Plasma levels of the adipokine leptin seem to be elevated in some cases of autism according to new research from David Rodrigues and colleagues* from the Institute of Biological Sciences at the Federal University of Minas Gerais, Brazil. Based on an analysis of levels of various adipokines – cell signaling molecules secreted by body fat – in a small participant group diagnosed with an autism spectrum condition, researchers reported elevated levels of plasma leptin compared to controls.
Leptin is an important molecule involved in regulating various processes including dietary intake and onwards body weight. Correlating with body fat, a complicated series of biological checks and balances mean that decreases in body fat lead to decreasing levels of leptin which leads to the stimulation of appetite. This relationship also being observed in reverse where higher levels of body fat are linked to a blocking of appetite through elevations in leptin. That being said, the notion of leptin resistance is also gaining popularity as a function of elevated levels of leptin being reported in cases of obesity, where similar to the effects of type 2 diabetes on insulin, typical homeostasis is not observed.
As a cytokine, leptin has also been the source of some research inquiry specifically with inflammation in mind. It’s similarity to other, more pro-inflammatory cytokines such as interleukin-6 (IL-6), has led to speculation about it’s role in modifying the delicate immune system balance between pro- and anti-inflammation.
It is with those immune system effects in mind that the researchers suggest a possible effect from elevations in leptin noted in their cohort of people with autism. Other similar investigations support the notion of elevations in plasma leptin being noted in other autism cohorts although further work is required to substantiate any effect and whether it has a direct or indirect role to play in the pathology of autism. Indeed, whether other issues linked to increased leptin such as sedentary behaviour may have a role to play and more positively, offer a solution to reducing heightened levels of leptin noted in some people with autism.
* Rodrigues DH. et al. Changes in Adipokine Levels in Autism Spectrum Disorders. Neuropsychobiology 2014;69:6-10
Further commentary on this study can be found at: http://questioning-answers.blogspot.com/2014/02/plasma-leptin-levels-and-autism-growing.html