Malignant disease in peptic ulcer surgery patients after long term follow-up: A cohort study of 1992 patients

Vagus innervation in the gastrointestinal tumor: Current understanding and challenges

The vagus nerve (VN) is the main parasympathetic nerve of the autonomic nervous system. It is widely distributed in the gastrointestinal tract and maintains gastrointestinal homeostasis with the sympathetic nerve under physiological conditions. The VN communicates with various components of the tumor microenvironment to positively and dynamically affect the progression of gastrointestinal tumors (GITs). The intervention in vagus innervation delays GIT progression. Developments in adeno-associated virus vectors, nanotechnology, and in vivo neurobiological techniques have enabled the creation of precisely regulated "tumor neurotherapies". Furthermore, the combination of neurobiological techniques and single cell sequencing may reveal more insights into VN and GIT. The present review aimed to summarize the mechanisms of communication between the VN and the gastrointestinal TME and to explore the potential and challenges of VN-based tumor neurotherapy in GITs.

Neurobiology of cancer: Definition, historical overview, and clinical implications

Studies published in the last two decades have clearly demonstrated that the nervous system plays a significant role in carcinogenesis, the progression of cancer, and the development of metastases. These studies, combining oncological and neuroscientific approaches, created the basis for the emergence of a new field in oncology research, the so‐called “neurobiology of cancer.” The concept of the neurobiology of cancer is based on several facts: (a) psychosocial factors influence the incidence and progression of cancer diseases; (b) the nervous system affects DNA mutations and oncogene‐related signaling; (c) the nervous system modulates tumor‐related immune responses; (d) tumor tissues are innervated; (e) neurotransmitters released from nerves innervating tumor tissues affect tumor growth and metastasis; (f) alterations or modulation of nervous system activity affects the incidence and progression of cancers; (g) tumor tissue affects the nervous system. The aim of this review is to characterize the pillars that create the basis of cancer neurobiology, to describe recent research advances of the nervous system's role in cancer diseases, and to depict potential clinical implications for oncology.

Role of the brain-gut axis in gastrointestinal cancer

Several studies have largely focused on the significant role of the nervous and immune systems in the process of tumorigenesis, including tumor growth, proliferation, apoptosis, and metastasis. The brain-gut-axis is a new paradigm in neuroscience, which describes the biochemical signaling between the gastrointestinal (GI) tract and the central nervous system. This axis may play a critical role in the tumorigenesis and development of GI cancers. Mechanistically, the bidirectional signal transmission of the brain-gut-axis is complex and remains to be elucidated. In this article, we review the current findings concerning the relationship between the brain-gut axis and GI cancer cells, focusing on the significant role of the brain-gut axis in the processes of tumor proliferation, invasion, apoptosis, autophagy, and metastasis. It appears that the brain might modulate GI cancer by two pathways: the anatomical nerve pathway and the neuroendocrine route. The simulation and inactivation of the central nervous, sympathetic, and parasympathetic nervous systems, or changes in the innervation of the GI tract might contribute to a higher incidence of GI cancers. In addition, neurotransmitters and neurotrophic factors can produce stimulatory or inhibitory effects in the progression of GI cancers. Insights into these mechanisms may lead to the discovery of potential prognostic and therapeutic targets.

Alterations of the gastric stump and not resected stomach mucosa after truncal vagotomy in rats

PURPOSE

To evaluate morphological changes of the gastric stump and not resected stomach mucosa after the completion of truncal vagotomy.

METHODS

Eighty male Wistar rats were divided into four groups: CT, TV, RY and RYTV. In CT group, abdominal viscera were manipulated and the abdominal cavity was closed, in TV vagal trunks were isolated and sectioned, in RY a partial Roux-en-Y gastrectomy was performed and in RYTV the vagal trunks were sectioned and a partial Roux-en-Y gastrectomy was performed. At the 54th week after surgery, the rats were euthanized. The findings were submitted to histological analyses.

RESULTS

None macroscopic or histological alterations in groups TV and CT was observed. Specimens from RY and RYTV groups did not show alterations in the gastric stump mucosa. At the jejunal side of the gastroenterostomy we found shallow ulcerative lesions always single, well-defined and with variable diameter 3 to 6 mm, six times in the RY group and none in the RYTV group (RY>RYTV, p=0.008). Neoplastic or preneoplastic lesions were not diagnosed in all groups.

CONCLUSION

Truncal vagotomy is a safe and non-carcinogenic method in not resected and partially resected stomach.

Helicobacter pylori-induced damage to the gastric mucosa is not modulated by previous vagotomy or medical treatment of peptic ulcer disease: a comparative study of vagotomized patients, medically treated peptic ulcer patients and community control subjects

BACKGROUND

An increase in the prevalence of precancerous lesions and atrophic changes in the gastric mucosa has been reported as long-term consequences of vagotomy-induced acid suppression. This study was designed to describe the long-term changes in the gastric mucosa caused by vagotomy and Helicobacter pylori infection.

METHODS

Seventy-nine patients with vagotomized peptic ulcers, 70 nonoperated patients with peptic ulcers, and 85 matched community control subjects were randomly selected to participate in an upper endoscopic study. Biopsy specimens were taken from predestined locations of the gastric mucosa.

RESULTS

Mean follow-up time for the vagotomized patients was 17.3 (range, 6-28) years and 12.7 (range, 10-17) years for the medically treated peptic ulcer patients. In H. pylori-positive subjects, severe atrophic changes in the distal gastric mucosa (prepylorus and angulus) was found in 30% (95% confidence interval (CI), 19-43) of the vagotomized patients and in 43% (95% CI, 29-58) of medically treated patients with peptic ulcers, and in 32% (95% CI, 20-46) of the community control subjects. Severe intestinal metaplasia was not found more frequently in vagotomized peptic ulcer patients compared with medically treated patients with peptic ulcers (p = 0.5). The histological picture of the age-matched community control subjects did not differ significantly from the patients with peptic ulcers when corrected for presence of H. pylori infection.

CONCLUSIONS

This study lends no support to theories of increased premalignant changes in the gastric mucosa of vagotomized patients. H. pylori infection rather than long-term acid suppression seems to be the explanation of the gastric mucosal changes seen after vagotomy.