Primecuts – This Week In The Journals

April 29, 2013

By Anish Parikh, MD

Faculty Peer Reviewed

This week, the nation continues to heal in the aftermath of the tragic bombings that took place during the Boston Marathon on April 15. While one of the two brothers behind the attacks was killed in a dramatic shootout with Boston police last week, the other escaped and was not found until a day-long search that effectively shut down the entire city was completed. As interrogations have begun, new developments in the case are already emerging. It has just been announced that the brothers were in the process of planning more attacks in the immediate future, with Times Square here in New York City being their next intended target. Thankfully, these attacks have been prevented and we can now start to focus on returning to normalcy.

While the mainstream media has been focusing on the fight against terrorism, recent medical literature has suggested a surge of interest in studying the effects of normal body flora in the pathogenesis of disease–oncological, cardiovascular, and gastrointestinal. This week the New England Journal of Medicine published a study that suggested a link between the metabolism of certain dietary elements by intestinal microbes and increased risk for cardiovascular (CV) disease. The authors demonstrated that gut microbes routinely metabolize phosphatidylcholine from the diet (mainly in eggs, pork, and beef) into trimethylamine-N-oxide (TMAO) by having patients without any medical history ingest two hard-boiled eggs and radio-labeled tracer, measuring elevated TMAO levels, then documenting suppression of these levels after a 7-day course of metronidazole and ciprofloxacin. TMAO levels rose after discontinuation of the antibiotics. They then followed a different set of 4000 patients, all with known CV disease, for adverse CV outcomes during a 3-year follow-up period and found higher TMAO levels to be linked to increased risk of death, myocardial infarction, and stroke. Although it is already widely acknowledged that a healthy diet is essential for CV health, this study suggests a possible mechanism for this relationship. Still, the clinical relevance of this study can be questioned. After all, it does not seem plausible to prescribe gut microbiome-altering antibiotics for every at-risk patient or for known cardiac patients. In addition, we already counsel these patients on following the “heart healthy diet.”

Also in the realm of cardiology, the Lancet recently published an article detailing the 5-year follow-up results for the Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) trial. You may recall this study as the one that showed that CABG resulted in fewer major CV events after 1 year compared to PCI with drug-eluting stents in patients with triple-vessel or left- main coronary disease. A follow-up study at 3 years confirmed the initial study results, and this study serves in the same capacity at 5 years of follow-up. Thus, it appears that we should continue our current standard of care, which is to recommend CABG to patients with triple-vessel or left-main coronary disease.

In other news, the World Health Organization is now reporting on an outbreak of the newest strain of avian influenza, the H7N9 virus. Since the first case was reported in February 2013, there have been 109 laboratory-confirmed human cases and 22 deaths, thus far all in either China or Taiwan. This outbreak has been gaining international attention because it is believed to be more virulent and lethal than recent strains, including the H5N1 bird flu outbreak that claimed hundreds of victims from 2004 to 2007. Indeed, the Lancet just published a fast-track article characterizing the genome of this virus, which has been shown to cause severe pneumonia and multi-organ failure.

Another article of interest from the recent literature offers a glimpse into the upcoming 5th edition of the Diagnostics and Statistical Manual of Mental Disorders. DSM-V will be published and widely available in May 2013, and will be the first revision of the DSM in over 20 years. According to the authors of this article, several “global” changes have been implemented throughout the manual in order to make the process of psychiatric diagnosis more resemble the process of medical diagnosis. For instance, diagnostic criteria will in general be more quantitative than in the DSM-IV. Moreover, the tradition of multi-axial diagnosis, in which clinicians listed psychiatric, medical, and social diagnoses as well as a number rating of functionality, will be abandoned for a simpler model of disease classification. These changes are, of course, in addition to very specific changes pertaining to the diagnosis and classification of individual conditions.

Other articles of note from the recent medical literature include the following:

Manenschijn L, Schaap L, van Schoor NM, et al. High long-term cortisol levels, measured in scalp hair, are associated with a history of cardiovascular disease. J Clin Endo Metab. 2013 Apr 17; 2012-3663. http://jcem.endojournals.org/content/early/2013/04/17/jc.2012-3663.abstract?rss=1

This article shows that long-term exposure to cortisol, which can be measured in scalp hair, is associated with an increased risk of CV disease as well as type 2 diabetes mellitus.

Cosentino CC, Skrypnyk NI, Brilli LL, et al. Histone deacetylase inhibitor enhances recovery after AKI. J Am S Nephr 2013; doi: 10.1681/ASN .2012111055. http://jasn.asnjournals.org/content/early/2013/04/24/ASN.2012111055.abstract

This article shows that histone deacetylase inhibitors have been used effectively in both zebrafish and mice models to increase proliferation of renal tubular epithelial cells and thereby enhance recovery from AKI.

Geske JB, McKie PM, Ommen SR, Sorajja P. B-type natriuretic peptide and survival in hypertrophic cardiomyopathy. J Am Coll Card 2013; doi:10.1016/j.jacc.2013.04.004.  http://content.onlinejacc.org/article.aspx?articleid=1681781

This article reports that BNP, which is released in response to myocardial stretch, neurohormonal activation, and wall tension, reflects hemodynamic changes in the heart and is an independent predictor or morbidity and mortality in patients with hypertrophic cardiomyopathy.

Dr. Anish Parikh is a 1st year resident at NYU Langone Medical Center

Peer Reviewed by Michael Tanner, MD, associate editor, Clinical Correlations

Image Courtesy of Wikimedia Commons

References

Wilson Tang WH, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. 2013; 368:1575-84.  http://www.nejm.org/doi/full/10.1056/NEJMoa1109400?query=featured_home

Mohr FW, Morice M-C, Kappetein AP, et al. Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomized, clinical SYNTAX trial. Lancet. 2013 February 23;381(9867):629-38. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60141-5/fulltext

Chen Y, Liang W, Yang S, et al. Human infections with the emerging avian influenza A H7N9 virus from wet market poultry: clinical analysis and characterization of viral genome. Lancet. 2013 Apr 25; doi:10.1016/S0140-6736(13)60903-4. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60903-4/fulltext

Kupfer DJ, Kuhl EA, Regier DA. DSM-V–the future arrived. JAMA. 2013;309(16):1691-2. http://jama.jamanetwork.com/article.aspx?articleid=1656312

 

 

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