Chronic pain in adults with sickle cell disease is associated with alterations in functional connectivity of the brain.

Chronic pain affects 50% of adults with sickle cell disease (SCD). Although central sensitization is thought to contribute to the pathogenesis of this chronic pain, no studies have examined differences in functional connectivity of the brain between patients with SCD with and without chronic pain. We performed an observational cohort study using resting-state functional MRI (rsfMRI) of the brain on adults with SCD with and without chronic pain. We tested the hypothesis that, compared to those without chronic pain, those with chronic pain would have differences in functional connectivity between the periaqueductal grey (PAG) and other regions of the brain. Twenty-two adults with SCD, 15 with chronic pain and 7 without chronic pain, as well as 10 African-American controls, underwent rsfMRI of the brain. When SCD patients with chronic pain were compared to those without chronic pain, significant differences in connectivity were noted between the PAG and 9 regions of the brain, including several in the default mode network, a network involved in introspection that has been implicated in other chronic pain syndromes. Changes in functional connectivity between patients with SCD with and without chronic pain suggest a mechanism for chronic pain that involves neuro-plastic changes to the brain

Contrast-enhanced ultrasound detects changes in microvascular blood flow in adults with sickle cell disease.

In patients with sickle cell disease (SCD), poor outcome measures compromise the potential success of clinical trials. Contrast-enhanced ultrasound (CEUS) is a technique that can non-invasively quantify deep tissue microvascular blood flow. We tested the hypothesis that CEUS of forearm skeletal muscle could be used to: 1) assess microvascular abnormalities that occur during vaso-occlusive crisis; and 2) test new therapies for SCD that are targeted to improving the status of the microcirculation. We performed a prospective study, CEUS perfusion imaging of resting forearm muscle was performed in adults with SCD: 1) during and after a pain episode, and 2) before, during, and after a 24-hour infusion of the investigative agent, regadenoson, an adenosine A2A agonist. CEUS destruction-replenishment time-intensity data were analyzed to measure microvascular blood flow, as well as its components, microvascular blood volume and flux rate. Serial CEUS measurements were obtained in 32 adults with SCD. For the studies during crisis, there was a 30% reduction in microvascular blood flow compared to steady-state (p = 0.031), a reduction that was largely due to microvascular flux rate. For the regadenoson group, a non-significant 25% increase in flux rate and 9% increase in microvascular blood flow compared to baseline were detected during infusion. In a study of adults with SCD, CEUS detected changes in microvascular blood flow associated with vaso-occlusive crises. No changes were found during an infusion of the adenosine A2A agonist, regadenoson. This study provides preliminary evidence that CEUS could detect blood flow changes consistent with SCD physiology

Predictive factors of daily opioid use and quality of life in adults with sickle cell disease

<p><b>Objectives:</b> In adults with sickle cell disease (SCD), pain often necessitates opioid use. Few studies have examined the relationship between opioid use and health-related quality of life (HRQOL) in adults with SCD. We tested the hypothesis that higher doses of opioids are associated with worse HRQOL.</p> <p><b>Methods:</b> A cross-sectional cohort study was performed in adults with SCD who completed standardized and validated HRQOL questionnaires: Patient Health Questionnaire-15 (PHQ-15), Patient Health Questionnaire-9 (PHQ-9), Medical Outcome Study 36 Item Short Form (SF-36), and Generalized Anxiety Disorder questionnaire (GAD-7). Daily outpatient opioid dose was converted into morphine milligram equivalents (MME) and categorized as < 90 mg/day or ≥ 90 mg/day. Subject's questionnaire scores were compared by opioid dose.</p> <p><b>Results:</b> Ninety-nine adults completed questionnaires. The majority had HbSS and median age was 30 years. The median MME was 80 mg/day. When the association between HRQOL and opioid dose was compared, those prescribed ≥ 90 MME had significantly lower SF-36 subscale scores in 7 of 8 domains, and significantly higher severity scores in the PHQ-15, GAD-7, and the PHQ-9 in comparison those prescribed < 90 MME. Using a multivariable regression tree analysis, in addition to the presence of chronic pain, mental health, physical health, and somatic burden were key predictors of ≥ 90 MME opioid use.</p> <p><b>Conclusion:</b> Higher daily opioid dose is associated with chronic pain. Among those with chronic pain, opioid dose ≥ 90 MME is associated with worse HRQOL.</p

Vascular dysfunction in a murine model of severe hemolysis

Spectrin is the backbone of the erythroid cytoskeleton; sph/sph mice have severe hereditary spherocytosis (HS) because of a mutation in the murine erythroid α-spectrin gene. sph/sph mice have a high incidence of thrombosis and infarction in multiple tissues, suggesting significant vascular dysfunction. In the current study, we provide evidence for both pulmonary and systemic vascular dysfunction in sph/sph mice. We found increased levels of soluble cell adhesion molecules in sph/sph mice, suggesting activation of the vascular endothelium. We hypothesized that plasma hemoglobin released by intravascular hemolysis initiates endothelial injury through nitric oxide (NO) scavenging and oxidative damage. Likewise, electron paramagnetic resonance spectroscopy showed that plasma hemoglobin is much greater in sph/sph mice. Moreover, plasma from sph/sph mice had significantly higher oxidative potential. Finally, xanthine oxidase, a potent superoxide generator, is decreased in subpopulations of liver hepatocytes and increased on liver endothelium in sph/sph mice. These results indicate that vasoregulation is abnormal, and NO-based vasoregulatory mechanisms particularly impaired, in sph/sph mice. Together, these data indicate that sph/sph mice with severe HS have increased plasma hemoglobin and NO scavenging capacity, likely contributing to aberrant vasoregulation and initiating oxidative damage