title: Spontaneous and Evoked Contractility of Human Intestinal Lymphatic Vessels.
abstract: Mesenteric lymphatic vessels (MLVs) from various animal species have been intensively studied. We aimed to establish the viability and basic contractile characteristics of human MLVs maintained in vitro and to determine the reactivity of MLVs with norepinephrine (NE) and substance P (SP) and to compare with the thoracic duct (TD).
  
  
  
  Isolated human lymphatic vessels were mounted on a wire myograph under isometric conditions and tension was recorded. The diameter-tension characteristics for MLVs were generated by stretching the vessels and stimulating with a 125 mM K+solution containing 10 μM NE. The diameter-tension data generated for MLVs from two separate surgical patient groups were found to be similar: maximum active tension for MLVs occurred when the passive stretch corresponded to a transmural pressure of 22 mmHg. Subsequent experiments on human MLVs were performed by normalization with 22 mmHg as the equivalent target pressure. The majority of MLVs were responders (spontaneous activity and/or reactivity with 10 μM NE or 125 mM K+solution). Nonresponders (16% of vessel segments) had significantly smaller inner diameters. MLVs responded consistently to NE (1 nM-10 μM) but the responsiveness of MLVs and TD to SP (0.1 nM-10 μM) was poor: TD reacted only with 10 μM SP, whereas MLVs were sensitive to nanomolar concentrations and the contractile response declined with higher concentrations.
  
  
  
  Under in vitro isometric conditions, human MLVs generate maximum tension when stretched to a passive level corresponding to 22 mmHg, and the majority of MLVs are responsive when normalized to this pressure. MLVs respond to NE and SP though NE produces a more consistent response in the concentration range tested.
authors.affiliation: 1 Department of Biomedicine, Aarhus University , Aarhus, Denmark .|2 Department of Cardiothoracic Surgery, Aarhus University Hospital , Aarhus, Denmark .
authors.forename: Niklas
authors.initials: N
authors.lastname: Telinius
authors.affiliation: 1 Department of Biomedicine, Aarhus University , Aarhus, Denmark .
authors.forename: Jens
authors.initials: J
authors.lastname: Majgaard
authors.affiliation: 1 Department of Biomedicine, Aarhus University , Aarhus, Denmark .|2 Department of Cardiothoracic Surgery, Aarhus University Hospital , Aarhus, Denmark .
authors.forename: Sheyanth
authors.initials: S
authors.lastname: Mohanakumar
authors.affiliation: 3 Department of Surgery, Viborg Hospital , Viborg, Denmark .
authors.forename: Einar
authors.initials: E
authors.lastname: Pahle
authors.affiliation: 3 Department of Surgery, Viborg Hospital , Viborg, Denmark .
authors.forename: Jørn
authors.initials: J
authors.lastname: Nielsen
authors.affiliation: 2 Department of Cardiothoracic Surgery, Aarhus University Hospital , Aarhus, Denmark .
authors.forename: Vibeke
authors.initials: V
authors.lastname: Hjortdal
authors.affiliation: 1 Department of Biomedicine, Aarhus University , Aarhus, Denmark .
authors.forename: Christian
authors.initials: C
authors.lastname: Aalkjær
authors.affiliation: 1 Department of Biomedicine, Aarhus University , Aarhus, Denmark .|2 Department of Cardiothoracic Surgery, Aarhus University Hospital , Aarhus, Denmark .
authors.forename: Donna Briggs
authors.initials: DB
authors.lastname: Boedtkjer
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007422:Intestines / Q000187:drug effects / Q000502:physiology*; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D042601:Lymphatic Vessels / Q000187:drug effects / Q000502:physiology*; D008643:Mesentery / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D055815:Young Adult
chemical_list: D014662:Vasoconstrictor Agents; D013373:Substance P; D009638:Norepinephrine
keywords: human lymphatic vessels; in vitro; length–tension; lymphatic contractility