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Intrarenal smooth muscle: Histology of a complex urodymamic machine
Músculo liso intrarrenal: histología de una compleja máquina urodinámica
Grupo PRYT, Departamento de Patología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
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Hematoxilina-eosina, aumento original, x100.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "L.F. Arias, N. Ortiz-Arango" "autores" => array:2 [ 0 => array:2 [ "nombre" => "L.F." "apellidos" => "Arias" ] 1 => array:2 [ "nombre" => "N." "apellidos" => "Ortiz-Arango" ] ] ] ] ] "idiomaDefecto" => "es" "Traduccion" => array:1 [ "en" => array:9 [ "pii" => "S2173578613000644" "doi" => "10.1016/j.acuroe.2012.05.017" "estado" => "S300" "subdocumento" => "" "abierto" => array:3 [ "ES" => false "ES2" => false "LATM" => false ] "gratuito" => false "lecturas" => array:1 [ "total" => 0 ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173578613000644?idApp=UINPBA00004N" ] ] "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0210480612001702?idApp=UINPBA00004N" "url" => "/02104806/0000003700000003/v1_201304251552/S0210480612001702/v1_201304251552/es/main.assets" ] ] "itemSiguiente" => array:19 [ "pii" => "S2173578613000656" "issn" => "21735786" "doi" => "10.1016/j.acuroe.2012.03.018" "estado" => "S300" "fechaPublicacion" => "2013-03-01" "aid" => "430" "copyright" => "AEU" "documento" => "article" "crossmark" => 0 "subdocumento" => "fla" "cita" => "Actas Urol Esp. 2013;37:135-41" "abierto" => array:3 [ "ES" => false "ES2" => false "LATM" => false ] "gratuito" => false "lecturas" => array:2 [ "total" => 1164 "formatos" => array:3 [ "EPUB" => 11 "HTML" => 970 "PDF" => 183 ] ] "en" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Elongation of the right renal vein in 120 consecutive transplant patients: A comparative analysis" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "en" 1 => "es" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "135" "paginaFinal" => "141" ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Alargamiento de la vena renal derecha en 120 trasplantes consecutivos. Análisis comparativo" ] ] "contieneResumen" => array:2 [ "en" => true "es" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0025" "etiqueta" => "Figure 5" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr5.jpeg" "Alto" => 1644 "Ancho" => 1661 "Tamanyo" => 81517 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">Kaplan–Meier curve in which it is seen that there are no statistically significant differences in the graft survival between kidneys with and without lengthened RRV (RK without lengthening and LK), log-rank (Mantel–Cox 2.266, <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.132).</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "O. Arango, J.A. Lorente, O. Bielsa, E. Rijo, A. Francés, L. Fumadó, A. Rodríguez" "autores" => array:7 [ 0 => array:2 [ "nombre" => "O." "apellidos" => "Arango" ] 1 => array:2 [ "nombre" => "J.A." "apellidos" => "Lorente" ] 2 => array:2 [ "nombre" => "O." "apellidos" => "Bielsa" ] 3 => array:2 [ "nombre" => "E." "apellidos" => "Rijo" ] 4 => array:2 [ "nombre" => "A." "apellidos" => "Francés" ] 5 => array:2 [ "nombre" => "L." "apellidos" => "Fumadó" ] 6 => array:2 [ "nombre" => "A." "apellidos" => "Rodríguez" ] ] ] ] ] "idiomaDefecto" => "en" "Traduccion" => array:1 [ "es" => array:9 [ "pii" => "S0210480612001131" "doi" => "10.1016/j.acuro.2012.03.009" "estado" => "S300" "subdocumento" => "" "abierto" => array:3 [ "ES" => false "ES2" => false "LATM" => false ] "gratuito" => false "lecturas" => array:1 [ "total" => 0 ] "idiomaDefecto" => "es" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0210480612001131?idApp=UINPBA00004N" ] ] "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173578613000656?idApp=UINPBA00004N" "url" => "/21735786/0000003700000003/v1_201307180032/S2173578613000656/v1_201307180032/en/main.assets" ] "en" => array:20 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>" "titulo" => "Intrarenal smooth muscle: Histology of a complex urodymamic machine" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "129" "paginaFinal" => "134" ] ] "autores" => array:1 [ 0 => array:4 [ "autoresLista" => "L.F. Arias, N. Ortiz-Arango" "autores" => array:2 [ 0 => array:4 [ "nombre" => "L.F." "apellidos" => "Arias" "email" => array:1 [ 0 => "lfarias@kidneypathology.com" ] "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">¿</span>" "identificador" => "cor0005" ] ] ] 1 => array:2 [ "nombre" => "N." "apellidos" => "Ortiz-Arango" ] ] "afiliaciones" => array:1 [ 0 => array:2 [ "entidad" => "Grupo PRYT, Departamento de Patología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia" "identificador" => "aff0005" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "Corresponding author." ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Músculo liso intrarrenal: histología de una compleja máquina urodinámica" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0030" "etiqueta" => "Figure 6" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr6.jpeg" "Alto" => 1026 "Ancho" => 951 "Tamanyo" => 117912 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Outline depicting how the periphery of the medullary pyramids would be seen, with muscle bundles that border it on its external portion (corticomedullary junction). Most longitudinal fibers arise at the junction of calyces with the renal parenchyma and accompany blood vessels, others are not accompanied by vessels, and others run oblique, like trying to surround the medulla, without forming complete circles.</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0065">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">For many years we have known that there is a small intrarenal muscular system, with a not very well described distribution and extent, which is important in their physiology. The rhythmic contractions of the renal pelvis, and probably of the intrarenal muscles, generate peristaltic waves that empty the papilla; this rhythmic contraction takes the blood to more external compartments of the medulla or to the renal cortex, and the intratubular fluid comes out of the calyces or goes back to more proximal tubular portions.<a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">1</span></a> In some animals, it has been documented that in the pelvic wall and in the calyces, there are two muscle layers, one internal which is inserted near the junction of the pelvis with the base of the papilla and it continues with the ureteral smooth muscle, and only one external covering the pelvis, ending at the junction with the ureter.<a class="elsevierStyleCrossRef" href="#bib0010"><span class="elsevierStyleSup">2</span></a> In human kidneys, it is considered that the external fibers extend to the perimedullary parenchyma or continue accompanying the arcuate vessels.<a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">1</span></a> Although the nomenclature of these intrarenal muscles is imprecise, the fibers which continue from the external layer of the calyces to the renal parenchyma Narath were called <span class="elsevierStyleItalic">musculus levator fornicis</span>.<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> Henle called a ring of fibers that tend to spirally surround the medulla <span class="elsevierStyleItalic">Ringmuskel der Papille</span>,<a class="elsevierStyleCrossRef" href="#bib0020"><span class="elsevierStyleSup">4</span></a> and Puigvert called the fibers accompanying arcuate vessels ‘peripyramidal fibers’.<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">In the calyces, there are a number of extensions in the form of slits, which are highly variable in different mammals, from a simple funnel shape to elaborate extensions and ramifications of the pelvis or calyces, with small bags and side fornices.<a class="elsevierStyleCrossRef" href="#bib0030"><span class="elsevierStyleSup">6</span></a> In human kidneys, the fornices are small and difficult to locate in macroscopic specimens; these fornices are better recognized in contrast urographies.<a class="elsevierStyleCrossRef" href="#bib0035"><span class="elsevierStyleSup">7</span></a> The contraction of intrarenal muscle fibers would produce some degree of variation in the shape and elongation of calyces and fornices, which could be important in the urinary flow and the medullary electrolyte movement.<a class="elsevierStyleCrossRef" href="#bib0040"><span class="elsevierStyleSup">8</span></a></p><p id="par0015" class="elsevierStylePara elsevierViewall">The anatomical features and distribution of these intrarenal muscles have not been very much studied, and we do not know their arrangement with certainty. In histological sections, it is common to find smooth muscle bundles of varying thickness and in different locations, usually near the corticomedullary junction. In order to better understand the anatomical arrangement of these muscle fibers and their relation to other structures of the renal parenchyma, we studied human kidneys trying to reconstruct this complex autonomous muscle system.</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0070">Materials and methods</span><p id="par0020" class="elsevierStylePara elsevierViewall">Five adult kidneys and a fetal kidney were processed <span class="elsevierStyleItalic">in toto</span> for the present study. They all come from clinical autopsies in patients without kidney disease; the cause of death was sepsis in three of them (two women aged 34 and 47 years and a man aged 24 years), acute myocardial infarction (a 57-year-old man), intracerebral hemorrhage due to ruptured aneurysm (58-year-old man), and the remaining was a stillbirth with gestational age of 36 weeks, acute fetal distress, weight of 3400<span class="elsevierStyleHsp" style=""></span>g, and no malformations.</p><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">Specimen processing</span><p id="par0025" class="elsevierStylePara elsevierViewall">After proper fixation in buffered formalin, all the kidneys were transected: cuts every 3<span class="elsevierStyleHsp" style=""></span>mm. In adult kidneys, a longitudinal (coronal) cut was previously made from the convexity to the hilum, in such a way that each cross-sectional cut was divided into two halves, thereby facilitating accommodation in cassettes, later inclusion in paraffin, and performing histological cuts with microtome. The numbering of each 3-mm cross-sectional fragment was consecutive from the first in the upper pole (#1) to the last in the lower pole (#X); each of these numbers was subdivided into “a” for the anterior half of the fragment and “b” for the posterior half, from #1a, #1b, and so on until numbers #Xa and #Xb. In the stillbirth kidney, it was carried out in the same way, except that it was not divided longitudinally into two halves. The total number of fragments (or paraffin embedded blocks) in adult kidneys varied between 58 and 74; in the fetal kidney, the number of fragments was 8. From each paraffin embedded block, we obtained a first cut with the microtome (the first to come out completely) and successive cuts every 300<span class="elsevierStyleHsp" style=""></span>μm, in order to obtain cuts every 0.3<span class="elsevierStyleHsp" style=""></span>mm of the whole organ. The histological sections were made with a thickness of 4<span class="elsevierStyleHsp" style=""></span>μm and conventionally stained with hematoxylin–eosin.</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Histological study</span><p id="par0030" class="elsevierStylePara elsevierViewall">In all the histological sections, we look for bundles or smooth muscle fibers that were not part of vessel walls, with special emphasis on spinal tissue, corticomedullary junction, interstitial tissue adjacent to the calyces, and in the connective tissue near neurovascular bundles. After locating these bundles, we followed them in successive sections (anterior and posterior) to determine their origin or insertion and direction. In some cases in which the muscle bundle was evident in the last section of the respective block, we obtained new cuts for Masson trichrome staining and silver-methenamine. In some cases we conducted immunohistochemistry for smooth muscle actin (clone 1A4, Dako, Carpinteria, U.S.A.) for a better location of the muscle fibers.</p></span></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Results</span><p id="par0035" class="elsevierStylePara elsevierViewall">In all the cases, smooth muscle bundles adjacent to vessels in the corticomedullary junction (arcuate vessels) are easily identified. These bundles are variable in thickness and length, some reach the base of the medullary pyramid, and others end gradually in the upward portion of these pyramids (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>). In a few cases some fibers accompany, in a variable tranche, the first branches of the arcuate arteries or veins in the cortex.</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia><p id="par0040" class="elsevierStylePara elsevierViewall">There are longitudinal bundles of smooth muscle in the interstitium of the corticomedullary junction, not adjacent to arcuate vessels, parallel to the sides of the medullary pyramids, and they go from the base of the papilla to the base of the external medulla; the first fibers arise in the area of the junction of the calyx wall or fornices with the renal parenchyma. They also have a variable thickness and they are not continuous films or sheets, but small bundles without constant intervals; in many cuts they fail to be detected. Other muscle bundles in the corticomedullary junction have an oblique direction, like trying to surround the medulla spirally. However, these bundles are not circumferential, they have a variable thickness and their start and end are difficult to determine accurately, they arise and disappear gradually in serial sections, without a precise anatomical site to be inserted (<a class="elsevierStyleCrossRef" href="#fig0010">Fig. 2</a>). The thickness of these fiber bundles varies, since the ones that are parallel to the sides of the medullary pyramid and the ones that try to surround it spirally have a thickness of up to about 80<span class="elsevierStyleHsp" style=""></span>μm, and the ones accompanying arcuate vessels are usually a little thicker: up to 200<span class="elsevierStyleHsp" style=""></span>μm approximately. In many histological cuts, these small bundles occur as groups of only a few muscle fibers of thickness: up to 2 or 3 fibers. In our work with cuts every 300<span class="elsevierStyleHsp" style=""></span>μm, we cannot accurately determine the frequency of these muscle bundles, as many cuts may remain in interfascicular areas.</p><elsevierMultimedia ident="fig0010"></elsevierMultimedia><p id="par0045" class="elsevierStylePara elsevierViewall">The fibers accompanying the arcuate vessels and those running parallel to the side edges of the medullary pyramid reach the junction of the wall of the calyces with the kidney tissue, and some muscle groups are in contact with the calyceal muscle; however, in many cuts, a direct continuity is not evidenced, there is a gradual transition, with sections that appear devoid of muscle fibers or these are extremely thin, with one or two rows of muscle cells (<a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>).</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia><p id="par0050" class="elsevierStylePara elsevierViewall">It was more unusual to find bundles of smooth muscle fibers within the renal parenchyma in locations other than the corticomedullary junction, and unrelated to arteries or veins. These fibers are seen in the cortex, perpendicular to the corticomedullary junction and extending in a variable tranche to their external side, usually a few millimeters. In an adult kidney, these bundles were so frequent that they were identified in 12 of the 74 fragments, some of them extending over 1<span class="elsevierStyleHsp" style=""></span>cm from the corticomedullary junction and reaching the external cortex (<a class="elsevierStyleCrossRef" href="#fig0020">Fig. 4</a>A). In the remaining cases, these beams were very unusual and small, measuring less than 80<span class="elsevierStyleHsp" style=""></span>μm thick and with a length lower than 3<span class="elsevierStyleHsp" style=""></span>mm. In 2 cases of adult kidney, we identified – only in a fragment of each – a small intramedullary muscle bundle, in contact with the corticomedullary junction and penetrating about 3<span class="elsevierStyleHsp" style=""></span>mm into the external medulla, consisting of 2–4 cells thick (<a class="elsevierStyleCrossRef" href="#fig0020">Fig. 4</a>B).</p><elsevierMultimedia ident="fig0020"></elsevierMultimedia><p id="par0055" class="elsevierStylePara elsevierViewall">Trying to make a reconstruction of this muscular system, we find that at the junction of the pyelocaliceal walls with the renal parenchyma, fiber bundles with varying thickness arise irregularly and in sections, with unknown frequency, parallel to the edges of the medullary pyramids. From the base of the papilla and to the base of the medullary pyramid, other bundles that try to surround it spirally are identified, also with an undetermined periodicity and without managing to identify complete circles. These spiral bundles begin and end gradually, without specific anatomical insertion sites. The muscle bundles accompanying arcuate vessels arise also in the junction area of the calyces and of the fornices with the renal parenchyma, and they extend in most of the way of these vessels, some reaching intracortical ramifications near the base of the medullary pyramid; these muscle groups are the most abundant, consistent, and easy to identify (see diagrams in <a class="elsevierStyleCrossRefs" href="#fig0025">Figs. 5 and 6</a>). More unusual, irregular in its distribution and thickness, and apparently with variation between individuals is the presence of small intracortical smooth muscle bundles, adjacent to the corticomedullary junction and not associated with vascular bundles. Exceptionally small groups of muscle fibers can be identified in the interstitium of the external medulla. These different muscle bundles show no continuity among them and they emerge or are gradually lost.</p><elsevierMultimedia ident="fig0025"></elsevierMultimedia><elsevierMultimedia ident="fig0030"></elsevierMultimedia></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Discussion</span><p id="par0060" class="elsevierStylePara elsevierViewall">The presence of small groups of smooth muscle fibers in kidney tissue biopsies is a common finding, but the nature of these fibers is poorly described in the texts of Urology, Histology, or Nephrology. Only some texts mention these muscle structures and their nomenclature is not homogeneous. The lack of clarity on these groups of muscle fibers led us to make this attempt to reconstruct the anatomy of this ‘muscle machine’, which was more complex than expected. Our work focused on the anatomical identification of these fibers, but from this reconstruction, we can approach its possible function, considering some previous papers on physiology.</p><p id="par0065" class="elsevierStylePara elsevierViewall">The arrangement of these groups of muscle fibers suggests that the ones that partially surround some portions of the medulla would, spirally, compress the outside and base of the papilla like ‘milking’ it.<a class="elsevierStyleCrossRef" href="#bib0020"><span class="elsevierStyleSup">4</span></a> The fibers accompanying arcuate vessels and those running parallel to the medullary pyramids, unrelated to vessels, probably contribute to moving or raising the most intrarenal portion of calyces and fornices and compressing the medulla. Piugvert called ‘peripyramidal fibers’<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a> to the groups of muscle cells adjacent to arcuate arteries and veins, and what Narath called <span class="elsevierStyleItalic">musculus levator fornicis</span><a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> probably includes groups of muscle fibers associated to arcuate vessels and other groups of fibers parallel to the medulla, unrelated to these vessels.<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> These muscle fibers, whether or not associated to vessels, whether they try to surround the medulla, or whether they are parallel to its edges would have a synergistic function. Perhaps the term for these muscle bundles could be the same for all ‘intrarenal smooth muscle’, ‘perimedullary smooth muscle’, ‘fornices levator muscle’,<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> or ‘peripyramidal muscle’.<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a></p><p id="par0070" class="elsevierStylePara elsevierViewall">The physiology of this muscular system is not completely understood, but previous studies in animals and humans<a class="elsevierStyleCrossRefs" href="#bib0045"><span class="elsevierStyleSup">9–13</span></a> have enabled us to know many aspects of its functioning. In humans, about 2–3 peristaltic contractions are detected per minute in the renal pelvis<a class="elsevierStyleCrossRef" href="#bib0050"><span class="elsevierStyleSup">10</span></a>; it is believed that these contractions are monitored by a pacemaker located at the junction of the wall of the pelvis with the connective tissue of the kidney.<a class="elsevierStyleCrossRef" href="#bib0070"><span class="elsevierStyleSup">14</span></a> The peristaltic contractions of the peripyramidal fibers near arcuate vessels or fornices levator muscle and the ring smooth muscle partially surrounding the base of each papilla, compress the medulla and narrow the adjacent urinary space; then these contractions would continue up to the renal pelvis and ureter.<a class="elsevierStyleCrossRefs" href="#bib0015"><span class="elsevierStyleSup">3,5</span></a> In hamsters, it has been determined that the speed of this peristaltic wave is about 1.6<span class="elsevierStyleHsp" style=""></span>mm/s.<a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">1</span></a> These periodic contractions empty the medullary tubules and peritubular capillaries and increase the pressure of the medullary interstitium. At the tip of the papilla, which is lined by the urothelium, there is no muscle. During relaxation, the papilla is shorter and wider, the entrance of the collecting ducts at the tip of the papilla is open and the urine flows slowly. The wall of the calyces contributes in generating this papillary compression.</p><p id="par0075" class="elsevierStylePara elsevierViewall">The peristaltic contraction forces move the urine not only toward the end of the collecting ducts, but also toward the cells of these ducts; the negative interstitial pressure in the relaxation phase mobilizes water from the epithelial cells to the interstitium; finally, from the interstitium, water and other particles are moved to peritubular capillaries with lower hydrostatic and osmotic gradient.<a class="elsevierStyleCrossRef" href="#bib0075"><span class="elsevierStyleSup">15</span></a> The interstitial matrix is like a visco-elastic gel and it is suggested that it can store mechanical energy of the pyelocaliceal contractions by direct compression, without needing to generate high hydrostatic pressures, and this energy can be used to lower the interstitial pressure after each contraction to direct the water outlet of the descending portion of the loop of Henle; this process would increase the luminal osmolarity above that of the interstitium, helping to increase the concentration of the urine.<a class="elsevierStyleCrossRefs" href="#bib0030"><span class="elsevierStyleSup">6,16</span></a></p><p id="par0080" class="elsevierStylePara elsevierViewall">We do not know the function of the few fibers that are found in the cortical interstitium and the exceptional fibers in the medullary interstitium. They could be isolated bundles that contribute to the function of the peripyramidal fibers or levator muscle of the fornices; these fibers may be an extension of these muscles. In this work, we were very careful in evaluating these isolated bundles, because we assumed at the beginning that they would be associated to vessels that were not in the section; however, with multiple additional serial sections, we could see that they were not accompanying these vessels and, therefore, did not correspond to perivascular fibers.</p><p id="par0085" class="elsevierStylePara elsevierViewall">In conclusion, there is a complex microscopic system of smooth muscle fibers partially lining the renal medulla and that is closely related to the renal pelvic muscles. This system seems very important in urodynamics. Our work allows for a better approach to the anatomy and nomenclature of this muscular system and opens the door for future works to better understand its physiology.</p></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">Conflict of interest</span><p id="par0090" class="elsevierStylePara elsevierViewall">The authors declare that they have no conflict of interest.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:10 [ 0 => array:2 [ "identificador" => "xres227336" "titulo" => array:5 [ 0 => "Abstract" 1 => "Objective" 2 => "Methods" 3 => "Results" 4 => "Conclusion" ] ] 1 => array:2 [ "identificador" => "xpalclavsec212224" "titulo" => "Keywords" ] 2 => array:2 [ "identificador" => "xres227337" "titulo" => array:5 [ 0 => "Resumen" 1 => "Objetivo" 2 => "Métodos" 3 => "Resultados" 4 => "Conclusión" ] ] 3 => array:2 [ "identificador" => "xpalclavsec212223" "titulo" => "Palabras clave" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:3 [ "identificador" => "sec0010" "titulo" => "Materials and methods" "secciones" => array:2 [ 0 => array:2 [ "identificador" => "sec0015" "titulo" => "Specimen processing" ] 1 => array:2 [ "identificador" => "sec0020" "titulo" => "Histological study" ] ] ] 6 => array:2 [ "identificador" => "sec0025" "titulo" => "Results" ] 7 => array:2 [ "identificador" => "sec0030" "titulo" => "Discussion" ] 8 => array:2 [ "identificador" => "sec0035" "titulo" => "Conflict of interest" ] 9 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2012-01-20" "fechaAceptado" => "2012-05-11" "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec212224" "palabras" => array:4 [ 0 => "Renal pelvis" 1 => "Smooth muscle" 2 => "Renal histology" 3 => "Renal medulla" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec212223" "palabras" => array:4 [ 0 => "Pelvis renal" 1 => "Músculo liso" 2 => "Histología renal" 3 => "Médula renal" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:2 [ "titulo" => "Abstract" "resumen" => "<span class="elsevierStyleSectionTitle" id="sect0010">Objective</span><p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">To know better the microscopic arrangement of the bundles of smooth muscle in the human renal parenchyma, its distribution and anatomical relationships, trying to make a reconstruction of this muscular system.</p> <span class="elsevierStyleSectionTitle" id="sect0015">Methods</span><p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">Five adult human kidneys and one fetal kidney were processed “in toto” with cross sections every 300<span class="elsevierStyleHsp" style=""></span>μm. In the histological sections we identify the smooth muscle fibers trying to determine its insertion, course and anatomical relationship with other structures of the kidney tissue.</p> <span class="elsevierStyleSectionTitle" id="sect0020">Results</span><p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">There are bundles of smooth muscle fibers of variable thickness parallel to the edges of the medullary pyramids, bundles that surrounding the medulla in a spiral course, and bundles that accompany arcuate vessels, the latter being the most abundant and easy to identify. These groups of muscle fibers do not have a precise or constant insertion site, their periodicity is not homogeneous and they are not a direct extension of the muscle of the renal pelvis, although some bundles are in contact with it. There are also unusual and inconstant small muscle fibers not associated to vessels in the interstitium of the cortex and, exceptionally, in the medulla.</p> <span class="elsevierStyleSectionTitle" id="sect0025">Conclusion</span><p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">There is a complex microscopic system of smooth muscle fibers that partially surround the renal medulla and are related to renal pelvic muscles without a direct continuity with them. Although this small muscular system is under-recognized, it could be very important in urodynamics.</p>" ] "es" => array:2 [ "titulo" => "Resumen" "resumen" => "<span class="elsevierStyleSectionTitle" id="sect0035">Objetivo</span><p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Conocer mejor la disposición microscópica de los haces de músculo liso que hay dentro del parénquima renal humano, su distribución y relaciones anatómicas, intentando hacer una reconstrucción de este sistema muscular.</p> <span class="elsevierStyleSectionTitle" id="sect0040">Métodos</span><p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">Cinco riñones humanos de adultos y un riñón fetal fueron procesados “in toto” con cortes transversales cada 300<span class="elsevierStyleHsp" style=""></span>μm. En los cortes histológicos identificamos las fibras musculares lisas tratando de determinar su inserción, recorrido y relación anatómica con otras estructuras del tejido renal.</p> <span class="elsevierStyleSectionTitle" id="sect0045">Resultados</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Hay haces de fibras de músculo liso con espesor variable paralelas a los bordes de las pirámides medulares, haces que tratan de rodear la médula en espiral y haces que acompañan a vasos arciformes, siendo estos últimos los más abundantes y fáciles de identificar. Estos grupos de fibras musculares no tienen un sitio de inserción preciso y constante, su periodicidad no es homogénea y no son una extensión directa del músculo de la pelvis renal, aunque algunos haces están en contacto con él. Más inusuales e inconstantes son pequeñas fibras musculares no asociadas a vasos en la corteza renal y, excepcionalmente, en el intersticio de la médula.</p> <span class="elsevierStyleSectionTitle" id="sect0050">Conclusión</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Hay un complejo sistema microscópico de fibras musculares lisas que bordean parcialmente la médula y que se relaciona con el músculo de la pelvis renal, sin ser una continuación directa de éste. Aunque este pequeño sistema muscular es poco reconocido, podría ser muy importante en urodinamia.</p>" ] ] "NotaPie" => array:1 [ 0 => array:2 [ "etiqueta" => "☆" "nota" => "<p class="elsevierStyleNotepara" id="npar0005">Please cite this article as: Arias LF, Ortiz-Arango N. Músculo liso intrarrenal: histología de una compleja máquina urodinámica. Actas Urol Esp. 2013;37:129–34.</p>" ] ] "multimedia" => array:6 [ 0 => array:7 [ "identificador" => "fig0005" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 693 "Ancho" => 951 "Tamanyo" => 266404 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">Smooth muscle bundles accompanying arcuate vessels (arrows). They are the most abundant intrarenal smooth muscle bundles and easy to identify. Hematoxylin–eosin, original magnification, 100×.</p>" ] ] 1 => array:7 [ "identificador" => "fig0010" "etiqueta" => "Figure 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr2.jpeg" "Alto" => 690 "Ancho" => 951 "Tamanyo" => 220269 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">Groups of perimedullary smooth muscle fibers. Some run parallel to the edges, between the cortico-medullary junction, and others have an oblique direction, as spirally around the medulla. Hematoxylin–eosin, original magnification, 200×.</p>" ] ] 2 => array:7 [ "identificador" => "fig0015" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 690 "Ancho" => 951 "Tamanyo" => 265772 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">In some sections, the intrarenal smooth muscle (perimedullary or perivascular) can be seen coming to the junction with the wall of the calyx or the fornix (thin arrows); however, there is no direct continuity with the calyceal muscle, with stretches devoid of muscle cells, or there is just one or two rows of cells (short and wide arrows). Hematoxylin–eosin, original magnification, 100×.</p>" ] ] 3 => array:7 [ "identificador" => "fig0020" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 496 "Ancho" => 1401 "Tamanyo" => 301889 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">(A) Intracortical smooth muscle fiber bundles, unrelated to arteries or veins. These are rare and usually small. In a case of adult kidney, they were more abundant and prominent, as it can be seen in the image. Hematoxylin–eosin, original magnification, 100×. (B) Small groups of smooth muscle fibers can be observed very occasionally in the external medulla (arrows). Their function is unknown, but they may contribute to the function of the other groups of intrarenal muscle fibers. Hematoxylin–eosin, original magnification, 400×.</p>" ] ] 4 => array:7 [ "identificador" => "fig0025" "etiqueta" => "Figure 5" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr5.jpeg" "Alto" => 734 "Ancho" => 1401 "Tamanyo" => 134973 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">(A) Diagram of a longitudinal section of the kidney; the arcuate vessels line the medullary pyramids. Many of these vessels (not all) are accompanied by small bundles of smooth muscle. (B) Image of a cross-sectional cut of the medullary pyramid, approximately as it would be found in the table demarcated in (A). In histological sections, we can find longitudinal smooth muscle fibers accompanying vessels (left of the diagram) or longitudinal fibers without vessels, or fibers in cross-sectional or oblique cut (right of the medullary pyramid).</p>" ] ] 5 => array:7 [ "identificador" => "fig0030" "etiqueta" => "Figure 6" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr6.jpeg" "Alto" => 1026 "Ancho" => 951 "Tamanyo" => 117912 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Outline depicting how the periphery of the medullary pyramids would be seen, with muscle bundles that border it on its external portion (corticomedullary junction). Most longitudinal fibers arise at the junction of calyces with the renal parenchyma and accompany blood vessels, others are not accompanied by vessels, and others run oblique, like trying to surround the medulla, without forming complete circles.</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:16 [ 0 => array:3 [ "identificador" => "bib0005" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "The renal pelvis: machinery that concentrates urine in the papilla" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "T.M. Dwyer" 1 => "B. 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Schmidt-Nielsen" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Am J Physiol" "fecha" => "1995" "volumen" => "268" "paginaInicial" => "R1087" "paginaFinal" => "R1100" "link" => array:1 [ 0 => array:2 [ "url" => "https://www.ncbi.nlm.nih.gov/pubmed/7539594" "web" => "Medline" ] ] ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "en" "url" => "/21735786/0000003700000003/v1_201307180032/S2173578613000644/v1_201307180032/en/main.assets" "Apartado" => array:4 [ "identificador" => "6274" "tipo" => "SECCION" "en" => array:2 [ "titulo" => "Original articles" "idiomaDefecto" => true ] "idiomaDefecto" => "en" ] "PDF" => "https://static.elsevier.es/multimedia/21735786/0000003700000003/v1_201307180032/S2173578613000644/v1_201307180032/en/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173578613000644?idApp=UINPBA00004N" ]
| Year/Month | Html | Total | |
|---|---|---|---|
| 2023 March | 3 | 2 | 5 |
| 2018 February | 37 | 0 | 37 |
| 2018 January | 20 | 0 | 20 |
| 2017 December | 24 | 1 | 25 |
| 2017 November | 29 | 0 | 29 |
| 2017 October | 50 | 2 | 52 |
| 2017 September | 18 | 2 | 20 |
| 2017 August | 29 | 2 | 31 |
| 2017 July | 28 | 1 | 29 |
| 2017 June | 26 | 5 | 31 |
| 2017 May | 35 | 2 | 37 |
| 2017 April | 27 | 2 | 29 |
| 2017 March | 26 | 1 | 27 |
| 2017 February | 40 | 4 | 44 |
| 2017 January | 29 | 0 | 29 |
| 2016 December | 25 | 3 | 28 |
| 2016 November | 33 | 6 | 39 |
| 2016 October | 38 | 16 | 54 |
| 2016 September | 33 | 1 | 34 |
| 2016 August | 22 | 3 | 25 |
| 2016 July | 10 | 3 | 13 |
| 2016 June | 13 | 3 | 16 |
| 2016 May | 23 | 22 | 45 |
| 2016 April | 18 | 11 | 29 |
| 2016 March | 29 | 14 | 43 |
| 2016 February | 27 | 14 | 41 |
| 2016 January | 31 | 18 | 49 |
| 2015 December | 13 | 8 | 21 |
| 2015 November | 4 | 11 | 15 |
| 2015 October | 20 | 14 | 34 |
| 2015 September | 10 | 6 | 16 |
| 2015 August | 12 | 4 | 16 |
| 2015 July | 11 | 5 | 16 |
| 2015 June | 16 | 1 | 17 |
| 2015 May | 9 | 5 | 14 |
| 2015 April | 13 | 6 | 19 |
| 2015 March | 30 | 16 | 46 |
| 2014 August | 1 | 1 | 2 |
| 2014 July | 2 | 0 | 2 |
| 2014 June | 2 | 0 | 2 |
| 2014 May | 5 | 1 | 6 |
| 2014 January | 5 | 2 | 7 |
| 2013 December | 21 | 1 | 22 |
| 2013 November | 22 | 5 | 27 |
| 2013 October | 9 | 3 | 12 |
| 2013 September | 4 | 1 | 5 |
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