Towards nitric oxide based diagnostics: call to action

Urinary nitric oxide metabolites in children with celiac disease after long-term consumption of oats-containing gluten-free diet

OBJECTIVE

Oats are accepted in the gluten-free diet (GFD) for children with celiac disease (CD). Some reports have indicated, however, that not all celiac patients tolerate oats. We have previously shown that some children still have high levels of urinary nitric oxide (NO) metabolites as markers of intestinal inflammation after 1 year on GFD with oats. In this study, we measured urinary NO metabolites in CD children who had been consuming oats-containing GFD for an extended, 2-6-year period, also taking into consideration ordinary consumption of nitrite/nitrate-rich foods close to the urine sampling.

MATERIALS AND METHODS

Morning urinary nitrite/nitrate concentrations were measured in 188 pediatric CD patients. A questionnaire was used to elucidate factors possibly affecting the urinary levels, for example, dietary factors, asthma, or urinary tract infection.

RESULTS

Oats were consumed by 89.4% of the patients for a median time of 3 years. The median nitrite/nitrate level was 980 μM. The majority (70.2%) who consumed oats had low levels of urinary nitrite/nitrate, that is, <1400 μM, while 29.8% demonstrated high levels, that is, >1400 μM. Nitrite/nitrate-rich foods did not significantly influence the urinary concentrations.

CONCLUSION

The urinary levels of NO metabolites revealed two subpopulations, one with high and one with low levels. The high levels could be possibly due to poor adherence to the GFD, sensitivity to oats, or some unknown factor(s). Nitrate-rich foods, asthma, or urinary tract infection did not affect the result. The elevated levels of NO metabolites could indicate mucosal inflammation and pinpoint the need of careful follow-up of children on oats-containing GFD.

A Biomarker-Based Approach to Infectious Disease in the Pediatric Emergency Department

In modern pediatric emergency medicine, biomarker-based assays that enable quick bedside diagnostics and subsequent disease management can be valuable. There is a growing need for novel, disease-specific biomarkers that can improve the outcome of pediatric infectious diseases commonly encountered in the emergency department (ED). Viral respiratory infections, central nervous system infections, sepsis, and septic shock are acute disease states frequently encountered in the ED. In this review, we describe a host of novel biomarkers, including a diverse set of cytokines, chemokines, and nitric oxide–based metabolites. Based on disease pathophysiology, a rationale is provided for a molecular- or biomarker-based approach in the ED. Throughout this review, emphasis is placed on diagnostic rapidity because this relates directly to timeliness and quality of care in a busy ED. Once the biomarkers become more clinically available, in a rapid ED setting as bedside point-of-care assays, quality of care will be enhanced, not only by means of diagnostics but also in prognosticating severity of illness.

Nitric oxide and its metabolites in the critical phase of illness: rapid biomarkers in the making

The potential of nitric oxide (NO) as a rapid assay biomarker, one that could provide a quantum leap in acute care, remains largely untapped. NO plays a crucial role as bronchodilator, vasodilator and inflammatory mediator. The main objective of this review is to demonstrate how NO is a molecule of heavy interest in various acute disease states along the emergency department and critical care spectrum: respiratory infections, central nervous system infections, asthma, acute kidney injury, sepsis, septic shock, and myocardial ischemia, to name just a few. We discuss how NO and its oxidative metabolites, nitrite and nitrate, are readily detectable in several body compartments and fluids, and as such they are associated with many of the pathophysiological processes mentioned above. With methods such as high performance liquid chromatography and chemiluminescence these entities are relatively easy and inexpensive to analyze. Emphasis is placed on diagnostic rapidity, as this relates directly to quality of care in acute care situations. Further, a rationale is provided for more bench, translational and clinical research in the field of NO biomarkers for such settings. Developing standard protocols for the aforementioned disease states, centered on concentrations of NO and its metabolites, can prove to revolutionize diagnostics and prognostication along a spectrum of clinical care. We present a strong case for developing these biomarkers more as point-of-care assays with potential of color gradient test strips for rapid screening of disease entities in acute care and beyond. This will be relevant to global health.

Nitric oxide and geriatrics: Implications in diagnostics and treatment of the elderly

The nation's aging population is growing rapidly. By 2030, the number of adults age 65 and older will nearly double to 70 million. Americans are living longer and older adults can now live for many years with multiple chronic illnesses but with a substantial cost to health care. Twenty percent of the Medicare population has at least five chronic conditions i.e., hypertension, diabetes, arthritis, etc. Studies in experimental models and even humans reveal that constitutive production of nitric oxide (NO) is reduced with aging and this circumstance may be relevant to a number of diseases that plague the aging population. NO is a multifunctional signaling molecule, intricately involved with maintaining a host of physiological processes including, but not limited to, host defense, neuronal communication and the regulation of vascular tone. NO is one of the most important signaling molecules in our body, and loss of NO function is one of the earliest indicators or markers of disease. Clinical studies provide evidence that insufficient NO production is associated with all major cardiovascular risk factors, such as hyperlipidemia, diabetes, hypertension, smoking and severity of atherosclerosis, and also has a profound predictive value for disease progression including cardiovascular and Alzheimers disease. Thirty plus years after its discovery and over 13 years since a Nobel Prize was awarded for its discovery, there have been no hallmark therapeutic breakthroughs or even NO based diagnostics. We will review the current state of the science surrounding NO in the etiology of a number of different diseases in the geriatric patient. From these observations, it can be concluded that enzymatic production of NO declines steadily with increasing age in healthy human subjects. Implementing strategies to diagnose and treat NO insufficiency may provide enormous benefit to the geriatric patient.