many ailments,such as diabetes,conjunctivitis,insomnia,senile dementia,Parkinson’s disease,nervous system disorders,rheumatism,and arthritis.These pharmacological activities are due to the presence of diverse active components and their derivatives.Some lead compounds are found to be effective against anxiety and other central nervous system disorders.W.somnifera has been proven to be effective and safe for a wide range of ailments from ancient to modern times.Its reported properties represent the traditional use of W.somnifera as indicated in the literature;furthermore,W.somnifera is one of the most important prescribed drugs in Ayurveda for its multimodal effects.This current review highlights the bioactive present and provides an overview of the toxicological and pharmacological studies on W.somnifera,including preclinical and clinical studies.From its earliest utilization to its current application,W.somnifera has been recognized to be effective at clinical levels for human health and welfare.Greater attention to the safety and efficacy of W.somnifera would provide more scientific evidence,promoting global acceptance of the Ayurvedic plant.

Fast-tracking regenerative medicine for traumatic brain injury

Traumatic brain injury remains a global health crisis that spans all demographics,yet there exist limited treatment options that may effectively curtail its lingering symptoms.Traumatic brain injury pathology entails a progression from primary injury to inflammation-mediated secondary cell death.Sequestering this inflammation as a means of ameliorating the greater symptomology of traumatic brain injury has emerged as an attractive treatment prospect.In this review,we recapitulate and evaluate the important developments relating to regulating traumatic brain injury-induced neuroinflammation,edema,and blood-brain barrier disintegration through pharmacotherapy and stem cell transplants.Although these studies of stand-alone treatments have yielded some positive results,more therapeutic outcomes have been documented from the promising area of combined drug and stem cell therapy.Harnessing the facilitatory properties of certain pharmaceuticals with the anti-inflammatory and regenerative effects of stem cell transplants creates a synergistic effect greater than the sum of its parts.The burgeoning evidence in favor of combined drug and stem cell therapies warrants more elaborate preclinical studies on this topic in order to pave the way for later clinical trials.

Postnatal therapeutic approaches in genetic neurodevelopmental disorders

Genetic neurodevelopmental disorders are characterized by abnormal neurophysiological and behavioral phenotypes,affecting individuals worldwide.While the subject has been heavily researched,current treatment options relate mostly to alleviating symptoms,rather than targeting the altered genome itself.In this review,we address the neurogenetic basis of neurodevelopmental disorders,genetic tools that are enabling precision research of these disorders in animal models,and postnatal gene-therapy approaches for neurodevelopmental disorders derived from preclinical studies in the laboratory.

A Review of Progress in the Construction and Application of Human-Derived Xenograft Models for Bladder Cancer

The patient-derived xenografts (PDX) model is an animal model established by transplanting primary tumors or fresh tumor tissues of patient origin directly into immunodeficient mice, which preserves the heterogeneity and survival microenvironment of the primary tumor and is widely used in preclinical and precision medicine research of tumors. This article reviews the construction of the PDX model of human bladder cancer and the progress of the application of the PDX model in bladder cancer.

Long-term safety and absorption assessment of a novel bioresorbable nitrided iron scaffold in porcine coronary artery

This study aimed to investigate the long-term biocompatibility, safety, and degradation of the ultrathin nitrided iron bioresorbable scaffold (BRS) in vivo, encompassing the whole process of bioresorption in porcine coronary arteries. Fifty-two nitrided iron scaffolds (strut thickness of 70 μm) and 28 Vision Co–Cr stents were randomly implanted into coronary arteries of healthy mini-swine. The efficacy and safety of the nitrided iron scaffold were comparable with those of the Vision stentwithin 52 weeks after implantation. In addition, the long-term biocompatibility, safety, and bioresorption of the nitrided iron scaffold were evaluated by coronary angiog-raphy, optical coherence tomography, micro-computed tomography, scanning electron microscopy, energy dispersive spectrometry and histopathological evaluations at 4, 12, 26, 52 weeks and even at 7 years after im-plantation. In particular, a large number of struts were almost completely absorbed in situ at 7 years follow-up, which were first illustrated in this study. The lymphatic drainage pathway might serve as the potential clearance way of iron and its corrosion products.

Advances in the formulation and defivery technology of paclitaxel for injection

Paclitaxel is a promising antineoplastic agent against a variety of human solid tumors, such as ovary, breast, lung, head and neck tumors, and melanoma. Owing to its poor solubility, the fast available formulation ofpaclitaxel （Taxol） exists as a non-aqueous concentrate composed of Cremophor EL （polyethoxylated castor oil） and ethanol. It must be diluted to a suitable aqueous solution prior to long time intravenous infusion. Based on the components and usage, Taxol has serious adverse effects and is inconvenient for clinical use. To address these problems, the development of a less-toxic, better-tolerated, Cremophor EL-free formulation of paclitaxel has been attempted. In recent years, new drug delivery systems （DDS） including albumin-based nanoparticles, micelles, liposomes, etc. have been investigated. In this review, we present the formulations and delivery technologies of paclitaxel for injection and focus on some of preclinical and clinical experience on the formulations which are already on the market or under clinical stages. Finally, possible nanotechnology advantages, existing challenges and future perspectives of paclitaxel delivery are highlighted.