BACKGROUND: Rhabdomyosarcoma, though rare in the middle ear, necessitates prompt recognition for optimal management. They are malignant mesenchymal neoplasms arising from the embryonic mesenchymal cells of striated skeletal muscles.
METHODS: We present a case of a 5-year-old child with massive right mastoid swelling and bloody ear discharge. Cytological examination via fine needle aspiration biopsy revealed features suggestive of a malignant mesenchymal tumor, confirmed on imaging and subsequent histopathology as embryonal rhabdomyosarcoma (ERMS) FNCLCC grade 2. Characteristic cytological findings included spindle-shaped cells in a myxoid stroma with tigroid background, aiding in early diagnosis. Despite radical mastoidectomy and adjuvant chemotherapy, ERMS in the middle ear remains challenging due to its aggressive nature and potential complications.
CONCLUSIONS: This case underscores the importance of cytological evaluation in identifying rare soft tissue tumors like ERMS, facilitating timely intervention and improved outcomes. Early recognition and multidisciplinary management are crucial in addressing the complexities of ERMS in uncommon sites like the middle ear.

Synovial sarcomas (SSs) are a rare group of malignant tumors originating from pluripotential mesenchymal cells, which commonly occur as the primary tumor in the soft tissues near the articular surface, tendons, and articular synovium. Herein, we report a rare case of mediastinal SS in an 18-year-old teenager who initially presented with cough as the primary symptom. In this case, plain chest CT and contrast-enhanced CT clearly revealed the lesion presenting as a round-like and uneven density mass in the mediastinum with heterogeneous enhancement, which compressed the trachea and invaded the adjacent vessels. Based on the results of immunohistochemistry and fluorescence in situ hybridization (FISH), combined with the differential diagnosis with other types of tumors in the mediastinum on imaging, we were able to diagnose the tumor as an SS located in the mediastinum. Subsequent resection of the lesion coupled with chemotherapy and immunotherapy led to an improvement in the patient\'s symptoms.

Liver kinase B1 (Lkb1), encoded by serine/threonine kinase (Stk11), is a serine/threonine kinase and tumor suppressor that is strongly implicated in Peutz-Jeghers syndrome (PJS). Numerous studies have shown that mesenchymal-specific Lkb1 is sufficient for the development of PJS-like polyps in mice. However, the cellular origin and components of these Lkb1-associated polyps and underlying mechanisms remain elusive. In this study, we generated tamoxifen-inducible Lkb1flox/flox;Myh11-Cre/ERT2 and Lkb1flox/flox;PDGFRα-Cre/ERT2 mice, performed single-cell RNA sequencing (scRNA-seq) and imaging-based lineage tracing, and aimed to investigate the cellular complexity of gastrointestinal polyps associated with PJS. We found that Lkb1flox/+;Myh11-Cre/ERT2 mice developed gastrointestinal polyps starting at 9 months after tamoxifen treatment. scRNA-seq revealed aberrant stem cell-like characteristics of epithelial cells from polyp tissues of Lkb1flox/+;Myh11-Cre/ERT2 mice. The Lkb1-associated polyps were further characterized by a branching smooth muscle core, abundant extracellular matrix deposition, and high immune cell infiltration. In addition, the Spp1-Cd44 or Spp1-Itga8/Itgb1 axes were identified as important interactions among epithelial, mesenchymal, and immune compartments in Lkb1-associated polyps. These characteristics of gastrointestinal polyps were also demonstrated in another mouse model, tamoxifen-inducible Lkb1flox/flox;PDGFRα-Cre/ERT2 mice, which developed obvious gastrointestinal polyps as early as 2-3 months after tamoxifen treatment. Our findings further confirm the critical role of mesenchymal Lkb1/Stk11 in gastrointestinal polyposis and provide novel insight into the cellular complexity of Lkb1-associated polyp biology. © 2024 The Pathological Society of Great Britain and Ireland.

Morphogenesis, wound healing, and some cancer metastases rely on the collective migration of groups of cells. In these processes, guidance and coordination between cells and tissues are critical. While strongly adherent epithelial cells have to move collectively, loosely organized mesenchymal cells can migrate as individual cells. Nevertheless, many of them migrate collectively. This article summarizes how migratory reactions to cell-cell contacts, also called \"contact regulation of locomotion\" behaviors, organize mesenchymal collective cell migration. It focuses on one recently discovered mechanism called \"guidance by followers\", through which a cell is oriented by its immediate followers. In the gastrulating zebrafish embryo, during embryonic axis elongation, this phenomenon is responsible for the collective migration of the leading tissue, the polster, and its guidance by the following posterior axial mesoderm. Such guidance of migrating cells by followers ensures long-range coordination of movements and developmental robustness. Along with other \"contact regulation of locomotion\" behaviors, this mechanism contributes to organizing collective migration of loose populations of cells.
La morphogénèse, la cicatrisation et certains types de métastases reposent sur la migration collective de groupes de cellules. Lors de ces processus, le guidage et la coordination entre cellules et entre tissus sont fondamentaux. Là où les tissus épithéliaux, très adhésifs, doivent se déplacer collectivement, les cellules mésenchymateuses, en ordre lâche, peuvent migrer individuellement. Cependant, de nombreuses cellules mésenchymateuses migrent de manière collective. Cet article résume comment les réactions migratoires aux contacts entre cellules, aussi appelées «  régulation de locomotion par contact  » , organisent la migration collective des cellules mésenchymateuses. Il décrit en particulier un mécanisme récemment découvert, le «  guidage par les suiveuses  » , par lequel une cellule est orientée par les suiveuses immédiatement en contact. Dans l’embryon de poisson-zèbre en gastrulation, lors de l’élongation du mésoderme axial, ce phénomène est responsable de la migration collective du tissu au front, le polster, et de son guidage par le tissu qui le suit, le mésoderme axial postérieur. Ce mécanisme de guidage par les suiveuses garantit la coordination des mouvements sur de longues distances ainsi que la robustesse du développement. Avec les autres processus de «  régulation de locomotion par contact  » , ce mécanisme contribue à organiser la migration de groupe de cellules en ordre lâche.

Advances in regenerative medicine have enabled the search for new solutions to current health problems in so far unexplored fields. Thus, we focused on cadaveric subcutaneous fat as a promising source of adipose-derived stem cells (ADSCs) that have potential to differentiate into different cell lines. With this aim, we isolated and characterized ADSCs from cadaveric samples with a postmortem interval ranging from 30 to 55 h and evaluated their ability to differentiate into chondrocytes or osteocytes. A commercial ADSC line was used as reference. Morphological and protein expression analyses were used to confirm the final stage of differentiation. Eight out of fourteen samples from patients were suitable to complete the whole protocol. Cadaveric ADSCs exhibited features of stem cells based upon several markers: CD29 (84.49 ± 14.07%), CD105 (94.38 ± 2.09%), and CD44 (99.77 ± 0.32%). The multiparametric assessment of differentiation confirmed the generation of stable lines of chondrocytes and osteocytes. In conclusion, we provide evidence supporting the feasibility of obtaining viable postmortem human subcutaneous fat ADSCs with potential application in tissue engineering and research fields.

Macrodystrophia lipomatosa (MDL) is a rare disorder characterized by overgrowth of mesenchymal cells, resulting in gigantism of one or more digit. We report a case of a woman in her late 60s who presented with abnormal enlargement of the right second toe. By debulking the pathological tissue while preserving the shape of the toe as much as possible without amputation of the entire phalanx, debulking surgery not only helps walking, but also allows wearing shoes of the same size on both feet and achieves cosmetic satisfaction for patients. The functional and cosmetic improvement obtained through debulking surgery in this case resulted in no recurrence of disease 5 years postoperatively and provided a desirable alternative to amputation. Therefore, through this case, we demonstrated that debulking surgery can be a reasonable option for MDL patients.

UNASSIGNED: To compare in vivo, the acute anti-inflammatory effects of a lysate derived from human umbilical perivascular mesenchymal cells with the cells themselves in both an established hind-paw model of carrageenan-induced inflammation and also in the inflamed temporomandibular joint.
UNASSIGNED: Human umbilical cord perivascular cells were harvested and cultured in xeno- and serum-free conditions to P3. In addition, P3 cells were used to prepare a proprietary 0.22 micron filtered lysate. First, CD1 immunocompetent mice underwent unilateral hind-paw injections of carrageenan for induction of inflammation, followed immediately by treatment with saline (negative control), 1% cell lysate, or viable cells. The contralateral paw remained un-injected with carrageenan. Paw circumference was measured prior to injections and 48 hr later and myeloperoxidase and TNF-alpha concentrations were measured post-sacrifice in excised tissue. Second, immunocompetent Male Wistar rats underwent unilateral intra-articular temporomandibular (TMJ) injections from the same treatment groups and were sacrificed at 4 and 48 hr post-injection. The contralateral TMJ remained un-injected with carrageenan. Articular tissue and synovial aspirates, from the treated TMJ were obtained for histologic and leukocyte infiltration analyses.
UNASSIGNED: The lysate and cell-treated hind-paw demonstrated reduced tissue edema, and significantly lower concentrations of myeloperoxidase and TNF-alpha at 48 hr compared to untreated controls. Treated TMJs demonstrated lower concentrations of leukocytes in the synovium compared to controls and histologic evidence, in the peri-articular tissue, of reduced inflammation.
UNASSIGNED: In this preliminary study, both the human umbilical perivascular cells and a highly diluted lysate produced therefrom were anti-inflammatory.

Mesenchymal stem cells (MSCs) are a type of versatile adult stem cells present in various organs. These cells give rise to extracellular vesicles (EVs) containing a diverse array of biologically active elements, making them a promising approach for therapeutics and diagnostics. This article examines the potential therapeutic applications of MSC-derived EVs in addressing neurodegenerative disorders such as Alzheimer\'s disease (AD), multiple sclerosis (MS), Parkinson\'s disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington\'s disease (HD). Furthermore, the present state-of-the-art for MSC-EV-based therapy in AD, HD, PD, ALS, and MS is discussed. Significant progress has been made in understanding the etiology and potential treatments for a range of neurodegenerative diseases (NDs) over the last few decades. The contents of EVs are carried across cells for intercellular contact, which often results in the control of the recipient cell\'s homeostasis. Since EVs represent the therapeutically beneficial cargo of parent cells and are devoid of many ethical problems connected with cell-based treatments, they offer a viable cell-free therapy alternative for tissue regeneration and repair. Developing innovative EV-dependent medicines has proven difficult due to the lack of standardized procedures in EV extraction processes as well as their pharmacological characteristics and mechanisms of action. However, recent biotechnology and engineering research has greatly enhanced the content and applicability of MSC-EVs.

Ascidians significantly change their body structure through metamorphosis, but the spatio-temporal cell dynamics in the early metamorphosis stage has not been clarified. A natural Ciona embryo is surrounded by maternally derived non-self-test cells before metamorphosis. However, after metamorphosis, the juvenile is surrounded by self-tunic cells derived from mesenchymal cell lineages. Both test cells and tunic cells are thought to be changed their distributions during metamorphosis, but the precise timing is unknown.
Using a metamorphosis induction by mechanical stimulation, we investigated the dynamics of mesenchymal cells during metamorphosis in a precise time course. After the stimulation, two-round Ca2+ transients were observed. Migrating mesenchymal cells came out through the epidermis within 10 min after the second phase. We named this event \"cell extravasation.\" The cell extravasation occurred at the same time as the backward movement of posterior trunk epidermal cells. Timelapse imaging of transgenic-line larva revealed that non-self-test cells and self-tunic cells temporarily coexist outside the body until the test cells are eliminated. At the juvenile stage, only extravasated self-tunic cells remained outside the body.
We found that mesenchymal cells extravasated following two-round Ca2+ transients, and distributions of test cells and tunic cells changed in the outer body after tail regression.

The ambiguous results of multiple CD34+ cell-based therapeutic trials for patients with heart disease have halted the large-scale application of stem/progenitor cell treatment. This study aimed to delineate the biological functions of heterogenous CD34+ cell populations and investigate the net effect of CD34+ cell intervention on cardiac remodeling. We confirmed, by combining single-cell RNA sequencing on human and mouse ischemic hearts and an inducible Cd34 lineage-tracing mouse model, that Cd34+ cells mainly contributed to the commitment of mesenchymal cells, endothelial cells (ECs), and monocytes/macrophages during heart remodeling with distinct pathological functions. The Cd34+-lineage-activated mesenchymal cells were responsible for cardiac fibrosis, while CD34+Sca-1high was an active precursor and intercellular player that facilitated Cd34+-lineage angiogenic EC-induced postinjury vessel development. We found through bone marrow transplantation that bone marrow-derived CD34+ cells only accounted for inflammatory response. We confirmed using a Cd34-CreERT2; R26-DTA mouse model that the depletion of Cd34+ cells could alleviate the severity of ventricular fibrosis after ischemia/reperfusion (I/R) injury with improved cardiac function. This study provided a transcriptional and cellular landscape of CD34+ cells in normal and ischemic hearts and illustrated that the heterogeneous population of Cd34+ cell-derived cells served as crucial contributors to cardiac remodeling and function after the I/R injury, with their capacity to generate diverse cellular lineages.