Breaking News
April 18, 2019 - Hickenlooper Expanded Medicaid, Created State-Run Marketplace To Insure Nearly All Coloradans
April 18, 2019 - Cancer cells grown in tumor-mimicking environment can help predict the effect of experimental drugs
April 18, 2019 - Albireo Announces FDA Clearance of IND to Commence Phase 2 Trial of Elobixibat for the Treatment of NAFLD/NASH
April 18, 2019 - Adhesive gel bonds to eye surface, could repair injuries without surgery
April 18, 2019 - The future of genomics: A podcast featuring Stanford geneticists
April 18, 2019 - As Syphilis Invades Rural America, A Fraying Health Safety Net Is Failing To Stop It
April 18, 2019 - APOE gene impacts sleep depending on gender and severity of Alzheimer’s
April 18, 2019 - PCORI’s newly approved awards focus on cancer pain and opioid use disorders
April 18, 2019 - New tool provides a standard way to measure effects of caring for survivors of TBI
April 18, 2019 - Smartphone use risks eye examination misdiagnosis
April 18, 2019 - How drug-resistant bugs grow in CF patients’ lungs
April 18, 2019 - Gordana Vunjak-Novakovic Elected to American Academy of Arts & Sciences
April 18, 2019 - Podcast: KHN’s ‘What The Health?’ You Have Questions, We Have Answers
April 18, 2019 - Diabetic drug shows potential to be repurposed as heart disease treatment for non-diabetic patients
April 18, 2019 - New estimation method assesses natural variations in sex ratio at birth
April 18, 2019 - UTA scientist receives $1.17 million grant for cancer research
April 18, 2019 - Coagulation factor VIIa prevents bleeds in hemophilia animal models
April 18, 2019 - Researchers identify risk factors for severe infection after knee replacement
April 18, 2019 - Mass drug administration can offer community-level protection against malaria
April 18, 2019 - FDA’s added sugar label could have substantial health and cost-saving benefits
April 18, 2019 - Researchers identify cause of inherited metabolic disorder
April 18, 2019 - Single strip of white paint not sufficient to protect people who ride bikes
April 18, 2019 - Partner status influences link between sexual problems and self-efficacy in breast cancer survivors
April 18, 2019 - Colorectal Neoplasia Risk Up for Hodgkin Lymphoma Survivors
April 18, 2019 - Rigid spine muscular dystrophy – Genetics Home Reference
April 18, 2019 - Simple bile acid blood test could tell risk of stillbirth
April 18, 2019 - Center for Experimental Therapeutics aims to enable all steps of drug development | News Center
April 18, 2019 - Falling for telephone scams could be an early sign of dementia
April 18, 2019 - Researchers annotate key neuronal proteins in lamprey genome
April 18, 2019 - Study uncovers new biomarker for personalized cancer treatments
April 18, 2019 - Scientists enter research collaboration to find a cure for cancer
April 18, 2019 - Study to compare benefits of tai chi and mindfulness meditation on MS symptoms
April 18, 2019 - Gestational diabetes during pregnancy may increase risk of type 1 diabetes in children
April 18, 2019 - Is a New Remedy for Body Odor on the Horizon?
April 18, 2019 - Orthostatic hypotension – Genetics Home Reference
April 18, 2019 - Healing the heartbreak of stillbirth and newborn death
April 18, 2019 - Conference to highlight advances in human immune monitoring, bioinformatics | News Center
April 18, 2019 - Bacteria use viruses for self-recognition, study reveals
April 18, 2019 - New adhesive patch could help reduce post-heart attack muscle damage
April 18, 2019 - Researchers analyze the effects of dark play in a serious video game
April 18, 2019 - Scientists revive pig brain cells four hours after death
April 18, 2019 - Filial cannibalism and offspring abandonment may be forms of parental care
April 18, 2019 - Two proteins act in concert to maintain a healthy heart in mice, shows study
April 18, 2019 - Scientists create a functioning 3D printed heart
April 18, 2019 - Non-invasive vagus nerve stimulation improves disease symptoms in patients with rheumatoid arthritis
April 18, 2019 - Majority of men struggle to understand diagnosis and treatment of prostate cancer
April 18, 2019 - Researchers create new small molecules that may combat equine encephalitis viruses
April 18, 2019 - Animal-assisted therapy improves social behavior in patients with brain injuries
April 18, 2019 - Some viruses help protect harmful bacteria in CF patients | News Center
April 18, 2019 - Outpatient healthcare providers inappropriately prescribe antibiotics to 40% of patients
April 18, 2019 - Men who have a resting heart rate of 75 bpm are twice as likely to die early
April 18, 2019 - Novel serum biomarkers to detect NAFLD-related fibrosis
April 18, 2019 - New study delves deeper into individual genomic differences than ever before
April 18, 2019 - Gilead and Galapagos Announce Filgotinib Meets Primary Endpoint in the Phase 3 FINCH 3 Study in Methotrexate-Naïve Rheumatoid Arthritis Patients
April 18, 2019 - Emotional mirror neurons found in rats
April 18, 2019 - Sylvia Plevritis appointed chair of biomedical data science | News Center
April 18, 2019 - Cervical cancer subtype increasing in several subpopulations of women
April 18, 2019 - Yeast strain provides manufacturing boost to low-calorie sweetener derived from lactose
April 18, 2019 - One in five children and youth suffer from a mental disorder
April 18, 2019 - Improper inhaler use common in children with asthma
April 18, 2019 - C-Path and CDISC release global Therapeutic Area Standard for HIV research
April 18, 2019 - Integrating AI to analyze imaging data allows early recognition of heart disease
April 18, 2019 - Low-cost, high-speed algorithm may allow animal-free chemical toxicity testing
April 18, 2019 - HPV-negative cervical cancers are more aggressive with worse prognosis
April 18, 2019 - AI detects prostate cancer with same level of accuracy as experienced radiologists
April 18, 2019 - Study resolves sex differences in psychiatric illness risk
April 18, 2019 - Novartis Announces FDA Filing Acceptance and Priority Review of Brolucizumab (RTH258) for Patients with Wet AMD
April 18, 2019 - Cocktail of common antibiotics can fight resistant E. coli
April 18, 2019 - Persis Drell to give keynote address at medical school diploma ceremony | News Center
April 18, 2019 - EpicTogether: Remembering Our Why
April 18, 2019 - Study identifies novel loci contributing to asthma susceptibility in adults
April 18, 2019 - Gut bacteria and pregnancy
April 18, 2019 - New study finds that screening could help prevent rare types of cervical cancer
April 17, 2019 - Spatial orgnization of the genome can be altered using small molecules
April 17, 2019 - AEDs Tied to Higher Pneumonia Risk in Alzheimer Patients
April 17, 2019 - Telemedicine tied to more antibiotics for kids, study finds
April 17, 2019 - Two medical students awarded 2019 Soros Fellowships for New Americans | News Center
April 17, 2019 - Sociologist Constance A. Nathanson Awarded Guggenheim Fellowship
April 17, 2019 - Empathy and hormones could account for aggressive behavior in children, shows study
April 17, 2019 - Researchers develop oral appliance to help sufferers of sleep apnea
Researcher studies how sickle cell disease affects blood flow and oxygen delivery

Researcher studies how sickle cell disease affects blood flow and oxygen delivery

image_pdfDownload PDFimage_print

Sickle Cell Disease (SCD) is rare but devastating. Due to a genetic mutation affecting hemoglobin, the component of the red blood cell that carries oxygen, a reduced amount of oxygen is supplied to vital tissues and organs. Blood cells also deform into a characteristic crescent shape and lodge into the smallest blood vessels, blocking blood flow and leading to excruciating pain. On top of these symptoms, patients face a high risk of stroke, the leading cause of death in SCD.

Specializing in the unique challenges facing SCD patients, physician and investigator John Wood, MD, PhD of CHLA studies how blood flow and oxygen delivery are affected by the disease. The compromised hemoglobin that is characteristic of SCD presents a serious danger to the brain. Just minutes without oxygen can kill brain cells. “We have learned a lot about how to prevent the large vessel strokes,” says Dr. Wood, who is also a Professor of Pediatrics at the Keck School of Medicine of USC. He is referring to strokes that have immediate, overt effects such as blindness or paralysis. “But patients with SCD still suffer from silent strokes.”

Silent strokes can have debilitating effects on executive function, the brain’s ability to execute complex tasks needed for things like maintaining a job or doing well in school. Dr. Wood is working to discover what causes these devastating silent strokes. On the surface, the cause for these strokes seems clear: blood cells are damaged in SCD, so the brain receives less oxygen. Less oxygen to the brain results in strokes. But Dr. Wood found that total oxygen to the brain is not actually reduced in SCD patients. His research shows that the body compensates for reduced oxygen content of the blood by increasing blood flow to the brain. This led him to wonder why these patients were continuing to suffer strokes.

“I began to think, ‘maybe there’s a distribution problem,” Dr. Wood says. “Total blood flow is fine, but is it going where it needs to go?” Using an advanced imaging technique called arterial spin labeling to measure blood flow, Dr. Wood’s team found a disparity among brain areas. While total oxygen delivery to the brain was unchanged, oxygen delivery to the white matter was reduced by more than a third – 35% – in patients with SCD. Critically, this part of the brain – the white matter – is where the majority of silent strokes occur in these patients.

Grey matter is composed of neurons, the brain cells that store information. White matter is the network of highways in the brain that neurons use to transmit this information. Dr. Wood’s finding demonstrates that the body differentiates between grey and white matter, clearly prioritizing neurons. This makes sense because keeping neurons alive is critical for survival. Strokes in grey matter are immediately catastrophic, while strokes in white matter appear silent because they simply cause informational processing to slow. Though they may not cause paralysis or major motor deficits, effects of white matter silent strokes can greatly impede important aspects of a patient’s day to day life.

The idea that blood flow can be adjusted to compensate for challenges like decreased oxygen is part of our design. When our physiological state changes, the body diverts blood to pertinent areas. During exercise, for example, blood flow is increased to our muscles to help meet metabolic needs, but decreased to the less immediately relevant digestive tract.

Similarly, under the stress of low oxygen in SCD, blood flow is diverted to neurons in the grey matter to prevent their death. Dr. Wood found that the oxygen delivery to the white matter was critically sensitive to the hemoglobin level – the more severe the anemia, the lower the oxygen delivery to the white matter – a powerful correlation that supports what he sees in the clinic.

Dr. Wood’s study is the first to use arterial spin labeling to quantify oxygen delivery separately to the white and grey matter in the brain, correcting for patient’s anemia severity. His research paves the way for a better understanding of strokes in SCD but it also has broader applications. He says the findings likely shed light on anemia in general, which is a growing concern in our aging population. He also hopes this technique will help the medical community assess how current and future SCD treatments, like novel gene therapy approaches, affect the brain. Results of this study were published recently in the American Journal of Hematology by lead author Yaqiong Chai, a senior PhD candidate.

Tagged with:

About author

Related Articles