Towards reperfusion-centric preclinical stroke research:outside the box of “reperfusion injury”

Stroke is a major health issue of increasing significance for any society with an aging population. Globally, stroke is the second-leading cause of death with approximately 5.9 million fatal events in 2010, equivalent to 11.1% of all deaths. Yet, despite years of preclinical research on neuroprotection and a multitude of clinical trials, tissue plas- minogen activator （tPA）-mediated recanalization remains the mainstay of acute ischemic stroke therapy, whereas tPA thrombolysis rarely provides benefits in the mechanical occlusion-based stroke models. This split between the bench and bedside raised the concern over the clinical ap- plicability of neuroprotection in acute ischemic stroke. In this perspective commentary, we call for attention to the differences between mechanical-occlusion and thrombo- embolic stroke models in cerebral hemodynamics （Figure 1A, B）, the implications of these differences in view of progressive pathobiology of ischemic stroke （Figure 1C）, and the need and strategies towards reperfusion-centric preclinical stroke research.

Progress,implications,and challenges in using humanized immune system mice in CAR-T therapy-Application evaluation and improvement

In recent years,humanized immune system(HIS)mice have been gradually used as models for preclinical research in pharmacotherapies and cell therapies with major breakthroughs in tumor and other fields,better mimicking the human immune system and the tumor immune microenvironment,compared to traditional immunodeficient mice.To better promote the application of HIS mice in preclinical research,we se-lectively summarize the current prevalent and breakthrough research and evaluation of chimeric antigen receptor(CAR)-T cells in various antiviral and antitumor treat-ments.By exploring its application in preclinical research,we find that it can better reflect the actual clinical patient condition,with the advantages of providing high-efficiency detection indicators,even for progressive research and development.We believe that it has better clinical patient simulation and promotion for the updated design of CAR-T cell therapy than directly transplanted immunodeficient mice.The characteristics of the main models are proposed to improve the use defects of the existing models by reducing the limitation of antihost reaction,combining multiple models,and unifying sources and organoid substitution.Strategy study of relapse and toxicity after CAR-T treatment also provides more possibilities for application and development.

A novel mouse model of central cord syndrome

Patients with potential spinal stenosis are susceptible to central cord syndrome induced by blunt trauma.Suitable animal models are helpful for studying the pathogenesis and treatment of such injuries.In this study,we established a mouse model of acute blunt traumatic spinal cord injury by compressing the C6 spinal cord with 5 and 10 g/mm~2 compression weights to simulate cervical central cord syndrome.Behavioral testing confirmed that this model exhibited the characteristics of central cord syndrome because motor function in the front paws was impaired,whereas basic motor and sensory functions of the lower extremities were retained.Hematoxylin-eosin staining showed that the diseased region of the spinal cord in this mouse model was restricted to the gray matter of the central cord,whereas the white matter was rarely affected.Magnetic resonance imaging showed a hypointense signal in the lesion after mild and severe injury.In addition,immunofluorescence staining showed that the degree of nerve tract injury in the spinal cord white matter was mild,and that there was a chronic inflammation reaction.These findings suggest that this mouse model of central cord syndrome can be used as a model for preclinical research,and that gray matter is most vulnerable to injury in central cord syndrome,leading to impaired motor function.

A novel long-term intravenous combined with local treatment with human amnion-derived mesenchymal stem cells for a multidisciplinary rescued uremic calciphylaxis patient and the underlying mechanism

Calciphylaxis is a rare disease characterized histologically by microvessel calcification and microthrombosis,with high mortality and no proven therapy.Here,we reported a severe uremic calciphylaxis patient with progressive skin ischemia,large areas of painful malodorous ulcers,and mummified legs.Because of the worsening symptoms and signs refractory to conventional therapies,treatment with human amnion-derived mesenchymal stem cells(hAMSCs)was approved.Preclinical release inspections of hAMSCs,efficacy,and safety assessment,including cytokine secretory ability,immunocompetence,tumorigenicity,and genetics analysis in vitro,were introduced.We further performed acute and long-term hAMSC toxicity evaluations in C57BL/6 mice and rats,abnormal immune response tests in C57BL/6 mice,and tumorigenicity tests in neonatal Balbc-nu nude mice.After the preclinical research,the patient was treated with hAMSCs by intravenous and local intramuscular injection and external supernatant application to the ulcers.When followed up to 15 months,the blood-based markers of bone and mineral metabolism improved,with skin soft tissue regeneration and a more favorable profile of peripheral blood mononuclear cells.Skin biopsy after 1-month treatment showed vascular regeneration with mature noncalcified vessels within the dermis,and 20 months later,the re-epithelialization restored the integrity of the damaged site.No infusion or local treatment-related adverse events occurred.Thus,this novel long-term intravenous combined with local treatment with hAMSCs warrants further investigation as a potential regenerative treatment for uremic calciphylaxis due to effects of inhibiting vascular calcification,stimulating angiogenesis and myogenesis,anti-inflammatory and immune modulation,multidifferentiation,re-epithelialization,and restoration of integrity.