Aging, Author Interviews, Neurological Disorders, Weight Research / 06.08.2016
Obesity Linked To Prematurely Aged Brains
MedicalResearch.com Interview with:
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Dr. Lisa Ronan[/caption]
Dr. Lisa Ronan, PhD
Department of Psychiatry
University of Cambridge Neuroscience
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: A growing body of literature relates common markers of aging to those observed in obesity and supports the hypothesis that obesity may accelerate or advance the onset of brain aging. To investigate this relationship at a population level we analysed the white matter volume of the brain in 473 adult subjects ages 20 - 87 years and contrasted these volumes between subjects who were lean (BMI between 18.5 - 25) and those who were overweight / obese (BMI > 25).
Our results suggest that the latter group had significantly smaller white matter volumes when compared to their lean age-matched counterparts. We found that this difference in volume equated to a brain-age increase of 10 years in the overweight / obese group. We found no evidence that obesity impacted on cognitive ability.
Dr. Lisa Ronan[/caption]
Dr. Lisa Ronan, PhD
Department of Psychiatry
University of Cambridge Neuroscience
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: A growing body of literature relates common markers of aging to those observed in obesity and supports the hypothesis that obesity may accelerate or advance the onset of brain aging. To investigate this relationship at a population level we analysed the white matter volume of the brain in 473 adult subjects ages 20 - 87 years and contrasted these volumes between subjects who were lean (BMI between 18.5 - 25) and those who were overweight / obese (BMI > 25).
Our results suggest that the latter group had significantly smaller white matter volumes when compared to their lean age-matched counterparts. We found that this difference in volume equated to a brain-age increase of 10 years in the overweight / obese group. We found no evidence that obesity impacted on cognitive ability.











Dr. Richard Leigh[/caption]
Dr. Richard Leigh MD
Neuro Vascular Brain Imaging Unit
National Institute of Neurological Disorders and Stroke
National Institutes of Health, Bethesda, MD
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Patients who suffer an ischemic stroke have limited treatment options. One of the reasons for this is that our treatments can sometimes make the stroke worse by transforming the ischemic stroke into a hemorrhagic stroke. In our study we identified a new piece of information that we can extract from the patient’s MRI scan that informs us on the risk of having a hemorrhage.
Dr. Katya Rubia[/caption]
Katya Rubia, PhD
Department of Child and Adolescent Psychiatry
Institute of Psychiatry, Psychology, and Neuroscience
King’s College London
London, England
MedicalResearch.com: What are the main findings?
Dr. Rubia: ADHD and OCD patients both suffer from poor inhibitory control and in both disorders this has been associated with structural and functional deficits in fronto-striatal networks. However, it is not clear to what extent the two disorders differ in their underlying neural substrates. This study therefore conducted a meta-analysis of all published whole brain structural and functional MRI studies of inhibitory control in both disorders.
MedicalResearch.com: What are the main findings?
Dr. Rubia: The main findings are that ADHD and OCD patients differ quite fundamentally in their structural and functional brain abnormalities. OCD patients have enlarged volume in basal ganglia and insula, while ADHD patients have reduced volumes in these regions. In fMRI, in the left hemisphere this was also observed for the left insula and putamen, which were increased in OCD and reduced in ADHD. In addition both disorders have different frontal deficits. OCD patients have deficits in rostro-dorsal medial frontal regions that are important for top-down control of affect while ADHD patients had reduced activation in lateral inferior frontal cortex, a key area of attention and cognitive control. The findings fit into the notion of fronto-striatal dysregulation in OCD where basal ganglia are overactive and poorly controlled by medial frontal regions and a delayed fronto-striatal maturation in ADHD where both lateral frontal regions and the basal ganglia/insula are smaller, and presumably less developed in structure and in function in ADHD.
Dr. Vincent Chung[/caption]
Dr Vincent Chung
Assistant Professor, Jockey Club School of Public Health and Primary Care
Associate Director (Education), Hong Kong Institute of Integrative Medicine
Registered Chinese Medicine Practitioner
The Chinese University of Hong Kong
MedicalResearch.com: What is the background for this study?
Response: Primary carpal tunnel syndrome (CTS) is one of the most common forms of peripheral entrapment neuropathy. It is a major cause of disability on the upper extremity incurring considerable limitation on daily activities among patients. Currently, there is no consensus on appropriate treatment for patients with chronic (≥6 months) mild to moderate symptoms [Archives of physical medicine and rehabilitation. 2014;95(12):2253-63].
Electroacupuncture is a common technique for managing pain and neuropathy in Chinese medicine. Current CTS treatment guidelines from the UK National Institute for Health and Care Excellence (NICE), American Academy of Orthopaedic Surgeons (AAOS) and the American College of Occupational and Environmental Medicine (ACOEM) made no specific recommendations for or against electroacupuncture.
Amanda Sierra, PhD
Research Professor and Group Leader
Ramón y Cajal Fellow
Achucarro Basque Center for Neuroscience
Laida Bidea
Bizkaia Science and Technology Park
Zamudio, Bizkaia, Spain
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Sierra: Microglia phagocytosis of apoptotic cells is at the core of the brain regenerative response to recover the homeostasis of the brain parenchyma after damage because it prevents the spillover of toxic intracellular contents and is actively anti-inflammatory. However, while neuronal death is widespread in neurodegenerative diseases (Alzheimer´s, Parkinson´s, multiple sclerosis) and well as in ischemic and traumatic brain injuries, we have a complete lack of knowledge of the efficiency of microglial phagocytosis in the diseased brain.
In this paper we have discovered that microglia have a generalized response to apoptotic challenges: when confronted to a rise in the number of newborn cells, microglia display a combination of different strategies to boost their phagocytic output: increase the phagocytic capacity of each cell, recruit more cells to become phagocytic, or increase the total number of microglia (Abiega et al., PLoS Biol 2015). Thus, microglia have a very large potential for phagocytosis that could be summoned when needed.
To our surprise, however, in pathological conditions such as epilepsy (mouse and human), microglial phagocytosis was blocked. We have made use of the adult neurogenic cascade, where newborn cells undergo apoptosis naturally and are engulfed by “unchallenged microglia” (Sierra et al. Cell Stem Cell 2010), to establish the baseline of microglial phagocytosis efficiency. Whereas in physiological conditions microglia phagocytose over 90% of the apoptotic cells and remove them in under 1.5h, soon after the seizures it only engulfed 10% of the apoptotic cells and took up to 6h to digest them. This is the first quantification of microglial phagocytosis efficiency in the diseased mouse and human brain..
The block in phagocytosis was a rather complex phenomenon related to an impaired recognition (reduction of phagocytosis receptors) as well as impaired motility and targeting (reduced basal motility). We have also shown that the impairment is mediated at least partially by altered ATP microgradients: ATP is not only a neuro- and gliotransmitter widely released during seizures but is also a well-known “find-me” signal released by apoptotic cells. Thus, during seizures microglia became “blinded” by the neuronal hyperactivity and could not find the apoptotic cells.
In addition, we have shown that impairing phagocytosis releases the break on the inflammatory response. In fact, the impaired microglia were in a pro-inflammatory state and produced more cytokines such as tumor necrosis factor alfa (TNFa) or interleukin-1beta (IL-1b), which are well known neurotoxic and epileptogenic factors.
Dr. Susanne Asu Wolf[/caption]
Susanne Asu Wolf PhD
Max-Delbrueck-Center for Molecular Medicine
Berlin, Germany
MedicalResearch.com: What inspired you to research this link between Ly6Chi monocytes, antibiotics and neurogenesis?
Dr. Wolf: As a neuroimmunologist I research the communication between the immune system and the brain. Amongst other research groups we found almost 10 years ago that T cells are needed to maintain brain homeostasis and plasticity, namely neurogenesis. Since only activated T cells enter the brain, we were looking for a mouse model, where immune cells are not activated. My former supervisor Polly Matzinger (NIH), a well-known immunologist, suggested to use germ free mice, born and raised in an isolator without any contact to a pathogen or any bacteria. I did a pilot experiment with the germ free mice, but wanted to get closer to possible applications in humans. Since humans are rarely born and raised in a sterile environment, I was looking for another model. By chance I met with the group of Bereswill and Heimesaat (Berlin, Charite) who provided me with a model, where due to prolonged treatment with an antibiotic cocktail, the microbiota are below detection level and the mice are also virtually germ free. They got me into contact with the second senior author of the paper Ildiko Dunay (University of Magdeburg). Her expertise is the function of Ly6Chi monocytes during infection with malaria or toxoplasmosis.
Now we were ready to investigate the gut-immune-brain axis with the focus on neurogenesis and cognition. Meanwhile the impact of the microbiome on behavior was reported by several research groups using “sterile” germ free mice and I was also curious if we could see similar differences in our antibiotic treated mice.
Dr. Mathias Buttmann[/caption]
PD Dr. Mathias Buttmann
Senior Consultant Neurologist and Head of the Multiple Sclerosis Outpatient Clinic
University of Wuerzburg
Wuerzburg, Germany
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Buttmann: The synthetic anthracenedione mitoxantrone is approved for disease-modifying treatment of patients with aggressive forms of relapsing or secondary progressive multiple sclerosis (MS). It has been known for years that this DNA-intercalating agent increases the risk of acute myeloid leukemia. We performed a retrospective cohort study to investigate whether mitoxantrone also increases the risk for other types of malignancies. We included all 677 mitoxantrone-treated multiple sclerosis patients who were seen at our large German academic MS centre between 1994 and 2007 and collected follow-up information on the occurrence of malignancies, death and causes of death as of 2011. Follow-up was complete in 676 patients. The median age at mitoxantrone initiation was 41 years and the median follow-up duration was 8.7 years. We identified 37 patients with a malignancy after mitoxantrone initiation, among them 4 cases of acute myeloic leukemia and 7 cases of colorectal cancer.
Compared to the general population matched for sex, age and year of occurrence, we calculated an 1.5-fold increased incidence of any type of malignancy, a tenfold increased incidence of acute myeloic leukemia and a threefold increased incidence of colorectal cancer, while the incidence of other types of malignancies was not increased. Higher age at mitoxantrone initiation but neither higher cumulative mitoxantrone dose nor treatment with other immuosuppressive agents was identified as a malignancy risk factor. Fifty-five patients had died, among them 12 from a malignancy. Our study confirmed previous reports on an increased incidence of acute myeloic leukemia after mitoxantrone treatment and newly described an association between mitoxantrone therapy and an increased incidence of colorectal cancer.
Dr. T. Dianne Langford[/caption]
Dr. T. Dianne Langford PhD
Associate Professor, Neuroscience and Neurovirology
Lewis Katz School of Medicine
Temple University
MedicalResearch.com: What is the background for this study?
Dr. Langford: The ocular-motor system has been shown to reflect neural damage, and one of ocular-motor functions, near point of convergence (NPC), was reported to worsen after a sport-related concussion (Mucha et al. Am J Sport Med). But the effects of subconcussive head impact, a milder form of head injury in the absence of outward symptoms remains unknown. Prior to this study, we found that in a controlled soccer heading experimental paradigm decreased NPC function, and even 24h after the headings, NPC was not normalized back to baseline (Kawata et al. 2016 Int J Sport Med). To extend our findings from the human laboratory study, we launched longitudinal clinical studies in collaboration with the Temple football team, to see if repetitive exposure to subconcussive head impacts negatively affects NPC.
Dr. Jennifer Graves[/caption]
Jennifer Graves, MD, PhD, MAS
Adult and Pediatric Multiple Sclerosis Centers
UCSF
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Graves: Cessation of medications with effects on immune trafficking may be more likely to cause rebound inflammatory activity in autoimmune diseases such as multiple sclerosis. We observed 5 strikingly severe relapses consistent with rebound events following cessation of fingolimod treatment and identified several similar cases in the literature. At our center the rebound events occurred with an approximate 10% frequency.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Graves: Fingolimod cessation may be complicated by rebound phenomena in some patients, similar to what has been observed with natalizumab. Both of these medications have effects on immune cell trafficking, likely explaining the association with rebound events. Careful consideration must be taken in stopping these medications.
Dr. Jacqueline French[/caption]
Jacqueline French, MD
Professor, Department of Neurology
Director Translational Research& Clinical Trials Epilepsy
NYU Langone Medical Center
MedicalResearch.com: What is the background for this study?
Dr. French: Tuberous sclerosis complex (TSC) is a disease associated with abnormal cell growth, caused by dysfunction of the TSC1 or TSC2 genes and dysruption of the MTOR pathway, which leads to cortical malformations, neuronal hyperexcitability, and seizures. Seizures in patients with TSC often start within the first year of life, and tend not to respond to traditional treatments. Everolimus is a marketed drug that has been used to treat other manifestations of TSC (including giant cell tumors of the brain, renal angiomyolipomas, and angiofibromas of the skin).
This study was a placebo-controlled add-on study of everolimus for the treatment of refractory seizures in children and adults with epilepsy.Following an 8-week baseline phase, patients aged 2-65 years (stratified by age) with TSC and refractory seizures on 1-3 antiepileptic drugs were randomized to EVE LT or HT Cmin target ranges or placebo, and treated in an 18 week Core Phase (6-wk titration + 12-wk maintenance). Primary endpoints were change from baseline in average weekly frequency of TSC-seizures (seizures not previously shown to be generalized in onset by EEG), expressed as response rate (≥50% reduction [RR]), and percentage reduction.
MedicalResearch.com: What are the main findings?
Dr. French: Overall, 366 patients were randomized to EVE LT (n=117), HT (n=130), or placebo (n=119). The median percentage reduction in TSC-seizures was significantly greater with EVE LT (29.3%, P=0.003) and HT (39.6%, P<0.001) vs placebo (14.9%). RR was also significantly greater with EVE LT (28.2%, P=0.008) and HT (40%, P<0.001) vs placebo (15.1%). The most frequent ≥10% all grade adverse events (AEs) reported with EVE LT/HT vs placebo included stomatitis (28.2%/30.8% vs 3.4%), diarrhea (17.1%/21.5% vs 5%), mouth ulceration (23.9%/21.5% vs 4.2%), nasopharyngitis (13.7%/16.2% vs 16%), upper respiratory tract infection (12.8%/15.4% vs 12.6%), aphthous ulcer (4.3%/14.6% vs 1.7%), and pyrexia (19.7%/13.8% vs 5%). Discontinuations due to AEs (5.1%/3.1% vs 1.7%) were low.





