Effect of repetitive SCUBA diving on humoral markers of endothelial and central nervous system integrity.

During SCUBA diving decompression, there is a significant gas bubble production in systemic veins, with rather frequent bubble crossover to arterial side even in asymptomatic divers. The aim of the current study was to investigate potential changes in humoral markers of endothelial and brain damage (endothelin-1, neuron-specific enolase and S-100ß) after repetitive SCUBA diving with concomitant assessment of venous gas bubble production and subsequent arterialization. Sixteen male divers performed four open-water no-decompression dives to 18 msw (meters of sea water) lasting 49 min in consecutive days during which they performed moderate-level exercise. Before and after dives 1 and 4 blood was drawn, and bubble production and potential arterialization were echocardiographically evaluated. In addition, a control dive to 5 msw was performed with same duration, water temperature and exercise load. SCUBA diving to 18 msw caused significant bubble production with arterializations in six divers after dive 1 and in four divers after dive 4. Blood levels of endothelin-1 and neuron-specific enolase did not change after diving, but levels of S-100ß were significantly elevated after both dives to 18 msw and a control dive. Creatine kinase activity following a control dive was also significantly increased. Although serum S-100ß levels were increased after diving, concomitant increase of creatine kinase during control, almost bubble-free, dive suggests the extracranial release of S-100ß, most likely from skeletal muscles. Therefore, despite the significant bubble production and sporadic arterialization after open-water dives to 18 msw, the current study found no signs of damage to neurons or the blood-brain barrier.

Effects of CBD supplementation on ambulatory blood pressure and serum urotensin-II concentrations in Caucasian patients with essential hypertension: A sub-analysis of the HYPER-H21-4 trial.

HYPER-H21-4 was a randomized crossover trial that aimed to determine if cannabidiol (CBD), a non-intoxicating constituent of cannabis, has relevant effects on blood pressure and vascular health in patients with essential hypertension. In the present sub-analysis, we aimed to elucidate whether serum urotensin-II concentrations may reflect hemodynamic changes caused by oral supplementation with CBD. The sub-analysis of this randomized crossover study included 51 patients with mild to moderate hypertension that received CBD for five weeks, and placebo for five weeks. After five weeks of oral CBD supplementation, but not placebo, serum urotensin concentrations reduced significantly in comparison to baseline (3.31 ± 1.46 ng/mL vs. 2.08 ± 0.91 ng/mL, P < 0.001). Following the five weeks of CBD supplementation, the magnitude of reduction in 24 h mean arterial pressure (MAP) positively correlated with the extent of change in serum urotensin levels (r = 0.412, P = 0.003); this association was independent of age, sex, BMI and previous antihypertensive treatment (ß ± standard error, 0.023 ± 0.009, P = 0.009). No correlation was present in the placebo condition (r = -0.132, P = 0.357). In summary, potent vasoconstrictor urotensin seems to be implicated in CBD-mediated reduction in blood pressure, although further research is needed to confirm these notions.

Effects of successive air and nitrox dives on human vascular function.

SCUBA diving is regularly associated with asymptomatic changes in cardiac, pulmonary and vascular function. The aim of this study was to evaluate the changes in vascular/endothelial function following SCUBA diving and to assess the potential difference between two breathing gases: air and nitrox 36 (36% oxygen and 64% nitrogen). Ten divers performed two 3-day diving series (no-decompression dive to 18 m with 47 min bottom time with air and nitrox, respectively), with 2 weeks pause in between. Arterial/endothelial function was assessed using SphygmoCor and flow-mediated dilation measurements, and concentration of nitrite before and after diving was determined in venous blood. Production of nitrogen bubbles post-dive was assessed by ultrasonic determination of venous gas bubble grade. Significantly higher bubbling was found after all air dives as compared to nitrox dives. Pulse wave velocity increased slightly (~6%), significantly after both air and nitrox diving, indicating an increase in arterial stiffness. However, augmentation index became significantly more negative after diving indicating smaller wave reflection. There was a trend for post-dive reduction of FMD after air dives; however, only nitrox diving significantly reduced FMD. No significant differences in blood nitrite before and after the dives were found. We found that nitrox diving affects systemic/vascular function more profoundly than air diving by reducing FMD response, most likely due to higher oxygen load. Both air and nitrox dives increased arterial stiffness, but decreased wave reflection suggesting a decrease in peripheral resistance due to exercise during diving. These effects of nitrox and air diving were not followed by changes in plasma nitrite.

Serum Adropin Levels in Patients with Rheumatoid Arthritis.

Adropin is a secretory protein that mainly modulates metabolic homeostasis and endothelial function. There is growing evidence supporting association of adropin with various inflammatory diseases, including rheumatoid arthritis (RA). This study aimed to compare serum adropin levels between 70 patients with RA and 70 matched healthy controls. Furthermore, we explored adropin correlations with RA disease activity, glucose metabolism parameters and inflammatory biomarkers. Serum adropin levels were determined by a competitive enzyme-linked immunosorbent assay. Serum adropin levels were significantly lower in RA patients than in the control group (2.85 ± 0.91 vs. 4.02 ± 0.99 ng/mL, p < 0.001). In the RA group, serum adropin levels had a significant negative correlation with total cholesterol (r = -0.172, p = 0.043), HbA1c (r = -0.406, p < 0.001), fasting glucose (r = -0.377, p < 0.001) and HOMA-IR (the homeostasis model assessment-estimated insulin resistance; (r = -0.315, p = 0.008)). Multiple linear regression analysis showed that serum adropin levels retained a significant association with levels of fasting glucose (ß ± SE, -0.450 ± 0.140, p = 0.002) and HbA1c (-0.528 ± 0.223, p = 0.021) after model adjustments. These findings imply that adropin could have an impact on metabolic homeostasis in RA, although further well-designed studies are warranted in order to establish this.

Haemoglobin A1c-based screening for prediabetes and diabetes mellitus: a multi-center study in Croatian adult population.

INTRODUCTION: Based on the hypothesis that there is a substantial rate of adults with prediabetes and undiagnosed diabetes mellitus (DM), our aim was to perform haemoglobin A1c (HbA1c)-based screening in a cohort of Croatian adults and estimate the prevalence of prediabetes and undiagnosed DM according to American Diabetes Association criteria. MATERIALS AND METHODS: This multi-center, cross-sectional study performed in six Croatian hospitals included 5527 patients aged 40 to 70 years admitted to the Emergency Department or undergoing a primary care check-up. Haemoglobin A1c was measured from leftover whole blood samples using the enzymatic method on either Alinity c or Architect c-series analyser (Abbott Laboratories, Chicago, USA). Haemoglobin A1c between 39-47 mmol/mol was classified as prediabetes, while ≥ 48 mmol/mol as undiagnosed DM. RESULTS: After exclusion of 435 patients with known DM, the final cohort included 5092 patients (median age 57; 56% males). A total of 882 (17.3%) patients had HbA1c values between 39 and 47 mmol/mol. There were 214 (4.2%) patients with HbA1c ≥ 48 mmol/mol. Prediabetes prevalence ranged from 14.2% to 20.5%, while undiagnosed DM from 3.3% to 7.3%, with statistically significant differences among settings (P < 0.001). Age-stratified analysis showed that prediabetes and undiagnosed DM prevalence increase with age (P < 0.001), being 25.4% and 5.8%, respectively, in patients aged 60 to 70 years. CONCLUSION: Underlying impairment of glucose metabolism was identified in about one in five adults, with significant number of patients with already overt DM. These results should serve as a starting point for further steps directed towards promotion of preventive measures for DM in Croatia.

Ultrasonic evidence of acute interstitial lung edema after SCUBA diving is resolved within 2-3h.

Recently, an increase in extravascular lung water (EVLW) accumulation with diminished left ventricular contractility within 60 min after SCUBA diving was reported. We have observed previously that diving was associated with reduced diffusing lung capacity for carbon monoxide (DLCO) and arterial oxygen pressure for up to 60-80 min postdive. Here we investigated whether increased EVLW persists 2-3h after successive deep dives in a group of seven male divers. The echocardiographic indices of pulmonary water accumulation (ultrasound lung comets (ULC)) and left ventricular function, respiratory functional measurements and arterial oxygen saturation (SaO(2)) were assessed 2-3h post diving, while venous gas bubbles (VGB) and the blood levels of NT-proBNP and proANP were analyzed 40 min after surfacing. Spirometry values, flow-volume, DLCO, SaO(2) and ULC were unchanged after each dive, except for significant increase in ULC after the second dive. Left ventricular function was reduced, while NT-proBNP and proANP levels were significantly elevated after majority of dives, suggesting a cardiac strain.

Effect of human splenic contraction on variation in circulating blood cell counts.

1. The human spleen sequesters 200-250 mL densely packed red blood cells. Up to 50% of this viscous blood is actively expelled into the systemic circulation during strenuous exercise or simulated apnoea (breath-hold) diving. The contribution of splenic contraction to changes in the circulating volume of red blood cells (RBCV), as well as the venous concentration of white blood cells (WBC) and platelets (PLT), was investigated following repeated breath-hold apnoeas. 2. Eighteen trained apnoea divers and 18 intact and six splenectomized subjects without diving experience repeated five maximal apnoeas with face immersion in cold water, with 2 min intervals between successive attempts. Venous blood samples were taken before and between consecutive apnoeas, as well as at 0, 10 and 20 min after the last breath hold. Arterial pressure, heart rate and transcutaneous partial pressure of oxygen and carbon dioxide were monitored continuously. 3. Plasma protein concentration decreased by 5.8, 2.2 and 9% in apnoea divers, untrained and splenectomized subjects, respectively, indicating an expansion of plasma volume. The RBCV and venous concentration of WBC, corrected for changes in plasma volume, increased in both trained apnoea divers (4.9+/-1.0 and 14.9+/-3.1%, respectively) and intact subjects (1.7+/-0.8 and 7.2+/-1.8%, respectively), whereas in splenectomized subjects there was no change in RBCV and a delayed increase in WBC concentration. Furthermore, an initial lymphocytosis detected during repeated breath holds in divers and intact subjects was completely absent in splenectomized subjects. None of the groups showed significant changes in PLT concentrations. The well-recognized diving response to apnoea (bradycardia and increased blood pressure) was seen during all breath-hold attempts in all subjects. 4. Repeated breath-holds (apnoeas) contribute to increased RBCV and venous blood concentrations of WBC through splenic contraction.