BACKGROUND: Recto-colic graft-versus-host disease (GVHD) is a frequent and serious complication of hematopoietic stem cell allogeneic transplantation, which is sometimes difficult to diagnose. The aim of our study was to identify histological diagnostic and prognostic criteria for recto-colic GVH.
METHODS: Patients allografted at Amiens university hospital from 2012 to 2017 were retrieved. Those who had a recto-colic biopsy were included and divided into two groups (final diagnosis of GVH and non-GVH), then biopsies were reviewed by 2 pathologists.
RESULTS: One hundred and nineteen patients were included. Sixty-seven were allocated to the GVH group and 52 to the non-GVH group. In the GVH group, we observed a significantly greater number of apoptotic bodies (AB) on standard HES staining and with the anti-Caspase 3 immunohistochemistry, cryptolytic AB abscesses, atrophy, regenerative glands and glands lined with eosinophilic cells (P<0.001). Anti-Caspase 3 immunohistochemistry revealed more AB than standard HES staining (P<0.005). But to differentiate GVH cases from non-GVH cases, we obtained a threshold value of 3.5 AB per 10 contiguous crypts on standard HE staining and with the anti-Caspase 3 immunohistochemistry. From 4 AB per 10 contiguous crypts, on HES staining and anti-Caspase 3 immunostaining, the diagnosis of GVH became consistent. No non-GVH case had more than 6 AB per 10 contiguous crypts. GVH patients with more than 8 AB per 10 contiguous crypts had a worse prognosis (P<0.001).
CONCLUSIONS: We confirm the value of AB and their counting in the diagnosis of GVH, with a diagnostic threshold of 4 AB and a prognostic threshold of 8 AB. Glands lined with eosinophilic cells could be an additional diagnostic criterion in favor of GVH to be confirmed by further studies.

Apoptotic bodies (ABs) are extracellular vesicles released during apoptosis and possess diverse biological activities. Initially, ABs were regarded as garbage bags with the main function of apoptotic cell clearance. Recent research has found that ABs carry and deliver various biological agents and are taken by surrounding and distant cells, affecting cell functions and behavior. ABs-mediated intercellular communications are involved in various physiological processes including anti-inflammation and tissue regeneration as well as the pathogenesis of a variety of diseases including cancer, cardiovascular diseases, neurodegeneration, and inflammatory diseases. ABs in biological fluids can be used as a window of altered cellular and tissue states which can be applied in the diagnosis and prognosis of various diseases. The structural and constituent versatility of ABs provides flexibility for tailoring ABs according to disease diagnostic and therapeutic needs. An in-depth understanding of ABs\' constituents and biological functions is mandatory for the effective tailoring of ABs including modification of bio membrane and cargo constituents. ABs\' tailoring approaches including physical, chemical, biological, and genetic have been proposed for bench-to-bed translation in disease diagnosis, prognosis, and therapy. This review summarizes the updates on ABs tailoring approaches, discusses the existing challenges, and speculates the prospects for effective diagnostic and therapeutic applications.

Alcohol ingestion is a widespread habituation that evolved along with a growing population, altering physiological conditions through immunomodulatory function. There is much research that has reported that consumption of alcohol at low and heavy levels causes different biological impacts, including cellular injury, leading to systemic dysfunction and increased inflammatory markers. In the fate of professional phagocytic cells, efferocytosis is an inevitable mechanism activated by the apoptotic cells, thus eliminating them and preventing the accumulation of cell corpses/debris in the microenvironment. Subsequently, it promotes the tissue repair mechanism and maintains cellular homeostasis. Unfortunately, defective efferocytosis is widely found in several inflammatory and age-related diseases such as atherosclerosis, autoimmune diseases, lung injury, fatty liver disease, and neurodegenerative diseases. Alcohol abuse is one of the factors that provoke an immune response that increases the rate of morbidity and mortality in parallel in systemic disease patients. Information regarding the emergence of immunomodulation during alcoholic pathogenesis and its association with efferocytosis impairment remain elusive. Hence, here in this review, we discussed the mechanism of efferocytosis, the role of defective efferocytosis in inflammatory diseases, and the role of alcohol on efferocytosis impairment.

Evidence demonstrating the involvement of apoptosis in the death of the potentially salvageable area (penumbra zone) in patients during stroke remains limited. Our aim was to investigate whether apoptotic processes occur in penumbral brain tissue by analyzing circulating neuron- and glia-derived apoptotic bodies (CNS-ApBs), which are vesicles released into the bloodstream during the late stage of apoptosis. We have also assessed the clinical utility of plasma neuronal and glial apoptotic bodies in predicting early neurological evolution and functional outcome. The study included a total of 71 patients with acute hemispheric ischemic stroke (73 ± 10 years; 30 women). Blood samples were collected from these patients immediately upon arrival at the hospital (within 9 h) and at 24 and 72 h after symptom onset. Subsequently, isolation, quantification, and phenotypic characterization of CNS-ApBs during the first 72 h post-stroke were performed using centrifugation and flow cytometry techniques. We found a correlation between infarct growth and final infarct size with the amount of plasma CNS-ApBs detected in the first 72 h after stroke. In addition, patients with neurological worsening (progressive ischemic stroke) had higher plasma levels of CNS-ApBs at 24 h after symptom onset than those with a stable or improving course. Circulating CNS-ApB concentration was further associated with patients\' functional prognosis. In conclusion, apoptosis may play an important role in the growth of the cerebral infarct area and plasma CNS-ApB quantification could be used as a predictive marker of penumbra death, neurological deterioration, and functional outcome in patients with ischemic stroke.

In the realm of large-area trauma flap transplantation, averting ischaemic necrosis emerges as a pivotal concern. Several key mechanisms, including the promotion of angiogenesis, the inhibition of oxidative stress, the suppression of cell death, and the mitigation of inflammation, are crucial for enhancing skin flap survival. Apoptotic bodies (ABs), arising from cell apoptosis, have recently emerged as significant contributors to these functions. This study engineered three-dimensional (3D)-ABs using tissue-like mouse adipose-derived stem cells (mADSCs) cultured in a 3D environment to compare their superior biological effects against 2D-ABs in bolstering skin flap survival. The findings reveal that 3D-ABs (85.74 ± 4.51) % outperform 2D-ABs (76.48 ± 5.04) % in enhancing the survival rate of ischaemic skin flaps (60.45 ± 8.95) % (all p < 0.05). Mechanistically, they stimulated angiogenesis, mitigated oxidative stress, suppressed apoptosis, and facilitated the transition of macrophages from M1 to M2 polarization (all p < 0.05). A comparative analysis of microRNA (miRNA) profiles in 3D- and 2D-ABs identified several specific miRNAs (miR-423-5p-up, miR30b-5p-down, etc.) with pertinent roles. In summary, ABs derived from mADSCs cultured in a 3D spheroid-like arrangement exhibit heightened biological activity compared to those from 2D-cultured mADSCs and are more effective in promoting ischaemic skin flap survival. These effects are attributed to their influence on specific miRNAs.

Preventing and treating avascular necrosis at the distal end of the flaps are critical to surgery success, but current treatments are not ideal. A recent study shows that apoptotic bodies (ABs) generated near the site of apoptosis can be taken up and promote cell proliferation. The study reveals that ABs derived from fibroblast-like cells in the subcutaneous connective tissue (FSCT cells) of skin flaps promoted ischaemic flap survival. It is also found that ABs inhibited cell death and oxidative stress and promoted M1-to-M2 polarization in macrophages. Transcriptome sequencing and protein level testing demonstrated that ABs promoted ischaemic flap survival in endothelial cells and macrophages by inhibiting ferroptosis via the KEAP1-Nrf2 axis. Furthermore, microRNA (miR) sequencing data and in vitro and in vivo experiments demonstrated that ABs inhibited KEAP1 by delivering miR-339-5p to exert therapeutic effects. In conclusion, FSCT cell-derived ABs inhibited ferroptosis, promoted the macrophage M1-to-M2 transition via the miR-339-5p/KEAP1/Nrf2 axis and promoted ischaemic flap survival. These results provide a potential therapeutic strategy to promote ischaemic flap survival by administering ABs.

Apoptosis releases numerous apoptotic vesicles that regulate processes such as cell proliferation, immunity, and tissue regeneration and repair. Now, it has also emerged as an attractive candidate for biotherapeutics. However, apoptotic vesicles encompass a diverse range of subtypes, and it remains unclear which specific subtypes play a pivotal role. In this study, we successfully isolated different apoptotic vesicle subtypes based on their sizes and characterized them using NTA and TEM techniques, respectively. We compared the functional variances among the distinct subtypes of apoptotic vesicles in terms of stem cell proliferation, migration, and differentiation, as well as for endothelial cell and macrophage function, effectively identifying subtypes that exhibit discernible functional differences. ApoSEV (with diameter <1000 nm) promoted stem cell proliferation, migration, and multi-potent differentiation, and accelerated skin wound healing of diabetes mouse model, while apoBD (with diameter >1000 nm) played the opposite effect on cell function and tissue regeneration. Lastly, employing protein analysis and gene sequencing techniques, we elucidated the intrinsic mechanisms underlying these differences between different subtypes of apoEVs. Collectively, this study identified that apoptotic vesicle subtypes possessed distinct bio-functions in regulating stem cell function and behaviour and modulating tissue regeneration, which primarily attribute to the distinct profiling of protein and mRNA in different subtypes. This comprehensive analysis of specific subtypes of apoEVs would provide novel insights for potential therapeutic applications in cell biology and tissue regeneration.

From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.

BACKGROUND: Adipose tissue-derived stem cell-derived apoptotic bodies (ADSC-ABs) have shown great potential for immunomodulation and regeneration, particularly in diabetic wound therapy. However, their local application has been limited by unclear regulatory mechanisms, rapid clearance, and short tissue retention times.
METHODS: We analyzed the key role molecules and regulatory pathways of ADSC-ABs in regulating inflammatory macrophages by mRNA sequencing and microRNA (miRNA) sequencing and then verified them by gene knockdown. To prevent rapid clearance, we employed microfluidics technology to prepare methacrylate-anhydride gelatin (GelMA) microspheres (GMS) for controlled release of ABs. Finally, we evaluated the effectiveness of ADSC-AB-laden GMSs (ABs@GMSs) in a diabetic rat wound model.
RESULTS: Our results demonstrated that ADSC-ABs effectively balanced macrophage inflammatory polarization through the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, mediated by miR-20a-5p. Furthermore, we showed that AB@GMSs had good biocompatibility, significantly delayed local clearance of ABs, and ameliorated diabetic wound inflammation and promoted vascularization, thus facilitating its healing.
CONCLUSIONS: Our study reveals the regulatory mechanism of ADSC-ABs in balancing macrophage inflammatory polarization and highlightsthe importance of delaying their local clearance by GMSs. These findings have important implications for the development of novel therapies for diabetic wound healing.
BACKGROUND: This research was supported by the National Key Research and Development Program of China (2020YFA0908200), National Natural Science Foundation of China (82272263, 82002053, 32000937, and 82202467), Shanghai \"Rising Stars of Medical Talents\" Youth Development Program (22MC1940300), Shanghai Municipal Health Commission (20204Y0354), and Shanghai Science and Technology Development Funds (22YF1421400).

Angiogenesis, the process of new blood vessels formation from existing vasculature, plays a vital role in development, wound healing, and various pathophysiological conditions. In recent years, extracellular vesicles (EVs) have emerged as crucial mediators in intercellular communication and have gained significant attention for their role in modulating angiogenic processes. This review explores the multifaceted role of EVs in angiogenesis and their capacity to modulate angiogenic signaling pathways. Through comprehensive analysis of a vast body of literature, this review highlights the potential of utilizing EVs as therapeutic tools to modulate angiogenesis for both physiological and pathological purposes. A good understanding of these concepts holds promise for the development of novel therapeutic interventions targeting angiogenesis-related disorders.