Alginate hydrogel as a potential alternative to hyaluronic acid as submucosal injection material.
BACKGROUND
Sodium alginate is currently used in medical products, including drugs and cosmetic materials. It can also be used as a submucosal injection material due to its excellent water retention ability. Alginate with a high water retention ability is called alginate hydrogel (AH). The aim of this study was to investigate the usefulness of AH as a submucosal injection material.


METHODS
To investigate the optimal viscosity of AH as a submucosal injection material, we observed the changes in submucosal height from the initial submucosal height in the stomachs of six miniature pigs for each injection material tested (0.3 % AH, 0.5 % hyaluronic acid, glycerol). All submucosal heights were compared serially over time (3, 5, 10, 20, and 30 min). Both immediate and 1-week delayed tissue reactions were investigated endoscopically in the same living pigs. Histological analyses were performed after the animals had been sacrificed.


RESULTS
In a preliminary study, we determined that 0.3 % sodium alginate mixed with BaCl2 (400 μl) was the optimal viscosity of AH as an injection material. Our comparison of submucosal height changes over time showed that there was a significant decrease in submucosal height just 3 min following the injection of hyaluronic acid and glycerol, but that following the injection of AH a significant decrease in submucosal height was observed only after 10 min (p < 0.05). The histological analyses revealed that there were mild capillary dilations with congestion and mild fibrotic changes with some lymphocytic infiltration at the AH injection site.


CONCLUSIONS
Alginate hydrogel demonstrated long-lasting maintenance of submucosal elevation, safety, and cost-effectiveness in a pig model, which makes it a potential alternative to hyaluronic acid.
Department of Medicine, Hallym University College of Medical School, Hallym University Sacred Heart Hospital, Anyang, Korea.
Ki Joo
KJ
Kang
Byung-Hoon
BH
Min
Jun Haeng
JH
Lee
Eun Ran
ER
Kim
Chang Ohk
CO
Sung
Joo Young
JY
Cho
Soo Won
SW
Seo
Jae J
JJ
Kim
D000464:Alginates / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D005753:Gastric Mucosa / Q000187:drug effects* / Q000473:pathology; D005773:Gastroscopy; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D020100:Hydrogels / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D007267:Injections; D015233:Models, Statistical; D013552:Swine; D013997:Time Factors; D014741:Video Recording; D055682:Viscoelastic Substances / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D014783:Viscosity
D000464:Alginates; D006603:Hexuronic Acids; D020100:Hydrogels; D055682:Viscoelastic Substances; D020723:Glucuronic Acid; D006820:Hyaluronic Acid