Lawrence Tabak, D.D.S., Ph.D.
Case Study Unlocks Clues to Rare Resilience to Alzheimer’s Disease
Posted on by Lawrence Tabak, D.D.S., Ph.D.
Biomedical breakthroughs most often involve slow and steady research in studies involving large numbers of people. But sometimes careful study of even just one truly remarkable person can lead the way to fascinating discoveries with far-reaching implications.
An NIH-funded case study published recently in the journal Nature Medicine falls into this far-reaching category [1]. The report highlights the world’s second person known to have an extreme resilience to a rare genetic form of early onset Alzheimer’s disease. These latest findings in a single man follow a 2019 report of a woman with similar resilience to developing symptoms of Alzheimer’s despite having the same strong genetic predisposition for the disease [2].
The new findings raise important new ideas about the series of steps that may lead to Alzheimer’s and its dementia. They’re also pointing the way to key parts of the brain for cognitive resilience—and potentially new treatment targets—that may one day help to delay or even stop progression of Alzheimer’s.
The man in question is a member of a well-studied extended family from the country of Colombia. This group of related individuals, or kindred, is the largest in the world with a genetic variant called the “Paisa” mutation (or Presenilin-1 E280A). This Paisa variant follows an autosomal dominant pattern of inheritance, meaning that those with a single altered copy of the rare variant passed down from one parent usually develop mild cognitive impairment around the age of 44. They typically advance to full-blown dementia around the age of 50 and rarely live past the age of 60. This contrasts with the most common form of Alzheimer’s, which usually begins after age 65.
The new findings come from a team led by Yakeel Quiroz, Massachusetts General Hospital, Boston; Joseph Arboleda-Velasquez, Massachusetts Eye and Ear, Boston; Diego Sepulveda-Falla, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and Francisco Lopera, University of Antioquia, Medellín, Colombia. Lopera first identified this family more than 30 years ago and has been studying them ever since.
In the new case report, the researchers identified a Colombian man who’d been married with two children and retired from his job as a mechanic in his early 60s. Despite carrying the Paisa mutation, his first cognitive assessment at age 67 showed he was cognitively intact, having limited difficulties with verbal learning skills or language. It wasn’t until he turned 70 that he was diagnosed with mild cognitive impairment—more than 20 years later than the expected age for this family—showing some decline in short-term memory and verbal fluency.
At age 73, he enrolled in the Colombia-Boston biomarker research study (COLBOS). This study is a collaborative project between the University of Antioquia and Massachusetts General Hospital involving approximately 6,000 individuals from the Paisa kindred. About 1,500 of those in the study carry the mutation that sets them up for early Alzheimer’s. As a member of the COLBOS study, the man underwent thorough neuroimaging tests to look for amyloid plaques and tau tangles, both of which are hallmarks of Alzheimer’s.
While this man died at age 74 with Alzheimer’s, the big question is: how did he stave off dementia for so long despite his poor genetic odds? The COLBOS study earlier identified a woman with a similar resilience to Alzheimer’s, which they traced to two copies of a rare, protective genetic variant called Christchurch. This variant affects a gene called apolipoprotein E (APOE3), which is well known for its influence on Alzheimer’s risk. However, the man didn’t carry this same protective variant.
The researchers still thought they’d find an answer in his genome and kept looking. While they found several variants of possible interest, they zeroed in on a single gene variant that they’ve named Reelin-COLBOS. What helped them to narrow it down to this variant is the man also had a sister with the Paisa mutation who only progressed to advanced dementia at age 72. It turned out, in addition to the Paisa variant, the siblings also shared an altered copy of the newly discovered Reelin-COLBOS variant.
This Reelin-COLBOS gene is known to encode a protein that controls signals to chemically modify tau proteins, which form tangles that build up over time in the Alzheimer’s brain and have been linked to memory loss. Reelin is also functionally related to APOE, the gene that was altered in the woman with extreme Alzheimer’s protection. Reelin and APOE both interact with common protein receptors in neurons. Together, the findings add to evidence that signaling pathways influencing tau play an important role in Alzheimer’s pathology and protection.
The neuroimaging exams conducted when the man was age 73 have offered further intriguing clues. They showed that his brain had extensive amyloid plaques. He also had tau tangles in some parts of his brain. But one brain region, called the entorhinal cortex, was notable for having a very minimal amount of those hallmark tau tangles.
The entorhinal cortex is a hub for memory, navigation, and the perception of time. Its degeneration also leads to cognitive impairment and dementia. Studies of the newly identified Reelin-COLBOS variant in Alzheimer’s mouse models also help to confirm that the variant offers its protection by diminishing the pathological modifications of tau.
Overall, the findings in this one individual and his sister highlight the Reelin pathway and brain region as promising targets for future study and development of Alzheimer’s treatments. Quiroz and her colleagues report that they are actively exploring treatment approaches inspired by the Christchurch and Reelin-COLBOS discoveries.
Of course, there’s surely more to discover from continued study of these few individuals and others like them. Other as yet undescribed genetic and environmental factors are likely at play. But the current findings certainly offer some encouraging news for those at risk for Alzheimer’s disease—and a reminder of how much can be learned from careful study of remarkable individuals.
References:
[1] Resilience to autosomal dominant Alzheimer’s disease in a Reelin-COLBOS heterozygous man. Lopera F, Marino C, Chandrahas AS, O’Hare M, Reiman EM, Sepulveda-Falla D, Arboleda-Velasquez JF, Quiroz YT, et al. Nat Med. 2023 May;29(5):1243-1252.
[2] Resistance to autosomal dominant Alzheimer’s disease in an APOE3 Christchurch homozygote: a case report. Arboleda-Velasquez JF, Lopera F, O’Hare M, Delgado-Tirado S, Tariot PN, Johnson KA, Reiman EM, Quiroz YT et al. Nat Med. 2019 Nov;25(11):1680-1683.
Links:
Alzheimer’s Disease & Related Dementias (National Institute on Aging/NIH)
“NIH Support Spurs Alzheimer’s Research in Colombia,” Global Health Matters, January/February 2014, Fogarty International Center/NIS
“COLBOS Study Reveals Mysteries of Alzheimer’s Disease,” NIH Record, August 19, 2022.
Yakeel Quiroz (Massachusetts General Hospital, Harvard Medical School, Boston)
Joseph Arboleda-Velasquez (Massachusetts Eye and Ear, Harvard Medical School, Boston)
Diego Sepulveda-Falla Lab (University Medical Center Hamburg-Eppendorf, Hamburg, Germany)
Francisco Lopera (University of Antioquia, Medellín, Colombia)
NIH Support: National Institute on Aging; National Eye Institute; National Institute of Neurological Disorders and Stroke; Office of the Director
Basic Researchers Discover Possible Target for Treating Brain Cancer
Posted on by Lawrence Tabak, D.D.S., Ph.D.
Over the years, cancer researchers have uncovered many of the tricks that tumors use to fuel their growth and evade detection by the body’s immune system. More tricks await discovery, and finding them will be key in learning to target the right treatments to the right cancers.
Recently, a team of researchers demonstrated in lab studies a surprising trick pulled off by cells from a common form of brain cancer called glioblastoma. The researchers found that glioblastoma cells steal mitochondria, the power plants of our cells, from other cells in the central nervous system [1].
Why would cancer cells do this? How do they pull it off? The researchers don’t have all the answers yet. But glioblastoma arises from abnormal astrocytes, a particular type of the glial cell, a common cell in the brain and spinal cord. It seems from their initial work that stealing mitochondria from neighboring normal cells help these transformed glioblastoma cells to ramp up their growth. This trick might also help to explain why glioblastoma is one of the most aggressive forms of primary brain cancer, with limited treatment options.
In the new study, published in the journal Nature Cancer, a team co-led by Justin Lathia, Lerner Research Institute, Cleveland Clinic, OH, and Hrvoje Miletic, University of Bergen, Norway, had noticed some earlier studies suggesting that glioblastoma cells might steal mitochondria. They wanted to take a closer look.
This very notion highlights an emerging and much more dynamic view of mitochondria. Scientists used to think that mitochondria—which can number in the thousands within a single cell—generally just stayed put. But recent research has established that mitochondria can move around within a cell. They sometimes also get passed from one cell to another.
It also turns out that the intercellular movement of mitochondria has many implications for health. For instance, the transfer of mitochondria helps to rescue damaged tissues in the central nervous system, heart, and respiratory system. But, in other circumstances, this process may possibly come to the rescue of cancer cells.
While Lathia, Miletic, and team knew that mitochondrial transfer was possible, they didn’t know how relevant or dangerous it might be in brain cancers. To find out, they studied mice implanted with glioblastoma tumors from other mice or people with glioblastoma. This mouse model also had been modified to allow the researchers to trace the movement of mitochondria.
Their studies show that healthy cells often transfer some of their mitochondria to glioblastoma cells. They also determined that those mitochondria often came from healthy astrocytes, a process that had been seen before in the recovery from a stroke.
But the transfer process isn’t easy. It requires that a cell expend a lot of energy to form actin filaments that contract to pull the mitochondria along. They also found that the process depends on growth-associated protein 43 (GAP43), suggesting that future treatments aimed at this protein might help to thwart the process.
Their studies also show that, after acquiring extra mitochondria, glioblastoma cells shift into higher gear. The cancerous cells begin burning more energy as their metabolic pathways show increased activity. These changes allow for more rapid and aggressive growth. Overall, the findings show that this interaction between healthy and cancerous cells may partly explain why glioblastomas are so often hard to beat.
While more study is needed to confirm the role of this process in people with glioblastoma, the findings are an important reminder that treatment advances in oncology may come not only from study of the cancer itself but also by carefully considering the larger context and environments in which tumors grow. The hope is that these intriguing new findings will one day lead to new treatment options for the approximately 13,000 people in the U.S. alone who are diagnosed with glioblastoma each year [2].
References:
[1] GAP43-dependent mitochondria transfer from astrocytes enhances glioblastoma tumorigenicity. Watson DC, Bayik D, Storevik S, Moreino SS, Hjelmeland AB, Hossain JA, Miletic H, Lathia JD et al. Nat Cancer. 2023 May 11. [Published online ahead of print.]
[2] CBTRUS statistical report: Primary brain and other central nervous system tumors diagnosed in the United States in 2011-2015. Ostrom QT, Gittleman H, Truitt G, Boscia A, Kruchko C, Barnholtz-Sloan JS. 2018 Oct 1, Neuro Oncol., p. 20(suppl_4):iv1-iv86.
Links:
Glioblastoma (National Center for Advancing Translational Sciences/NIH)
Brain Tumors (National Cancer Institute/NIH)
Justin Lathia Lab (Cleveland Clinic, OH)
Hrvoje Miletic (University of Bergen, Norway)
NIH Support: National Institute of Neurological Disorders and Stroke; National Center for Advancing Translational Sciences; National Cancer Institute; National Institute of Allergy and Infectious Diseases
Groundbreaking at NIH Clinical Center
Posted on by Lawrence Tabak, D.D.S., Ph.D.
Testifying Before Senate
Posted on by Lawrence Tabak, D.D.S., Ph.D.
Help for Babies Born Dependent on Opioids
Posted on by Lawrence Tabak, D.D.S., Ph.D.
It’s been estimated that every 18 minutes in the United States, a newborn baby starts life with painful withdrawals from exposure to opioids in the womb. It’s called neonatal opioid withdrawal syndrome (NOWS), and it makes for a challenging start in life. These infants may show an array of withdrawal symptoms, including tremors, extreme irritability, and problems eating and sleeping.
Many of these infants experience long, difficult hospital stays to help them manage their withdrawal symptoms. But because hospital staff have no established evidence-based treatment standards to rely on, there is substantial variation in NOWS treatment around the country. There also are many open questions about the safest and most-effective way to support these babies and their families.
But answers are coming. The New England Journal of Medicine just published clinical trial results that evaluated care for infants with NOWS and which offer some much needed—and rather encouraging—data for families and practitioners [1]. The data are from the Eating, Sleeping, Consoling for Neonatal Opioid Withdrawal (ESC-NOW) trial, led by Leslie W. Young, The University of Vermont’s Larner College of Medicine, Burlington, and her colleagues Lori Devlin and Stephanie Merhar.
The ESC-NOW study is supported through the Advancing Clinical Trials in Neonatal Opioid Withdrawal (ACT NOW) Collaborative. ACT NOW is an essential part of the NIH Helping to End Addiction Long-term (HEAL) Initiative, an aggressive effort to speed scientific solutions to stem the national opioid public health crisis and improve lives.
The latest study puts to the test two different approaches to care for newborns with NOWS. The first approach relies on the Finnegan Neonatal Abstinence Scoring Tool. For almost 50 years, doctors primarily assessed NOWS using this tool. It is based on a scoring system of 21 signs of withdrawal, including disturbances in a baby’s nervous system, metabolism, breathing, digestion, and more. However, there have been concerns that this scoring tool has led to an overreliance on treating babies with opioid medications, including morphine and methadone.
The other approach is known as Eat, Sleep, Console (ESC) care [2]. First proposed in 2014, ESC care has been adopted in many hospitals around the world. Rather than focusing on a long list of physical signs of withdrawal, this approach relies on a simpler functional assessment of whether an infant can eat, sleep, and be consoled. It emphasizes treatments other than medication, such as skin-to-skin contact, breastfeeding, and care from their mothers or other caregivers in a calm and nurturing environment.
The ESC care approach places an emphasis on the use of supportive interventions and aims to empower families in the care and nurturing of their infants. While smaller quality improvement studies of ESC have been compelling, the question at issue is whether the Eat, Sleep, Console care approach can reduce the time until infants with NOWS are medically ready to go home from the hospital in a wide variety of hospital settings—and, most importantly, whether it can do so safely.
To find out, the ESC-NOW team enrolled 1,305 infants with NOWS who were born after at least 36 weeks gestation. The study’s young participants were largely representative of infants with NOWS in the U.S., although non-Hispanic Black and Hispanic infants were slightly overrepresented. The babies were born at one of 26 U.S. hospitals, and each hospital was randomly assigned to transition from usual care using the Finnegan tool to the ESC care approach at a designated time.
Each hospital had a three-month transition period between the usual care and the ESC to allow clinical teams time to train on the new approach. The trial primarily aimed to understand if there was a significant difference in how long newborns with NOWS spent in the hospital before being medically ready for discharge between those receiving usual care versus those receiving ESC care. Researchers also assessed infants for safety, tracking both safety events that occurred during the hospital stay and events that occurred after the baby left the hospital, such as non-accidental trauma or death during an infant’s first three months.
The reported results reflect 837 of the 1,305 infants, who met the study definition of being medically ready for discharge. Infants who were discharged before meeting the study criteria, which were informed by the 2012 American Academy of Pediatrics recommendations for monitoring of infants with NOWS, were not included in the primary analysis.
Among the 837 infants, those who received ESC care were medically ready for discharge significantly sooner than those who received usual care. On average, they were medically ready to go home after about eight days compared to almost 15 days for the usual care group.
Many fewer infants in the ESC care group were treated with opioids compared to the usual care group (19.5 percent versus 52.0 percent). In more good news for ESC care, there was no difference in safety outcomes through the first three months despite the shorter hospital stays and reduced opioid treatment in the hospital. Infants who were cared for using the ESC care approach were no more likely to visit the doctor’s office, emergency room, or hospital after being discharged from the hospital.
More long-term study is needed to evaluate these children over months and years as they continue to develop and grow. Many of the infants in this study will be evaluated for the first two years of life to assess the long-term impact of ESC care on development and other outcomes. These findings offer encouraging early evidence that the ESC care approach is safe and effective. Although there was some variability in the outcomes, this study also shows that this approach can work well across diverse hospitals and communities.
The ESC-NOW trial is just one portion of the NIH Heal Initiative’s ACT NOW program, focused on gathering scientific evidence on how to care for babies with NOWS. Other studies are evaluating how to safely wean babies who do receive treatment with medication off opioids more quickly. The ACT NOW Longitudinal Study also will enroll at least 200 babies with prenatal opioid exposure and another 100 who were not exposed to better understand the long-term implications of early opioid exposure.
I’ve been anxious to see the results of the ESC-NOW study for a few months. It’s been worth the wait. The results show that we’re headed in the right direction with learning how best to treat NOWS and help to improve the lives of these young children and their families in the months and years ahead.
References:
[1] Eat, Sleep, Console Approach versus usual care for neonatal opioid withdrawal. Young LW, Ounpraseuth ST, Merhar SL, Newman S, Snowden JN, Devlin LA, et al. NEJM, 2023 Apr 30 [Published online ahead of print]
[2] An initiative to improve the quality of care of infants with neonatal abstinence syndrome. Grossman MR, Berkwitt AK, Osborn RR, Xu Y, Esserman DA, Shapiro ED, Bizzarro MJ. Pediatrics. 2017 Jun;139(6):e20163360.
Links:
SAMHSA’s National Helpline (Substance Abuse and Mental Health Services Administration, Rockville, MD)
“Eat, Sleep, Console” reduces hospital stay and need for medication among opioid-exposed infants, NIH news release, May 1, 2023
Helping to End Addiction Long-term® (HEAL) Initiative (NIH)
Advancing Clinical Trials in Neonatal Opioid Withdrawal (ACT NOW)
Environmental Influences on Child Health Outcomes (ECHO) Program (NIH)
Leslie Young (The University of Vermont, Larner College of Medicine, Burlington)
NIH Support: The Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Center for Advancing Translational Sciences; Office of the Director
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