Physical activity - an important preanalytical variable

Laboratory medicine and sports: where are we now?

Laboratory medicine in sport and exercise has significantly developed during the last decades with the awareness that physical activity contributes to improved health status, and is present in monitoring both professional and recreational athletes. Training and competitions can modify concentrations of a variety of laboratory parameters, so the accurate laboratory data interpretation includes controlled and known preanalytical and analytical variables to prevent misleading interpretations. The paper represents a comprehensive summary of the lectures presented during the 35th Annual Symposium of the Croatian Society of Medical Biochemistry and Laboratory Medicine. It describes management of frequent sport injuries and sums up current knowledge of selected areas in laboratory medicine and sports including biological variation, changes in biochemical parameters and glycemic status. Additionally, the paper polemicizes sex hormone disorders in sports, encourages and comments research in recreational sports and laboratory medicine. In order to give the wider view, the connection of legal training protocols as well as monitoring prohibited substances in training is also considered through the eyes of laboratory medicine.

Impact of COVID-19 Lockdown on Metabolic/Inflammatory Profile in Adolescents: Cellular Studies and Predictive Biomarkers

CONTEXT

The COVID-19 pandemic and its lockdown restrictions changed people's lifestyles with potential negative impact on health.

OBJECTIVE

This longitudinal study aimed to assess the COVID-19 lockdown influence on the adherence to the Mediterranean diet (MD) pattern and its effects on the metabolic inflammatory profile in a cohort of healthy adolescents.

METHODS

We analyzed anthropometric measurements, body composition, and MD adherence along with serum metabolic and inflammatory profile in 77 healthy adolescents from southern Italy before and after the COVID-19 pandemic lockdown. Additionally, we evaluated the biological properties of prelockdown and postlockdown serum on human HepG2 and HuH-7 hepatic cells.

RESULTS

We did not observe any significant differences in anthropometric and body composition parameters as well as MD adherence score in adolescents between prelockdown and postlockdown COVID-19. Intriguingly, although the metabolic profile of adolescents postlockdown was within the normal range, we evidenced increased levels of fasting glucose, triglycerides, total cholesterol, and low-density lipoprotein (LDL) along with a reduction in high-density lipoprotein (HDL) in postlockdown compared with prelockdown adolescent serum. In addition, elevated levels of tumor necrosis factor (TNF)-α, interleukin-1β, and ferritin were found in postlockdown adolescents compared with their prelockdown counterparts. Consistent with the biochemical parameters, we observed enhanced lipid accumulation with altered mitochondrial functions and increased reactive oxygen species production in HepG2 and HuH-7 cells treated with pooled serum from postlockdown with respect to prelockdown period. Receiver operator characteristic curve analysis identified total cholesterol, LDL, HDL, TNF-α, and ferritin to be predictive serum markers for metabolic and inflammatory profiling after the lockdown period.

CONCLUSION

Our findings highlight that the COVID-19 lockdown, forcing sedentary behavior, had a negative impact on adolescents' metabolic and inflammatory profile which may result in long-term poor health outcomes.

Total Iron Concentrations in Different Biological Matrices-Influence of Physical Training

Iron (Fe) is one of the most widely studied trace mineral elements. Fe metabolism and homeostasis could be altered by physical training. The aim of this study was to analyze the influence of long-term physical training on serum, plasma, urine (extracellular), erythrocyte and platelet (intracellular) Fe concentrations. Forty men from the same geographical area divided into a training group (TG; n = 20; 18.15 ± 0.27 years) and a control group (CG; n = 20; 19.25 ± 0.39 years) participated in this study. The TG was composed of soccer players of the highest youth category. The CG consisted of young people who did not follow any training routine and had not practiced any sport for at least the previous six months. The TG showed higher plasma and serum Fe concentrations (p < 0.05), but lower concentrations in erythrocytes and platelets compared to the CG (p < 0.01). Due to the differences observed in the extracellular and intracellular compartments, it seems necessary to perform a global Fe analysis to assess Fe status.

Basal Values of Biochemical and Hematological Parameters in Elite Athletes

The purpose of this study was to show how continuous exercise affects the basal values of biochemical and hematological parameters in elite athletes. A total of 14,010 samples (male = 8452 and female = 5558 (March 2011–March 2020)) from 3588 elite athletes (male = 2258 and female = 1330, mean age 24.9 ± 6.9 vs. 24.1 ± 5.5 years, respectively) from 32 sport modalities, were studied over 9 years to check the variation of basal biochemical and hematological parameter values. There were differences seen in the basal values of creatine kinase (CK), urea, creatinine, aspartate transaminase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), potassium, total bilirubin, and eosinophil percentage compared to reference population data. However, other analytes showed narrow ranges of variation like glucose, total protein, albumin, sodium, hemoglobin, mean cell volume (MCV), and platelet count. Exercise produces changes in biochemical and hematological basal values of athletes compared to the general population, with the greatest variation in CK, but AST, ALT, LDH, potassium, and total bilirubin (TBil) show high values in serum, only with a wider distribution of values. The data here reflects the effect of exercise on biochemical and hematological parameter baseline ranges in elite athletes. As clinical laboratories use reference intervals to validate clinical reports, these “pseudo” reference intervals should be used when validating laboratory reports.

Exercise Training Increases Serum Cardiac Troponin T Independent of Left Ventricular Mass

The purpose of this study was to determine whether exercise training mediated cardiac troponin T (cTnT) and whether this was associated with increases in left ventricular mass (LVM). Fifty-four sedentary obese women were randomised to high-intensity interval training (HIIT, repeated 4-min cycling at 90% V̇O_2max interspersed with 3-min rest), work-equivalent continuous aerobic training (CAT, continuous cycling at 60% V̇O_2max) or a control group (CON). Resting serum cTnT was assessed using a high-sensitivity assay before and after 12 weeks of training. LVM was determined from 2D echocardiography at the same timepoints. Both HIIT and CAT induced a similar elevation (median 3.07 to 3.76 ng.l^-1, p<0.05) in resting cTnT compared with pre-training and the CON (3.49 to 3.45 ng.l^-1, p>0.05). LVM index in HIIT increased (62.2±7.8 to 73.1±14.1 g.m^-2, p<0.05), but not in CAT (66.1±9.7 to 67.6±9.6 g.m^-2, p>0.05) and CON (67.9±9.5 to 70.2±9.1 g.m^-2, p>0.05). Training-induced changes in resting cTnT did not correlate with changes in LVM index (r=-0.025, p=0.857). These findings suggest that twelve weeks of either HIIT or CAT increased resting cTnT, but the effects were independent of any changes in LVM in sedentary obese women.

Haematological, Biochemical and Hormonal Biomarkers of Heat Intolerance in Military Personnel

Simple Summary

This study focuses on the biomarkers that are predictive of heat intolerance in military populations. Military personnel are at risk of exertional heat stroke when the body’s temperature increases during intense physical activity in hot weather. Exertional heat stroke (EHS) may accompany or precede heat intolerance, an unusual sensitivity to heat. However, it is unknown if blood biomarkers (haematological, biochemical and hormonal) are predictive of heat intolerance. We subjected a sample of Australian Defence Force personnel and civilian volunteers to a heat tolerance test (HTT), and blood samples were obtained pre-and post–HTT. The results showed that a history of EHS was associated with changes in creatinine and urea. The biochemical and hormonal biomarkers associated with heat intolerance were alanine amino transaminase, creatine kinase, cortisol and creatinine. Furthermore, creatinine and cortisol were identified as predictors and useful biomarkers of heat intolerance. This study also highlights the need for further exploration of genetic biomarkers to aid early identification and the return to duty process for military personnel who may be at risk of heat intolerance.

Abstract

Heat intolerance is the inability to withstand heat stress and this may occur due to exertional heat stroke (EHS). However, it is unknown if heat intolerance is associated with immune and hormonal disturbances. This study investigates haematological, biochemical and hormonal biomarkers related to heat intolerance and EHS in military and civilian volunteers. A quasi-experimental pre-and post-test design was used, with participants drawn from the Australian Defence Force (ADF) and the general populace. Blood samples were collected and analysed for biomarkers. Inferential statistics compared the biomarkers between the groups. Changes in alanine amino transaminase (p = 0.034), creatine kinase (0.044), cortisol (p = 0.041) and creatinine (p < 0.001) differed between the heat-intolerant and heat-tolerant groups. Participants with a history of EHS showed significant changes in creatinine (p = 0.022) and urea (p = 0.0031) compared to those without EHS history. Predictors of heat intolerance were increasing post-HTT creatinine and cortisol (OR = 1.177, p = 0.011 and OR = 1.015, p = 0.003 respectively). Conclusively, EHS history is associated with changes in creatinine and urea concentrations, while the predictors of heat intolerance are creatinine and cortisol. However, further exploration of other biomarkers, such as genetic polymorphism, is needed.

Exercise Effects On Cardiovascular Disease: From Basic Aspects To Clinical Evidence

Cardiovascular (CV) disease (CVD) remains the leading cause of major morbidity and CVD- and all-cause mortality in most of the world. It is now clear that regular physical activity (PA) and exercise training (ET) induces a wide range of direct and indirect physiologic adaptations and pleiotropic benefits for human general and CV health. Generally, higher levels of PA, ET, and cardiorespiratory fitness (CRF) are correlated with reduced risk of CVD, including myocardial infarction, CVD-related death, and all-cause mortality. Although exact details regarding the ideal doses of ET, including resistance and, especially, aerobic ET, as well as the potential adverse effects of extreme levels of ET, continue to be investigated, there is no question that most of the world's population have insufficient levels of PA/ET, and many also have lower than ideal levels of CRF. Therefore, assessment and promotion of PA, ET, and efforts to improve levels of CRF should be integrated into all health professionals' practices worldwide. In this state-of-the-art review, we discuss the exercise effects on many areas related to CVD, from basic aspects to clinical practice.

Vitamin D Status and Its Correlation With Anthropometric and Biochemical Indicators of Cardiometabolic Risk in Serbian Underground Coal Miners in 2016

The status of vitamin D in underground working coal miners and its association with their cardiometabolic health is rarely studied. This study aimed to examine vitamin D (VitD) status in Serbian underground coal miners and to correlate it with anthropometric and laboratory indicators of cardiometabolic risk. Nutritional data (food frequency questionnaire, FFQ, and two times repeated 24 h recall), anthropometric data (including segmental analysis by bio-impedance analyzer TANITA BC-545N), arterial tension, and biochemical and hematological data of 103 coal miners (aged 22-63 years) were correlated with their late summer (early September) serum 25 (OH)D levels (measured by HPLC). 68.9% of the studied coal miners were overweight/obese, and 48.5% had metabolic syndrome. Their mean VitD nutritional intakes were low: 5.3 ± 3.8 μg/day (FFQ) and 4.9 ± 8 μg/day (24 h recalls), but their mean serum 25 (OH)D levels were surprisingly high (143.7 ± 41.4 nmol/L). Only 2.9% of the coal miners had 25(OH)D levels lower than 75 nmol/L (indicating an insufficient/deficient status), while 63.2% had values above 125 nmol/L (upper optimal limit), and even 10.7% had values above 200 nmol/L. There were no statistical differences in 25 (OH)D levels in the coal miners with or without metabolic syndrome (or overweight/obesity). Interestingly, 25(OH)D levels had significant positive correlations with body mass index (BMI), fat mass (FM), fat mass percentage (FM%), limbs FM%, serum triglycerides, GGT, AST, ALT, and ALT/AST ratio, and had significant negative correlations with serum HDL-cholesterol and age. All these correlations were lost after corrections for age, FM, FM%, and legs FM%. In Serbian coal miners, high levels of early September VitD levels were observed, indicating sufficient non-working-hour sun exposure during the summer period. Furthermore, the unexpected positive correlations of VitD levels with anthropometric and biochemical parameters indicative of obesity, metabolic syndrome, and fatty liver disease were found. More research is needed on the VitD status of coal miners (particularly in the winter period) and its relationship with their cardiometabolic status.

A Physically Active Status Affects the Circulating Profile of Cancer-Associated miRNAs

Circulating miRNAs are ideal diagnostics and prognostics biomarkers in cancer since altered levels of specific miRNAs have been associated to development/progression of several cancers. Physical activity is a recognized preventive strategy against several cancers, but it may also modify the baseline levels of cancer-associated miRNAs and, hence, may act as a confounding pre-analytical variable. This study aimed at understanding whether physical activity-dependent changes in cancer-associated circulating miRNAs profile could act as a confounding variable. A panel comprising 179 miRNAs was assayed in plasma from 20 highly trained and 10 sedentary men. RT-qPCR data were analyzed with the 2^−2ΔΔCT methods and normalized on hsa-miR-320d, as determined by bioinformatics analysis. miRNAs associated with the diagnosis of the most prevalent cancers were considered. Only those miRNAs, relevantly associated with cancers, found ≥2-fold up- or downregulated in highly trained subjects compared to sedentary were disclosed. The results reveal that chronic physical activity determined modifications altering the baseline level of several cancer-associated miRNAs and, hence, their diagnostic and prognostic potential. In conclusion, based on our results, a physically active status emerges as an important pre-analytical variable able to alter the basal level of circulating miRNAs, and these alterations might be considered as potentially misleading the analytical output.

Basal myokine levels are associated with quality of life and depressed mood in older adults

In an aging society, late-life depression has become an increasing problem. There is evidence that physical activity ameliorates depressive symptoms and increases the quality of life (QoL). However, the underlying mechanisms are still poorly understood. Myokines are molecules secreted in response to muscle contraction. Some of them can cross the blood-brain barrier, making them promising candidates for mediating the beneficial effects of physical activity on mood. The present study aims to compare circulating myokine levels to depression/QoL in older athletes and controls. 55 athletes, 57 controls >59 years were enrolled. The assessment included ergometry, magnetic resonance imaging, blood withdrawal, and neuropsychological testing. Serum interleukin-6 (IL-6), irisin, brain-derived neurotrophic factor (BDNF), kynurenine, and cathepsin B were analyzed and compared to surrogates of depression and quality of life. Athletes presented with higher levels of Cathepsin B. Among controls, all myokines but irisin were associated with age. Also, among controls, kynurenine and IL-6 correlated inversely with specific dimensions of quality of life questionnaires, and IL-6 further with depressive symptoms and decreased physical performance. No such associations could be found among athletes. Irisin levels were inversely associated with mild depression and low-grade white matter-lesions in the brain and predicted impaired QoL. The circulating levels of several myokines/muscle activity-related factors appear to be associated with depressive symptoms and impaired QoL among older adults. However, in athletes, some of these connections seem ameliorated, suggesting additional stressors (as f.e. age) or a different pathomechanism among athletes.

Effect of endurance training on copper, zinc, iron and magnesium status

BACKGROUND

Physical activity related energy expenditure, environmental stresses, body composition, dietary intake, etc., are key factors influencing the nutritional requirements of minerals. The present study was designed to study the nutritional status of metals with respect to extensive endurance training.

METHODS

The participants of the study were navy sailors (N.=37, mean age±SD: 25.2±4.8 y) undergoing one month of endurance training. Nutritional status was assessed by determining their body composition using bioelectrical impedance (BIA), food intake and urinary excretion levels. Fasting blood samples were taken to separate plasma and red blood cells for analysis of copper, zinc, magnesium and iron and certain metal dependent enzymatic biomarkers.

RESULTS

Endurance training significantly decreased the plasma levels of copper (P<0.01), zinc and iron (P<0.05) while in erythrocytes a significant (P<0.001) decrease was observed only for Mg and Zn. There was a concomitant increase (P<0.05) in urinary Zn excretion. In addition, the concentrations of certain metal dependent enzymatic biomarkers like RBC metallothionein (P<0.05) and carbonic anhydrase (P<0.01) (Zn biomarker), plasma ferritin (Fe biomarker) (P<0.001) and RBC Mg ATPase (Mg biomarker) (P<0.05) decreased after physical activity.

CONCLUSIONS

The findings of the present study suggested the increased requirements of these minerals during physical activity.

Survey of patient perception of pre-analytical requirements for blood testing in the UK and RoI

BACKGROUND

A patient survey developed by the Pre-Analytical Phase Special Interest Group of the Association for Clinical Biochemistry and Laboratory Medicine (ACB-PA-SIG) was conducted during November and December 2019. The survey aimed to determine the quality of information provided to patients in preparation for their blood test(s). In addition, the ACB-PA-SIG provide a number of recommendations, which, if adopted, may yield higher quality test results and improve patient management.

METHODS

The survey was distributed at phlebotomy suites in two Hospitals: Ipswich Hospital (United Kingdom [UK]), and Cork University Hospital (Republic of Ireland [RoI]).

RESULTS

Overall, 235 survey responses were received from the two sites. A total of 103 respondents received no information about preparing for their blood test and 92 had been told they did not need to fast. None of the patients surveyed had been instructed to fast for 12 h. Twenty-two patients had been told to avoid certain foods, drinks or medication, 14 were told to avoid strenuous activity and 41 respondents had been informed of the need to avoid alcohol/smoking prior to their blood test. Overall, only approximately 78 felt well informed about the blood taking process.

CONCLUSIONS

Based on the results of this survey, the ACB-PA-SIG conclude that: (1) clinicians should provide clear written information to patients regarding pre-analytical requirements; and (2) effective communication between laboratories and General Practitioners is required to disseminate information. In this paper, the ACB-PA-SIG provide a list of pre-analytical recommendations to standardize and improve practice across the UK and RoI.

Influence of chronic training workload on the hematological profile: a pilot study in sedentary people, amateur and professional cyclists

Background and aim:

The assessment of hematological profile requires to identify possible sources of biological variability, including exercise-related variations. This study was hence aimed to evaluate hematological profile variations in amateur and professional athletes, and establish their possible dependence on cumulative training volume.

Materials and Methods:

The study population consisted of 59 sedentary male subjects, 78 amateur and 80 professional male cyclists, in whom a large number of hematological variables were measured at rest.

Results:

Red blood cell (RBC) count and hemoglobin were decreased in the two athlete cohorts compared to sedentary subjects, but did not differ between amateur and professional cyclists. Hematocrit was gradually and significantly decreased in parallel with cumulative training volume. Amateur cyclists displayed higher mean corpuscular volume (MCV) and lower mean corpuscular hemoglobin concentration (MCHC) values than sedentary subjects and professional cyclists, whilst mean corpuscular hemoglobin (MCH) was higher in professional cyclists. The reticulocyte count and soluble transferrin receptor (sTFR) values were similar across all groups. Serum ferritin was higher in professional cyclists than in the other two groups, whilst transferrin gradually decreased from sedentary group to the two cohorts of amateur and professional cyclists. In univariate analysis, cumulative training volume was inversely associated with age, body mass index (BMI), RBC count, hematocrit, hemoglobin and transferrin, whilst a positive association was found with ferritin. In multivariate analysis, BMI, RBC count and ferritin remained significantly associated with training volume.

Conclusions:

These results show that the volume of endurance training may affect some hematological variables. (www.actabiomedica.it)

Hemolysis Is Responsible for Elevation of Serum Iron Concentration After Regular Exercises in Judo Athletes

Serum iron concentration increases in marathon athletes after running due to mechanical destruction of red blood cells (hemolysis). This study was performed to examine whether serum iron concentration increases after regular Judo exercise, and if so, whether such post-exercise iron increase is caused by hemolysis. We examined biochemical parameters related to red blood cell and iron metabolism in 16 male competitive Judo athletes before and after traditional exercise training composed of basic movements and freestyle matchup. The parameters were adjusted for changes in plasma volume based on simultaneously measured albumin concentration. The red blood cell count, hemoglobin concentration, and hematocrit levels decreased significantly, by 6.0-8.4%, after Judo exercise. The serum iron concentration and transferrin saturation increased significantly, from 87 ± 34 μg/dL to 98 ± 29 μg/dL and from 27.1 ± 9.7% to 31.2 ± 9.0%, respectively. Furthermore, the serum free hemoglobin level increased by 33.9% (p < 0.05), and haptoglobin concentration decreased by 19.2% (p < 0.001). A significant negative correlation was observed between Δ haptoglobin concentration and Δ serum iron concentration (r = - 0.551, p = 0.027). The results of this study indicate that serum iron concentration increases significantly after Judo exercise due to hemolysis.

The Influence of Floorball on Hematological Parameters: Consequences in Health Assessment and Antidoping Testing

Assessment of hematological parameters is common in sports medicine. Although physical exercise is an important preanalytical variable, data about acute hematological changes after high-intensity intermittent exercise are scarce. This study aimed to examine floorball as a potential preanalytical variable for hematological parameters used in health assessment and antidoping testing. Twenty-three professional male floorball players participated in a floorball game. Hematological parameters including hemoglobin, erythrocyte count and erythrocyte indices, reticulocytes, white blood cells (WBC), platelets, reticulocytes, and OFF-hr score were assessed at baseline, immediately postgame, and at 2 h postgame. Median hemoglobin concentration decreased significantly from 146 g/L pregame to 141 g/L immediately postgame (p < 0.001). WBC count increased from 7.2 × 10⁹/L pregame to 10.1 × 10⁹/L 2 h postgame (p < 0.001). The median OFF-hr score decreased from 99.5 to 94.2 immediately postgame and remained significantly lower than baseline at 2 h postgame (94.4, p=0.030). Looking at individual results, the highest OFF-hr score increased from 120 at baseline to 124 at 2 h postgame. Our findings suggest that participation in a floorball game affects several hematological parameters and consequently can affect health assessment and antidoping testing.

Increased level of circulating cell-free mitochondrial DNA due to a single bout of strenuous physical exercise

Purpose

Physical exercise is reported to affect the immune response in various ways. Thus, the levels of pro-inflammatory cytokines as well as the abundance of circulating leukocytes are changed. In this study, the occurence of circulating cell-free mitochondrial DNA (cfmtDNA) and nuclear DNA (nDNA) was investigated in connection with a single bout of strenuous physical exercise.

Methods

Healthy volunteers performed a controlled ergo-spirometry cycle test and venous blood samples were taken at different time-points to analyze the concentration of blood components before, during and after the test. The number of circulating leukocytes was measured, as well as secretion of the soluble urokinase activator receptor (suPAR).

Results

Cf-mtDNA significantly increased during exercise, compared to baseline values and after 30 and 90 min of rest. Circulating leukocytes increased during exercise, but returned to baseline levels afterwards. Surface expression of the urokinase plasminogen activating receptor (uPAR) on neutrophils decreased significantly during exercise. The concentration of suPAR tended to increase during exercise but only significantly after 90 min of rest.

Conclusion

Increased concentration of cf-mtDNA indicates that cell damage takes place during high intensity training. Hypoxia and tissue damage are likely causes of cf-mtDNA from muscle cells. The levels of cf-mtDNA remain high during the initial rest, due to the decreasing numbers of leukocytes normally clearing the plasma from cf-mtDNA. The increased levels of suPAR further emphasize that strenuous physical exercise causes a reaction similar to inflammation. Further studies are needed to detect the source of increased cf-mtDNA and the corresponding increase of suPAR liberation.

Physical activity and laryngeal cancer

Although an active lifestyle physical has been convincingly associated with a decreased risk of developing many forms of cancers, including neck and head malignancies, uncertainty surrounds the relationship between physical activity (PA) and laryngeal carcinogenesis. Epidemiologic evidence, garnered from some well-conducted cross-sectional, prospective and retrospective studies, seemingly attests that the impact of PA may be not so straightforward in lowering laryngeal cancer risk as for other malignancies. Reasonable consensus has been reached that moderate-intensity PA may generate the larger potential benefits, whilst the effect of high-intensity PA appears more controversial and even contradictory. This is mainly attributable to the fact that moderate PA may have more favorable effects than high-intensity exercise in decreasing the impact of some risk factors of laryngeal cancer such as metabolic syndrome, cigarette smoking, inflammation, and gastroesophageal reflux disease. Significant biological and psychological benefits from moderate-intensity exercise have also been described in patients surviving from primary laryngeal cancers. This would hence lead us to conclude that promotion of an active lifestyle, characterized by performance of moderate-intensity PA (e.g., between 3 and 6 metabolic equivalents, equaling short distance running), may be beneficial for lowering the risk of developing laryngeal cancer and for improving the quality of life of larynx cancer survivors.

Exertional hematuria: definition, epidemiology, diagnostic and clinical considerations

Exertional hematuria can be considered a subcategory of exercise-induced hematuria, characterized by painless appearance of erythrocytes in urine after recent physical exercise, not directly attributable to external traumatic injuries to the genitourinary system, and spontaneously resolving with rest. Although its frequency has enormous heterogeneity, depending on the athlete population, duration and intensity of exercise, technique used for identifying or quantifying hematuria and relative diagnostic thresholds, what clearly emerges from the scientific literature is that a certain degree of hematuria is commonplace after non-contact sports, especially running. This exertional hematuria, which appears self-limiting, may be attributable to some frequently concomitant causes, involving organs of the genitourinary system, and mostly encompassing bladder or urethral injuries. Renal injuries caused by internal movements, vascular spasm and ischemia are also potential causes of increased glomerular permeability to erythrocytes, whilst the presence of preexisting genitourinary diseases cannot be ruled out, especially when post-exercise hematuria is recurrent or endures. Therefore, whenever hematuria is observed in a random urine specimen, recent sports performance (especially running) should be investigated and urinalyses scheduled for the following days. When no temporal association of hematuria with exercise can be found, when genitourinary traumas have been excluded or hematuria persists for >72 h, specific diagnostic investigations should be planned to identify possible genitourinary diseases.

Normalization strategies differently affect circulating miRNA profile associated with the training status

MicroRNAs are fine regulators of the whole-body adaptive response but their use as biomarkers is limited by the lack of standardized pre- and post-analytical procedures. This work aimed to compare different normalization approaches for RT-qPCR data analyses, in order to identify the most reliable and reproducible method to analyze circulating miRNA expression profiles in sedentary and highly-trained subjects. As the physically active status is known to affect miRNA expression, they could be effective biomarkers of the homeostatic response. Following RNA extraction from plasma, a panel of 179 miRNAs was assayed by RT-qPCR and quantified by applying different normalization strategies based on endogenous miRNAs and exogenous oligonucleotides. hsa-miR-320d was found as the most appropriate reference miRNA in reducing the technical variability among the experimental replicates and, hence, in highlighting the inter-cohorts differences. Our data showed an association between the physically active status and specific skeletal muscle- and bone-associated circulating miRNAs profiles, revealing that established epigenetic modifications affect the baseline physiological status of these tissues. Since different normalization strategies led to different outputs, in order to avoid misleading interpretation of data, we remark the importance of the accurate choice of the most reliable normalization method in every experimental setting.

Errors in the Extra-Analytical Phases of Clinical Chemistry Laboratory Testing

The total testing process consists of various phases from the pre-preanalytical to the post-postanalytical phase, the so-called brain-to-brain loop. With improvements in analytical techniques and efficient quality control programmes, most laboratory errors now occur in the extra-analytical phases. There has been recent interest in these errors with numerous publications highlighting their effect on service delivery, patient care and cost. This interest has led to the formation of various working groups whose mission is to develop standardized quality indicators which can be used to measure the performance of service of these phases. This will eventually lead to the development of external quality assessment schemes to monitor these phases in agreement with ISO15189:2012 recommendations. This review focuses on potential errors in the extra-analytical phases of clinical chemistry laboratory testing, some of the studies performed to assess the severity and impact of these errors and processes that are in place to address these errors. The aim of this review is to highlight the importance of these errors for the requesting clinician.

Effects of testosterone enanthate and resistance training on myocardium in Wistar rats; clinical and anatomical pathology

This study was performed to determine the effects of 8 weeks testosterone enanthate (TE) injection and resistance training (RT) on cardiac muscle in male Wistar rats. A total of 28 male adult Wistar rats were randomly divided into 4 groups; control + placebo, RT + placebo, TE and TE + RT. Testosterone enanthate (20 mg/kg BW, IM) and placebo (olive oil; 0.2 ml, IM) were injected twice a week for 2 months. The RT consisted of climbing (5 reps/3 sets) a ladder carrying a load suspended from the tail. The serum activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and creatine kinase MB (CK-MB) and serum level of creatinine, urea and cardiac troponin I (CTnI) were evaluated. After sacrifice, samples from myocardial muscle were collected for histopathology evaluation. The serum concentration of CTnI and CK-MB activity significantly increased in group RT compared with control (p < .05). In group RT + TE, all biomarkers of muscle damage (CTnI, CK-MB, AST, LDH) were significantly more than those in control (p < .05). Also, mild myocardial hypertrophy was observed in RT and RT + TE groups. The higher level of all heart damage biomarkers in the RT + TE group rather than control may indicate the synergistic effects of medication and exercise.

Does recreational scuba diving have clinically significant effect on routine haematological parameters?

Introduction

Scuba diving represents a combination of exercise and changes in environmental conditions. This study aimed to evaluate changes in haematological parameters after recreational scuba diving in order to identify clinically significant changes.

Materials and methods

The study included males, 17 recreational divers, median age (range) 41 (30-52) years. Blood samples were taken before diving, immediately after diving to 30 meters for 30 minutes, 3 hours and 6 hours after diving. Complete blood counts were analyzed on the Cell Dyn Ruby haematology analyzer. Statistical significance between successive measurements was tested using Friedman test. The difference between the two measurements was judged against desirable bias (DSB) derived from biological variation and calculated reference change values (RCV). The difference higher than RCV was considered clinically significant.

Results

A statistically significant increase and difference judging against DSB was observed: for neutrophils immediately, 3 and 6 hours after diving (18%, 34% and 36%, respectively), for white blood cells (WBCs) 3 and 6 hours after diving (20% and 25%, respectively), for lymphocytes (20%) and monocytes (23%) 6 hours after diving. A statistically significant decrease and difference judging against DSB was found: immediately after diving for monocytes (- 15%), 3 and 6 hours after diving for red blood cells (RBCs) (- 2.6% and -2.9%, respectively), haemoglobin (- 2.1% and - 2.8%, respectively) and haematocrit (- 2.4% and - 3.2%, respectively). A clinically significant change was not found for any of the test parameters when compared to RCV.

Conclusions

Observed statistically significant changes after recreational scuba diving; WBCs, neutrophils, lymphocytes, monocytes increase and RBCs, haemoglobin, haematocrit decrease, probably will not affect clinical decision.

Acutely developing, spurious anaemia without actual blood loss. A paradigmatic case report

We describe the case of a 55-year old women admitted at night to the emergency department (ED), complaining for acute abdominal pain lasting for nearly 5 hours. A first blood testing, performed immediately after admission, revealed mild anaemia. A second blood sample, drawn two hours after admission, revealed a considerable decrease of haemoglobin, haematocrit, total white blood cell and platelet counts (between 10-15% reduction). Abdominal ultrasonography was normal and the patient had no signs or symptoms of internal or external haemorrhage. Pre-analytical and analytical errors were accurately excluded. No infusion therapy was administered. After thoughtful discussing the sequence of events, it was ascertained that the first set of blood samples was drawn with the patient in seated position, immediately after ED admission (i.e., approximately 1 min passed from standing to seated position before venipuncture), whereas the second set of blood samples was drawn with the patient lying for two hours in supine position. This case report highlights the importance of standardizing patient position before venous blood collection, along with the crucial role played by cooperation and communication between laboratory and clinical wards for identifying and troubleshooting potential causes of spurious results of in vitro diagnostic testing.

Redox status alterations during the competitive season in élite soccer players: focus on peripheral leukocyte-derived ROS

It is well known that exercise training can deeply affect redox homeostasis by enhancing antioxidant defenses. However, exhaustive exercise can induce excessive reactive oxygen species (ROS) production, leading to oxidative stress-related tissue injury and impaired muscle contractility. Hence, ROS represent important signaling molecules whose level has to be maintained to preserve normal cellular function, but which can also accumulate in response to repetitive muscle contraction. In fact, low levels of oxidants have been suggested to be essential for muscle contraction. Both aerobic and anaerobic exercise induce ROS production from several sources (mitochondria, NADPH oxidases and xanthine oxidases); however, the exact mechanisms underlying exercise-induced oxidative stress remain undefined. Professional athletes show a high risk for oxidative stress, and consequently muscle injury or decreased performance. Based on this background, we investigated leukocyte redox homeostasis alterations during the soccer season in élite soccer players. Overall blood redox status was investigated in twenty-seven male soccer players from primary division (Italian "Serie A" team) at four critical time points during the soccer season: T0: just before the first team training session; T1: at the beginning of the season; T2: in the middle of the season and T3: at the end of the season. The main markers of muscular damage (CK, myoglobin, LDH), assessed by standard routine methods, are significantly altered at the considered time points (T0 vs T1 P < 0.01). In peripheral leukocyte subpopulations, ROS production shows significant alterations at the considered time points during the soccer season, and strictly and significantly correlates with CK values at every considered time point. Our experimental data indicate that deep redox homeostasis alterations are evident during the soccer season in élite soccer players, and that oxidative stress can be easily monitored, besides using the standard plasma biochemical parameters, by leukocyte ROS production analysis.

A combination of routine blood analytes predicts fitness decrement in elderly endurance athletes

Endurance sports are enjoying greater popularity, particularly among new target groups such as the elderly. Predictors of future physical capacities providing a basis for training adaptations are in high demand. We therefore aimed to estimate the future physical performance of elderly marathoners (runners/bicyclists) using a set of easily accessible standard laboratory parameters. To this end, 47 elderly marathon athletes underwent physical examinations including bicycle ergometry and a blood draw at baseline and after a three-year follow-up period. In order to compile a statistical model containing baseline laboratory results allowing prediction of follow-up ergometry performance, the cohort was subgrouped into a model training (n = 25) and a test sample (n = 22). The model containing significant predictors in univariate analysis (alanine aminotransferase, urea, folic acid, myeloperoxidase and total cholesterol) presented with high statistical significance and excellent goodness of fit (R2 = 0.789, ROC-AUC = 0.951±0.050) in the model training sample and was validated in the test sample (ROC-AUC = 0.786±0.098). Our results suggest that standard laboratory parameters could be particularly useful for predicting future physical capacity in elderly marathoners. It hence merits further research whether these conclusions can be translated to other disciplines or age groups.

Pre-analytical phase management: a review of the procedures from patient preparation to laboratory analysis

The pre-analytical phase encompasses all the procedures before the start of laboratory testing. This phase of the testing process is responsible for the majority of the laboratory errors, since the related procedures involve many sorts of non-laboratory professionals working outside the laboratory setting, thus without direct supervision by the laboratory staff. Therefore, either correct organization or management of both personnel and procedures that regard blood specimen collection by venipuncture are of fundamental importance, since the various steps for performing blood collection represent per se sources of laboratory variability. The aim of this (non-systematic) review addressed to healthcare professionals is to highlight the importance of blood specimen management (from patient preparation to laboratory analyses), as a tool to prevent laboratory errors, with the concept that laboratory results from inappropriate blood specimens are inconsistent and do not allow proper treatment nor monitoring of the patient.

Non-traumatic rhabdomyolysis: Background, laboratory features, and acute clinical management

Rhabdomyolysis is a relatively rare condition, but its clinical consequences are frequently dramatic in terms of both morbidity and mortality. Although no consensus has been reached so far about the precise definition of this condition, the term rhabdomyolysis describes a rapid breakdown of striated, or skeletal, muscle. It is hence characterized by the rupture and necrosis of muscle fibers, resulting in release of cell degradation products and intracellular elements within the bloodstream and extracellular space. Notably, the percentage of patients with rhabdomyolysis who develop acute kidney injury, the most dramatic consequence, varies from 13% to over 50% according to both the cause and the clinical and organizational setting where they are diagnosed. Despite direct muscle injury (i.e., traumatic rhabdomyolysis) remains the most common cause, additional causes, frequently overlapping, include hypoxic, physical, chemical or biological factors. The conventional triad of symptoms includes muscle pain, weakness and dark urine. The laboratory diagnosis is essentially based on the measurement of biomarkers of muscle injury, being creatine kinase (CK) the biochemical "gold standard" for diagnosis, and myoglobin the "gold standard" for prognostication, especially in patients with non-traumatic rhabdomyolysis. The essential clinical management in the emergency department is based on a targeted intervention to manage the underlying cause, combined with infusion of fluids and eventually sodium bicarbonate. We will present and discuss in this article the pathophysiological and clinical features of non-traumatic rhabdomyolysis, focusing specifically on Emergency Department (ED) management.

Physical Exercise and DNA Injury: Good or Evil?

Regular, low-intensity physical activity is currently advocated for lowering the risk of developing many acute and especially chronic diseases. However, several lines of evidence attest that strenuous exercise may enhance inflammation and trigger the generation of free radical-mediated damage, thus overwhelming the undisputable benefits of regular, medium-intensity physical activity. Since reactive oxygen species are actively generated during high-intensity exercise, and these reactive compounds are known to impact DNA stability, we review here the current evidence about strenuous exercise and DNA injury. Despite the outcome of the various studies cannot be pooled due to considerable variation in design, sample population, outcome, and analytical techniques used to assess DNA damage, it seems reasonable to conclude that medium- to high-volume exercise triggers a certain amount of DNA injury, which appears to be transitory and directly proportional to exercise intensity. This damage, reasonably attributable to direct effect of free radicals on nucleic acids, is efficiently repaired in vivo within 24-72h. Therefore, physical exercise should not bear long-term consequences for athlete's health provided that an appropriate time of recovery between volumes of high-intensity exercise is set. Regular exertion, with a step-by-step increase of exercise load, also seems to be the most safe approach for eluding DNA instability.

Low Vitamin D Levels Do Not Predict Hyperglycemia in Elderly Endurance Athletes (but in Controls)

BACKGROUND AND AIM

Recent studies revealed a link between hypovitaminosis D3 and the risk for hyperglycemia. Further mechanistic and interventional investigations suggested a common reason for both conditions rather than a causal relationship. Exposure to sunlight is the most relevant source of vitamin D3 (25(OH)D), whereas adipose tissue is able to store relevant amounts of the lipophilic vitamin. Since running/bicycling leads to increased out-door time and alters physiological response mechanisms, it can be hypothesized that the correlation between hypovitaminosis D3 and hyperglycemia might be disturbed in outdoor athletes.

METHODS

47 elderly marathoners/bicyclists and 47 age/sex matched controls were studied in a longitudinal setting at baseline and after three years. HbA1c as a surrogate for (pre-)diabetic states was quantified via HPLC, 25(OH)D levels were measured by means of chemiluminescent assays. Physical performance was assessed by ergometry.

RESULTS

When adjusted for seasonal variations, 25(OH)D was significantly higher in athletes than in controls. 25(OH)D levels inversely correlated with triglycerides in both groups, whereas only in controls an association between high BMI or low physical performance with hypovitaminosis D3 had been found. Likewise, the presence of hypovitaminosis D3 at baseline successfully predicted hyperglycemia at the follow up examinations within the control group (AUC = 0.85, 95% CI [0.74, 0.96], p < .001, statistically independent from BMI), but not in athletes.

CONCLUSION

Our data suggest that mechanisms of HbA1c elevation might differ between athletes and controls. Thus, intense physical activity must be taken into account as a potential pre-analytic confounder when it is aimed to predict metabolic risk by vitamin D3 levels.

The role of European Federation of Clinical Chemistry and Laboratory Medicine Working Group for Preanalytical Phase in standardization and harmonization of the preanalytical phase in Europe

Patient safety is a leading challenge in healthcare and from the laboratory perspective it is now well established that preanalytical errors are the major contributor to the overall rate of diagnostic and therapeutic errors. To address this, the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for Preanalytical Phase (EFLM WG-PRE) was established to lead in standardization and harmonization of preanalytical policies and practices at a European level. One of the key activities of the WG-PRE is the organization of the biennial EFLM-BD conference on the preanalytical phase to provide a forum for National Societies (NS) to discuss their issues. Since 2012, a year after the first Preanalytical phase conference, there has been a rapid growth in the number of NS with a working group engaged in preanalytical phase activities and there are now at least 19 countries that have one. As a result of discussions with NS at the third conference held in March 2015 five key areas were identified as requiring harmonisation. These were test ordering, sample transport and storage, patient preparation, sampling procedures and management of unsuitable specimens. The article below summarises the work that has and will be done in these areas. The goal of this initiative is to ensure the EFLM WG-PRE produces work that meets the needs of the European laboratory medicine community. Progress made in the identified areas will be updated at the next preanalytical phase conference and show that we have produced guidance that has enhanced standardisation in the preanalytical phase and improved patient safety throughout Europe.

Pre-analytic variability in cardiovascular biomarker testing

The impact of laboratory medicine on clinical cardiology has dramatically increased over the years and a lot of cardiovascular biomarkers have been recently proposed. In order to avoid clinical mistakes, physicians should be well aware of all the aspects, which could affect the quality of laboratory results, remembering that pre-analytic variability is an often overlooked significant source of bias, determining the vast majority of laboratory errors. This review addresses the determinants of pre-analitycal variability in cardiovascular biomarker testing, focusing on the most widespread biomarkers, which are cardiac troponins and natriuretic peptides.

Renal Function in Kidney and Liver Transplant Recipients After A 130-km Road Cycling Race

BACKGROUND

A few patients, after receiving solid organ transplantation, return to performing various sports and competitions; however, at present, data no study had evaluated the effects of endurance cycling races on their renal function.

METHODS

Race times and short form (36) health survey questionnaires of 10 kidney transplant recipients (KTR) and 8 liver transplant recipients (LTR) transplanted recipients involved in a road cycling race (130 km) were compared with 35 healthy control subjects (HCS), also taking laboratory blood and urine tests the day before the race, at the end of the race, and 18 to 24 hours after competing.

RESULTS

The 3 groups showed similar race times (KTR, 5 hours 59 minutes ± 0 hours 39 minutes; LTR, 6 hours 20 minutes ± 1 hour 11 minutes; HCS, 5 hours 40 minutes ± 1 hour 28 minutes), similar short form (36) health survey scores, and similar trend of laboratory parameters which returned to baseline after 18 to 24 hours. After the race, there was an increase in creatinine (0.24 mg/dL; effect size [ES] = 0.78; P < 0.001), urea (22 mg/dL; ES = 1.42; P < 0.001), and a decrease of estimated glomerular filtration rate (-17 mL/min; ES = 0.85; P < 0.001). The increase of blood uric acid was more remarkable in HCS and KTR (2.3 mg/dL; ES = 1.39; P < 0.001). The KTR showed an increase of microalbuminuria (167.4 mg/L; ES = 1.20; P < 0.001) and proteinuria (175 mg/mL; ES = 0.97; P < 0.001) similar to LTR (microalbuminuria: 176.0 mg/L; ES = 1.26; P < 0.001; proteinuria: 213 mg/mL; ES = 1.18; P < 0.001), with high individual variability. The HCS had a nonsignificant increase of microalbuminuria (4.4 mg/L; ES = 0.03; P = 0.338) and proteinuria (59 mg/mL; ES = 0.33; P = 0.084).

CONCLUSIONS

Selected and well-trained KTR and LTR patients can participate to an endurance cycling race showing final race times and temporary modifications of kidney function similar to those of HCS group, despite some differences related to baseline clinical conditions and pharmacological therapies. Patients involved in this study represent the upper limit of performance currently available for transplant recipients and cannot be considered representative of the entire transplanted population.

Changes in urinary amino acids excretion in relationship with muscle activity markers over a professional cycling stage race: in search of fatigue markers

The aim of this study was to identify the relationship between metabolic effort, muscular damage/activity indices, and urinary amino acids profile over the course of a strenuous prolonged endurance activity, as a cycling stage race is, in order to identify possible fatigue markers. Nine professional cyclists belonging to a single team, competing in the Giro d'Italia cycling stage race, were anthropometrically characterized and sampled for blood and urine the day before the race started, and on days 12 and 23 of the race. Diet was kept the same over the race, and power output and energy expenditure were recorded. Sera were assayed for muscle markers (lactate dehydrogenase, aspartate aminotransferase, and creatine kinase activities, and blood urea nitrogen), and creatinine, all corrected for plasma volume changes. Urines were profiled for amino acid concentrations, normalized on creatinine excretion. Renal function, in terms of glomerular filtration rate, was monitored by MDRD equation corrected on body surface area. Creatine kinase activity and blood urea were increased during the race as did serum creatinine while kidney function remained stable. Among the amino acids, taurine, glycine, cysteine, leucine, carnosine, 1-methyl histidine, and 3-methyl histidine showed a net decreased, while homocysteine was increased. Taurine and the dipeptide carnosine (β-alanyl-L-histidine) were significantly correlated with the muscle activity markers and the indices of effort. In conclusion, the metabolic profile is modified strikingly due to the effort. Urinary taurine and carnosine seem useful tools to evaluate the muscle damage and possibly the fatigue status on a long-term basis.

The quality and scope of information provided by medical laboratories to patients before laboratory testing: Survey of the Working Group for Patient Preparation of the Croatian Society of Medical Biochemistry and Laboratory Medicine

INTRODUCTION

The aim of this work was to evaluate to what extent the scope and content of information provided to patients is standardized across medical biochemistry laboratories in Croatia.

MATERIALS AND METHODS

Two on-line self-report surveys were sent out: Survey A regarding attitudes on importance of patient preparation and Survey B on the contents of patient preparation instructions.

RESULTS

13/118 laboratories (11%) do not provide written instructions to patients on how to prepare for laboratory testing, and 36 (40%) do not include information about water intake in their instructions. Only half of laboratories provide instructions for prostate-specific antigen (53.8%), female sex hormones (53.7%) and therapeutic drug monitoring (TDM) (52.5%). Inadequate information about fasting status (55.0%) and 24 hour urine collection (77.9%) were frequent errors with high severity and were associated with the greatest potential to cause patient harm.

CONCLUSIONS

Laboratory professionals in Croatia have a positive attitude towards the importance of patient preparation for laboratory testing. However, the information for laboratory testing is not standardized and frequently lacks guidance for tests related to TDM, coagulation and endocrinology. This study highlights the need for standardized, updated and evidence-based recommendations for patient preparation in order to minimize the risk for patients.

Effect of training status on the changes in platelet parameters induced by short-duration exhaustive exercise

It is now well known that hemostasis is directly involved in the benefits induced by physical activity. It has recently been shown that the baseline mean platelet volume (MPV) may be a predictor of endurance performance. We aimed to explore whether platelet parameters are associated with VO2max as well as running duration and speed in a short-duration exhaustive exercise test. Thirty healthy male subjects (10 sedentary and 20 trained) performed an incremental running test until exhaustion. MPV, platelet distribution width (PDW), platelet (Plt) count, and plateletcrit (Pct) were determined before exercise, immediately after exercise and after 30' recovery. Training status did not produce any difference in the baseline levels or in the post-exercise increases found in all the parameters tested. VO2max, test duration, and running speed were not correlated with any baseline parameter. Although MPV was found to be a predictor of endurance performance in long-duration exercise, the results of the present study are consistent with the hypothesis that MPV may not be a significant marker of performance in short-duration exhaustive exercise. Likewise, more research is needed to ascertain whether platelet activation is a reliable performance predictor in other exercise settings.

Microcentrifuge or Automated Hematological Analyzer to Assess Hematocrit in Exercise? Effect on Plasma Volume Loss Calculations

The assessment of plasma volume loss (∆PV) induced by exercise can be estimated from changes in hematocrit (Htc) and hemoglobin (Hb), and it is essential when investigating the metabolic or biologic response to exercise of circulating biomarkers. We aimed to ascertain whether the estimation of ∆PV may differ when Hb and Htc are determined by automated hematological analyzer (AHA) versus manual methods. Twenty-five healthy male subjects performed a maximal running incremental exercise. Blood samples were taken before exercise, immediately after exercise, and after a 30-min recovery. Hb and Htc (Htc-AHA) were determined by an AHA. Htc was also determined by microcentrifugation (Htc-M). The ∆PV immediately after exercise and after recovery was calculated. The serum concentrations of several specimens were determined and corrected for ∆PV derived from Htc-AHA (∆PVAHA) and from Htc-M (∆PVM). Htc-M was found to be higher than Htc-AHA at all time points (p < 0.001). However, no differences were observed between ∆PVM and ∆PVAHA either post exercise (∆PVM -12.43% versus ∆PVAHA -12.41%, p = 0.929) or after recovery (∆PVM 1.47% versus ∆PVAHA 1.97%, p = 0.171). No significant differences were found between both ∆PV corrected concentrations of any biomarker (p ≥ 0.076). In conclusion, both AHA and the microcentrifuge may be reliably used to estimate ∆PV during exercise.

Effects of allopurinol on exercise-induced muscle damage: new therapeutic approaches?

Intensive muscular activity can trigger oxidative stress, and free radicals may hence be generated by working skeletal muscle. The role of the enzyme xanthine oxidase as a generating source of free radicals is well documented and therefore is involved in the skeletal muscle damage as well as in the potential transient cardiovascular damage induced by high-intensity physical exercise. Allopurinol is a purine hypoxanthine-based structural analog and a well-known inhibitor of xanthine oxidase. The administration of the xanthine oxidase inhibitor allopurinol may hence be regarded as promising, safe, and an economic strategy to decrease transient skeletal muscle damage (as well as heart damage, when occurring) in top-level athletes when administered before a competition or a particularly high-intensity training session. Although continuous administration of allopurinol in high-level athletes is not recommended due to its possible role in hampering training-induced adaptations, the drug might be useful in non-athletes. Exertional rhabdomyolysis is the most common form of rhabdomyolysis and affects individuals participating in a type of intense exercise to which they are not accustomed. This condition can cause exercise-related myoglobinuria, thus increasing the risk of acute renal failure and is also associated with sickle cell trait. In this manuscript, we have reviewed the recent evidence about the effects of allopurinol on exercise-induced muscle damage. More research is needed to determine whether allopurinol may be useful for preventing not only exertional rhabdomyolysis and acute renal damage but also skeletal muscle wasting in critical illness as well as in immobilized, bedridden, sarcopenic or cachectic patients.

Hemoconcentration induced by exercise: Revisiting the Dill and Costill equation

The Dill and Costill equation is used to estimate the exercise-induced hemoconcentration. However, this calculation requires drawing an extra whole-blood sample, which cannot be frozen and has to be analyzed with dedicate instrumentation in a relative short time. The aim of the present study was to explore the usefulness of some serum biochemical parameters to estimate hemoconcentration induced by exhaustive exercise. Fourteen healthy male subjects (19-34 years) performed a15-min running test at 110% of anaerobic threshold speed. Hemoglobin, hematocrit, brain natriuretic peptide (BNP), creatinine, gamma-glutamyltransferase (GGT), total-proteins, albumin, total calcium (Ca), K(+), Na(+), and Cl(-) were determined in blood samples taken before, after exercise, and after a 30-min recovery period. Plasma volume loss (ΔPV) was calculated by Dill and Costill equation. At post-exercise and after recovery, the percentage increments of total-proteins, albumin, GGT and Ca correlated significantly with ΔPV. Bland-Altman analyses showed that correcting BNP, creatinine, and K(+) concentration by Ca percentage increments yield biases and limits of agreement that are acceptable when compared with Dill and Costill equation correction. Ca concentration may be used as a hemoconcentration biomarker in high-intensity exercise, which would allow scientists and physicians avoid extra costs, facilitate in-field research, and delayed estimation of hemoconcentration using stored serum samples.

Methodological considerations to determine the effect of exercise on brain-derived neurotrophic factor levels

OBJECTIVES

Physical exercise up-regulates brain-derived neurotrophic factor (BDNF) in the brain and blood. However, there is yet no consensus about the adequate blood processing conditions to standardize its assessment. We aimed to find a reliable blood sample processing method to determine changes in BDNF due to exercise.

DESIGN AND METHODS

Twelve healthy university students performed an incremental cycling test to exhaustion. At baseline, immediately after exercise, and 30 and 60 min of recovery, venous blood was drawn and processed under different conditions, i.e. whole blood, serum coagulated for 10 min and 24 h, total plasma, and platelet-free plasma. BDNF concentration was measured by ELISA.

RESULTS

Exercise increased BDNF in whole blood and in serum coagulated for 24 h when corrected by hemoconcentration. We did not find effects of exercise on BDNF in serum coagulated for 10 min or in plasma samples. Plasma shows heterogeneous BDNF values in response to exercise that are not prevented when platelets are eliminated while homogeneous BDNF levels were found in whole blood or serum coagulated for 24 hour samples.

CONCLUSIONS

In exercise studies, BDNF levels should be adjusted by hemoconcentration. Our data highlight the importance of blood sample selection since the differences between each one affect significantly the BDNF factor changes due to exercise.