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Summary Sickle cell anaemia (SCA) patients display elevated levels of circulating pro‐inflammatory cytokines and endothelial activation markers compared to healthy peers. The impact of exercise on the pro‐inflammatory state in SCA remains unclear. This study aimed to characterize the whole‐blood transcriptome profile in response to an acute bout of exercise in paediatric SCA patients. Twenty‐three SCA participants (13 ± 3 years, 52% girls) and 17 healthy controls (14 ± 3 years, 29% girls) performed eight 2‐min bouts of cycle ergometry interspersed with 1‐min rest intervals. Whole‐blood transcriptome profile (RNA‐seq) was performed before and after exercise. At baseline, gene pathways associated with gas transport in erythrocytes were up‐regulated in SCA patients compared to controls. Following exercise, gene pathways associated with innate immunity were altered in both groups. Interaction analyses revealed 160 annotated genes (101 up‐ and 59 down‐regulated) that differentially altered by exercise in SCA patients. Moreover, genes that exhibited a blunted response to exercise in SCA patients were enriched in the IL‐17 signalling pathway, suggesting an impaired innate immune response to exercise. This data will contribute to the development of evidence‐based exercise prescription guidelines for this patient population. [ABSTRACT FROM AUTHOR]

Transfusional iron overload represents a substantial challenge in the management of patients with sickle cell disease ( SCD) who receive chronic or episodic red blood cell transfusions. Iron-induced cardiomyopathy is a leading cause of death in other chronically transfused populations but rarely seen in SCD. Study objectives were to: (i) examine the extent of myocardial and hepatic siderosis using magnetic resonance imaging ( MRI) in chronically transfused SCD patients, and (ii) evaluate the relationship between long-term (over the 5 years prior to enrolment) mean serum ferritin ( MSF), spot-ferritin values and liver iron content ( LIC) measured using MRI and liver biopsy. Thirty-two SCD patients (median age 15 years) with transfusional iron overload were recruited from two U.S. institutions. Long-term MSF and spot-ferritin values significantly correlated with LIC by MRI-R2* ( r = 0·77, P < 0·001; r = 0·82, P < 0·001, respectively). LIC by MRI-R2* had strong positive correlation with LIC by liver biopsy ( r = 0·98, P < 0·001) but modest inverse correlation with cardiac MRI-T2* ( r = −0·41, P = 0·02). Moderate to severe transfusional iron overload in SCD was not associated with aberrations in other measures of cardiac function based on echocardiogram or serum biomarkers. Our results suggest that SCD patients receiving chronic transfusions may not demonstrate significant cardiac iron loading irrespective of ferritin trends, LIC and erythropoiesis suppression. [ABSTRACT FROM AUTHOR]

Although individuals with sickle cell anaemia (SCA) have elevated baseline inflammation and endothelial activation, the acute phase response to maximal exercise has not been evaluated among children with SCA. We measured the acute phase response to maximal exercise testing for soluble vascular cell adhesion molecule (sVCAM) as well as interleukin 6 (IL6), total white blood cell (WBC) count, C-reactive protein (CRP) and D-dimer in a cohort of children with SCA and matched controls at baseline, immediately after, and 30, 60 and 120 min following exercise. Despite higher baseline levels of all biomarkers except CRP, the acute phase response from baseline to immediately after exercise was significantly greater in subjects versus controls for CRP (2.1 vs. 0.2 mg/l, P = 0.02) and D-dimer (160 vs. 10 µg/l, P < 0.01) only. Similar between-group trends were observed over time for all biomarkers, including sVCAM, IL6, total WBC, CRP and D-dimer. Lower fitness, defined by peak oxygen consumption (VO2), was independently associated with greater acute phase responses to exercise for sVCAM. Our results suggest maximal exercise may not be associated with any greater escalation of endothelial activation or inflammation in SCA and provide preliminary biomarker evidence for the safety of brief, high-intensity physical exertion in children with SCA. [ABSTRACT FROM AUTHOR]

Red blood cell ( RBC) transfusions can be life-sustaining in chronic inherited anaemias, such as thalassaemia, and the indications for blood transfusions in patients with sickle cell disease continue to expand. Complications of transfusions, such as allosensitization, can create significant medical challenges in the management of patients with haemoglobinopathies. This review summarizes key findings from the medical literature related to alloimmunization in haemoglobinopathies and examines potential measures to mitigate these risks. Areas where future studies are needed are also addressed. [ABSTRACT FROM AUTHOR]

Summary: We examined heart rate variability (HRV) during exercise testing in 20 children with sickle cell anaemia (SCA) and 12 controls. Subjects achieved lower median HRV at peak exercise [standard deviation of R‐wave to R‐wave intervals (SDNN), 2·3 vs 2·9 ms, P = 0·027; logarithmic transformation of high frequency power (lnHF), 0·9 vs 1·3 ln(ms2), P = 0·047] and had lower post‐exercise HRV across minute‐by‐minute analysis of recovery. After adjustment for haemoglobin, fitness and SCA status, subjects had lower HRV at the end of recovery with differences increasing as baseline HRV increased. Further investigation of HRV and exercise safety in SCA is warranted. [ABSTRACT FROM AUTHOR]

Summary: We used near‐infrared spectroscopy to examine tissue oxygenation (StO2) during exercise in 17 children and young adults with sickle cell anaemia (SCA) and 13 controls. Patients had lower cerebral StO2 at all exercise stages and demonstrated significantly greater decreases in cerebral StO2 later during exercise. Quadriceps StO2 increased similarly in patients and controls during early exercise, but decreases from baseline were greater in patients during later exercise. At similar workloads, patients demonstrated lower cerebral StO2 (69·2 ± 6·6 vs. 79·5 ± 5·3%, P < 0·001) and trended towards lower quadriceps StO2 (67·7 ± 9·0 vs. 73·2 ± 7·9%, P = 0·09). Further studies of tissue oxygenation during exercise in SCA are warranted. [ABSTRACT FROM AUTHOR]