RESUMO
The often well-developed microvasculature in pancreatic neuroendocrine tumors (PanNETs) has been studied from different perspectives. However, some detailed structural findings have received less attention. Our objective is to study an overlooked event in PanNETs: "enclosed vascular tufts" (EVTs). For this purpose, 39 cases of PanNETs were examined with conventional (including serial sections) and immunochemistry procedures. In typical EVTs, the results show: 1) an insulated terminal vascular area, with a globular (glomeruloid) aspect, formed by a cluster of coiled microvessels, presenting CD31-, CD34-positive endothelial cells, αSMA-positive pericytes, and perivascular CD34-positive stromal cells/telocytes, separated by a pseudoglandular space from the surrounding trabeculae of tumor neuroendocrine cells; and 2) a pedicle joining the insulated terminal vascular area, with connective tissue tracts around the enclosing tumor trabeculae. EVTs predominate in the trabecular and nested gyriform pattern of PanNETs, with tumor trabeculae that follow a ribbon coil (winding ribbon pattern) around small vessels, which acquire a tufted image. In EVTs, secondary modifications may occur (fibrosis, hyalinization, myxoid changes, and calcification), coinciding or not with those of the connective tracts. In conclusion, the typical characteristics of unnoticed EVTs allow them to be considered as a morphological sign of PanNETs (a vascular tuft sign). Further in-depth studies are required, mainly to assess the molecular pathways that participate in vascular tuft formation and its pathophysiological implications.
RESUMO
Intussusceptive angiogenesis (IA) is currently considered an important alternative and complementary form of sprouting angiogenesis (SA). Conversely, intussusceptive lymphangiogenesis (IL) is in an initial phase of study. We compare their morphofunctional characteristics, since many can be shared by both processes. To that end, the following aspects are considered: A) The concept of IA and IL as the mechanism by which blood and lymphatic vessels split, expand and remodel through transluminal pillar formations (hallmarks of intussusception). B) Terminology and historical background, with particular reference to the group of Burri, including Djonov and Patan, who initiated and developed the vessel intussusceptive concept in blood vessels. C) Incidence in normal (e.g. in the sinuses of developing lymph nodes) and pathologic conditions, above all in vessel diseases, such as dilated veins in hemorrhoidal disease, intravascular papillary endothelial hyperplasia (IPEH), sinusoidal hemangioma, lobular capillary hemangioma, lymphangiomas/lymphatic malformations and vascular transformation of lymph nodes. D) Differences and complementarity between vessel sprouting and intussusception. E) Characteristics of the cover (endothelial cells) and core (connective tissue components) of pillars and requirements for pillar identification. F) Structures involved in pillar formation, including endothelial contacts of opposite vessel walls, interendothelial bridges, merged adjacent capillaries, vessel loops and spilt pillars. G) Structures resulting from pillars with intussusceptive microvascular growth, arborization, remodeling and segmentation (compartmentalization). H) Influence of intussusception in the morphogenesis of vessel tumors/ pseudotumors; and I) Hemodynamic and molecular control of vessel intussusception, including VEGF, PDGF BB, Hypoxia, Notch, Endoglobin and Nitric oxide.
Assuntos
Vasos Sanguíneos/patologia , Linfangiogênese , Vasos Linfáticos/patologia , Neovascularização Patológica , Neovascularização Fisiológica , Proteínas Angiogênicas/metabolismo , Animais , Vasos Sanguíneos/metabolismo , Humanos , Vasos Linfáticos/metabolismo , Transdução de Sinais , Terminologia como AssuntoRESUMO
We review the morpho-functional basis of the different types of angiogenesis and report our observations, including the formation of angiogenesis-related secondary structures. First of all, we consider the following issues: a) conceptual differences between angiogenesis and vasculogenesis, b) incidence of angiogenesis in pre- and postnatal life, c) regions of vascular tree with angiogenic capacity, d) cells (endothelial cells, pericytes, CD34+ adventitial stromal cells of the microvasculature and inflammatory cells) and extracellular matrix components involved in angiogenesis, e) events associated with angiogenesis, f) different types of angiogenesis, including sprouting and intussusceptive angiogenesis, and other angiogenic or vascularization forms arising from endothelial precursor cells (postnatal vasculogenesis), vasculogenesis mimicry, vessel co-option and piecemeal angiogenesis. Subsequently, we consider the specific morpho-functional characteristics of each type of angiogenesis. In sprouting angiogenesis, we grouped the events in three phases: a) activation phase, which includes vasodilation and increased permeability, EC, pericyte and CD34+ adventitial stromal cell activation, and recruitment and activation of inflammatory cells, b) sprouting phase, encompassing EC migration (concept and characteristics of endothelial tip cells, tip cell selection, lateral inhibition, localized filopodia formation, basal lamina degradation and extracellular changes facilitating EC migration), EC proliferation (concept of endothelial stalk cells), pericyte mobilization, proliferation, recruitment and changes in CD34+ adventitial stromal cells and inflammatory cells, tubulogenesis, formation of a new basal lamina, and vascular anastomosis with capillary loop formation, and c) vascular remodelling and stabilization phase (concept of phalanx cells). Subsequently, the concept, incidence, events and mechanisms are considered in the other forms of angiogenesis. Finally, we contribute the formation of postnatal angiogenesis-related secondary structures: a) intravascular structures through piecemeal angiogenesis, including intravascular papillae in vessel tumours and pseudotumours (intravascular papillary endothelial hyperplasia, vascular transformation of the sinus in lymph nodes, papillary intralymphatic angioendothelioma or Dabska tumour, retiform hemangioendothelioma, hemangiosarcoma and lymphangiosarcoma), vascular septa in hemorrhoidal veins and intravascular projections in some tumours; b) arterial intimal thickening; c) intravascular tumours and pseudotumours (e.g. intravenous pyogenic granulomas and intravascular myopericytoma); d) vascular glomeruloid proliferations; and e) pseudopalisading necrosis in glioblastoma multiform.
Assuntos
Vasos Sanguíneos/embriologia , Vasos Sanguíneos/crescimento & desenvolvimento , Neovascularização Fisiológica/fisiologia , Animais , HumanosRESUMO
Testicular Leydig cells (LC) regulate the proper development of male individuals, both during fetal life (fetal LC) and puberty (adult LC). In the ovaries of adult women, there are cells that are very similar to Leydig cells, the ovarian hilus cells (OHC), which also produce testosterone. The origin of these cells, in both sexes, remains unknown and is still a matter of debate. We have studied the location, characteristics and relationships of the OHC in 90 patients. The indications for oophorectomy were: metrorrhagia (n=9), prolapse (n=8), endometrial hyperplasia (n=14), cancer (endometrial, myometrial, or cervical) (n=35), uterine leiomyomata (n=14), and various ovarian tumors (cysts and benign tumors, borderline and malignant) (n=10). In addition to the hilus, occasionally the nodules, nests and clusters of OHC were located in the mesovarium, the mesosalpinx, and in the medullar and cortical regions of the ovaries. The morphological (including crystalloids of Reinke) and immunohistochemical (positivity for calretinin and alpha-inhibin) findings were similar to those described for testicular LC. Therefore, OHC can be considered ovarian Leydig cells (OLC). LC are usually found in small numbers in the ovaries, but if one looks for them intentionally, one always finds them. Close relationships were observed between the OLC with nerves and vessels. Moreover, an intraneural location of the OLC was demonstrated in all cases, and these intraneural cells showed similar characteristics to extraneural OLC, suggesting that they derive from endoneural cells which are present in the vegetative nerves of the ovaries.
Assuntos
Células Intersticiais do Testículo/patologia , Ovário/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Células Intersticiais do Testículo/metabolismo , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurônios/patologia , Doenças Ovarianas/patologia , Doenças Ovarianas/cirurgia , Ovariectomia , Ovário/inervação , Ovário/metabolismoRESUMO
In this chapter, we outline the role of human CD34+ stromal cells/telocytes (CD34+ SC/TCs) as progenitor cells during repair. The in vivo activation phenomena of CD34+ SC/TCs in this process include increased size; separation from the neighbouring structures (mainly of the vascular walls); association with inflammatory cells, predominantly macrophages; development of the organelles of synthesis (rough endoplasmic reticulum and Golgi apparatus); cell proliferation with presence of mitosis and high proliferative index (transit-amplifying cells); and fibroblastic and myofibroblastic differentiation. A procedure to study these tissue-resident cells, comparison of their behaviour in vivo and in vitro and different behaviour depending on location, time, type of injury (including tumour stroma) and greater or lesser proximity to the injury are also considered.
Assuntos
Fibroblastos Associados a Câncer/patologia , Macrófagos/patologia , Neoplasias/patologia , Células-Tronco/citologia , Telócitos/citologia , Ferimentos Penetrantes/patologia , Animais , Antígenos CD34/genética , Antígenos CD34/metabolismo , Biomarcadores/metabolismo , Fibroblastos Associados a Câncer/metabolismo , Diferenciação Celular , Proliferação de Células , Expressão Gênica , Humanos , Inflamação , Macrófagos/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Células-Tronco/metabolismo , Telócitos/metabolismo , Cicatrização , Ferimentos Penetrantes/genética , Ferimentos Penetrantes/metabolismoRESUMO
Intravascular papillary endothelial hyperplasia (IPEH) is a reactive process of questioned pathogenesis (primary proliferation of endothelial cells/ECs versus organizing thrombi). The aim of this study is to assess the organization of morphologic patterns, with precise location of neovascularization and papillary distribution in IPEH to clarify the role of the vein wall (mainly vein intimal ECs) in lesion development and papillary formation. We studied 12 cases of IPEH in skin and subcutaneous veins by serial histological sections and immunohistochemical procedures. In four well-structured cases (the remaining cases showed overlapping events), we found four principal histological patterns organized by zone: 1) invaginated vein wall zone with microvascular networks. The intraparietal microvessels presented CD34+ and CD31+ ECs arising from ECs of the vein intima, and αSMA+ pericyte-like cells originating from modified SMCs of the media layer. 2) Papillary zone, generally with myriad papillae, formed by ECs of intraparietal microvessel networks encircling vein wall components (parietal papillae). 3) Organizing thrombotic zone from microvascular networks of invaginated vein wall zone. 4) Unorganized thrombotic zone partially covered by ECs, also originating from vein intimal endothelium and arranged in a monolayer or encircling thrombotic fibrin (thrombotic papillae). In conclusion, the capacity of vein intimal ECs and those originating from them (in newly-formed microvessels in the vein itself and covering the unorganized thrombi) to encircle vein wall components or fibrin, and to form papillae (ECs form the cover and encircled components the core) supports a piecemeal mode of angiogenesis as a pathogenic basis of IPEH. This mechanism encompasses the two histogenetic hypotheses outlined above.
Assuntos
Células Endoteliais/patologia , Endotélio Vascular/patologia , Neovascularização Patológica/patologia , Veias/patologia , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Hiperplasia/patologia , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
INTRODUCTION: Intraoperative neurophysiological monitoring has experienced a spectacular development in the past 20 years, particularly in the fields of neurosurgery and spine surgery. it has become a useful, almost indispensable, tool in preventing nerve damage during surgery. The aim of this article is to describe the intraoperative technique and analyze its results in the field of peripheral nerve surgery. OBJECTIVE: To describe the usefulness of a technique in peripheral nerve surgery, the technique used and the experience in a centre. PATIENTS AND METHODS: A retrospective study was conducted on 30 cases of peripheral nerve surgery performed in this centre from 2009 to 2013, using the intraoperative monitoring technique. RESULTS: Of the total of 13 peripheral nerve tumors recorded, there were 11 excellent results and 2 good results, one temporary hypoesthesia and one with almost complete sensory, except for motor, recovery. Traumatic injury was recorded in 17 cases, of which 6 required performing a graft, and the remaining 11 cases only neurolysis was performed, with complete motor and sensory recovery. CONCLUSIONS: Intraoperative neurophysiological monitoring is a useful tool in the secondary surgery of peripheral nerve injury and the intraneural tumor pathology.
Assuntos
Complicações Intraoperatórias/prevenção & controle , Monitorização Neurofisiológica Intraoperatória/métodos , Neurilemoma/cirurgia , Procedimentos Neurocirúrgicos/efeitos adversos , Traumatismos dos Nervos Periféricos/prevenção & controle , Neoplasias do Sistema Nervoso Periférico/cirurgia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Complicações Intraoperatórias/diagnóstico , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Traumatismos dos Nervos Periféricos/diagnóstico , Traumatismos dos Nervos Periféricos/etiologia , Estudos Retrospectivos , Resultado do Tratamento , Adulto JovemRESUMO
We studied the progenitor capacity of human resident CD34+ stromal cells/telocytes (SC/TCs) in the enteric wall affected by inflammatory/repair processes (appendicitis, diverticulitis of large bowel and Crohn's disease of the terminal ileum) at different stages of evolution (inflammatory, proliferative and remodelling). In these conditions, CD34+ SC/TCs are activated, showing changes, which include the following overlapping events: 1) separation from adjacent structures (e.g., from vascular walls) and location in oedematous spaces, 2) morphological modifications (in cell shape and size) with presence of transitional cell forms between quiescent and activated CD34+ SC/TCs, 3) rapid proliferation and 4) loss of CD34 expression and gain of αSMA expression. These events mainly occur in the inflammatory and proliferative stages. During the loss of CD34 expression, the following findings are observed: a) irregular cell labelling intensity for anti-CD34, b) co-localization of CD34 and actin, c) concurrent irregular labelling intensity for αSMA and d) αSMA expression in all stromal cells, with total loss of CD34 expression. While CD34 expression was conserved, a high proliferative capacity (Ki-67 expression) was observed and vice versa. In the segments of the ileum affected by Crohn's disease, the stromal cells around fissures were αSMA+ and, in the transitional zones with normal enteric wall, activated CD34+ SC/TCs were observed. In conclusion, human resident CD34+ SC/TCs in the enteric wall have progenitor capacity and are activated with or without differentiation into αSMA+ stromal cells during inflammatory/repair processes.
Assuntos
Actinas/metabolismo , Antígenos CD34/metabolismo , Íleo/metabolismo , Miócitos de Músculo Liso/citologia , Células-Tronco/citologia , Células Estromais/citologia , Telócitos/citologia , Adolescente , Adulto , Idoso , Apendicite/metabolismo , Diferenciação Celular , Proliferação de Células , Criança , Doença de Crohn/metabolismo , Diverticulite/metabolismo , Feminino , Humanos , Inflamação/metabolismo , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
We review the morphofunctional characteristics of CD34+ stromal fibroblastic/fibrocytic cells (CD34+ SFCs) and report our observations. We consider the following aspects of CD34+ SFCs: A) The confusing terms applied to this cell type, often combining the prefix CD34 with numerous names, including fibroblasts, fibrocytes, dendrocytes, keratocytes, telocytes and stromal, dendritic, adventitial, supraadventitial, perivascular, paravascular and delimiting cells; B) Changes in their immunophenotype, e.g., loss of CD34 expression and gain of other markers, such as those defining mesenchymal and derivate cells (myofibroblasts, osteoblasts, chondroblasts, adipocytes); C) Morphology (elongated or triangular cell body and thin, moniliform, bipolar or multipolar cytoplasmic processes), immunohistochemistry (co-expression of and changes in molecular expression) and structure (characteristics of nucleus and cytoplasmic organelles, and points of contact and junctions in quiescent and activated stages by light and electron microscopy); D) Location and distribution in the vessels (adventitia or external layer), in the tissues (connective, adipose, blood, muscle and nervous) and in the organs and systems (skin, oral cavity and oropharynx, respiratory, digestive, urinary, male, female, endocrine and lymphoid systems, serosal and synovial membranes, heart, eye and meninges); E) Origin from the mesoderm and cranial neural crest in the embryo, and from stem cells (themselves or other cells) and/or peripheral blood pluripotent stem cells (circulating progenitor cells) in post-natal life; F) Functions, such as synthesis of different molecules, progenitor of mesenchymal cells, immunomodulation, parenchymal regulation (growth, maturation and differentiation of adjacent cells), induction of angiogenesis, scaffolding support of other cells and phagocytic properties. Since CD34+ SFCs are the main reservoir of tissue mesenchymal cells (great mesenchymal potential, probably higher than that proposed for pericytes and other stromal cells), we dedicate a broad section to explain their in vivo behaviour during proliferation and differentiation in different physiologic and pathologic conditions, in addition to their characteristics in the human tissues of origin (adult stem cell niches); G) Involvement in pathological processes, e.g., repair (regeneration and repair through granulation tissue), fibrosis, tumour stroma formation and possible CD34+ SFC-derived tumours (e.g., solitary fibrous tumour, dermatofibrosarcoma protuberans, giant cell fibroblastoma, nuchal-type fibroma, mammary and extramammary myofibroblastoma, spindle and pleomorphic cell lipoma, and elastofibroma) and H) Clinical and therapeutic implications.
Assuntos
Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Células Estromais/citologia , Células Estromais/fisiologia , Animais , Antígenos CD34/metabolismo , Biomarcadores , Diferenciação Celular , Linhagem da Célula , Fibroblastos/citologia , Fibroblastos/fisiologia , Humanos , ImunofenotipagemRESUMO
The authors report the ultrastructural characteristics of myopericytoma, a recently described variant of perivascular (pericytic) tumors, mainly with regard to their myopericytic cells and vessels. Myopericytes range between pericytes and vascular smooth muscle cells (SMCs) in a morphologic continuum. The principal findings of the intermediate phenotypes are (1) elongated or annular morphology with processes of varying length and thickness (usually long and thin); (2) a continuous, irregularly thickened and zonally duplicated basement membrane; (3) heterocellular "peg and socket" junctions with neighboring endothelial cells, and scarce specialized junctions between myopericytes; (4) numerous micropinocytotic vesicles, whether continuous or forming focal rows; (5) abundant thin microfilaments, grouped in bundles with dense bodies and adhesion plaques; (6) poorly developed synthetic system (RER and Golgi); (7) pseudointracellular bodies formed by invagination of basement and plasma membranes, with numerous endocytic vesicles; and (8) zones of cytoplasmic rarefaction near micropinocytotic vesicles and intracellular organelles. The ultrastructure of myopericytes therefore makes it possible to distinguish them from pericytes, SMCs, and fibroblast/myofibroblasts, which is useful for myopericytoma diagnosis. The main pattern of the vessels, with perivascular concentric and multilayered growth of myopericytes (a thick wall in contrast to a small lumen) and lack of elastic material, also supports an intermediate form between pericytic and muscular microvasculature. The presence of myopericytes more similar to SMCs and of hemangiopericytoma-like vessels concurs with transitional forms with angioleyomyoma and true hemangiopericytoma, histogenetically representing a morphologic continuum for the perivascular tumors.
Assuntos
Hemangiopericitoma/ultraestrutura , Neoplasias de Tecido Vascular/ultraestrutura , Pericitos/ultraestrutura , Citoesqueleto de Actina/ultraestrutura , Adulto , Biomarcadores Tumorais/metabolismo , Estruturas Citoplasmáticas/ultraestrutura , Feminino , Hemangiopericitoma/metabolismo , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/ultraestrutura , Neoplasias de Tecido Vascular/metabolismo , Pericitos/metabolismo , PinocitoseRESUMO
The administration of prostaglandin (PG) E2, triacetylglycerol and glycerol induce the formation of numerous vascular buds arising from the femoral vein, as previously demonstrated by our group. In the present study, a great number of peg-and-socket junctions (PSJs) between smooth muscle cells (SMCs) (providing the pegs) and ECs (forming the sockets) were demonstrated. At the first stage, days 1 to 3, PSJs connect subendothelial penetrating processes from activated SMCs with activated ECs of the intima. Subsequently, during angiogenesis (days 4 to 6), SMCs, showing transitional aspects with pericytes, also form PSJs with intimal ECs, but also new PSJs between SMCs and sprouting ECs in the media layer were now observed. Immunohistochemically, α-smooth muscle actin (α-SMA) and H-caldesmon are positive in the cytoplasm of the SMCs, showing a higher expression in pegs. Desmin, however, although it is also positive in the cytoplasm of the SMCs, is negative in the pegs. The expression of CD34 in ECs reveals abundant positive folding that appears to correspond to the sockets. The peculiar expression of caldesmon, whose isoforms may contribute to the regulation of cell motility, and to vasculogenesis and angiogenesis, may have a role in the different mechanisms by which PSJs act in the vein wall.
Assuntos
Dinoprostona/metabolismo , Células Endoteliais/metabolismo , Veia Femoral/metabolismo , Glicerol/metabolismo , Miócitos de Músculo Liso/metabolismo , Neovascularização Patológica , Actinas/biossíntese , Animais , Antígenos CD34/biossíntese , Proteínas de Ligação a Calmodulina/biossíntese , Movimento Celular , Imuno-Histoquímica/métodos , Masculino , Músculo Liso/metabolismo , Isoformas de Proteínas , Ratos , Ratos Sprague-DawleyRESUMO
Congophilic birefringent amyloid deposits, with immunostaining for transthyretin (TTR) and amyloid P, associated with numerous coarse, enlarged and thick elastic fibres, are reported in the stroma of two choroid plexus papillomas, a finding not previously described in choroid plexus tumours. TTR was expressed as aggregates of 'doughnut-shaped' bodies, in which the TTR-positive peripheral area encircled the elastic fibre (TTR-negative core). Ultrastructurally, the amyloid microfibrils surrounded the elastic fibres and appeared to continue into the microfibrillar mantle of the latter. The stromal TTR-amyloid deposits associated with abundant elastic fibres in tumours that occur in the choroid plexus may be related to the alteration (production/accumulation, insufficient breakdown and/or extracellular matrix modifications) of some of the choroid plexus functions (removal, target and source of polypeptides, including TTR synthesis) and may be of interest for future studies on choroid plexus polypeptide activity and on protein development into elastomeric and amyloidogenic microfibrils.
Assuntos
Amiloide/metabolismo , Tecido Elástico/metabolismo , Papiloma do Plexo Corióideo/metabolismo , Papiloma do Plexo Corióideo/patologia , Adulto , Tecido Elástico/patologia , Humanos , Lactente , MasculinoRESUMO
We review the morphofunctional characteristics of pericytes and report our observations. After a brief historical background, we consider the following aspects of pericytes: A) Origin in embryonic vasculogenesis (mesenchymal stem cells, neurocrest and other possible sources) and in embryonic and postnatal life angiogenesis (pre-existing pericytes, fibroblast/ myofibroblasts and circulating progenitor cells). B) Location in pericytic microvasculature and in the other blood vessels (including transitional cell forms and absence in lymphatic vessels), incidence (differences depending on species, topographical location, and type and stage of vessels) and distribution (specific polarities) in blood vessels. C) Morphology (cell body, and longitudinal and circumferential cytoplasmic processes), structure (nucleus, cytoplasmic organelles and distribution of microtubules, intermediate filaments and microfilaments) and surface (caveolae system). D) Basement membrane disposition, formation, components and functions. E) Contacts with endothelial cells (ECs) (peg and socket arrangements, adherent junctions and gap junctions) and with basal membrane (adhesion plaques). F) Molecular expression (pericyte marker identification). G) Functions, such as vessel stabilization, regulation of vascular tone and maintenance of local and tissue homeostasis (contractile capacity and vessel permeability regulation), matrix protein synthesis, macrophage-like properties, immunological defense, intervention in coagulation, participation in mechanisms that regulate the quiescent and angiogenic stages of blood vessels (including the behaviour of pericytes during sprouting angiogenesis and intussuceptive vascular growth, as well as pericyte interactions with endothelium and other cells, and with extracellular matrix) and plasticity, as progenitor cells with great mesenchymal potential, originating other pericytes, fibroblast/myofibroblasts, preadipocytes, chondroblasts, osteoblasts, odontoblasts, vascular smooth muscle and myointimal cells. This mesenchymal capacity is seen in a broad section on the perivascular mesenchymal cell niche hypothesis and in the concept of pericyte and EC "marriage and divorce". H) Peculiar pericyte types, such as hepatic stellate cells (Ito cells), bone marrow reticular cells and mesangial cells. I) Involvement in pathological processes, such as repair through granulation tissue, pericyte-derived tumors, tumor angiogenesis and tumoral cell metastasis, diabetic microangiopathy, fibrosis, atherosclerosis and calcific vasculopathy, lymphedema distichiasis, chronic venous insufficiency, pulmonary hypertension, Alzheimer disease and multiple sclerosis. J) Clinical and therapeutic implications (de-stabilization of vessels or formation of a stable vasculature).
Assuntos
Neovascularização Patológica/fisiopatologia , Neovascularização Fisiológica/fisiologia , Pericitos/patologia , Pericitos/fisiologia , Células-Tronco/citologia , Animais , Biomarcadores , Humanos , Mesoderma/citologia , Pericitos/ultraestruturaRESUMO
This article reviews the current status of research about the histogenesis and morphofunctional characteristics of chromaffin cells in the adrenal medulla. First, this study reports the selective migration, transcription and activation factors, and the morphological events of the chromaffin cell precursors during adrenal medulla development. Subsequently, the morphofunctional characteristics of adrenergic and non-adrenergic cells are considered, with particular reference to the characteristics of chromaffin granules and their biological steps, including their formation, traffic (storage, targeting and docking), exocytosis in the strict sense and recapture. Moreover, the relationship of chromaffin cells with other tissue components of the adrenal medulla is also revised, comprising the ganglion cells, sustentacular cells, nerves and connective-vascular tissue.
Assuntos
Medula Suprarrenal/embriologia , Células Cromafins/citologia , Células Cromafins/metabolismo , Hormônios/metabolismo , Animais , Vasos Sanguíneos/citologia , Comunicação Celular , Grânulos Cromafim/metabolismo , Grânulos Cromafim/ultraestrutura , Células do Tecido Conjuntivo/citologia , Humanos , Organogênese/fisiologiaRESUMO
In occluded femoral artery segments, intimal thickening occurred and abundant neovascularization from the surrounding microcirculation developed. Under these conditions, the contribution of vasa-vasorum as a source of supplementary population of cells during the early intimal thickening formation was studied. Using a technique that specifically labels venules, predominantly postcapillary venules, a marker-Monastral Blue B-was used as a tracer to follow the pericyte, endothelial cell and monocyte/macrophage lineages. In the first two days of the experiment, the marker was restricted to the wall of the periarterial microcirculation, being incorporated by endothelial cells, pericytes and some monocytes/macrophages crossing the venule walls. Later, the marker continues to be observed in some of the following cells: endothelial cells and pericytes of the newly-formed vessels, fibroblast-like cells, transitional cells between pericytes and fibroblast-like cells, macrophages migrating into the interstitium, myointimal cells and neoendothelial cells of the arterial lumen. These findings provide evidence that, during arterial intimal thickening formation in occluded arterial segments, the periarterial microvascularization contributes, in addition to recruited macrophages, newly-formed endothelial cells and a supplementary population of fibroblast-like cells and myointimal cells.
Assuntos
Artéria Femoral/patologia , Túnica Íntima/patologia , Vasa Vasorum/patologia , Animais , Células Endoteliais/metabolismo , Fibroblastos/metabolismo , Imuno-Histoquímica/instrumentação , Imuno-Histoquímica/métodos , Indóis/farmacologia , Macrófagos/metabolismo , Compostos Organometálicos/farmacologia , Pericitos/metabolismo , Ratos , Ratos Sprague-Dawley , Células-Tronco/metabolismoRESUMO
This study assesses the action of hypercortisolism on the hormone and peptide periadenoma region of removed ACTH-producing microadenoma. Our findings show that cortisol excess affects both ACTH and GH production, with no immunoreaction for these hormones. The remaining pituitary hormones (TSH, FSH and PRL) and POMC-derived peptides (betaEnd, alphaMSH and betaMSH) were not modified. Likewise, we observed pituitary immunoreactive cells for Neurotensin (NT), Intestinal vasoactive peptide (VIP), Substance P (SP) and Angiotensin-II (Ang-II). The colocalization demonstrated that NT was expressed in thyrotrope and gonadotrope cells, VIP in gonadotrope cells and SP in corticotrope cells. The results about Ang-II were inconclusive. On the other hand, immunoreaction for the NPY and Gal peptides were not present. In the adenomatous cells, the peptide NT is present in ACTH cells as well as SP. These results suggest a peptide regulation of pituitary cells in the pathological state that can differ between normal and tumoural cells of the same pituitary.
Assuntos
Adenoma Hipofisário Secretor de ACT/química , Adenoma/química , Síndrome de Cushing/etiologia , Neuropeptídeos/análise , Hormônios Hipofisários/análise , Adenoma Hipofisário Secretor de ACT/complicações , Adenoma Hipofisário Secretor de ACT/patologia , Adenoma/complicações , Adenoma/patologia , Hormônio Adrenocorticotrópico/análise , Adulto , Angiotensina II/análise , Corticotrofos/química , Síndrome de Cushing/metabolismo , Síndrome de Cushing/patologia , Feminino , Gonadotrofos/química , Hormônio do Crescimento Humano/análise , Humanos , Imuno-Histoquímica , Neurotensina/análise , Substância P/análise , Tireotrofos/química , Peptídeo Intestinal Vasoativo/análiseRESUMO
Adult stem cells (ASC)--able to self renew and to intervene in maintaining the structural and functional integrity of their original tissue--can express greater plasticity than traditionally attributed to them, adopting functional phenotypes and expression profiles of cells from other tissues. Therefore, they could be useful to regenerative medicine and tissue engineering. Transit-amplifying cells (TAC) are committed progenitors among the ASC and their terminally differentiated daughter cells. The ASC reside in a specialized physical location named niche, which constitutes a three-dimensional microenviroment where ASC and TAC are protected and controlled in their self-renewing capacity and differentiation. The niche can be located near or far from the recruitment point, requiring a short or long-distance cellular migration, respectively. This paper briefly reviews the current status of research about ASC plasticity, transdifferentiation, fusion and functional adaptation mechanisms. Subsequently, ASC and TAC occurrence, characteristics and location have been considered in the skin, cornea, respiratory tract, teeth, gastrointestinal tract, liver, pancreas, salivary glands, kidney, breast, prostate, endometrium, mesenchyma, bone marrow, skeletal and cardiac muscle, nervous system and pituitary gland. Moreover, the role of cancer ASC has also been revised.
Assuntos
Células-Tronco/citologia , Animais , Diferenciação Celular , Linhagem da Célula , Movimento Celular , Regulação da Expressão Gênica , Humanos , Monócitos/metabolismo , Neoplasias/metabolismo , Fenótipo , Regeneração , Medicina Regenerativa , Transplante de Células-Tronco , Distribuição TecidualRESUMO
The ectopic spleen characterizes for absence of its suspensory ligaments and a long pedicle that are predisposed to complicate it for a torsion with commitment of the venous drainage at first and arterial at a later time himself, producing increase of its volume and infarct. This anomalous situation, it can be had to a congenital malformation of the development of its suspensory elements and fall toward the inferior abdomen or else to an inferior growth of the mesodermic yolk of that this organ originates itself. The suitable treatment is the laparoscopic splenopexy, but when it exists infarction, it is no possible avoid the splenectomy.