Plain Water Intake Is Positively Associated with Physical Activity and Ambient Temperature in Free-Living Adults

Objectives

Water loss via sweating increases during exercise especially in the heat, however, the evidence is limited as to whether moderate physical activity (PA) and ambient temperature (Ta) influence water intake in daily life. The purpose of this study was to examine the influence of PA and Ta on water intake and hydration state in free-living individuals.

Methods

Ninety-five healthy, but non-athletic (< 4 h of exercise per week), adults (52 females) participated in the study. PA was assessed via the International Physical Activity Questionnaire and scored/stratified into PAhigh, PAmoderate, and PAlow. Fluid consumption was assessed by a validated 7-day fluid diary and was used to assess water intake from liquids (WI-L), plain water intake (PWI) and water intake from other beverages (WI-B). Food consumption was also recorded for 7 days and analyzed with the Nutrition Data System for Research (NDSR) software and was used to calculate water from foods (WI-F). All sources of water were pooled to calculate total water intake (TWI). Hydration was assessed with blood and a 24-h urine sample.

Results

People with PAhigh had higher TWI (4.0 ± 1.4 L·d−1 vs. 2.8 ± 0.7 L·d−1; P = 0.010) and WI-L (3.2 ± 1.4 L·d−1 vs. 2.1 ± 0.5 L·d−1; P = 0.009), compared to PAlow. PWI was also higher in PAhigh group (2.20 ± 1.20 L·d-1) compared to PAlow (1.10 ± 0.72 L·d−1, P = 0.003), but there was no significant difference in WI-B and WI-F (P ≥ 0.05). PWI showed a significant association with Ta (R2 = 0.08; P = 0.008), while WI-B did not (P ≥ 0.05). Positive associations between PWI and Ta only remained in the PAhigh group when stratified by different PA levels (R2 = 0.40; P = 0.028). However, the hydration state was not affected by PA nor Ta (P ≥ 0.05).

Conclusions

Higher PA and Ta were associated with higher TWI, and this appeared to be driven by PWI, and not by other beverages nor water from food. Hydration state was similar across levels of PA, likely because of the higher TWI in the PAhigh group.

Funding Sources

This study was funded by Danone Research.

Characterizing Dietary and Physical Activity Patterns in Relation to Hydration Among Pre-Adolescent Children

Objectives

The aim of this study was to characterize food and fluid consumption as well as and physical activity patterns in children in relation to ad libitum hydration.

Methods

Child participants aged 9–11 years (N = 55, 28 females) reported beverage consumption with a 7-day fluid diary. Overall diet was reported using a 7-day diet record and analyses were run using the Nutritional Data System for Research (NDSR). Physical activity was assessed with hip worn accelerometers (Actigraph wGT3x+, Pensacola, FL) over 7 days and aerobic fitness was measured with a VO2 max test. Body composition was assessed with dual energy x-ray absorptiometry (DXA). Urine was collected over a 24hr period and was analyzed separately with a refractometer and freezing point depression for specific gravity (USG) and osmolality (UOsm), respectively.

Results

Children reported ad libitum consumption of 1645 ± 856 mL of total fluid per day, which was comprised of 37% plain water and 12% milk. The remaining 51% was composed of juice, carbonated, sports, fruit, and caffeinated beverages. Mean 24 h UOsm was 780 ± 250 mOsm/kg and USG was 1.019 ± 0.007. Activity data showed participants spent 52 minutes of MVPA/day. Partial correlations, adjusting for VO2 max, % body fat, sex, energy intake, and accelerometer wear time per day, revealed relationships between plain water consumption and USG (r = −0.32, P = 0.05). USG was related to sedentary activity/day (r = −0.37, P = 0.03); however, there were no other relationships between physical activity and urine hydration markers or plain water intake (all p's > 0.05). Total healthy eating index score (HEI) was not related to plain water intake (r = 0.16, P = 0.34) but trended with UOsm (r = −0.30, P = 0.07). Further, UOsm was inversely correlated with the specific HEI subcomponents of higher vegetable (Rho = −0.32, P = 0.02) and lower saturated fat (Rho = −0.28, P = 0.04) consumption.

Conclusions

Water consumption in children was below recommendations, and fruit drinks, carbonated drinks, and juice comprised a significant proportion of beverages consumed. Higher water consumption was correlated with lower urine concentration, providing additional support for the importance of water for hydration in children. Finally, hydration was not related to weight status, % body fat, or habitual physical activity.

Funding Sources

Danone Research, Palaiseau, France.

Validation and Reliability of a Water Frequency Questionnaire to Estimate Daily Water Intake in Adults (P13-006-19)

Objectives

Investigators sought to: 1) evaluate the validity of a water frequency questionnaire (WFQ) to estimate mean daily water intake (WI) in adults through comparison to the gold standard, deuterium oxide (D2O) disappearance, and 2) evaluate reliability of WFQ to estimate WI.

Methods

Data collection occurred over three weeks, with validity of WFQ (vs. D2O) assessed during week one (W1) and reliability assessed between W1 and week three (W3). Healthy, free-living adults (n = 103; 51% female; 41 ± 14 y; BMI, 26.5 ± 5.5 kg·m−2) consumed D2O (0.1 g·kg−1 lean mass) at the start of W1 and provided urine samples immediately before ingestion, the following day, and at the end of the week to calculate total body water turnover (WTO). Seven day beverage consumption during W1 and W3 was retrospectively estimated using the WFQ. The WFQ included 17 beverage types with specified volumes (e.g., water (8 oz); soft drink (12 oz)) and nine frequency options ranging from ‘Never or less than 1 per week’ to ‘7+ per day’. Investigators converted beverage volumes to mL and calculated WI for each week. Food frequency questionnaires were also completed at the end of both weeks. Diets were analyzed with Nutritional Data System for Research software to estimate water intake from solid foods and metabolic water production by macronutrient oxidation. Water from food and macronutrient oxidation were subtracted from WTO to estimate WI via D2O. WFQ reliability was assessed via intraclass correlation (ICC) and Cronbach α, and validity was assessed via Bland-Altman plots.

Results

The mean difference in WI between D2O (2902 ± 1321 mL·day−1) and WFQ (2589 ± 1560 mL·day−1) was −308 ± 166 mL (P = 0.065). No systematic bias was observed between methods (R2 = 0.032, P = 0.071) as 3% of WI variance was explained by differences between methods. WFQ WI was not different between W1 (2589 ± 1560 mL·day−1) and W3 (2441 ± 1334 mL·day−1, P = 0.135). Cronbach α = 0.8415 demonstrated high internal consistency in WI estimation. The ICC was 0.834 (95% CI: 0.754, 0.887), demonstrating good test-retest reliability of WFQ.

Conclusions

In conclusion, the WFQ produced reliable WI estimates that were comparable to the gold standard of D2O assessment. This questionnaire may be a practical and easy method for assessing water intake in adults.

Funding Sources

The study was funded by Danone Research.

Osmotic Stimulation of Thirst in Men and Women (P15-017-19)

Objectives

Examine potential sex differences in osmotically stimulated thirst.

Methods

60 healthy adults (30 female - measured in early follicular phase, age: 39 ± 8 y, weight: 78.2 ± 15.2 kg, body mass index: 26.9 ± 4.0 kg·m−2) were infused intravenously with 3% (HYPER) or 0.9% (ISO) NaCl for 120 min (0.1 ml·kg−1·min−1) in a counterbalanced, cross-over design. The same volume of saline was infused in both trials. Blood samples and thirst responses were collected prior to infusion and every 30 minutes. Plasma osmolality (POsm) and sodium (PNa) were measured. Thirst was assessed via a 180-mm visual analog scale consisting of a line with an anchor on the left side (0 mm, “not at all”) and a second anchor on the 125-mm mark with the label “extremely”.

Results

From 0 min to 120 min in the HYPER trial, PNa increased from 136 ± 2 mmol ·L−1 to 146.5 ± 3 mmol ·l−1 (P < 0.001). Similarly, POsm and thirst increased significantly from 286 ± 3 mmol·kg−1 to 305 ± 4 mmol·kg−1 (P < 0.001) and from 38 ± 29 mm to 88 ± 35 mm (P < 0.001), respectively. During the ISO trial, PNa (0 min: 135.9 ± 1.9; 120 min: 137.6 ± 1.6 mmol·L−1), POsm (0 min: 285 ± 4 mmol·kg−1; 120 min: 287 ± 3 mmol·kg−1), and thirst (0 min: 30 ± 27 mm; 120 min: 44 ± 32 mm) remained unchanged (P > 0.05). POsm at the end of the infusion did not differ between men and women for the HYPER (men: 306 ± 5 mmol·kg−1; women: 305 ± 3 mmol·kg−1) or ISO (men: 288 ± 3 mmol·kg−1; women: 288 ± 3 mmol·kg−1) trials. When thirst responses were split by sex women exhibited greater thirst (98 ± 27 mm) than men (77 ± 38 mm) at the end of the HYPER trial (P < 0.0001), but not at the end of the ISO trial (women: 43 ± 32 mm, men 44 ± 31 mm; P > 0.05).

Conclusions

These data suggest that similar hypertonic stimulus may lead to greater thirst stimulation in women.

Funding Sources

This study was funded by Danone Research.

Hypertonic Saline Infusion Acutely Degrades Mood in Healthy Volunteers (P23-014-19)

Objectives

Mild and moderate dehydration adversely affect mood and cognitive function. During dehydration, hypertonic hypovolemia activates both osmo- and baro-receptors but it is not known which physiological pathway is associated with degraded mood state. This study examined the acute effect of osmoreceptor stimulation on mood.

Methods

Sixty healthy adults (50% females, 30 ± 1 y; BMI: 26.9 ± 4.0 kg·m−2) were infused intravenously with 3.0% (HYPER) or 0.9% (ISO) NaCl for 2 h (0.1 ml·kg−1·min−1) using a counterbalanced, crossover design. Blood samples were collected every 30 minutes to measure plasma osmolality (POsm), copeptin (a surrogate marker of vasopressin), and renin-angiotensin-aldosterone system (RAAS) hormones. Mood was assessed with the short version of Profile of Mood State (POMS) questionnaire before and after the infusion.

Results

POsm and copeptin increased from 286 ± 3 mmol·kg−1 to 305 ± 4 mmol·kg−1 and from 4.5 ± 3.7 pmol·L−1 to 20.4 ± 12.8 pmol·L−1, respectively in HYPER (P < 0.05), and were unchanged in ISO (P > 0.05). No hormonal differences were observed between trials for RAAS hormones (P > 0.05). During HYPER copeptin, following the 2-h infusion, was greater in females than in males (female: 23.4 ± 13.9 pmol·L−1, male: 17.4 ± 10.9 pmol·L−1; P < 0.05). The POMS total mood disturbance (TMD) score increased from 10.5 ± 0.9 to 16.5 ± 1.6 in HYPER (P < 0.05), but not in ISO (P > 0.05). Among POMS subscales, depression-dejection and fatigue-inertia increased in HYPER compared to ISO (P < 0.05). When TMD responses in the HYPER trial were analyzed with sex as a between-subjects factor, the increase was significant in females (pre: 10.2 ± 1.0, post: 18.6 ± 2.3; P < 0.001) but not in males (pre: 10.8 ± 1.4, post: 14.0 ± 2.0; P > 0.05). The confusion-bewilderment subscales and fatigue-inertia of the POMS were also elevated post HYPER in females (P < 0.05), but not in ISO (P > 0.05) in either sex.

Conclusions

Hypertonic saline infusion acutely degrades mood state, and women appear to have a more pronounced response. The underlying mechanisms remain to be determined but may be related to higher copeptin levels in women.

The study was registered at ClinicalTrials.gov as NCT02761434.

Funding Sources

Danone Research.

Supporting Tables, Images and/or Graphs

The Effect of Hydration on Cognition in Children: The WITiKids Randomized Controlled Crossover Trial (OR32-08-19)

Objectives

Previous work in adults has shown that dehydration has negative effects on cognitive function. However, the effect of changes in hydration on cognitive function remain understudied in children. This is relevant since epidemiological data suggests that a large proportion of children in the United States exhibit highly concentrated urine, suggestive of insufficient hydration. This study aimed to determine the effects of changes in daily water intake on urinary markers of hydration and cognitive control among school-aged children.

Methods

9–11-year-old children (N = 82) completed a three-intervention crossover water intake intervention where they were asked to either maintain their regular water intake (ad libitum) or consume High [2.5 L/d] or Low [0.5 L/d]) water for 4 consecutive days. Following the interventions, cognitive control tasks requiring inhibition, working memory, and cognitive flexibility were assessed using a modified flanker, Go/NoGo, and color-shape switch tasks. During day 4 of each intervention, children collected their urine over a 24-hour period for urine color, urine specific gravity (USG), and osmolality assessment.

Results

Hydration differed significantly between interventions. Urine color during the Low intervention was significantly higher than ad libitum and both were significantly greater than High intervention (Low: 6 [median] and 2 [iqr], ad libitum: 5 [median] and 2 [iqr], High: 3 [median] and 0 [iqr], all P ≤ 0.01). Similar intervention effects were observed for osmolality (Low: 912 ± 199, ad libitum: 790 ± 257.0, High: 260 ± 115 mOsmol/kg, all P < 0.001) and USG (Low: 1.023 ± 0.005, ad libitum: 1.020 ± 0.007, High: 1.005 ± 0.004, all P < 0.001). Ad libitumhydration was positively related to switch task performance. Benefits of the High intervention were observed during the switch task whereby participants exhibited lower working memory cost relative to the Low intervention. No significant changes in cognition were observed for the flanker and Go/NoGo tasks.

Conclusions

Children with better habitual hydration exhibited superior performance during the cognitive flexibility task. Additionally, the 4d water intervention resulted in significant changes in urinary markers of hydration and had selective benefits during task switching.

Funding Sources

Danone Research, Palaiseau, France.

Validation of a urine color scale for assessment of urine osmolality in healthy children

AIM

Urine color (UC) is a practical tool for hydration assessment. The technique has been validated in adults, but has not been tested in children.

PURPOSE

The purpose of the study was to test the validity of the urine color scale in young, healthy boys and girls, as a marker of urine concentration, investigate its diagnostic ability of detecting hypohydration and examine the ability of children to self-assess UC.

METHODS

A total of 210 children participated (age: 8-14 years, body mass: 43.4 ± 12.6 kg, height: 1.49 ± 0.13 m, body fat: 25.2 ± 7.8 %). Data collection included: two single urine samples (first morning and before lunch) and 24-h sampling. Hydration status was assessed via urine osmolality (UOsmo) and UC via the eight-point color scale.

RESULTS

Mean UC was 3 ± 1 and UOsmo 686 ± 223 mmol kg(-1). UC displayed a positive relationship as a predictor of UOsmo (R (2): 0.45, P < 0.001). Based on the receiver operating curve, UC has good overall classification ability for the three samples (area under the curve 85-92 %), with good sensitivity (92-98 %) and specificity (55-68 %) for detecting hypohydration. The overall accuracy of the self-assessment of UC in the morning or the noon samples ranged from 67 to 78 %. Further threshold analysis indicated that the optimal self-assessed UC threshold for hypohydration was ≥4.

CONCLUSIONS

The classical eight-point urine color scale is a valid method to assess hydration in children of age 8-14 years, either by researchers or self-assessment.

Effects of changes in water intake on mood of high and low drinkers

Objective

To evaluate the effects of a change in water intake on mood and sensation in 22 habitual high-volume (HIGH; 2-4 L/d) and 30 low-volume (LOW; <1.2 L/d) drinkers who were asked to respectively decrease and increase their daily water intake.

Method

During baseline HIGH consumed 2.5 L and LOW 1 L of water/day. During 3 controlled intervention days HIGH's water intake was restricted to 1 L/day whereas LOW's was increased to 2.5 L water/day. Several mood scales (Bond & Lader Visual Analog Scale (VAS), Profile of Mood States, Karolinska Sleepiness Scale, Thirst & Emotional VAS) were administered at different time points during the study. ANOVA including intervention, time point and intervention by time point as fixed effects on mean values (i.e.; baseline data vs. mean of 3 intervention days) for each mood scale was performed.

Results

At baseline HIGH and LOW were comparable in mood state, except for thirst scores (estimate = 17.16, p<0.001) and POMS depression-dejection scores (estimate = 0.55, p<0.05) which were both higher in the HIGH vs. LOW. In HIGH the restricted water intake resulted in a significant increase in thirst (p<0.001) and a decrease in contentedness (p<0.05), calmness (p<0.01), positive emotions (p<0.05) and vigor/activity (p<0.001). In LOW, increased water consumption resulted in a significant decrease in fatigue/inertia (p<0.001), confusion/bewilderment (p = 0.05) and thirst (p<0.001) and a trend to lower sleepiness (p = 0.07) compared to baseline.

Conclusion

Increasing water intake has beneficial effects in LOW, especially sleep/wake feelings, whereas decreasing water intake has detrimental effects on HIGH's mood. These deleterious effects in HIGH were observed in some sleep/wake moods as well as calmness, satisfaction and positive emotions.

RBC deformability and amino acid concentrations after hypo-osmotic challenge may reflect chronic cell hydration status in healthy young men

Biomarkers of chronic cell hydration status are needed to determine whether chronic hyperosmotic stress increases chronic disease risk in population-representative samples. In vitro, cells adapt to chronic hyperosmotic stress by upregulating protein breakdown to counter the osmotic gradient with higher intracellular amino acid concentrations. If cells are subsequently exposed to hypo-osmotic conditions, the adaptation results in excess cell swelling and/or efflux of free amino acids. This study explored whether increased red blood cell (RBC) swelling and/or plasma or urine amino acid concentrations after hypo-osmotic challenge might be informative about relative chronic hyperosmotic stress in free-living men. Five healthy men (20-25 years) with baseline total water intake below 2 L/day participated in an 8-week clinical study: four 2-week periods in a U-shaped A-B-C-A design. Intake of drinking water was increased by +0.8 ± 0.3 L/day in period 2, and +1.5 ± 0.3 L/day in period 3, and returned to baseline intake (0.4 ± 0.2 L/day) in period 4. Each week, fasting blood and urine were collected after a 750 mL bolus of drinking water, following overnight water restriction. The periods of higher water intake were associated with significant decreases in RBC deformability (index of cell swelling), plasma histidine, urine arginine, and urine glutamic acid. After 4 weeks of higher water intake, four out of five participants had ½ maximal RBC deformability below 400 mmol/kg; plasma histidine below 100 μmol/L; and/or undetectable urine arginine and urine glutamic acid concentrations. Work is warranted to pursue RBC deformability and amino acid concentrations after hypo-osmotic challenge as possible biomarkers of chronic cell hydration.

Relation between urinary hydration biomarkers and total fluid intake in healthy adults

BACKGROUND/OBJECTIVES

In sedentary adults, hydration is mostly influenced by total fluid intake and not by sweat losses; moreover, low daily fluid intake is associated with adverse health outcomes. This study aimed to model the relation between total fluid intake and urinary hydration biomarkers.

SUBJECTS/METHODS

During 4 consecutive weekdays, 82 adults (age, 31.6±4.3 years; body mass index, 23.2±2.7 kg/m(2); 52% female) recorded food and fluid consumed, collected one first morning urine (FMU) void and three 24-h (24hU) samples. The strength of linear association between urinary hydration biomarkers and fluid intake volume was evaluated using simple linear regression and Pearson's correlation. Multivariate partial least squares (PLS) modeled the association between fluid intake and 24hU hydration biomarkers.

RESULTS

Strong associations (|r| &#8805; 0.6; P<0.001) were found between total fluid intake volume and 24hU osmolality, color, specific gravity (USG), volume and solute concentrations. Many 24hU biomarkers were collinear (osmolality versus color: r=0.49-0.76; USG versus color: r=0.46-0.78; osmolality versus USG: 0.86-0.97; P<0.001). Measures in FMU were not strongly correlated to intake. Multivariate PLS and simple linear regression using urine volume explained >50% of the variance in fluid intake volume (r(2)=0.59 and 0.52, respectively); however the error in both models was high and the limits of agreement very large.

CONCLUSIONS

Hydration biomarkers in 24hU are strongly correlated with daily total fluid intake volume in sedentary adults in free-living conditions; however, the margin of error in the present models limits the applicability of estimating fluid intake from urinary biomarkers.

Circadian variation and responsiveness of hydration biomarkers to changes in daily water intake

Biomarkers of hydration change in response to acute dehydration; however, their responsiveness to changes in fluid intake volume, without exercise or heat exposure, has not been adequately described. Moreover, patterns of circadian variation in hydration biomarkers have not been established. The study aims were to (1) assess the response of hydration biomarkers to changes in daily water intake; and (2) evaluate circadian variation in urinary and salivary biomarkers. Fifty-two adults (24.8 ± 3.1 years; 22.3 ± 1.6 kg/m²; 79 % female), grouped based on habitual fluid intake (low drinkers, n = 30, <1.2 L/day; high drinkers, n = 22, >2.0 L/day), completed a 5-day inpatient crossover trial. On days 1 and 2, low drinkers received 1.0 L/day of water while high drinkers received 2.5 L/day. On days 3 through 5, intake was reversed between groups. Plasma and saliva osmolality were assessed daily at predetermined times, and all urine produced over 24 h was collected in timed intervals. ANOVA with intake (1.0 vs. 2.5 L/day), day, and time revealed that (1) urine concentration (osmolality, specific gravity, color) and volume, but not plasma nor saliva osmolality, responded to changes in water intake; (2) urinary hydration biomarkers and saliva osmolality vary as a function of the time of day; and (3) urine osmolality measured in samples collected during the afternoon most closely reflects the corresponding 24 h value. Overall, urinary hydration biomarkers are responsive to changes in water intake, and stabilize within 24 h of modifying intake volume. Moreover, short afternoon urine collections may be able to replace 24 h collections for more convenience in hydration assessment.

Economic benefit of the PHLAME wellness programme on firefighter injury

BACKGROUND

Work-related injuries and illness are prevalent and costly. Firefighting is especially hazardous and many firefighters sustain work-related injuries. Workplace health promotion programmes have shown positive return on investment (ROI). Little is known about how similar programmes would impact injury and cost among firefighters.

AIMS

To evaluate the impact of a workplace health promotion intervention on workers' compensation (WC) claims and medical costs among Oregon fire departments participating in the PHLAME (Promoting Healthy Lifestyles: Alternative Models' Effects) health promotion programme compared with Oregon fire departments not participating in PHLAME.

METHODS

Data from firefighters from four large urban fire departments in Oregon were evaluated using a retrospective quasi-experimental study design. Outcomes were (i) total annual firefighter WC claims, (ii) total annual incurred medical costs prior to and after implementation of the PHLAME firefighter worksite health promotion programme (iii) and an ROI analysis.

RESULTS

Data were obtained from 1369 firefighters (mean age of 42 years, 91% white, 93% male). WC claims (P < 0.001) and medical costs (P < 0.01) were significantly lower among PHLAME fire departments compared with Oregon fire departments not participating in the programme. Fire departments participating in the PHLAME TEAM programme demonstrated a positive ROI of 4.61-1.00 (TEAM is used to indicate the 12-session peer-led health promotion programme).

CONCLUSIONS

Fire department WC claims and medical costs were reduced after implementation of the PHLAME workplace health promotion programme. This is a low cost, team-based, peer-led, wellness programme that may provide a feasible, cost-effective means to reduce firefighter injury and illness rates.

Chondrogenic potential of bone marrow- and adipose tissue-derived adult human mesenchymal stem cells

Regarding cartilage repair, tissue engineering is currently focusing on the use of adult mesenchymal stem cells (MSC) as an alternative to autologous chondrocytes. The potential of stem cells from various tissues to differentiate towards the chondrogenic phenotype has been investigated and it appears that the most common and studied sources are bone marrow (BM) and adipose tissue (AT) for historical and easy access reasons. In addition to three dimensional environment, the presence of member(s) of the transforming growth factor (TGF-β family and low oxygen tension have been reported to promote the in vitro differentiation of MSCs. Our work aimed at characterizing and comparing the degree of chondrogenic differentiation of MSCs isolated from BM and AT cultured in the same conditions. We also further aimed at and at determining whether hypoxia (2% oxygen) could affect the chondrogenic potential of AT-MSCs. Cells were first expanded in the presence of FGF-2, then harvested and centrifuged to allow formation of cell pellets, which were cultured in the presence of TGF-β3 and/or Bone Morphogenetic Protein-2 (BMP-2) and with 2 or 20% oxygen tension, for 24 days. Markers of the chondrocyte (COL2A1, AGC1, Sox9) and hypertrophic chondrocyte (COL10A1, MMP-13) were monitored by real-time PCR and/or by immunohistological staining. Our data show that BMP-2/TGF-β3 combination is the best culture condition to induce the chondrocyte phenotype in pellet cultures of BM and AT-MSCs. Particularly, a switch in the expression of the pre-chondrogenic type IIA form to the cartilage-specific type IIB form of COL2A1 was observed. A parallel increase in gene expression of COL10A1 and MMP-13 was also recorded. However when AT-MSCs were cultured in hypoxia, the expression of markers of hypertrophic chondrocytes decreased when BMP-2/TGF-β3 were present in the medium. Thus it seems that hypoxia participates to the control of AT-MSCs chondrogenesis. Altogether, these cellular model systems will help us to investigate further the potential of different adult stem cells for cartilage engineering.

[Treatment specifics for spontaneous pneumothorax in flight personnel]

Spontaneous pneumothorax is one cause of aeronautical unfitness in flight personnel, because of the risk of recurrence in flight, making it an issue of flight safety. Specific treatment is required for fighter pilots, pilots flying single-pilot and pilots in professional training: surgical synthesis via video-thoracoscopy is obligatory from the first episode. Considering the exposure to an accumulation of aeronautical factors that are likely to encourage pneumothorax recurrence in flight, it is apical pleurectomy together with abrasion of the remaining pleura and resection of bullae/blebs that is required for fighter pilots to allow them to recover aeronautical fitness unrestrictedly. For all other categories of flight personnel, treatment is no different from that of the common patient. Knowledge of these treatment specifics is essential, to avoid unnecessary systematic surgical indication for all flight personnel, or jeopardise professional fitness in some of them due to inappropriate treatment.

A Hibiscus Abelmoschus seed extract as a protective active ingredient to favour FGF-2 activity in skin

In the skin, heparin, heparan sulphate and heparan sulphate proteoglycans control the storage and release of growth factors and protect them from early degradation. We developed a cosmetic active ingredient containing Hibiscus Abelmoschus seed extract (trade name Linefactor) that can maintain the FGF-2 content in the skin by mimicking the protective effect of heparan sulphate proteoglycans. By preventing the natural degradation of FGF-2, Hibiscus Abelmoschus seed extract maintains the bioavailability of this growth factor for its target cells, i.e. skin fibroblasts. Our in vitro evaluations showed that this ingredient exhibited heparan sulphate-like properties and dose-dependently protected FGF-2 from thermal degradation. We could also show that, in turn, the protected FGF-2 could stimulate the synthesis of sulphated GAGs, the natural protective molecules for FGF-2, thus providing a double protection. Finally, the in vitro results were confirmed in vivo thanks to a clinical study in which skin biomechanical properties and reduction in wrinkles were assessed.

Mechanistic model of fuel selection in the muscle

Fuel selection in human muscle is key to explaining insulin resistance. In obesity and type 2 diabetes mellitus, there is an increased content of lipid within and around muscle fibers. Changes in muscle fuel partitioning of lipid, between oxidation and storage of fat, contribute to the accumulation of intramuscular triglycerides and to the pathogenesis of both obesity and type 2 diabetes mellitus. A mathematical model of the aggregated metabolism in skeletal muscle was developed and the effects of fuel selection for lean and obese individuals under fasting conditions, insulin-stimulated conditions, and oscillating insulin conditions were examined. Model results were complementary to prior observations that elevated lipid oxidation during insulin-stimulated conditions is correlated with insulin resistance. The model also adequately simulated metabolic inflexibility between fat and glucose oxidation in the obese individual. A novel sensitivity analysis indicated the strong interaction effects of parameters of glucose and lipid oxidation pathways on the variables of each pathway.

Les modèles cellulaires 3D : un accès puissant à la physiologie cutanée et aux développements innovants de principes actifs cosmétiques

Two different anti-ageing cosmetic actives based respectively, on dermal compartment regeneration and on dermoepidermal reinforcement, have been developed using tissular engineering models. Conjointly use of different innovative three-dimensional models such as reconstructed dermis and skin built with human cells coming from variable aged donors allowed first, a better understanding of matrix modifications due to ageing and second, the screening of active ingredients highly targeted to reverse observed damages. The validity of such three-dimensional models has been then confirmed by in vivo studies on healthy volunteers.

[Right bundle branch block: electrocardiographic and prognostic features]

The electrocardiographic appearances and the significance of right bundle branch block were described at the beginning of the 20th century. Typical appearances include prolongation > 0.12 s of the QRS complex, RR' or rR' or Rr' appearances in V1 and widened S waves in the leads exploring the left ventricle (SI, aVL, V5 and V6). A delay in the appearance of the intrinsic deflection > 0.08 s may also be observed in the right precordial leads and negative T waves with ST depression may be seen in V1 and sometimes in V2. Left axis deviation of the QRS complex greater than - 45 degrees suggests associated left anterior hemiblock. Right axis deviation beyond + 120 degrees is equivocal. The principal differential ECG diagnosis is the Brugada syndrome, a familial arrhythmogenic autosomal dominant cardiomyopathy of variable penetration. This diagnosis is suggested when ECG abnormalities are observed in patients with a personal or family history of sudden death. Right bundle branch block only seems to have haemodynamic consequences in cardiac failure with associated asynchrony of the left ventricle or in certain cases of right ventricular dilatation encountered in congenital heart disease. The prognosis of right bundle branch block in the absence of underlying cardiac disease is good but it may be poor in other cases, particularly coronary artery disease. Moreover, the prognosis of right bundle branch block to complete atrioventricular block is rare in the absence of associated cardiac disease.

[Multislice computed tomography to detect coronary stenosis among asymptomatic patients with cardiovascular risk factors and equivocal prior stress test: preliminary study]

Multislice computed tomography (MSCT) is a non-invasive and validated technique to detect coronary stenoses. Some questions remain about its accuracy to detect coronary stenoses (CS), especially for asymptomatic patients (P) when a prior stress test isn't conclusive.

METHODS

MSCT was performed among 45 asymptomatic men (mean age: 58,3 +/- 16), with a high ten year risk of fatal cardiovascular disease (SCORE 2003 data for low-risk regions of Europe), without any previous coronary history and with previous non conclusive exercise testing. When significant (> 50%) CS was suspected at MSCT, an angiocoronarography (AC) was done.

RESULTS

Eighteen MSCT were normal, unsignificant CS (< 50%) were detected on 14 MSCT and significant coronary stenoses (SCS) for 13 P. Among this 13 P, 19 SCS were identified: 2 SCS of left main coronary artery (CA), 9 of the left descending CA, 6 of the right CA and 2 of the left circumflex CA. 13 CS were confirmed at AC. Finally, because of critical angiographic lesions +/- ischemia at nuclear tomoscintigraphy (NT), 9 P had coronary revascularization (7 catheter based, 2 surgical bypass), 4 P had medical treatment.

DISCUSSION

Benefits of this preliminary study are obvious: 9 coronary revascularization/45 P. However, the place of MSCT for the screening of CS is uncertain, but may be usefull as a complement for the screening of coronary arterial disease.

Choc vasoplégique et infarctus du myocarde lors de l’administration d’iloprost

INTRODUCTION

The association of vasoplegic shock and myocardial infarction in a patient under iloprost treatment for critical ischemia of the lower limbs has not previously been reported.

OBSERVATION

A 56 year-old man suffering from type 2 diabetes, hypertension and dyslipidemia developed critical ischemia of the right leg and was treated with iloprost. On the 19th day of infusion, he developed a vasoplegic shock with myocardial infarction. The shock resolved and he recovered from the infarction.

DISCUSSION

This case report indicates the need for reinforced blood pressure and electrocardiographic monitoring in diabetes patients treated with iloprost.

[Automobile driving and implantable defibrillators]

The consequences of implanting an automatic cardioverter defibrillator (ICD) on vehicle driving in France are poorly known. This retrospective study examined the behaviour at the wheel of ICD recipients who were recommended to abstain from driving for 3 to 6 months after device implantation. The study population included 98 patients (mean age = 59.5 +/- 14.8 years) followed for a mean of 24. +/- 23.9 months, who underwent ICD implant for ventricular tachycardia (65% of patients ventricular fibrillation (15%), syncope (8%), as part of a research protocol of myocardial cell transplantation 6%, or for primary prevention (5%). The underlying heart disease was ischemic in 59% of patients dilated cardiomyopathy in 11%,hypertrophic cardiomyopathy in 8%, valvular in 6%. Brugada syndrome in 4%, right ventricular arrhythmogenic cardiomyopathy in 2%, and miscellaneous disorders in 9% of patients. Five patients died without post mortem interrogation of the ICD. Only 28% of drivers remembered, and 13% observed, the recommended driving limitations. However, 45% (the oldest) claimed to drive prudently. During follow-up, 47% of patients received an ICD shock. Their mean it ventricular ejection fraction was 34 +/- 14%, versus 43 +/- 18% in patients who received no ICD therapy (p = 0.015). Syncope occurred in 16% who received ICD shocks. Shocks were delivered during driving in 6 patients, without consequent accident. Despite their non-observance of recommended driving limitations. ICD recipients suffered few traffic accidents. Legislation in France should reproduce the guidelines issued by European professional societies and enacted by the British laws.

[The heart and aerobatics]

Aerobatics is an aerial sport which has many physiological constraints, principally cardiovascular, with a risk if not adapted of sudden mid-air incapacity which could jeopardise aviation safety, and thus justifies the selection and surveillance of pilots. The aeronautical constraints during flight are multiple, related to the environment traversed, how the aircraft functions and its movements. Those which cause accelerations (+G in particular) pose the problem of haemodynamic tolerance because they can induce loss of consciousness due to cerebral hypoxia. Tolerance of acceleration varies among individuals; it can be improved with training, certain protective manoeuvres, and is reduced by hypoxia, certain medications, dehydration and heat. Moreover, in aerobatics certain tricks require manoeuvres which reduce this tolerance to +G accelerations. This is the "push-pull" effect (_G acceleration immediately followed by +G acceleration). This leads to a risk of sudden loss of consciousness with a load factor much lower than that which the pilot knows he is capable of tolerating. Besides the haemodynamic effects, the existence of an actual acceleration cardiomyopathy has been suggested but has not been proven in man. Finally, while changes in cardiac rhythm during accelerations are usual and relate to changes in vaso-sympathetic balance, ventricular and supra-ventricular rhythm disturbances are rare and are related to the intensity and duration of the acceleration.

Calcium triggers beta-defensin (hBD-2 and hBD-3) and chemokine macrophage inflammatory protein-3 alpha (MIP-3alpha/CCL20) expression in monolayers of activated human keratinocytes

The inducible epidermal beta-defensins and the chemokine macrophage inflammatory protein-3alpha (MIP-3alpha/CCL20) are important mediators involved in innate and adaptive immunity and in the recruitment of immune cells. The aim of our study was to determine whether calcium could trigger the induction of beta-defensins (hBD-2 and hBD-3) mRNA and the release of MIP-3alpha by normal human keratinocyte monolayers. Epidermal cells derived from foreskin were cultured in defined medium supplemented with different calcium levels (0.09, 0.8 and 1.7 mM) and were stimulated or not with the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha 1-500 ng/ml) or interferon-gamma (INF-gamma 1-100 ng/ml). A high calcium concentration (1.7 mM) alone applied in culture medium for 4 days was sufficient to induce hBD-2 and hBD-3 mRNA expression. Whatever interindividual variability in the expression of hBD-2 and hBD-3 mRNA and MIP-3alpha secretion, the addition of TNF-alpha for a short duration (26h), initiated a dose-dependent and coordinated up-regulation of hBD-2 and hBD-3 mRNA and MIP-3alpha release in keratinocyte cultures. Unlike hBD-2 and hBD-3 mRNA was preferentially stimulated by IFN-gamma rather than TNF-alpha. In our experimental conditions, L-isoleucine, described to stimulate beta-defensin in bovine epithelial cells, did not exert any effect either on hBD-2 and hBD-3 transcripts or MIP-3alpha protein. Taken together, these results confirm the major role of the maturation/differentiation process of normal human keratinocytes in the induction of inducible beta-defensins and MIP-3alpha chemokine, which contribute in vivo to the immunosurveillance of the skin barrier function.

Nano-emulsion formulation using spontaneous emulsification: solvent, oil and surfactant optimisation

Nano-emulsions consist of fine oil-in-water dispersions, having droplets covering the size range of 100-600 nm. In the present work, nano-emulsions were prepared using the spontaneous emulsification mechanism which occurs when an organic phase and an aqueous phase are mixed. The organic phase is an homogeneous solution of oil, lipophilic surfactant and water-miscible solvent, the aqueous phase consists on hydrophilic surfactant and water. An experimental study of nano-emulsion process optimisation based on the required size distribution was performed in relation with the type of oil, surfactant and the water-miscible solvent. The results showed that the composition of the initial organic phase was of great importance for the spontaneous emulsification process, and so, for the physico-chemical properties of the obtained emulsions. First, oil viscosity and HLB surfactants were changed, alpha-tocopherol, the most viscous oil, gave the smallest droplets size (171 +/- 2 nm), HLB required for the resulting oil-in-water emulsion was superior to 8. Second, the effect of water-solvent miscibility on the emulsification process was studied by decreasing acetone proportion in the organic phase. The solvent-acetone proportion leading to a fine nano-emulsion was fixed at 15/85% (v/v) with EtAc-acetone and 30/70% (v/v) with MEK-acetone mixture. To strength the choice of solvents, physical characteristics were compared, in particular, the auto-inflammation temperature and the flash point. This phase of emulsion optimisation represents an important step in the process of polymeric nanocapsules preparation using nanoprecipitation or interfacial polycondensation combined with spontaneous emulsification technique.

[Anaesthesia and amiodarone-associated hyperthyroidism]

Amiodarone can induce severe hyperthyroidism that justifies its withdrawal and initiation of antithyroid drugs. Impossibility to stop amiodarone, failure to control hyperthyroidism and unfavourable evolution can lead to thyroidectomy. Cardiac manifestations, persistence of hyperthyroidism and interactions between amiodarone and anaesthetic or haemodynamic drugs may contraindicate anaesthesia. We report nine consecutive cases of amiodarone-associated hyperthyroidism that prompted us to perform thyroidectomy under general anaesthesia. The features and anaesthetic data of patients were noted. The antithyroid medical treatment failed in all patients. After thyroidectomy, evolution was favourable in all nine cases, without any intra or postoperative complication, in spite of the extent of hyperthyroidism and the severity of the associated cardiac problems. Despite potential high risks, thyroidectomy for amiodarone-induced hyperthyroidism does not seem to increase morbidity or mortality and allows a quick return to euthyroidism and reintroduction of amiodarone.

Synthesis and characterization of polyurethane and poly(ether urethane) nanocapsules using a new technique of interfacial polycondensation combined to spontaneous emulsification

Polyurethane polymers and poly(ether urethane) copolymers were chosen as drug carriers for alpha-tocopherol. This active ingredient is widely used as a strong antioxidant in many medical and cosmetic applications, but is rapidly degraded, because of its light, heat and oxygen sensitivity. Polyurethane and poly(ether urethane)-based nanocapsules were synthesized by interfacial reaction between two monomers. Interfacial polycondensation combined with spontaneous emulsification is a new technique for nanoparticles formation. Nanocapsules were characterized by studying particle size (150-500 nm), pH, yield of encapsulation and morphologies. Polyurethanes (PUR) were obtained from the condensation of diisocyanate (isophorone diisocyanate: IPDI) and polyol: 1,2-ethanediol (EG), 1,4-butanediol (BD), 1,6-hexanediol (HD). Poly(ether urethane) copolymers were obtained by replacing diols by polyethylene glycol oligomers (PEG) M(w) 200, 300, 400 and 600. Molecular weights of di- and polyols have a considerable influence on nanocapsules characteristics cited above. The increase of molecular weight of polyols tends to increase the mean size of nanocapsules from (232+/-3)nm using EG to (615+/-39)nm using PEG 600, and led to the apparition of a population of agglomerate particles. We also noted that the yield of encapsulation increases with the increase of polyol length (from 85.6 to 92.2% w/w). Microscopic observations confirmed particle size analysis, but cannot predict the membrane structure owing the small size of the particles.