Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. May 15, 2021; 12(5): 658-672
Published online May 15, 2021. doi: 10.4239/wjd.v12.i5.658
Diabetes-related intestinal region-specific thickening of ganglionic basement membrane and regionally decreased matrix metalloproteinase 9 expression in myenteric ganglia
Nikolett Bódi, Diána Mezei, Payal Chakraborty, Zita Szalai, Bence Pál Barta, János Balázs, Zsolt Rázga, Edit Hermesz, Mária Bagyánszki
Nikolett Bódi, Diána Mezei, Zita Szalai, Bence Pál Barta, János Balázs, Mária Bagyánszki, Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Szeged 6726, Hungary
Payal Chakraborty, Edit Hermesz, Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged 6726, Hungary
Zsolt Rázga, Department of Pathology, Faculty of Medicine, University of Szeged, Szeged 6720, Hungary
Author contributions: Bódi N was responsible for the conceptualization, methodology, investigation, writing, funding acquisition; Mezei D, Barta BP, Chakraborty P were responsible for the investigation, formal analysis; Szalai Z was responsible for the visualization; Balázs J was responsible for the validation; Hermesz E was responsible for the validation, supervision; Rázga Z was responsible for the resources; Bagyánszki M was responsible for the visualization, writing-review and editing, supervision.
Supported by European Union and the Hungarian Government in the framework, No. EFOP-3.6.1-16-2016-00008; Hungarian NKFIH fund project, No. FK131789 (to Bódi N); János Bolyai Research Scholarship of the Hungarian Academy of Sciences (to Bódi N); and New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation Fund, No. ÚNKP-20-5 (to Bódi N).
Institutional review board statement: The study was reviewed and approved by Csaba Varga, the head of Dept. of Physiology, Anatomy and Neuroscience.
Institutional animal care and use committee statement: All animal experiments conformed to the internationally accepted principles for the care and use of laboratory animals.
Conflict-of-interest statement: I certify that there is no actual or potential conflict of interest in relation to this article.
Data sharing statement: Dataset available from the corresponding author at bmarcsi@bio.u-szeged.hu e-mail address.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Mária Bagyánszki, PhD, Associate Professor, Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, Szeged 6726, Hungary. bmarcsi@bio.u-szeged.hu
Received: February 2, 2021
Peer-review started: February 2, 2021
First decision: February 27, 2021
Revised: March 10, 2021
Accepted: April 21, 2021
Article in press: April 21, 2021
Published online: May 15, 2021
Processing time: 92 Days and 14.4 Hours
Abstract
BACKGROUND

The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane (BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9 (MMP9) and its tissue inhibitor (TIMP1) are essential in regulating extracellular matrix remodelling.

AIM

To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.

METHODS

Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex- and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Whole-mount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid (mRNA) level was measured by quantitative polymerase chain reaction.

RESULTS

Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the mRNA levels.

CONCLUSION

These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.

Keywords: Type 1 diabetes; Diabetic enteric neuropathy; Neuronal microenvironment; Basement membrane; Matrix metalloproteinase 9; Tissue inhibitor of metalloproteinase 1

Core Tip: These findings demonstrate an intestinal segment-specific thickening of basement membrane (BM) surrounding myenteric ganglia. In diabetes, ganglionic BM is thickened in the ileum, but not in the duodenum. Insulin prevented the diabetes-related BM thickening. The matrix degrading matrix metalloproteinase 9 (MMP9) expression was decreased in myenteric ganglia and its environment in the diabetic ileum, however, it remained unchanged in the duodenum. Similarly, MMP9/Tissue inhibitor of metalloproteinase 1 (TIMP1) ratio decreased only in ileal myenteric ganglia. Intestinal segment-specific induction of MMP9 and TIMP1 messenger ribonucleic acid levels was revealed. Regionally decreased MMP9 expression in ganglia correlates well with segment-specific thickening of ganglionic BM and these coincide with region-dependent enteric neuronal damage.