By Alexandra Balcer
Now you might be thinking, how on earth can my bladder help me get the beach-bod I’ve always wanted? Well I’m here to tell you that a study conducted by Dr. Aaron Cypess of Harvard University to help rid you of that pesky over-active bladder may have also found a way to let you lose weight and minimize those trips to the bathroom at the same time. It all comes down to the simple activation of brown fat cells. Once those fat burning machines get kicked into gear, the pounds can just melt away.
First and foremost, it’s necessary to understand that brown adipose tissue, or brown fat, isn’t the run-of-the-mill, fat storing cell type that we’re used to. When picturing fat, most see those creamy blobs extracted during liposuction. This white fat houses lipids in giant droplets that take up the entire cell, hence their white-ish coloring. These stores of fat remain as a fuel source to get us through the lean times, like in that hour between class and lab when you forgot to bring a snack. Brown fat, on the other hand, won’t do a great job of feeding you when you’re hungry but it will keep you warm. Brown adipose cells contain an increased number of mitochondria, the double membrane powerhouse organelle of the cell, which give it more of a brown coloring. Mitochondria is dubbed the power house because its major function is to create energy molecules call adenosine triphosphate, or ATP, using an energy storing technique called a proton gradient. A proton gradient is established on the inner membrane of a mitochondria by the lopsided diffusion of hydrogen molecules out of the cell interior into the mitochondrial inner membrane space. This stored energy along the inner membrane can be released through the production of those ATP molecules but also through the release of heat . To be able to keep up these high energy functions, the mitochondria must have high metabolic activity, in other words, mitochondria must burn calorie after calorie so we don’t freeze . Brown fat cells are highly specialized for this heat making process named, officially, non-shivering thermogenesis.
These brown fat cells exist in our adult human bodies but over time begin to act like white fat cells and shift their activity toward more lipid storage. Techniques have been tried where subjects are exposed to cold temperature to stimulate brown adipose non-shivering thermogenic activity. Basically, they place people in really cold environments for an extended period of time (that won’t kill them) and assess their metabolic activity, specifically that of brown adipose tissue. In general, it has been successful. They have seen an increase in metabolism and calories have been burned, but this metabolic activity shuts off once the cells are warmed again. To constantly burn calories your body would have to be experiencing uncomfortably cold temperatures all the time. Brown adipose tissue is found in hibernating animals that spend their days in the extreme cold, as well as in infants. These hibernating, fur covered animals require this heat source to sustain their body temperature when 'sleeping' for months at a time, while infants use brown fat to maintain warmth because they are less capable of regulating their body temperature by other means, such as blankets and walking indoors… on their own... Infants also have a smaller surface area-volume ratios, which means they have a higher ratio of exposed skin compared to their overall body size, which results in amplified heat loss. Since becoming a human popsicle isn’t a plausible or healthy way to lose weight, an alternative method to stimulating this metabolic activity had to be found.
The functional differences between brown and white fat have been studied and known for quite some time, but it was the accidental discovery by Dr. Cypess on his quests to cure the over-active bladder that opened a window to harnessing brown fat’s natural calorie burning capabilities to facilitate weight loss. In his original, study Dr. Cypess was aiming to treat over-active bladders with a dose of mirabegron, a lovely, oral β3-adrenergic receptor antagonist . β3-adrenergic receptor antagonist is a fancy scientific way of saying that mirabegron activates this particular receptor, found in fat cells and the bladder, to do its job. This receptor acts in the bladder to prevent urination, while in brown fat it inspires the cell to increase its metabolism and generate more heat . Although this treatment has not been approved as a weight loss technique, it stands as a promising glimpse into the future of metabolic regulation to moderate unhealthy weight gain and facilitate weight loss.
Long story short, brown adipose tissue is the fat that will work for you, not against you. By stimulating your brown fat to get to work and increase energy expenditure, brown fat stands as a great potential approach to treat diabetes and obesity, two major problems that plague our society today. All it takes is a healthy dose of mirabegron and those β3-adrenergic receptor antagonist will kick right in, jump-starting your preexisting, fat burning cells. Of course, maintaining a healthy diet and exercise routine will only help to improve your overall healthy and help you reach your desired weight but isn’t physiology great? Only in the body can you make fat and burn it too, all in one cell.
 Caputo, J. 2015. Drug stimulates brown fat and boosts metabolism. Cell Press: 1.
 Cypess, A.M. 2015. Activation of Human Brown Adipose Tissue by a β3-Adrenergic Receptor Antagonist. Cell Metabolism 21: 33-38.
 Doheny, K. 2009. The Truth About Fat. WebMD: 1-4.
 Himms-Hagen, J. 1984. Nonshivering thermogenesis. Brain Research Bulletin 2: 151-160.