Assessment of pN-GAL as a marker of renal function in elite cyclists during professional competitions.

Glomerular filtration rate (GFR) has been shown to be lower than physiological values during exercise with a strong negative correlation with exercise intensity. Among new markers of renal function, neutrophil gelatinase-associated lipocalin (NGAL) seems to be very promising. It is an early, sensitive and specific marker of acute kidney injury (AKI) with two isoforms: plasma NGAL (pNGAL) and urinary NGAL (uNGAL). The aim of the present study was to assess acute variations in NGAL plasma levels after performing high endurance physical exercise in a group of professional cyclists during the two major European professional cycling competitions (Giro D'Italia and Tour de France). Eighteen professional cyclistis were recruited for the study. A blood sample was collected during rest (after 8 hours fasting) and immediately after the competition (mountain stages) in order to assess the effect of very intense exercise on kidney function by measuring the variations of pNGAL. We also assessed plasma levels of creatinine, creatine-kinase (CK), LDH, transaminases and electrolytes. The results showed that Creatinine, CK and electrolytes levels remained almost stable between rest and post-competition. The levels of transaminases and NGAL showed a mild increase between rest and post-competition, with a significant difference between the two values only for transaminases (p=0.005). However, post-competition values of all investigated variables remained within the physiological range. The results of the present study suggest that even if NGAL values mildly rose after competition, no kidney injury occurred in these highly trained athletes during mountain stages of professional competitions. Other studies in literature confirmed that high endurance physical exercise seems not to cause renal injury in elite athletes. This is probably due to adaptive mechanisms of renal function and to the adaptation to physical stress gained with training.

Urinary hepcidin identifies a serum ferritin cut-off for iron supplementation in young athletes: a pilot study.

The use of iron supplements should be a judicious choice, primarily when considering the possible risks deriving from an unjustified treatment. In trained athletes, levels of ferritin between 15 and 30 microg/L are frequently observed. Within this ferritin range, the usefulness of iron supplementation is still controversial. The aim of the present study is to evaluate the clinical usefulness of hepcidin assessment in the analysis of the iron status of young non-anemic athletes. Fifty young athletes were enrolled. The subjects were divided into 4 groups according to their ferritin levels. No statistically significant difference was found regarding hepcidin levels between athletes with ferritin lower than 15 microg/L and those in the 15-30 microg/L range. Similarly, no difference was found between athletes with ferritin higher than 50 microg/L and those in the 30-50 microg/L range. On the contrary, statistically significant differences were found between athletes with ferritin levels ranging from 15 to 30 microg/L and those in the 30-50 microg/L range. The present study suggests that serum ferritin levels below 30 microg/L indicate an asymptomatic iron deficiency status inhibiting hepcidin expression and that 30 microg/L should be considered the ferritin cut-off when considering an iron supplementation in young athletes.

Health risk screening in adolescents: a pilot study.

AIM: Even if youths are generally perceived to be healthy, adolescent years are associated with significant morbidity. Screening and counselling programmes seem to be cost-effective but adolescents prefer to rely on health care services for the treatment of diagnosed diseases or injuries rather than for preventive actions. Age oriented studies are needed for better understanding the health needs of adolescents in order to provide an adequate offer of preventive opportunities. METHODS: Eight hundred youths ranging from 13 to 18 years of age were recruited. Health status and risks were clustered into the following five categories: clinical assessment, substance use/abuse, nutritional habits, alcohol and tobacco consumption, physical status. Surprisingly, 33% of the youths were suggested to perform further clinical assessment and even more interestingly a significant number of them received a diagnosis of a symptomatic disorder for which he or she did not previously consider a medical visit to be necessary. RESULTS: As expected, alcohol consumption, tobacco smoking, drug use/abuse and sedentary habit represent the risky lifestyles commonly followed by adolescents. CONCLUSION: The present study confirms the importance of screening programs addressed to health issues and behavioural attitudes of adolescents even in light of the fact that they may underestimate even indicative symptoms.

A biparametric flow cytometry analysis for the study of reticulocyte patterns of maturation.

Automated haematological analysers still represent the gold standard for the study of reticulocyte maturation even if this technique is based on structural properties and staining affinity rather than on functional aspects. On the contrary, flow cytometry allows the simultaneous analysis of multiple cellular characteristics including functional features. Aim was to investigate whether simultaneous analysis of different reticulocyte parameters using flow cytometry may add functional information when considering their pattern of maturation. Thirty-nine healthy donors (H) and 31 haemodialysed patients on treatment with rHuEpo (HDT) were analysed. Reticulocyte counts and their stages of maturation were studied both with ADVIA 2120 and by flow cytometry. TO/CD71 scattergraph reticulocyte analysis designed a peculiar distribution which was similar among the same group of subjects (H or HDT), but different between H and HDT. distribution of the percentage of reticulocytes in low, medium and high boxes calculated by ADVIA 2120 did not show any difference between H and HDT groups, while the analysis using flow cytometry pointed out statistically significant differences between H and HDT groups in the three boxes where the TO+/CD71+ reticulocytes were localized. The present study suggests that TO/CD71 analysis was reproducible and could detect different pattern of maturation of a particular clinical setting.

N-terminal proB-type natriuretic peptide and homocysteine concentrations in athletes.

AIM: Several studies suggest that intense exercise may increase the athlete's thrombotic tendency. Available data on those metabolic alteration are still conflicting and their clinical significance is still worth of interest. The aim of the present study was to investigate if widely used markers of cardiac damage such as NT-proBNP levels are affected by homocysteine concentrations during sustained sport activities. METHODS: Seventy-eight competitive, non-professional athletes were enrolled in the study; 70 healthy age matched subjects, recruited from blood donors, served as controls. Besides the general clinical determinations, the assessed variables included homocysteine, folate, vitamin B12, total and HDL cholesterol, LDH, CPK, NT-proBNP and IL-6. RESULTS: The percentages of athletes with normal and elevated homocysteine levels resulted 46% and 54%, respectively. Mean NT-proBNP levels were significantly higher in athletes than in controls (1176.66 + or - 442.15 pg/mL versus 450.34 + or - 180.39 pg/mL). No correlation was found between homocysteine and NT-proBNP values. CONCLUSIONS: The previously described "sport related" homocysteine is not related to other markers of cardiovascular stress such as NT-proBNP. Available data suggest that both hyperhomocysteinemia and high NT-proBNP levels in healthy young athletes could be interpreted as markers of metabolic and morphologic adaptation to training rather than a risk factor for cardio-vascular diseases.

Oxygen delivery enhancers: past, present, and future.

In endurance sport the delivery of oxygen to muscles plays a critical role. Indeed, muscle performance declines during prolonged and intense activity as a consequence of the shift from the aerobic to the anaerobic metabolism with an increase of lactate. To enhance the aerobic capacity 2 alternatives may be used: increasing either the transport or the delivery of oxygen. In this setting, blood doping is the practice of illicitly using a drug or blood product to improve athletic performance. Based on this definition, blood doping techniques may include: 1) blood transfusion (autologous or omologous); 2) erythropoiesis-stimulating substances [recombinant human erythropoietin (alpha, beta, omega), darbepoietin-alpha, continuous erythropoiesis receptor activator, hematide]; 3) blood substitutes (hemoglobin-based oxygen carriers, perfluorocarbon emulsions); 4) allosteric modulators of hemoglobin (RSR-13 and RSR-4); 5) gene doping (human erythropoietin gene transfection); 6) gene regulation (hypoxia-inducible transcription factors pathway). In the present overview we will briefly describe the above-mentioned techniques with the aim of underlining potential hematological alternatives to gene doping for increasing aerobic capacity in sport.

Sport-related hyperhomocysteinaemia: a putative marker of muscular demand to be noted for cardiovascular risk.

OBJECTIVE: Regular physical activity is associated with a reduction of cardiovascular morbidity and mortality; however, evidence of unfortunate cardiovascular events accompanying elite sport involvement continues to accumulate. To date, no information is available on possible peculiarities of the cardiovascular risk profile in athletes. DESIGN: The aim of this study was to evaluate plasma homocysteine levels in a group of athletes and to search for relationship with vitamin status and other metabolic variables in order to confirm the existence of a "sport-related hyperhomocysteinaemia" and to explain its clinical significance. The study population was composed of 82 athletes (59 male and 23 female) practising different sports and 70 healthy age-matched subjects (40 male and 30 female) as a control group. Besides the general clinical and analytical determinations, the assessed variables included homocysteine, folate, vitamin B12, total and high-density lipoprotein (HDL) cholesterol, lactate dehydrogenase (LDH), creatine kinase (CPK) and interleukin-6 (IL-6). RESULTS: The prevalence of hyperhomocysteinaemia (>15 micromol/l) in athletes and controls was 47% and 15%, respectively. No correlation was found between homocysteine and any of the other investigated variables, in particular plasma folate, blood pressure, LDH, CPK, total and HDL cholesterol and IL-6. CONCLUSION: The results of this study confirm the existence of a sport-related hyperhomocysteinaemia which appears linked neither to the same variables found in the general population, nor to specific training-related variables. We suggest that it would represent an adaptation to training but the possibility of a secondary vascular damage cannot be excluded.

Synergistic effects against post-ischemic cardiac dysfunction by sub-chronic nandrolone pretreatment and postconditioning: role of beta2-adrenoceptor.

Beta(2)-adrenoreceptor overexpression is beneficial against ischemia/reperfusion (I/R) injury. Whether beta-adrenoreceptors are involved in postconditioning (PostC) is unknown. We investigated whether nandrolone-decanoate (ND)-pretreatment can modulate (1) beta-adrenoreceptor expression and (2) post-ischemic cardiac function in response to I/R and PostC. Finally, we tested whether cardioprotection can be prevented by the inhibition of beta(2)-adrenoreceptors. Isolated rat hearts from ND pretreated (15 mg/kg/day i.m., for 14 days) and untreated-animals underwent 30-min ischemia and 120-min reperfusion. In subgroups, at the end of ischemia a PostC protocol (five cycles of 10-s reperfusion and 10-s ischemia) was applied and/or a beta(2)-adrenoreceptor blocker, ICI-118.551 (10 microM), was infused. Left ventricular pressure (LVP) was measured with an electromanometer, and infarct-size was evaluated using nitro-blue-tetrazolium staining. ND-pretreatment increased beta(2)-adrenoreceptor expression, but did not alter cardiac-weight, LVP and maximum rate of increase of LVP (dP/dt(max)). After I/R, infarct-size was smaller in ND-pretreatment than in untreated-animals. Infarct-size was also reduced by PostC, both in untreated and ND-pretreated animals. Contracture was less marked in ND-pretreated animals. PostC reduced contracture in both ND-pretreated and untreated hearts. Moreover, PostC improved post-ischemic recovery of developed LVP and dP/dt(max) much more in earts of ND-pretreated than untreated-animals. ICI-118.551 abolished ND protection and PostC-protection both in ND-pretreated and untreated hearts. Data show that two-weeks ND-pretreatment induces 1) an overexpression of beta(2)-ARs without cardiac hypertrophy and 2) improves the post-ischemic diastolic and systolic cardiac function. Intriguingly, ND-pretreatment potentiates the improvement of systolic function induced by postconditioning via beta(2)-adrenoreceptor activation.

A peculiar pattern of expression of the transferrin receptor (CD71) by reticulocytes in patients given recombinant human erythropoietin (rHuEPO): a novel marker for abuse in sport?

To overcome the limitation of the currently adopted direct method to detect recombinant Human Erythropoietin (rHuEpo) abuse in sport, indirect analysis of blood parameters are increasingly used as part of the anti-doping strategies. The aim of the present work is to identify whether immunophenotype modifications on erythroid cells may be indicative of previous rHuEPO administration. The study was conducted on dialyzed patients under treatment with rHuEPO (DPT). Dialyzed patients without rHuEPO therapy (DP) and volunteer donors (H) were used as controls. The analysis of erythroid cells immunophenotype, performed using a multiparametric flow cytometry technique, showed a peculiar pattern of CD71 expression following rHuEPO treatment. In particular CD71 showed an increased expression in mature and intermediate reticulocytes and a surprisingly decreased expression in immature reticulocytes. In conclusion, the analysis of reticulocyte maturation stages with TO/CD71 double staining may be considered as a valid alternative indirect method for the detection of rHuEPO abuse.