Sickle cell trait in Ivory Coast athletic throw and jump champions, 1956-1995

Lower Muscle and Blood Lactate Accumulation in Sickle Cell Trait Carriers in Response to Short High-Intensity Exercise

It remains unclear whether sickle cell trait (SCT) should be considered a risk factor during intense physical activity. By triggering the polymerization-sickling-vaso-occlusion cascade, lactate accumulation-associated acidosis in response to high-intensity exercise is believed to be one of the causes of complications. However, our understanding of lactate metabolism in response to high-intensity exercise in SCT carriers is incomplete. Thirty male SCT carriers (n = 15) and healthy subjects (n = 15) with and without α-thalassemia performed a 2-min high-intensity exercise. Blood and muscle lactate concentrations were measured at exercise completion. Time courses of blood lactate and glucose concentrations were followed during the subsequent recovery. Additional biochemical analyses were performed on biopsies of the vastus lateralis muscle. SCT was associated with lower blood and muscle lactate concentrations in response to the short high-intensity exercise. Compared to controls, the muscle content among SCT carriers of lactate transporter MCT4 and β2-adrenergic receptor were higher and lower, respectively. During recovery, the lactate removal ability was higher in SCT carriers. In the present study, no effect of α-thalassemia was observed. The lower blood and muscle lactate accumulations in SCT carriers may, to some extent, act as protective mechanisms: (i) against exercise-related acidosis and subsequent sickling, that may explain the relatively rare complications observed in exercising SCT carriers; and (ii) against the deleterious effects of intracellular lactate and associated acidosis on muscle function, that might explain the elevated presence of SCT carriers among the best sprinters.

VMP35 MNC, a novel iron-free supplement, enhances cytoprotection against anemia in human subjects: a novel hypothesis

Background

The American Society of Hematology reported that according to the National Heart, Lung, and Blood Institute (NHLBI) anemia is the most common blood disorder, which affects more than 3 million Americans, while the Global Burden of Disease 2016 (GBD 2016) reported that iron deficiency anemia (IDA) is the leading cause of anemia, which affects 1.93 billion people worldwide. Anemia is intricately linked to chronic inflammation, chronic kidney disease, gastrointestinal and gynecological malignancies, and autoimmune disorders. Hemorrhagic anemia results in substantial loss of blood, which causes significant alterations in all blood parameters, including reduced iron. The other type of anemia is chronic anemia syndrome (CAS), which is a constellation of disorders and chronic inflammatory events caused by an increasing anaerobic/acidic environment (promoting the growth of anaerobic organisms), inducing a defensive expenditure of alkalinizing buffers in hemoglobin (i.e. histidine), to prevent a dangerous lowering of blood pH. In this process, iron is cleaved from heme groups and transferred out of blood circulation into other organs, like the liver, appearing to be IDA, where excessive accumulation can lead to hemochromatosis, also known as 'iron overload anemia'.

Design

A pilot clinical study was conducted in 38 subjects (men = 10; women = 28; age = 22-82 years) to evaluate the rate of absorption and effects on blood of VMP35 multi-nutrient complex (MNC), a non-iron containing liquid nutraceutical supplement. Subjects consumed either placebo or VMP35 (30 mL) over a period of 0, 5, or 30 min.

Methods

Changes in peripheral blood smears from 38 subjects were observed using live blood cell imaging (LBCI) with phase contrast microscopy. Adverse events were rigorously monitored.

Results

VMP35 caused positive changes in the blood, including morphological, hematological (including restoration of hemoglobin), and rheological changes following 5 min of administration, which were sustained for at least 30 min.

Conclusion

Overall, the non-iron containing VMP35 can induce improvements in blood properties and potential benefits for subjects even with compromised digestive systems. No adverse events were reported. Further research studies are in progress to explore the mechanistic insight.

Moderate and intense muscular exercises induce marked intramyocellular metabolic acidosis in sickle cell disease mice

Sickle cell disease (SCD) is associated with an impaired oxygen delivery to skeletal muscle that could alter ATP production processes. The present study aimed to determine the effects of sickle hemoglobin (HbS) on muscle pH homeostasis in response to exercise in homozygous (HbSS, n = 9) and heterozygous (HbAS, n = 10) SCD (Townes) mice in comparison to control (HbAA, n = 10) littermates. Magnetic resonance spectroscopy of phosphorus 31 enabled to measure intramuscular pH and phosphocreatine (PCr) concentration during rest-stimulation-recovery protocols at two different intensities. Maximal activity of some enzymes involved in muscle energetics and content of proteins involved in pH regulation were also investigated. HbSS mice presented a more pronounced exercise-induced intramuscular acidosis, whatever the intensity of exercise. Moreover, the depletion of PCr was also exacerbated in HbSS mice in response to intense exercise as compared with both HbAA and HbAS mice ( P < 0.01). While no difference was observed concerning proteins involved in muscle pH regulation, the activity of enolase (a glycolytic enzyme) was higher in both HbSS and HbAS mice as compared with controls ( P < 0.05). Interestingly, HbAS mice presented also metabolic impairments as compared with their control counterparts. This study has identified for the first time an exacerbated exercise-induced intramuscular acidosis in SCD mice.

NEW & NOTEWORTHY The main finding of the present study was that the exercise-induced intramuscular acidosis was systematically more pronounced in sickle cell disease (SCD) mice as compared with their control counterparts. This result is important since it has been demonstrated in vitro that acidosis can trigger hemoglobin polymerization. From that point of view, our results tend to support the idea that high-intensity exercise may increase the risk of hemoglobin polymerization in SCD.

ACSM and CHAMP summit on sickle cell trait: mitigating risks for warfighters and athletes

INTRODUCTION

An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy.

METHODS

On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse.

RESULTS

New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified.

CONCLUSION

Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

A policy impact analysis of the mandatory NCAA sickle cell trait screening program

OBJECTIVE

To estimate the impact of the mandatory National Collegiate Athletic Association (NCAA) sickle cell trait (SCT) screening policy on the identification of sickle cell carriers and prevention of sudden death.

DATA SOURCE

We used NCAA reports, population-based SCT prevalence estimates, and published risks for exercise-related sudden death attributable to SCT.

STUDY DESIGN

We estimated the number of sickle cell carriers identified and the number of potentially preventable sudden deaths with mandatory SCT screening of NCAA Division I athletes. We calculated the number of student-athletes with SCT using a conditional probability based upon SCT prevalence data and self-identified race/ethnicity status. We estimated sudden deaths over 10 years based on published attributable risk of exercise-related sudden death due to SCT.

PRINCIPAL FINDINGS

We estimate that over 2,000 NCAA Division I student-athletes with SCT will be identified under this screening policy and that, without intervention, about seven NCAA Division I student-athletes would die suddenly as a complication of SCT over a 10-year period.

CONCLUSION

Universal sickle cell screening of NCAA Division I student-athletes will identify a substantial number of sickle cell carriers. A successful intervention could prevent about seven deaths over a decade.

Skeletal muscle structural and energetic characteristics in subjects with sickle cell trait, α-thalassemia, or dual hemoglobinopathy

Previous studies have shown that subjects with sickle cell trait (SCT), α-thalassemia (α-t), and the dual hemoglobinopathy (SCT/α-t) manifest subtle, albeit significant, differences during exercise. To better understand such differences, we assessed skeletal muscle histomorphological and energetic characteristics in 10 control HbAA subjects (C), 5 subjects with α-t (α-t), 6 SCT carriers (SCT) and 9 SCT carriers with α-t (SCT/α-t). Subjects underwent a muscle biopsy and also performed an incremental maximal exercise and a time to exhaustion test. There were no observable differences in daily energy expenditure, maximal power output (Pmax), or time to exhaustion at 110% Pmax ( Tex) among the groups. Blood lactate concentrations measured at the end of the Tex, muscle fiber type distribution, and mean phosphofructokinase (PFK), lactate dehydrogenase (LDH), β-hydroxyacyl-CoA-dehydrogenase (HAD), and citrate synthase (CS) activities were all similar among the four groups. However, SCT was associated with a lower cytochrome- c oxidase (COx) activity in type IIa fibers ( P < 0.05), and similar trends were observed in fiber types I and IIx. Trends toward lower creatine kinase (CK) activity ( P = 0.0702) and higher surface area of type IIx fibers were observed in SCT ( P = 0.0925). In summary, these findings support most of the previous observations in SCT, such as 1) similar maximal power output and associated maximal oxygen consumption (V̇o2max) values and 2) lower exercise performances during prolonged submaximal exercise. Furthermore, performances during short supramaximal exercise were not different in SCT. Finally, the dual hemoglobinopathy condition does not seem to affect muscle characteristics.

The epidemiology of abnormal hemoglobins in Mediterranean high-level athletes

The aim of this study was to determine the prevalence and nature of hemoglobin (Hb) defects in a Mediterranean high-level (HL) athlete population. Five hundred and ninety-four HL male and female athletes were recruited during the annual follow-up of the members of Tunisian national teams. Hematological data, Hb electrophoresis, and DNA analysis were assessed using conventional techniques. Sporting discipline, type of sport, and performance levels were assessed using a questionnaire. The results showed that 32 HL athletes had abnormal Hb (5.4%): beta-thalassemia (2.2%), alpha-thalassemia (0.5%), HbAS (1.5%), HbAC (0.5%), and rare Hb variants (0.7%). Of the 32 defect carriers, all but one (a alpha-thalassemia) were heterozygous. All the detected hemoglobinopathies but one (an Hb Hope) had already been reported in the country. The prevalence of Hb defect in the HL athletes was similar to that described in the general Tunisian population (P > 0.05). The percentage of Hb defect in the athletes was not dependent on gender, or performance level (P > 0.05). Within each type of sport the percentages of athletes with normal and abnormal Hb were similar (P > 0.05). The hematological data revealed the diversity of anemia, microcytosis, and hypochromia in thalassemic HL athletes. We concluded that HL athletes in Tunisia were a representative sample of the general Tunisian population regarding the prevalence and nature of benign abnormal Hb. The hematological data of the thalassemia carriers exhibited high variability and raised the question of genetic and sporting counseling, as well as biological follow-up for these carriers.

Hematologic Disorders in the Athlete

Optimal athletic performance depends on proper function of many organs, including the blood. This is underscored by the focus of endurance athletes on increased hemoglobin through training at altitude or exogenous erythropoietin. Several other aspects of the hematologic system can also affect or be influenced by physical activity. In this article, the authors briefly discuss inherited abnormalities of the blood that can manifest themselves in athletes. We then discuss the effects of exercise on the blood, and acquired abnormalities of blood cells or coagulation parameters that occur in athletes, and that can influence performance or cause other symptoms.