Blastema Cells Research Articles

Effect of Wilms tumor histology on response to neoadjuvant chemotherapy

PurposeTo evaluate the association between Wilms tumor histology at diagnosis and the change in Wilms' tumor volume during preoperative chemotherapy. MethodsWe included all the 52 patients operated for Wilms tumor at 1988–2015, who had both pathology samples and either CT or MRI-images before and after preoperative chemotherapy, available for reevaluation. ResultsThe median tumor volume was 586 ml (IQR 323–903) at diagnosis. The median change in tumor volume was −68% (IQR −85 to −40, p < 0.001) and the proportion of tumor necrosis 85% (IQR 24–97), after preoperative chemotherapy. There was a correlation between blastemal cell content in prechemotherapy cutting needle biopsy (CNB) sample and the reduction in tumor volume (Rho = −0.452, p = 0.002). High stromal and epithelial cell contents in CNB samples were associated with the lesser change in tumor volume (Rho = 0.279, p =0.053 and Rho = 0.300, p = 0.038 respectively). Reduction of tumor volume and the proportion of tumor necrosis after chemotherapy were associated (Rho = −0.502, p < 0.001). The actual viable tumor volume decreased in median by 97% (IQR 65–100), and the decrease could be seen in all cellular components. In three patients, the tumor volume increased more than 10% during the preoperative chemotherapy. Two of them had anaplastic tumor in the nephrectomy specimen. ConclusionWilms tumor total and viable tumor volumes were reduced by 68% and 97% with preoperative chemotherapy, respectively. High proportion of blastemal cells in CNB was associated with greatest decrease in Wilms tumor volume. Increase in tumor volume during preoperative chemotherapy may indicate anaplastic tumor and prolonging of preoperative therapy should be avoided. Type of studyRetrospective review. Level of evidenceLevel III.

Newt‐derived extracellular vesicles drive mammalian neuron differentiation

Newts have the extraordinary ability to regenerate amputated limbs, as well as damaged heart, nerve and retinal tissue. This remarkable ability relies on the ability of the newt to generate a cluster of cells at site on injury, called a blastema, which is made up of progenitor cells from multiple tissue types. The blastema then directs the proliferation of cells to form new tissue and then the differentiation of those blastemal cells into their mature cell fates. The initial formation of the blastema requires rapid innervation of wound area.We have discovered that newt myogenic precursor cells (A1 cells) secrete extracellular vesicles (EVs) that, like all mammalian cell types, contain RNA and protein cargo that can modulate the morphology and gene expression patterns of the recipient cells that take up EVs. However, these newt EVs contain messenger RNA for multiple nerve differentiation factors. Cultured mammalian dorsal root ganglion (DRG) neurons, a type of peripheral sensory neuron, respond to treatments of newt EVs through increased axon growth and the up‐regulation of genes involved in neural cell differentiation and nerve cell fate determination. We hypothesize that the newt cells are responding to isolated culture conditions as though tissue injury has occurred and secrete EVs to promote nerve growth to facilitate blastema formation.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Nephroblastoma in bester sturgeon, a cultured hybrid of Huso huso × Acipenser ruthenus: Diagnostic imaging, clinical and histopathological study.

Abdominal distention occurred at an incidence of 1% (15 from 1500 fish) in the population of 1-year-old bester (Huso huso×Acipenser ruthenus). Computed tomography (CT) images and radiographs showed a soft tissue mass compressed the posterior part of the swim bladder. Ultrasonography showed that the masses had different patterns. Internal examination revealed the abdominal cavities to be filled with large masses which appeared to encompass most of the visceral organs, including the swim bladder. The masses originated from the posterior kidney. Histologically, the masses were composed of mixtures of embryonal epithelial (tubules and glomeruli), blastema and mesenchymal tissues. The tubules showed cystic, papillary and tubular patterns. Tubules and glomeruloid structures were surrounded by proliferating blastema cells. The primitive mesenchyme was composed of loose streams and whorls of spindle to stellate cells with elongate nuclei. Histological findings in the skeletal muscles, hypoderm and spleen confirmed the metastatic tumour from the kidney in two cases. Immunohistochemically, neoplastic cells of the tubules and glomeruloid structures were positive for cytokeratin AE1/AE3. Sections stained with Masson's trichrome showed blue staining of the stroma. The histopathologic findings were consistent with nephroblastoma.

Non-invasive cell tracking of SPIO labeled cells in an intrinsic regenerative environment: The axolotl limb.

Non-invasive methods to track the progress of stem cell therapies are important in the development of future regenerative therapies. Super-paramagnetic iron oxide particles (SPIOs) have previously been applied to track cells using magnetic resonance imaging (MRI) in vivo in non-regenerative animal models. To the best of the author's knowledge, the present study investigated for the first time, the feasibility of tracking SPIO labeled cells in an intrinsic regenerative environment, the regenerating limb of the axolotl, and investigated the homing of stem cell-like blastema cells to the regenerative zone. Viability and labeling success of labeled axolotl blastema cells was tested in vitro using cell culture and histology. SPIO labeling was performed in situ by intramuscular injections and mapped using MRI. Enhanced permeability and retention (EPR) effects were evaluated in the blastema, liver, heart, kidney and a back muscle. Finally, SPIO/Fluorophore-labeled blastema cells were injected intravascularly and tracked using MRI and fluorescence imaging. It was demonstrated that SPIO labeling had no effect on axolotl cell viability in vitro. In situ labeling resulted in an MRI signal alteration during 48 days of regeneration. EPR effect of unbound SPIO was observed only in the liver. MRI tracking revealed increased concentrations of SPIO labeled blastema cells in the liver, kidney and heart, however not the blastema of intravascularly injected axolotls. In conclusion, the results demonstrated that SPIO labeling facilitated non-invasive tracking of injected cells in the regenerating axolotl limb. An early homing mechanism of injected blastema cells to an injury site was not observed.

TISSUE REPAIR AND EPIMORPHIC REGENERATION: AN OVERVIEW.

This manuscript discusses wound healing as a component of epimorphic regeneration and the role of the immune system in this process. Epimorphic regeneration involves formation of a blastema, a mass of undifferentiated cells capable of giving rise to the regenerated tissues. The apical epithelial cap plays an important role in blastemal formation. True regeneration is rarely observed in mammals. With the exception of transgenic strains, tissue repair in mammals usually leads to non-functional fibrotic tissue formation. In contrast, a number of lower order species including planarians, salamanders, and reptiles, have the ability to overcome the burden of scarring and tissue loss through complex adaptations that allow them to regenerate various anatomic structures through epimorphic regeneration. Blastemal cells have been suggested to originate via various mechanisms including de-differentiation, transdifferentiation, migration of pre-existing adult stem cell niches, and combinations of these.

Decellularized Bovine Articular Cartilage Matrix Reinforced by Carboxylated-SWCNT for Tissue Engineering Application

ABSTRACT Nanotubes with their unique properties have diversified mechanical and biological applications. Due to similarity of dimensions with extracellular matrix (ECM) elements, these materials are used in designing scaffolds. In this research, Carboxylated Single-Wall Carbon Nanotubes in optimization of decellularized scaffold of bovine articular cartilage was used. At first, the articular cartilage was decellularized. Then the scaffolds were analyzed in: (i) decellularized scaffolds, and (ii) scaffolds plunged into homogenous suspension of nanotubes in distilled water, were smeared with Carboxylated-SWCNT. The tissue rings derived from the rabbit's ear were assembled with reinforced scaffolds and they were placed in a culture media for 15 days. The scaffolds in two groups and the assembled scaffolds underwent histologic and electron microscopy. Scanning electron microscopy showed that the structure of ECM of articular cartilage has been maintained well after decellularization. Fourier transform infrared analysis showed that the contents of ECM have not been changed under treatment process. Atomic force microscopy analysis showed the difference in surface topography and roughness of group (ii) scaffolds in comparison with group (i). Transmission electron microscopy studies showed the Carboxylated-SWCNT bond with the surface of decellularized scaffold and no penetration of these compounds into the scaffold. The porosity percentage with median rate of 91.04 in group (i) scaffolds did not have significant difference with group (ii) scaffolds. The electron microscopy observations confirmed migration and penetration of the blastema cells into the group (ii) assembled scaffolds. This research presents a technique for provision of nanocomposite scaffolds for cartilage engineering applications.

Tail regeneration reduction in lizards after repetitive amputation or cauterization reflects an increase of immune cells in blastemas.

Lizards are key amniote models for studying organ regeneration. During tail regeneration in lizards, blastemas contain sparse granulocytes, macrophages, and lymphocytes among the prevalent mesenchymal cells. Using transmission electron microscopy to examine scarring blastemas after third and fourth sequential tail amputations, the number of granulocytes, macrophages, and lymphocytes increased at 3–4 weeks in comparison to the first regeneration. An increase in granulocytes and agranulocytes also occurred within a week after blastema cauterization during the process of scarring. Blood at the third and fourth regeneration also showed a significant increase in white blood cells compared with that under normal conditions and at the first regeneration. The extracellular matrix of the scarring blastema, especially after cauterization, was denser than that in the normal blastema and numerous white blood cells and fibroblasts were surrounded by electron-pale, fine fibrinoid material mixed with variable collagen fibrils. In addition to previous studies, the present observations support the hypothesis that an increase in inflammation and immune reactions determine scarring rather than regeneration. These new findings verify that an immune reaction against mesenchymal and epidermal cells of the regenerative blastema is one of the main causes for the failure of organ regeneration in amniotes.

A regulatory pathway involving retinoic acid and calcineurin demarcates and maintains joint cells and osteoblasts in regenerating fin.

During zebrafish fin regeneration, blastema cells lining the epidermis differentiate into osteoblasts and joint cells to reconstruct the segmented bony rays. We show that osteoblasts and joint cells originate from a common cell lineage, but are committed to different cell fates. Pre-osteoblasts expressing runx2a/b commit to the osteoblast lineage upon expressing sp7, whereas the strong upregulation of hoxa13a correlates with a commitment to a joint cell type. In the distal regenerate, hoxa13a, evx1 and pthlha are sequentially upregulated at regular intervals to define the newly identified presumptive joint cells. Presumptive joint cells mature into joint-forming cells, a distinct cell cluster that maintains the expression of these factors. Analysis of evx1 null mutants reveals that evx1 is acting upstream of pthlha and downstream of or in parallel with hoxa13a Calcineurin activity, potentially through the inhibition of retinoic acid signaling, regulates evx1, pthlha and hoxa13a expression during joint formation. Furthermore, retinoic acid treatment induces osteoblast differentiation in mature joint cells, leading to ectopic bone deposition in joint regions. Overall, our data reveal a novel regulatory pathway essential for joint formation in the regenerating fin.

Multifocal Spinal Cord Nephroblastoma in a Dog

A 1-year-old male American pit bull terrier was presented with a history of proprioceptive deficits and mild lameness of the right hindlimb, which progressed after 5 months to paraparesis, culminating in tetraparesis after 2 weeks. Necropsy findings were limited to the spinal cord and consisted of multiple, intradural, extramedullary, slightly red masses which produced segmental areas of medullary swelling located in the cervical intumescence, thoracolumbar column, sacral segment and cauda equina. Histological evaluation revealed a tumour, composed of epithelial, stromal and blastemal cells, with structures resembling tubules, acini and embryonic glomeruli. Immunohistochemical labelling for vimentin, cytokeratin and S100 was positive for the stromal, epithelial and blastemal cells, respectively. A final diagnosis of multifocal spinal cord nephroblastoma was established. This is the first report of such a tumour showing concomitant involvement of the cervicothoracic, thoracolumbar, sacral and cauda equina areas of the spinal cord.

GATA3 differential expression in neuroblastoma and nephroblastoma

We have read with great interest the report by Wiles et al, published in Cancer Cytopathology, about the immunohistochemical expression of the GATA3 antibody in cytological material from neuroblastomas.1 They evaluated GATA3 immunohistochemical expression in neuroblastoma cytology and/or biopsy samples, and diffuse nuclear positivity was found in all 30 specimens studied. Each sample revealed either strong (n = 26) or moderate nuclear staining (n = 4) in more than 75% of neuroblastoma cells, regardless of the presence or lack of stromata, necrosis, or differentiation. GATA3 is a relatively recent marker useful for diagnosing tumors of various epithelial and nonepithelial origins such as mammary tumors, urothelial tumors, renal tumors, germ cell tumors, mesotheliomas, and paragangliomas. Moreover, it is usually negative in round cell sarcomas.2 In contrast, little is known about GATA3 expression in blastemal or other small round cell pediatric tumors. Nonaka et al3 reported the presence of diffuse GATA3 expression in the neuroblastoma family of tumors and a lack of expression in other small round cell tumors. The distinction between neuroblastomas and nephroblastomas may be delicate because the clinical and radiological presentation may be overlapping. Moreover, we have previously encountered important difficulties in the cytological differential diagnosis between poorly differentiated neuroblastomas without neuropils or differentiating cells from blastema-rich monophasic nephroblastomas.4 We initiated this study to evaluate GATA3's immunohistochemical utility in the cytological differential diagnosis between neuroblastomas and nephroblastomas. Six cell blocks from the most recent consecutive ultrasound-guided fine-needle aspirates from neuroblastomas and 6 cell blocks from nephroblastomas were investigated. Paraffin-embedded sections were stained with the GATA3 antibody (clone L50-823; Biocare, Concord, California). Immunostaining was scored as negative, weakly positive, or strongly positive. The percentage of positive cells was also estimated. Nuclear staining was found in all 6 cases of neuroblastoma but in only 1 case of nephroblastoma. No cytoplasmic staining was observed. The intensity varied from weak (4 cases) to strong (2 cases; Figs. 1 and 2). The percentage of positive cells varied from 5% to 100%. Only 1 of the 6 cases of nephroblastoma showed weak nuclear positivity in 5% of tumor cells. The clinical data and the results of immunohistochemistry are presented in Table 1 On the basis of our results, we conclude that GATA3 may be a useful marker for differentiating neuroblastomas from nephroblastomas, especially when it is used with Phox2b and tyrosine-hydroxylase antibodies.3 Moreover, in some cases, GATA3 may be not specific, and positivity in a blastemal nephroblastoma may be a pitfall of a differential diagnosis with a poorly differentiated neuroblastoma. No specific funding was disclosed. The authors made no disclosures. Jerzy Klijanienko, MD, PhD, MIAC Martial Caly, PhD Paul Frénaux, MD Department of Pathology, Curie Institute, Paris, France Jan Klos, MD Department of Pathology, Stavanger University Hospital, Stavanger, Norway

Hyaluronic acid in the tail and limb of amphibians and lizards recreates permissive embryonic conditions for regeneration due to its hygroscopic and immunosuppressive properties.

The present review focuses on the role of hyaluronate (hyaluronic acid; HA) during limb and tail regeneration in amphibians and lizards mainly in relation to cells of the immune system. This non-sulfated glycosaminoglycan (GAG) increases in early stages of wound healing and blastema formation, like during limb or tail embryogenesis, when the immune system is still immature. The formation of a regenerating blastema occurs by the accumulation of mesenchymal cells displaying embryonic-like antigens and HA. This GAG adsorbs large amount of water and generates a soft tissue over 80% hydrated where mesenchymal and epithelial cells can move and interact, an obligatory passage for organ regeneration. GAGs and HA in particular rise to a high amount and coat plasma membranes of blastema cells forming a shield that likely impedes to the circulating immune cells to elicit an immune reaction against the embryonic-like antigens present on blastema cells. The evolution of limb-tail regeneration in amphibians dates back to the Devonian-Carboniferous, while tail regeneration in lizards is a more recent evolution process, possibly occurred since the Jurassic, which is unique among amniotes. Both processes are associated with the reactivation of proliferating embryonic programs that involve the upregulation of genes for Wnt, non-coding RNAs, and HA synthesis in an immune-suppress organ, the regenerative blastema. Failure of maintaining a lasting HA synthesis for the formation of a highly hydrated blastema leads to scarring, the common healing process of amniotes equipped with an efficient immune system. The study of amphibian and lizard regeneration indicates that attempts to stimulate organ regeneration in other vertebrates require the induction of a highly hydrated and immune-depressed, HA-rich environment, similar to the extracellular environment present during development.

Isolation, Characterization and Osteogenic Potential of Mouse Digit Tip Blastema Cells in Comparison with Bone Marrow-Derived Mesenchymal Stem Cells In Vitro.

Objective Limb regeneration mediated by blastema cells (BlCs) in mammals is limited to the digit tips of neonates. Due to the lack of access to BlCs in adults and the difficulty in isolating and expanding BlCs from neonates, the use of a cellular population with similar features of BlCs would be a valuable strategy to direct a non-regenerative wound towards regeneration. In this study, we have initially isolated and cultured BlCs, and explored their characteristics in vitro. Next, we compared the capability of bone marrow-derived mesenchymal stem cells (BM-MSCs) as an alternative accessible cell source to BlCs for regeneration of appendages. Materials and Methods In this experimental study, BM-MSCs were isolated from BM and we obtained BlCs from the neonatal regenerating digit tip of C57B/6 mice. The cells were characterized for expressions of cell surface markers by flow cytometry. Quantitative-reverse transcription polymerase chain reaction (qRT-PCR) and lineage-specific staining were used to assess their ability to differentiate into skeletal cell lineages. The colony forming ability, proliferation, alkaline phosphatase (ALP) activity, calcium content, and osteogenic gene expression were evaluated in both BM- MSCs and BlCs cultures at days 7, 14, and 21. Results qRT-PCR analysis revealed that the cells from both sources readily differentiated into mesodermal lineages. There was significantly higher colony forming ability in BM-MSCs compared to BlCs (P<0.05). Alizarin red staining (ARS), calcium, and the ALP assay showed the same degree of mineral deposition in both BlCs and BM-MSCs. Gene expression levels of osteblastic markers indicated similar bone differentiation capacity for both BlCs and BM-MSCs at all time-points. ConclusionCharacteristics of BlCs in vitro appear to be similar to BM-MSCs. Therefore, they could be considered as a substitute for BlCs for a regenerative approach with potential use in future clinical settings for regenerating human appendages.

Cartilage and Muscle Cell Fate and Origins during Lizard Tail Regeneration.

Human cartilage is an avascular tissue with limited capacity for repair. By contrast, certain lizards are capable of musculoskeletal tissue regeneration following tail loss throughout all stages of their lives. This extraordinary ability is the result of a complex process in which a blastema forms and gives rise to the tissues of the regenerate. Blastemal cells have been shown to originate either from dedifferentiated tissues or from existing progenitor cells in various species, but their origin has not been determined in lizards. As reptiles, lizards are the closest relatives to mammals with enhanced regenerative potential, and the origin of blastemal cells has important implications for the regenerative process. Hence, the aim of this study is to determine the cellular origin of regenerated cartilage and muscle tissues in reptiles using the mourning gecko lizard as the regenerative model. To trace the fate and differentiation potential of cartilage during tail regeneration, cartilage cells pre-labeled with the fluorescent tracer Dil were injected into lizard tails, and the contribution of cartilage cells to regenerated tail tissues was assessed by histologic examination at 7, 14, and 21 days post-tail amputation. The contribution of muscle cells to regenerated tail tissues was evaluated using muscle creatine kinase promoter-driven Cre recombinase in conjunction with the Cre-responsive green-to-red fluorescence shift construct CreStoplight. 21 days after amputation, tail tissues were analyzed by histology for red fluorescent protein (RFP)-positive cells. At 7 days post-amputation, Dil-labeled cartilage cells localized to the subapical space contributing to the blastema. At 14 and 21 days post-amputation, Dil-labeled cells remained in the subapical space and colocalized with Collagen type II (Col2) staining in the cartilage tube and myosin heavy chain (MHC) staining in regenerated muscle. Lineage tracing of myocytes showed colocalization of RFP with Col2 and MHC in differentiated tissues at 21 days post-amputation. This study demonstrates that differentiated cartilage cells contribute to both regenerated muscle and cartilage tissues following tail loss, and in turn, differentiated muscle cells contribute to both tissue types as well. These findings suggest that dedifferentiation and/or transdifferentiation are at least partially responsible for the regenerative outcome in the mourning gecko.

Ultrastructural immunolocalization of hyaluronate in regenerating tail of lizards and amphibians supports an immune-suppressive role to favor regeneration.

Hyaluronate is produced in high amount during the initial stages of regeneration of the tail and limbs of lizards, newts, and frog tadpoles. The fine distribution of hyaluronate in the regenerating tail blastemas has been assessed by ultrastructural immunolocalization of the Hyaluronate Binding Protein (HABP), a protein that indirectly reveals the presence of hyaluronate in tissues. The present electron microscopic study shows that HABP is detected in the cytoplasm but this proteins is mainly localized on the surfaces of cells in the wound epidermis and mesenchymal cells of the blastema. HABP appears, therefore, accumulated along the cell surface, indicating that hyaluronate coats these embryonic-like cells and their antigens. The high level of hyaluronate in the blastema, aside favoring tissue hydration, cell movements, and remodeling for blastema formation and growth, likely elicits a protection from the possible immune-reaction of lymphocytes and macrophages to embryonic-fetal-like antigens present on the surface of blastema and epidermal cells. Their survival, therefore, allows the continuous multiplication of these cells in regions rich in hyaluronate, promoting the regeneration of a new tail or limbs. The study suggests that organ regeneration in vertebrates is only possible in the presence of high hyaluronate content and hydration. These two conditions facilitate cell movement, immune-protection, and activate the Wnt signaling pathway, like during development.

Transcriptional correlates of proximal-distal identify and regeneration timing in axolotl limbs

Cells within salamander limbs retain memories that inform the correct replacement of amputated tissues at different positions along the length of the arm, with proximal and distal amputations completing regeneration at similar times. We investigated the possibility that positional memory is associated with variation in transcript abundances along the proximal-distal limb axis. Transcripts were deeply sampled from Ambystoma mexicanum limbs at the time they were administered fore arm vs upper arm amputations, and at 19 post-amputation time points. After amputation and prior to regenerative outgrowth, genes typically expressed by differentiated muscle cells declined more rapidly in upper arms while cell cycle transcripts were expressed more highly. These and other expression patterns suggest upper arms undergo more robust tissue remodeling and cell proliferation responses after amputation, and thus provide an explanation for why the overall time to complete regeneration is similar for proximal and distal amputations. Additionally, we identified candidate positional memory genes that were expressed differently between fore and upper arms that encode a surprising number of epithelial proteins and a variety of cell surface, cell adhesion, and extracellular matrix molecules. Also, genes were discovered that exhibited different, bivariate patterns of gene expression between fore and upper arms, implicating dynamic transcriptional regulation for the first time in limb regeneration. Finally, 43 genes expressed differently between fore and upper arm samples showed similar transcriptional patterns during retinoic acid-induced reprogramming of fore arm blastema cells into upper arm cells. Our study provides new insights about the basis of positional information in regenerating axolotl limbs.

Inhibition of apoptosis signal-regulating kinase 1 alters the wound epidermis and enhances auricular cartilage regeneration.

Why regeneration does not occur in mammals remains elusive. In lower vertebrates, epimorphic regeneration of the limb is directed by the wound epidermis, which controls blastema formation to promote regrowth of the appendage. Herein, we report that knockout (KO) or inhibition of Apoptosis Signal-regulated Kinase-1 (ASK1), also known as mitogen-activated protein kinase kinase kinase 5 (MAP3K5), after full thickness ear punch in mice prolongs keratinocyte activation within the wound epidermis and promotes regeneration of auricular cartilage. Histological analysis showed the ASK1 KO ears displayed enhanced protein markers associated with blastema formation, hole closure and regeneration of auricular cartilage. At seven days after punch, the wound epidermis morphology was markedly different in the KO, showing a thickened stratum corneum with rounded cell morphology and a reduction of both the granular cell layer and decreased expression of filament aggregating protein. In addition, cytokeratin 6 was expressed in the stratum spinosum and granulosum. Topical application of inhibitors of ASK1 (NQDI-1), the upstream ASK1 activator, calcium activated mitogen kinase 2 (KN93), or the downstream target, c-Jun N-terminal kinase (SP600125) also resulted in enhanced regeneration; whereas inhibition of the other downstream target, the p38 α/β isoforms, (SB203580) had no effect. The results of this investigation indicate ASK1 inhibition prolongs keratinocyte and blastemal cell activation leading to ear regeneration.

Evaluation of effect of preoperative chemotherapy on Wilms' tumor histopathology

PurposeTo evaluate usefulness of cutting needle biopsy (CNB) to recognize pediatric renal tumors and to predict the evolution of histology during preoperative chemotherapy of Wilms tumors. MethodsNinety pediatric patients were operated for renal tumors at our institution in 1988–2015. We included all 64 patients who had undergone CNB at diagnosis and whose CNB and nephrectomy samples were available for re-evaluation. ResultsThe CNB was diagnostic in all 59 Wilms tumors but only in two out of five non-Wilms tumors. Anaplasia was missed by CNB in one of three with diffuse anaplasia in nephrectomy specimens. In Wilms tumors the proportions of the blastemal, stromal and epithelial components were 55% (IQR 25–85), 28% (IQR 10–58) and 2% (IQR 0–10) in CNB samples and 5% (IQR 0–64), 15% (IQR 0–50) and 15% (IQR 0–44) in the nephrectomy specimens (p-values 0.002, 0.599 and 0.005 respectively). The degree of tumor necrosis was in median 80% (IQR 21–97), after preoperative chemotherapy. The degree of tumor necrosis after chemotherapy had a positive correlation with the proportion of blastemal component (p=0.008) and a negative correlation with proportion of epithelial component in pre-chemotherapy CNB samples (p<0.001). ConclusionsWilms tumors are usually recognizable unlike non-Wilms tumors in CNB at diagnosis. In Wilms tumors, high blastemal cell content is associated with significant tumor necrosis during pre-operative chemotherapy. Our results do not support routine use of CNB in diagnosis of renal tumors. Type of studyRetrospective review. Level of evidenceLevel III.

SINONASAL TERATOCARCINOSARCOMA - A RARE CASE REPORT

Sinonasal teratocarcinosarcoma is a rare and highly malignant tumor characterized by complex admixture of teratomatous and carcinosarcomatous component. Here, we report a case of 72-year-old male presented with complaints of epistaxis, recurrent sinusitis, nasal stuffiness, and nasal blockade for past 5-6 months and his computed tomography report revealed as an inflammatory sinonasal disease with polyposis. Histopathology examination showed fragments of upper respiratory mucosa admixed with fragments of tumor composed of benign and malignant counterparts of both epithelial and mesenchymal components in a variety of histologic patterns. Also noted were the characteristic squamous epithelium with “fetal-type” clear cells, areas of necrosis, mitotic figure and sheets of undifferentiated blastemal like cells. Immunohistochemistry demonstrated positive staining for cytokeratin, epithelial membrane antigen, vimentin, synaptophysin, S-100, chromogranin, and CD99. This polyimmunophenotypic characteristic and diverse histological differentiation provided the basis for the diagnosis. Knowing its highly aggressive behavior, the patient should be treated aggressively and followed up closely. Key words: Carcinosarcom, Fetal epithelium, Polyimmunophenotypic, Teratoid

BMP signaling regulates the skeletal and connective tissue differentiation during caudal fin regeneration in sailfin molly (Poecilia latipinna).

Caudal fin regeneration in sailfin molly, Poecilia latipinna (Lesueur 1821) involves an initial wound healing stage, followed by blastema that is formed of fast proliferating cells. In order to replicate the lost fin, correct differentiation of the blastemal cells into various tissues is the prime essence. Among the molecular signals governing proper differentiation of blastemal cells, members of the bone morphogenetic protein (BMP) family are crucial. Herein, we investigated the specific effects of inhibition of BMP signaling using LDN193189 on skeletal and connective tissue formation in the regenerating tail fin of P.latipinna during early differentiation phase. It was observed that BMP inhibition leads to reduction in the length of regeneration, which can be correlated with compromised proliferation of blastemal cells. Decreased expression of cell proliferation marker like pcna together with reduced BrdU positive cells consolidate the above observation. Further, histological analysis revealed stunted progression of skeletal tissues and this correlated with the reduced expression of sox9, runx2 and dlx5, Osc and Osn genes in response to BMP inhibition. Also, defective bone patterning was observed due to BMP inhibition, which was associated with diminished levels of shh, ptc-1, gli2 and other BMP ligands. Moreover, histochemical analysis revealed that collagen, one of the most prominent components of connective tissue, was formed below par in treated fin tissues which was subsequently confirmed by biochemical and transcript level analyses. Overall our results highlight the importance of the BMP pathway in proper differentiation of skeletal and connective tissues during the differentiation stage of regenerating caudal fin.

Hyaluronate likely contributes to the immunesuppression of the regenerating tail blastema in lizards: Implications for organ regeneration in amniotes

AbstractThe regenerating tail blastema of lizards appears immunesuppressed, and the distribution of hyaluronate, a possible agent of immunesuppression, is evaluated. Transcriptome data show upregulation of genes stimulating hyaluronate production in the tail and limb blastemas. The distribution of hyaluronate in the tail and limb blastemas has been studied using alcian blue at pH 2.5 and 1.0 and by immunohistochemistry for hyaluronate receptors. Both tail and limb blastemas initially contain hyaluronate, but this glycosaminoglycan disappears in the scarring limb blastema at 25‐ to 30‐day postamputation after intense inflammation. The regenerating tail tip moves distally during regeneration but conserves hyaluronate that is replaced by sulphated glycosaminoglycans and glycoproteins in proximal regions of the regenerating tail. Hyaluronate receptors are diffuse among blastema cells and ependyma of the tail, intense in wound epidermis but low to absent in the scarring limb. The electron microscope shows that an amorphous extracellular matrix likely containing hyaluronate surrounds mesenchymal cells, ependyma and wound epidermis in the tail but is scarce to absent in the limb, whereas collagen fibrils prevail. Extracellular matrix containing hyaluronate may shield blastema cells from circulating immune cells preventing deleterious immune reactions in the tail but not in the limb, a process leading to scarring.