Covid-19, Coronavirus, SARS-CoV-2 and the small bowel

Although SARS-CoV-2 may primarily enter the cells of the lungs, the small bowel may also be an important entry or interaction site…

ABSTRACT – Although SARS-CoV-2 may primarily enter the cells of the lungs, the small bowel may also be an important entry or interaction site, as the enterocytes are rich in angiotensin converting enzyme (ACE)-2 receptors. The initial gastro- intestinal symptoms that appear early during the course of Covid-19 support this hypothesis. Furthermore, SARS- CoV virions are preferentially released apically and not at the basement of the airway cells. Thus, in the setting of a productive infection of conducting airway epithelia, the apically released SARS-CoV may be removed by mucocil- iary clearance and gain access to the GI tract via a luminal exposure. In addition, post-mortem studies of mice infected by SARS-CoV have demonstrated diffuse damage to the GI tract, with the small bowel showing signs of enterocyte desquamation, edema, small vessel dilation and lympho- cyte infiltration, as well as mesenteric nodes with severe hemorrhage and necrosis. Finally, the small bowel is rich in furin, a serine protease which can separate the S-spike of the coronavirus into two “pinchers” (S1 and 2).The sep- aration of the S-spike into S1 and S2 is essential for the attachment of the virion to both the ACE receptor and the cell membrane. In this special review, we describe the inter- action of SARS-CoV-2 with the cell and enterocyte and its potential clinical implications.

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Prevalence of small intestine bacterial overgrowth in patients with gastrointestinal symptoms

Carolina Piedade MARTINS, Caio Henrique Amorim CHAVES, Maurício Gustavo Bravim de CASTRO, Isabel Cristina GOMES3 and Maria do Carmo Friche PASSOS

ABSTRACT – Background – Small intestine bacterial overgrowth is a heterogeneous syndrome characterized by an increase in the number and/or the presence of atypical microbiota in the small intestine. The symptoms of small intestine bacterial overgrowth are unspecific, encompassing abdominal pain/distension, diarrhea and flatulence. Due to the increased cost and complexity for carrying out the jejunal aspirate, the gold standard for diagnosis of the syndrome, routinely the hydrogen (H2) breath test has been used, utilizing glucose or lactulose as substrate, which is able to determine, in the exhaled air, the H2 concentration produced from the intestinal bacterial metabolism. However, due to a number of individuals presenting a methanogenic microbiota, which does not produce H2, the testing on devices capable of detecting, concurrently, the concentration of exhaled H2 and methane (CH4) is justified. Objective – This study aimed to determine the prevalence of small intestine bacterial overgrowth in patients with digestive symptoms, through a comparative analysis of breath tests of H2 or H2 and CH4 associated, using glucose as substrate. Methods – A total of 200 patients of both sexes without age limitation were evaluated, being directed to a Breath Test Laboratory for performing the H2 test (100 patients) and of exhaled H2 and CH4 (100 patients) due to gastrointestinal complaints, most of them patients with gastrointestinal functional disorders. Results – The results indicated a significant prevalence of small intestine bacterial overgrowth in the H2 test and in the test of exhaled H2 and CH4 (56% and 64% respectively) in patients with gastrointestinal symptoms, and higher prevalence in females. It found further that methane gas was alone responsible for positivity in 18% of patients. Conclusion – The data found in this study is consistent with the findings of the current literature and underscores the need for using devices capable of capturing the two gases (exhaled H2 and CH4) to improve the sensitivity and hence the accuracy of small intestine bacterial overgrowth diagnosis in daily medical practice.

HEADINGS – Bacterial growth. Small intestine. Breath tests. Hydrogen. Methane.

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Crédits:
Maurício Gustavo Bravim de Castro – CRM MG: 29.496
Cirurgião do aparelho digestivo do Hospital Lifecenter (2002 – 2017)
Formado em medicina pela UFMG (1995)
Residência de cirurgia geral e do trauma pelo Hospital Felício Rocho e Hospital João XXIII da Fundação Hospitalar da Estado de Minas Gerais (1998)
Membro titular do Colégio Brasileiro de Cirurgia Digestiva (CBCD)
Membro efetivo da Federação Brasileira de Gastroenterologia (FBG)
Membro do conselho consultivo da Sociedade Brasileira de Motilidade Digestiva e Neurogastroenterologia (SBMDN)
Diretor técnico do CEMAD – Centro de Motilidade do Aparelho Digestivo – Belo Horizonte

Long-term tolerability of the combination naproxen and esomeprazole magnesium in fixed dose

Gastrointestinal risk factors have been extensively studied. During the last CNS Latin American Forum on pain, Dr. Angel Lanas explained that in the last 10 years there has been an important reduction of complications in the upper gastrointestinal tract, although complications in the lower gastrointestinal tract have increased.

In view of this situation, Lanas considered that it is essential to define an ideal strategy to achieve the protection of both digestive tracts. At the same time, special attention should be paid to those patients who may develop an ulcer.

In line with the above, it is pertinent to mention a study published in Current Medical Research and Opinion. The objective of this study was to assess the long-term tolerability of the combination of enteric-coated naproxen at a dose of 500 mg and immediate-release esomeprazole magnesium at a fixed dose of 20 mg (FDC) in patients at risk of NSAID-related gastric ulcers.

This was an open-label, multicenter, phase III study involving Helicobacter pylori-negative patients aged ≥50 50 years or 18 to 49 years with a history of uncomplicated ulcer in the past five years. Patients in turn had osteoarthritis, rheumatoid arthritis, or other disorder requiring daily NSAIDs for ≥12 months, received naproxen/esomeprazole twice daily for 12 months.

The primary endpoints consisted of adverse effects, vital signs, physical examination, and laboratory tests. Subgroup analyses included use of low-dose acetylsalicylic acid (LDA) and age.

Adverse effects of NSAID-related gastric ulcer and predefined cardiovascular adverse effects were analyzed.
Of 239 treated patients (tolerability population), 135 completed ≥ 348 days of treatment (those who completed 12 months). The frequency of adverse effects was approximately 70%; dyspepsia, constipation, upper respiratory infections, nausea, dorsalgia, and contusion were most frequent (≥ 5 patients, in each population).

Treatment-related adverse effects occurred in 28.0% and 23.7% of patients in the tolerability and 12-month completion populations, respectively; 18.8% of patients discontinued medication as a result of adverse effects (tolerability population).
There were few serious adverse effects and no deaths. In the tolerability population, the frequency of adverse effects was 71.4% and 76.9% in patients <65 years of age (n = 161) and ≥65 years (n = 78), respectively, and 67.6% and 75.8% in LDA users (n = 74) and nonusers (n = 165), respectively.

High digestive and cardiovascular adverse effects were observed in 18.8% and 6.3% of patients, respectively, in the tolerability population and 16.3% and 5.2%, respectively, in those concluding 12 months of treatment. Dyspepsia and hypertension were more frequent. Additional assessments showed no unexpected findings.

Based on these endpoints, long-term treatment with FDX naproxen/esomeprazole was not associated with any new tolerability issues, including predefined UGI and cardiovascular adverse effects, in patients requiring NSAID therapy who were at risk for upper gastrointestinal complications.

Source: Medcenter Medical News

Metabolic fingerprinting of tumors useful in bowel cancer patients

It is possible to assess how advanced a bowel cancer is by analyzing its metabolic fingerprint, according to new research.
Bowel cancer is the third most common type of cancer worldwide and more than 1 million new cases are diagnosed each year. Pinpointing the exact stage a tumor has reached is critical in determining which treatments to offer.

When determining the metabolic fingerprint, a blood, urine or tissue sample is analyzed for the concentrations of many different metabolites, which are the products of chemical reactions in the body’s cells. This mixture of metabolites alters as cancer occurs and grows. The researchers who collaborated on the new study, from Imperial College London, point out that clinicians could use metabolic fingerprinting in conjunction with available imaging techniques to perform the most accurate analysis of a tumor possible. This research is published in the journal Annals of Surgery. Physicians currently use a combination of CT, MRI, and ultrasound to assess how advanced a tumor is, but because these tests rely on visual estimates of the size and location of a tumor, they are not always as sensitive or specific. Previous studies have shown that these techniques regularly indicate that a tumor is more advanced or less advanced than it actually is.

Dr. Reza Mirnezami, lead author of the study from the Department of Surgery and Cancer at Imperial College London, said, “Investigating the stage of a tumor is critical in planning a patient’s treatment. It is becoming increasingly common that before we carry out surgical resection of a tumor we give treatments to try to shrink its mass, but the kinds of treatments we offer depend on our assessment of how advanced the tumor is. The more precise we can be, the better the patient’s chances of survival.

“Our research indicates that using metabolic fingerprinting techniques in addition to assessment with imaging studies could give us the clearest possible picture of how the cancer is progressing.”

For the new study, the researchers analyzed the metabolic fingerprint of 44 intestinal tumor tissue samples, provided by patients seen at Imperial College Healthcare NHS Trust, using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR). Their results for determining the stage the cancer had reached were as accurate as existing radiological methods.

Lord Ara Darzi, Paul Hamlyn Chair of Surgery at Imperial College London, and lead author of the study, said, “We know that even with the impressive scanning technology we have available so far, it is not always possible to correctly verify the local stage of a cancer. Our study seems to indicate that if used in conjunction with medical imaging, metabolic fingerprinting could allow us to obtain more accurate information. This could give us more certainty about the correct treatment to administer to patients, and spare some of them from invasive treatment when they do not need it.”

The research also indicates that tumors adopt unique metabolic properties as they progress further, opening up new avenues for treatment. The researchers hope that it will ultimately be possible to identify different metabolic targets when the cancer is at different stages, in order to render the tumor impossible or slow it down. Professor Jeremy Nicholson, Head of the Department of Surgery and Cancer at Imperial College London and corresponding author of the study, said, “This study represents one part of our program to develop advanced technology to improve patient tolerability in the surgical setting and shows the enormous potential of using metabolic models to stratify patients and optimize treatment.”

Source: Medical News Today