Molecular Imaging Finds Link Between Obesity and Low Estrogen Levels

A new study presented at SNM’s 58th Annual Meeting could throw open the door to a recently established area of obesity research. Investigators have developed a novel molecular imaging agent that targets estrogenic mechanisms in the brain to find out what effect an enzyme called aromatase has on body mass index (BMI), a measurement of body fat based on height and weight. Aromatase is crucial for the production of estrogen in tissues throughout the body, including the brain.

According to the World Health Organization, worldwide obesity has more than doubled since 1980. As of 2008, an estimated 1.5 billion adults were overweight, and in 2010 nearly 43 million children under the age of five were overweight.

“We used this imaging agent to evaluate the amount of aromatase activity in the brain regions related to eating behaviors, such as the hypothalamus and amygdala, in both overweight and normal weight subjects. We were really surprised to see the highest correlation between aromatase availability and BMI happening in the amygdala, which controls emotional memory,” says Gene-Jack Wang, MD, senior scientist and chair of the medical department at Brookhaven National Laboratory, Upton, N.Y. “Our eating is not only controlled by the hunger centers in the brain. It is also related to memory, and that could have a big impact on a person’s eating behavior. This agent could potentially translate into a number of new studies evaluating estrogen and obesity, food intake and appetite suppression.”

For this study, five healthy overweight subjects and 13 normal-weight subjects of the same age were chosen to undergo positron emission tomography, a molecular imaging technique that provides digital representations of physiological functions of the body. Subjects were injected before imaging with the novel imaging agent (C-11)vorozole, which is composed of a medical isotope bound with an aromatase inhibitor that binds strongly with the active sites of the enzyme in the brain. This allowed investigators to track and quantify the availability of this enzyme to selected areas of the brain associated with hunger and feeding behavior.

A significant correlation was found between high BMI of subjects and decreased uptake of the aromatase inhibitor. Imaging agent uptake was decreased in the hypothalamus (25 percent less), thalamus (27 percent less) and amygdala (30 percent less) in subjects with high BMI. This means that there was less availability of the enzyme in these selected brain regions. There was also a strong inverse correlation between low BMI and imaging agent uptake in the amygdala, meaning BMI was less in subjects showing higher aromatase availability. These findings suggest that there is decreased availability of aromatase in the brains of overweight subjects, conceivably leading to reduced availability of estrogen and potentially less control over appetite and food intake, resulting in weight gain; however, further studies need to be conducted to validate the relationship between estrogen synthesis and high BMI.

Future studies could be introduced to screen eating behaviors of obese subjects in order to further validate the correlation between BMI and estrogen availability in the brain. Based on the current research, theoretically the less estrogen available to the brain, the less control patients may have over their appetite. Studies moderating estrogen and feeding behavior could result in novel drugs for appetite suppression and perhaps even reduction of BMI. This is just the first step toward discovering the mechanisms behind appetite, BMI and estrogen availability.

Read more http://www.sciencedaily.com/releases/2011/06/110606131709.htm

Share

Posted: June 7th, 2011 under Uncategorized.

RSS Medical Imaging News

  • MRI pinpoints region of brain injury in some concussion patients April 15, 2014
    Researchers using information provided by a magnetic resonance imaging technique have identified regional white matter damage in the brains of people who experience chronic dizziness and other symptoms after concussion. The findings suggest that information provided by MRI can speed the onset of effective treatments for concussion patients.
  • New PET/CT scanner more patient friendly April 10, 2014
    A new patient-friendly PET/CT scanner does combined exams in just 15 or 20 minutes, and the patient is never completely enclosed. The state-of-the-art system is improving the diagnosis and treatment of cancer, heart disease, epilepsy, Alzheimer's disease and other conditions. "It is the most patient-friendly system of its kind," said a hospita […]
  • Potential marker to better identify, resect glioblastoma multiforme tumors April 7, 2014
    Researchers have highlighted the results of research that explores whether 5 aminolevulinic-acid fluorescence (5-ALA) offers additional detection benefits compared to intraoperative MRI (iMRI) when dealing with invasive tumors.
  • Green tea extract boosts your brain power, especially the working memory, new research shows April 7, 2014
    Green tea is said to have many putative positive effects on health. Now, researchers are reporting first evidence that green tea extract enhances the cognitive functions, in particular the working memory. The findings suggest promising clinical implications for the treatment of cognitive impairments in psychiatric disorders such as dementia.
  • New method for prostate cancer detection can save millions of men painful examination April 7, 2014
    Each year prostate tissue samples are taken from over a million men around the world -- in most cases using 12 large biopsy needles -- to check whether they have prostate cancer. This medical procedure shows that 70% of the subjects do not have cancer. The examination is unnecessarily painful and involves risk for these patients, and it is also costly to car […]
  • Role of magnetic nanoparticles in breast cancer treatment April 7, 2014
    While exploring the promise of magnetic nanoparticle (mNP) hyperthermia in breast cancer treatment, a researcher reviews preclinical studies and discusses plans for early-phase clinical studies in humans. This evolving treatment approach involves the injection of nanoparticles into the tumor, which are then activated with magnetic energy. Once activated the […]
  • Six months hormonal treatment in addition to radiotherapy improves survival for men with localized prostate cancer April 7, 2014
    Men with prostate cancer that is small and confined to the prostate gland but that is at risk of growing and spreading, do better if they are treated with radiotherapy combined with androgen deprivation therapy, which lowers their levels of the male hormone, testosterone, according to new research.
  • Non-invasive imaging instead of repeated biopsy in active monitoring of prostate cancer April 6, 2014
    A novel method to 'manipulate the lipid metabolism in the cancer cell to trick them to use more radiolabeled glucose, the basis of PET scanning' is being described by researchers. The current study used the clinically safe drug etomoxir to block prostate cancer cells' ability to oxidize lipids. With the lipid energy source removed, cells switc […]
  • Toward a clearer diagnosis of chronic fatigue syndrome April 4, 2014
    Functional PET imaging to show that levels of neuroinflammation, or inflammation of the nervous system, are higher in patients with chronic fatigue syndrome than in healthy people, research has shown. Chronic fatigue syndrome, which is also known as myalgic encephalomyelitis, is a debilitating condition characterized by chronic, profound, and disabling fatig […]
  • Diffeomorphometry, geodesic positioning systems for human anatomy April 3, 2014
    New algorithmic technologies for the parametric representation of human shape and form have been recently demonstrated by researchers. Coupled with advanced imaging technologies, this presents opportunities for tracking soft-tissue deformations associated with cardiovascular studies, radiation treatment planning in oncology, and neurodegenerative brain illne […]

News Items

Links