Applications of deuterium oxide in human health

Development and validation of anthropometric predictive equations that estimate the total body water and fat-free mass in Tunisian adults

OBJECTIVE

To develop and validate equations that estimate total body water (TBW) and fat-free mass (FFM) in adults using anthropometric measurements.

METHODS

A cross-sectional study was conducted among 178 adults (77 men and 101 women; aged 18-59 years). Participants were distributed by sex and age groups, and then randomly assigned to equal two groups; the development (n = 89) and the validation (n = 89). The anthropometric measurements included height and weight. The deuterium dilution technique (DDT) estimated TBW and FFM. Linear regression models were used with the TBW and FFM as the dependent variable, and height and weight as the independent variables. Cross-validation was performed by Bland and Altman plot, and the new anthropometric equations were developed.

RESULTS

In the validation sample, the developed equations had high R2 of 94.4 for both TBW and FFM in all age groups, and low standard errors (RMSE: 1.80 kg for TBW and 2.44 kg for FFM). The pure error was 2.03 for the TBW equation and 2.71 for the FFM equation. The Bland-Altman plot illustrated the good level of concordance between the TBW and FFM predicted by the new equations as determined by DDT. The following developed equations showed a better agreement with the DDT: [Formula: see text]; [Formula: see text].

CONCLUSION

In this study, we developed and validated prediction equations for the estimation of TBW and FFM from DDT in healthy adult Tunisian population. The newly anthropometric prediction equations seem to be the most accurate for Tunisian adult.

Observing the water handling in humans to resolve the role of the interstitium: preliminary results of the usability of deuterium oxide and bio-impedance analysis - a pilot analysis

The aim of this research was to evaluate the relevance of using deuterium oxide (²H₂O) and bio-impedance analysis (BIA) to assess size and function of the interstitium for urological research. Nineteen volunteers were recruited to this prospective trial combining ingestion of ²H₂O and BIA. Blood samples were obtained every 10 min after ingestion of ²H₂O. Urine was collected before and after the experiment. BIA was performed every 5 min. Body position was alternated to study the effect on fluid distribution. First order kinetics were assumed for the uptake of ²H₂O from the gastrointestinal tract to the blood. Sex seemed to have an influence with a significantly slower exchange for women (p = 0.041, men: 0.052 min^-1, women: 0.038 min^-1). Impedance measured in legs (men: p = 0.012, women: p = 0.008) and trunk (both p < 0.001) decreased significantly with posture change. These changes probably reflect the orthostatic redistribution of fluid with an increase of fluid in both trunk and legs. Both methods were tested and found to be useful for further urological research. Significant gender differences in ²H₂O uptake dynamics from the gastrointestinal pool were observed. An impact of posture changes on the electrical impedance measured was observed.

Relevance of body mass index and bioelectrical impedance analysis vs. deuterium dilution technique to assess excess of fat among young adults

Our study aimed to assess the nutritional status by using body composition among young Tunisian adults through three measurement methods: body mass index (BMI), bioelectrical impedance analysis (BIA) and deuterium oxide dilution technique (²H₂O) and to determine the accuracy of BMI and BIA in order to evaluate the overweight and obesity among young adults in Tunisia. Our study involved 144 young adults. Anthropometric parameters were measured. The fat mass percentage (%FM) was determined by ²H₂O and BIA techniques. The analysis of deuterium enrichment was performed using a Fourier transform infrared spectrophotometer (FTIR). According to BMI, 26.4% of subjects were overweight and 5.5% were obese. The mean of %FM estimated by BIA was significantly higher than that determined by ²H₂O (29.7 ± 7.7 vs. 26.3 ± 10.6, p < .0001). Consequently, the prevalence of overweight and obesity assessed by BIA was significantly higher than by ²H₂O (51.4% vs. 34%, p < .0001). Using BMI, the prevalence of overweight and obesity was similar to that estimated by ²H₂O (31.9% vs. 34%, p = 0.544). Compared to ²H₂O, BIA overestimates the prevalence of overweight and obesity in young adults. On the other hand, the BMI showed an interesting correlation with the %FM determined by ²H₂O.

ICI-RS 2019 nocturia think tank: How can experimental science guide us in understanding the pathophysiology of nocturia?

INTRODUCTION

The following is a report on the proceedings of the 2019 International Consultation on Incontinence-Research Society nocturia think tank (NTT).

OBJECTIVES

The objectives of the 2019 NTT were as follows: (a) to evaluate the role of urothelium in the pathophysiology of nocturia; (b) to determine whether nocturia is a circadian disorder; (c) to discuss the role of melatonin in nocturia; (d) to consider ambulatory urodynamic monitoring in evaluating patients with nocturia; (e) to explore studies of water handling in human compartments utilizing heavy water; and (f) to explore whether basic science is the key to understanding the treatment options for diminished bladder capacity in patients with nocturia.

METHODS

A compendium of discussions of the role of experimental science in understanding the pathophysiology of nocturia is described herein.

RESULTS AND CONCLUSIONS

Translational science will play an increasing role in understanding the pathophysiology of nocturia, which may result in improved treatment strategies.

Highly Sensitive Real-Time Isotopic Quantification of Water by ATR-FTIR

A method has been developed to reliably quantify the isotopic composition of liquid water, requiring only immersion of a "ReactIR" probe in the sample under test. The accuracy and robustness of this method has been extensively tested using a deuterium/protium system, and substantial improvements in sensitivity were obtained using highly novel chemical signal amplification methods demonstrating a standard deviation of 247 ppb D (a δD of 1.6 ‰). This compares favorably with other more costly and time-consuming techniques and is over 20 times more sensitive than any previously published FTIR study. Computational simulations of a model system match the experimental data and show how these methods can be adapted to a tritium/protium system.

Possible Mechanisms of Biological Effects Observed in Living Systems during 2H/1H Isotope Fractionation and Deuterium Interactions with Other Biogenic Isotopes

This article presents the original descriptions of some recent physics mechanisms (based on the thermodynamic, kinetic, and quantum tunnel effects) providing stable 2H/1H isotope fractionation, leading to the accumulation of particular isotopic forms in intra- or intercellular space, including the molecular effects of deuterium interaction with 18O/17O/16O, 15N/14N, 13C/12C, and other stable biogenic isotopes. These effects were observed mainly at the organelle (mitochondria) and cell levels. A new hypothesis for heavy nonradioactive isotope fractionation in living systems via neutron effect realization is discussed. The comparative analysis of some experimental studies results revealed the following observation: "Isotopic shock" is highly probable and is observed mostly when chemical bonds form between atoms with a summary odd number of neutrons (i.e., bonds with a non-compensated neutron, which correspond to the following equation: Nn - Np = 2k + 1, where k ϵ Z, k is the integer, Z is the set of non-negative integers, Nn is number of neutrons, and Np is number of protons of each individual atom, or in pair of isotopes with a chemical bond). Data on the efficacy and metabolic pathways of the therapy also considered 2H-modified drinking and diet for some diseases, such as Alzheimer's disease, Friedreich's ataxia, mitochondrial disorders, diabetes, cerebral hypoxia, Parkinson's disease, and brain cancer.

Aquaporin 11-Dependent Inhibition of Proliferation by Deuterium Oxide in Activated Hepatic Stellate Cells

Deuterium oxide (D₂O) has been reported to be active toward various in vitro cell lines in combination with phytochemicals. Our objective was to describe, for the first time, the effect of D₂O on the proliferation of hepatic stellate cells (HSCs). After D₂O treatment, the p53-cyclin-dependent kinase (CDK) pathway was stimulated, leading to inhibition of the proliferation of HSCs and an increase in the [ATP]/[ADP] ratio. We also evaluated the role of aquaporin (AQP) 11 in activated HSCs. We found that D₂O treatment decreased AQP11 expression levels. Of note, AQP11 levels elevated by a genetic approach counteracted the D₂O-mediated inhibition of proliferation. In addition, the expression levels of AQP11 negatively correlated with those of p53. On the other hand, cells transfected with an AQP11-targeted small interfering RNA (siRNA) showed enhanced inhibition of proliferation. These findings suggest that the inhibition of cell proliferation by D₂O in activated HSCs could be AQP11 dependent. Our previous studies have documented that bisdemethoxycurcumin (BDMC) induces apoptosis by regulating heme oxygenase (HO)-1 protein expression in activated HSCs. In the current study, we tested whether cotreatment with BDMC and D₂O can modulate the AQP11-dependent inhibition of cell proliferation effectively. We observed that D₂O cotreatment with BDMC significantly decreased cell proliferation compared to treatment with D₂O alone, and this effect was accompanied by downregulation of HO-1 and an increase in p53 levels.