Small intestinal malabsorption in chronic alcoholism: a retrospective study of alcoholic patients by the ¹⁴C-D-xylose breath test

Infrared analysis of lipoproteins in the detection of alcohol biomarkers

Background:

Alcoholism is a major public health problem. Alcohol causes modifications in the composition and concentration of lipoproteins and influences the enzymes and transfer proteins that transform lipoproteins in plasma. Alcohol is associated with the presence of alcohol biomarkers (fatty acid ethyl esters [FAEEs] and phosphatidylethanol [PEth]) in lipoproteins. We explore the possibilities of detecting alcohol biomarkers in non-high-density-lipoproteins (non-HDLs) precipitated from serum using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR).

Methods:

Analyzes were carried out on stored serum samples, with known % carbohydrate-deficient transferrin (CDT) values, included in a driver’s license regranting program under the control of the Belgian Institute of Road Safety. The study consisted of 127 control samples (CDT≤1.3%) and 114 alcoholic samples (CDT>1.3%). Liver enzymes, CRP, triglycerides, total, HDL- and LDL-cholesterol values were determined. Non-HDLs were precipitated with sodium phosphotungstate and MgCl2 and analyzed using ATR-FTIR in the range from 4500 cm−1 to 450 cm−1 using a Perkin Elmer ATR-FTIR Spectrometer Two.

Results:

The area under the curve of the 1130–990 cm−1 region (AUC1130−990 cm−1) was able to discriminate controls from alcoholics (p<0.0001) due to the presence of FAEEs in lipoproteins. Multiple regression analysis significantly predicted the AUC1130−990 cm−1 (adj. r2=0.13, p<0.0001). Significant correlations were found between AUC1130−990 cm−1 and CDT values (r=0.32, p<0.0001), AST/ALT ratio (r=0.21, p=0.001). GGT showed no significant correlation.

Conclusions:

Infrared analysis of lipoproteins is a potential tool in the detection of alcohol biomarkers.

Impact of Xylose on Glucose-Dehydrogenase-Based Blood Glucose Meters for Patient Self-Testing

The pentose xylose is enriched in edible algae, and is increasingly used as a slowly metabolized carbohydrate in functional food. It is known to interfere with glucose-dehydrogenase-based (GDH) blood glucose measurement systems for patients self-testing. The aim of our study was to investigate the extent of xylose interference in commercially available blood glucose meters. A heparinized whole blood sample was manipulated to contain 3 different glucose concentrations (50-80 mg/dL, 130-160 mg/dL, and 250-300 mg/dL) and 4 different xylose concentrations (0 mg/dL, 25 mg/dL, 50 mg/dL, and 100 mg/dL). Each sample was measured 3 times with 2 different strip lots per test meter (AccuChek Aviva, AccuChek Connect, Contour Next, FreeStyle Freedom Lite, FreeStyle Insulinx, MyStar Extra, OneTouch Verio IQ, and Wellion Calla, reference: YSI GlucoStat analyzer). For analysis, we calculated the xylose capture rate, that is, the xylose amount wrongly displayed as glucose. No xylose interference was seen with 4 meters: AccuChek Aviva (mean capture rate 0%), AccuChek Connect (-2%), MyStar Extra (10%), and Wellion Calla (8%). In contrast, substantial interference was observed with Contour Next (100%), FreeStyle Freedom Lite (104%), FreeStyle Insulinx (120%), and OneTouch Verio IQ (162%). We observed xylose interference in several GDH-based meters. This may become important with increased use of xylose in dietary and functional food products, in particular in products designed for weight loss. Our findings may affect the meter selection for patients who are consuming such food products as part of their lifestyle treatment regimen.

Chronic alcohol overconsumption may alter gut microbial metabolism: a retrospective study of 719 13C-D-xylose breath test results

Objective: Alterations of gut microbiota composition or function may participate in the pathophysiology of several diseases. We aimed to explore the effect of chronic alcohol overconsumption on gut microbial metabolism, as assessed by evaluating 13C-D-xylose breath test results. Materials and methods: We investigated all 13C-D-xylose breath tests performed at Lovisenberg Diaconal Hospital during the years 2005 to 2011, using patient files for diagnosing the patients into one of three patient categories: alcohol overconsumption, coeliac disease and functional bowel disorder. In addition, a group of healthy controls was included. The time curves of 13CO2 excretion in breath samples were divided into two phases, evaluating small intestinal absorption (0-60 min) and colonic microbial metabolism (90-240 min), respectively. Results: A total of 719 patients underwent 13C-D-xylose breath testing during the inclusion period. Thirty-five had a history of alcohol overconsumption, 66 had coeliac disease, and 216 had a functional bowel disorder, while 44 healthy controls were included for comparison. The alcohol overconsumption group had similar small intestinal phase results as the group of patients with untreated coeliac disease. During the colonic phase, the group of patients with alcohol overconsumption differed from all the other groups in terms of 13C-xylose recovery, with significantly less 13CO2 excretion compared to the other groups. Conclusion: The results suggest that patients with a history of alcohol overconsumption suffer from both small intestinal malabsorption and impaired colonic microbial metabolism. The role of gut microbiota in chronic alcohol overconsumption should be investigated further.

Breath testing for small intestinal bacterial overgrowth: maximizing test accuracy

The diagnosis of small intestinal bacterial overgrowth (SIBO) has increased considerably owing to a growing recognition of its association with common bowel symptoms including chronic diarrhea, bloating, abdominal distention, and the irritable bowel syndrome. Ideally, an accurate and objective diagnosis of SIBO should be established before initiating antibiotic treatment. Unfortunately, no perfect test exists for the diagnosis of SIBO. The current gold standard, small-bowel aspiration and quantitative culture, is limited by its high cost, invasive nature, lack of standardization, sampling error, and need for dedicated infrastructure. Although not without shortcomings, hydrogen breath testing provides the simplest noninvasive and widely available diagnostic modality for suspected SIBO. Carbohydrates such as lactulose and glucose are the most widely used substrates in hydrogen breath testing, with glucose arguably providing greater testing accuracy. Lactose, fructose, and sorbitol should not be used as substrates in the assessment of suspected SIBO. The measurement of methane in addition to hydrogen can increase the sensitivity of breath testing for SIBO. Diagnostic accuracy of hydrogen breath testing in SIBO can be maximized by careful patient selection for testing, proper test preparation, and standardization of test performance as well as test interpretation.