<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2500-5006</journal-id>
<journal-title><![CDATA[Revista Colombiana de Nefrología]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. colom. nefrol.]]></abbrev-journal-title>
<issn>2500-5006</issn>
<publisher>
<publisher-name><![CDATA[Asociación Colombiana de Nefrología e Hipertensión Arterial]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2500-50062025000200009</article-id>
<article-id pub-id-type="doi">10.22265/acrief.12.2.884</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Mecanismo multiplicador de contracorriente renal: un desafío desde la etapa de aprendizaje hasta la práctica clínica]]></article-title>
<article-title xml:lang="en"><![CDATA[Renal countercurrent multiplication mechanism: A challenge from the learning to clinical practice]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Jaurretche]]></surname>
<given-names><![CDATA[Sebastián]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
<xref ref-type="aff" rid="Aaf"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Brajkovic]]></surname>
<given-names><![CDATA[María Luana]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rosal]]></surname>
<given-names><![CDATA[María Victoria del]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Venera]]></surname>
<given-names><![CDATA[Graciela]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Sanatorio Parque  ]]></institution>
<addr-line><![CDATA[Rosario ]]></addr-line>
<country>Argentina</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Instituto Universitario Italiano de Rosario  ]]></institution>
<addr-line><![CDATA[Rosario ]]></addr-line>
<country>Argentina</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Instituto Universitario Italiano de Rosario Departamento de Investigación ]]></institution>
<addr-line><![CDATA[Rosario ]]></addr-line>
<country>Argentina</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>08</month>
<year>2025</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>08</month>
<year>2025</year>
</pub-date>
<volume>12</volume>
<numero>2</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S2500-50062025000200009&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S2500-50062025000200009&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S2500-50062025000200009&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen  Contexto: El mecanismo multiplicador de contracorriente (MMCC) del asa de Henle es esencial para la concentración y dilución de la orina, pero su comprensión sigue siendo un reto en la docencia de fisiología renal y en la práctica clínica. Persisten vacíos sobre la hiperosmolaridad de la médula interna y la papila.  Objetivo: Revisar de forma integral la fisiología, fundamentos históricos y modelos actuales del MMCC, resaltando hallazgos recientes que complementan los conceptos clásicos.  Metodología: Revisión narrativa basada en búsqueda en PubMed, Medline, Scopus, SciELO, La-tindex y Google Académico, incluyendo literatura histórica y contemporánea sobre fisiología tubular y mecanismos de contracorriente.  Resultados: Se describen la evolución conceptual desde las teorías vitalista y mecanicista hasta el modelo clásico de Wirz, y su refinamiento con la teoría pasiva de Kokko y Rector. Se detallan propiedades segmentarias, función de los vasos rectos, recirculación de urea y la integración de mecanismos de intercambio y multiplicación. Hallazgos recientes incluyen el papel diferencial de transportadores de urea (UT-A1, UT-&#1040;&#1047;), acuaporinas (AQP1) y canales de cloruro (C1C-K1), así como la organización tridimensional de nefronas y vasos rectos, lo que sugiere microdominios de intercambio.  Conclusiones: El MMCC es un proceso dinámico y multifactorial cuyo entendimiento requiere integrar la anatomía funcional, transporte de solutos y regulación hormonal. Los hallazgos recientes amplían y matizan el modelo clásico, con implicaciones en fisiología comparada y enseñanza médica.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract  Background: The renal countercurrent multiplication mechanism (CCMM) of the loop of Henle is essential for urine concentration and dilution, yet remains challenging in renal physiology education and clinical practice. Uncertainties persist regarding inner medullary and papillary hyperosmolarity.  Purpose: To comprehensively review the physiology, historical foundations, and current models of the CCMM, highlighting recent findings that complement classical concepts.  Methodology: Narrative review based on searches in PubMed, Medline, Scopus, SciELO, Latindex, and Google Scholar, including historical and contemporary literature on tubular physiology and counter-current mechanisms.  Results: The review traces the conceptual evolution from vitalist and mechanistic theories to Wirz's classical model, and its refinement with Kokko and Rector's passive theory. Segmental properties, vasa recta function, urea recirculation, and the integration of exchange and multiplication mechanisms are described. Recent findings include the differential role of urea transporters (UT-A1, UT-A3), aquaporins (AQP1), and chloride channels (ClC-K1), as well as the three-dimensional organization of nephrons and vasa recta, suggesting microdomains for solute exchange.  Conclusions: The CCMM is a dynamic, multifactorial process requiring integration of functional anatomy, solute transport, and hormonal regulation. Recent discoveries expand and refine the classical model, with implications for comparative physiology and medical education.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Fisiología renal]]></kwd>
<kwd lng="es"><![CDATA[concentración urinaria]]></kwd>
<kwd lng="es"><![CDATA[función tubular renal]]></kwd>
<kwd lng="es"><![CDATA[contracorriente]]></kwd>
<kwd lng="es"><![CDATA[docencia médica]]></kwd>
<kwd lng="es"><![CDATA[hormona antidiurética]]></kwd>
<kwd lng="es"><![CDATA[Asa de Henle]]></kwd>
<kwd lng="es"><![CDATA[urea]]></kwd>
<kwd lng="en"><![CDATA[Renal physiology]]></kwd>
<kwd lng="en"><![CDATA[Urine concentration]]></kwd>
<kwd lng="en"><![CDATA[Renal tubular function]]></kwd>
<kwd lng="en"><![CDATA[Countercurrent]]></kwd>
<kwd lng="en"><![CDATA[Medical teaching]]></kwd>
<kwd lng="en"><![CDATA[Antidiuretic hormone]]></kwd>
<kwd lng="en"><![CDATA[Loop of Henle]]></kwd>
<kwd lng="en"><![CDATA[Urea]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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