New Light on H. Pylori Infection and Stomach Cancer Prevention

About half of the world’s population is currently infected with a spiral-shaped bacterium known as Helicobacter pylori (H. pylori). Commonly found in the stomach, this particular bacterium causes inflammation in the stomach wall and can predispose people to ulcers, gastritis, and gastric cancer. The microbe plays a key role in the development of stomach tumors and various gastrointestinal diseases.

Due to the rapid emergence of antibiotic resistance to conventional drug therapy for H. pylori infection, medical scientists have been seeking alternative treatments. Early clinical studies of the light-sensitizing approach known as photodynamic therapy (PDT) demonstrated significant eradication of H. pylori infection in the stomach. Recent cell culture studies out of Spain and China found a near 100% eradication of H. pylori following PDT, as reported last year in the European Journal of Medicinal Chemistry.

Intriguingly, Dr. Michael Hamblin and his colleagues at Harvard Medical School (USA) have demonstrated that H. pylori naturally accumulates a number of light-sensitizing compounds (porphyrins). This accumulation renders the bacterial cells exceptionally sensitive to light-triggered inactivation even without requiring the addition of a photosensitizing agent or drug.

Researchers in Lisboa, Portugal, recently noted that treatment failure is one of the major problems associated with H. pylori infection and is mainly associated with the bacterium’s ability to develop resistance to the antibiotics. In order to counteract this situation, the authors point to various therapeutic alternatives beyond antibiotics, including vaccines, probiotics, and photodynamic inactivation (the use of PDT to kill disease-casuing bacteria). They also note that various studies have demonstrated that many herbal or phytomedicine products have an anti-H. pylori activity and gastroprotective action, as reported in the May 2014 issue of the World Journal of Gastroenterology.

As noted above, a major incentive for developing PDT as a treatment to infectious diseases is the overuse of antibiotics and antibiotic resistance, i.e., various species of bacteria developing resistance to one or more varieties of antibiotics. It is well established that H. pylori can become resistant to antibiotics such as metronidazole, clarithromycin, and levofloxacin, among others, as well as multiple antibiotics. Overall, the problem of antibiotic resistance has made H. pylori and other common bacterial infections an increasingly daunting treatment challenge that is forcing many physicians and medical policymakers to look for reasonable alternatives to these medications.

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Vale FF, Oleastro M. Overview of the phytomedicine approaches against Helicobacter pylori. World J Gastroenterol. 2014 May 21;20(19):5594-5609.

Calvino-Fernández M, García-Fresnadillo D, Benito-Martínez S, McNicholl AG, Calvet X, Gisbert JP, Parra-Cid T. Helicobacter pylori inactivation and virulence gene damage using a supported sensitiser for photodynamic therapy. Eur J Med Chem. 2013 Oct;68:284-90.

Giuliani F. Photodynamic therapy as a novel antimicrobial strategy against biofilm-based nosocomial infections: study protocols. Methods Mol Biol. 2014;1147:287-98.

Yin R, Dai T, Avci P, Jorge AE, de Melo WC, Vecchio D, Huang YY, Gupta A, Hamblin MR. Light based anti-infectives: ultraviolet C irradiation, photodynamic therapy, blue light, and beyond. Curr Opin Pharmacol. 2013 Oct;13(5):731-62.


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