Barbara S. Rocha
PostDoctoral Fellow
Group at CNC

Bachelor degree in Pharmaceutical Sciences (2001-2007) at University of Coimbra. PhD in Pharmacy (2008-2012) at University of Coimbra in collaboration with the University of La República (Montevideo, Uruguay) and the Karolinska Institute (Stockholm, Sweden). Postdoctoral researcher at Center for Neuroscience and Cell Biology (Coimbra, Portugal) (2013-present).




Area of Research: 

My scientific activity focuses on the non-enzymatic pathway for nitric oxide (NO) production in the gut: the nitrate-nitrite-NO pathway. The field of NO biology has gained renewed interest in the past few years as nitrate, from dietary sources (green leaf vegetables), was shown to be reduced to nitrite by the oral microbiome. Nitrite, once mixed with saliva, is chemically reduced to NO in the stomach. In the gut, nitrite-derived NO has been shown to increase mucosal blood flow, mucus production and to eradicate endogenous pathogens. Our group have recently contributed to this field by showing that nitrite-derived NO triggers a complex network of chemical reactions in the human stomach, including the generation of radicals able to induce post-translational modifications. Accordingly, we have shown that pepsin (a gastric protease) is nitrated and inactivated in vivo. The physiological impact of pepsin nitration was traduced by a decreased proteolytic activity thereby improving the prognosis of acute gastric ulceration.
Moreover, we are now also interested on how nitrite-derived NO modulates gut commensal microbiome. Preliminary studies are now suggesting that that dietary nitrate reshapes gut microbiome under dysbiosis (altered gut flora induced by antibiotic consumption), which, in turn, is associated with the preservation of gastric tight junctions architecture and enhanced mucus secretion. Locally, the constitutive inflammatory status of the gastric mucosa is up-regulated under dysbiosis, but nitrate supplementation (likely through NO production), reverts this scenario. We are now convinced that the modulation of host-microbiome interactions by the nitrate-nitrite-NO pathway may open new avenues on the management of not only functional bowel diseases but also of neuropsychological disorders that fall in the spectrum of the gut-brain axis.

Research Summary: 
Selected Publications: 

1. Ethyl nitrite is produced in the human stomach from dietary nitrate and ethanol, releasing nitric oxide at physiological pH: potential impact on gastric motility. Rocha BS, Gago B, Barbosa RM, Cavaleiro C, Laranjinha J. Free Radic Biol Med. 2015; 82:160-6. IF: 5.7

2. Pepsin is nitrated in the rat stomach, acquiring antiulcerogenic activity: a novel interaction between dietary nitrate and gut proteins. Rocha BS, Gago B, Barbosa RM, Lundberg JO, Mann GE, Radi R, Laranjinha J.
Free Radic Biol Med. 2013; 58:26-34. IF: 5.7

3. Intragastric nitration by dietary nitrite: implications for modulation of protein and lipid signaling. Rocha BS, Gago B, Barbosa RM, Lundberg JO, Radi R, Laranjinha J. Free Radic Biol Med. 2012; 52(3):693-8. IF: 5.7

4. Diffusion of nitric oxide through the gastric wall upon reduction of nitrite by red wine: physiological impact. Rocha BS, Gago B, Barbosa RM, Laranjinha J. Nitric Oxide. 2010; 22(3):235-41. IF: 3.5

5. Dietary polyphenols generate nitric oxide from nitrite in the stomach and induce smooth muscle relaxation. Rocha BS, Gago B, Barbosa RM, Laranjinha J. Toxicology. 2009; 265(1-2):41-8. IF: 3.6

Other information: 

Researcher ID: M-7768-2014

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