Leptin to laminitis..... from friend to foe
Leptin is a hormone and signalling chemical that originates and is released from adipose tissue, it starts out as a friend by regulating and creating an energy balance through a wide range of functions, it also adjusts the feeling of hunger and tells the horse to stop eating when it is full. Its main purpose is to prevent death from starvation through the control of energy when food is sparse, but in our modern equine management systems this hormone is beginning to mutate and take on a different more sinister role.
Because leptin is released from the adipose tissue, the more fat deposits the horse has the more leptin these fat pads produce. In a well covered but not fat BMI score of less than 7 cresty neck score of 3 or less leptin will be working in a normal way, active during meal times telling the horse to stop eating and causing the horse to feel full. The problems start when the horse has access to too many simple carbs (eg high sugar grass, corn syrup sprayed onto many bagged foods) and processed foods which disrupt the ability of leptin to stop the horse from consuming too much. This creates Hungry Horse Syndrome, with leptin unregulated the horse is permanently hungry and desires to eat continually (think we all know a pony/horse like that!) A high sugar/simple carb diet sort of diet triggers or starts a resistance to the action of leptin, causing it to gorge on its food and seek to eat more and more high sugar food to satiate the continuous feeling of emptiness leptin resistance creates. As leptin resistance increases so does insulin resistance causing spikes of blood sugar levels as the horse is driven to consume more and more sugar without becoming satiated or full. It’s interesting to note that stress and periods of box rest also cause leptin levels to rise.
During leptin resistance the hormone starts to act in an uncontrolled fashion and simply starts to do its own thing (self regulation) it undergoes a process of genetic mutation. Evidence suggests that central leptin resistance in horses causes obesity and that obesity-induced leptin resistance injures numerous peripheral tissues, including liver, pancreas, platelets and the vascular system (laminitis). This metabolic- and inflammatory-mediated damage may result from either resistance to leptin's action in selective tissues such as the vascular system, or excess leptin action from adiposity-associated hyperleptinemia. In this sense, the term "leptin resistance" encompasses a complex pathophysiological phenomenon. The leptin pathways include functional interactions with insulin, and the innate immune system, such as interleukin-6.
Leptin levels will decrease with exercise and limited or no access to sugar or processed food, track systems and paradise paddocks come into their own through the long winter months as they prevent the horse from standing for long periods in a box which causes a natural rise in leptin
Blackberry tips contain high levels of the anti-oxidants which help reduce the size of a cresty neck and prevent leptin dysregulation.