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.
For the past seven years we have been working with a team of scientists attempting to manufacture an anti -diabetic compound from ivy (hedera), the problems include harvesting the berries and making the end product stable enough to add to a manufacturing process. The saponin has been tested on dairy cattle and we have done some initial tests on horse (gut bacteria) However there is still a long way to go and most of the work is protected by IP and Patents so forgive my lack of detail, initially I was horrified at the thought of horses consuming ivy and was adamant that I had never seen any of my horses eating it, EVER! I soon realised that was probably because they had never had access to it…. Some of our herd eat it, some don’t and for that reason I wouldn’t cut any and offer it to a stabled horse but I would try to make it available to the horse in the field (growing). A user friendly saponin can be found in Phytolean Plus.
The word sapo means soap in latin. Saponins make great natural detergents but are toxic if injected into the blood stream, however if eaten in small quantities, all horses require minute amounts to aid digestion, though some horses particularly ‘good doers’ seem to have a large appetite for plants containing these chemicals. Saponins have many medicinal properties because they mimic and interact with the endocrine system (hormones) leading to positive changes within the metabolism.
Saponins are also able to feed the good gut bacteria and make new substances (metabolites) which are then absorbed across the gut wall and are further changed by the liver. These new molecules are fatty esters which have a significant effect on many chronic disease and a positive effect on metabolism.
Saponins reduce those bacteria capable of breaking down the otherwise indigestible alimentary polysaccharides fructans.
Saponins slow down the rate of both gastric emptying and the rate of sugar transport across the gut wall, if you see a horse taking snatches of ivy (hedera) the reason is likely to buffer the effects of a high carbohydrate meal.
In more detail the saponins in ivy (and sarsaparilla) are alpha-glucosidase inhibitors which delay the absorption of complex carbohydrates, inhibiting postprandial glucose peaks thereby leading to decreased postprandial insulin levels. I have a family of ‘good doers’ who are all avid eaters of ivy, if I cut down the tree like ivy shrubs from the stone walls and leave it in the fields it is stripped within days leaving only the large branches.
Plants containing high levels of plant saponins include woody shrubby bushes with small berries such as hedera (ivy) and berberine. Many evergreen shrubs contain saponins such as holly and the very sharp and prickly Butchers Broom. In our experience horse do seek them out and seem to enjoy nibbling the young green leaves (probably because they are less sharp!) and berries. The ivy (hedera) seems to be a chosen in early spring before the berries turn a dark purple.
Could a small daily dose of white willow bark protect against the onset of laminitis?
The use of metabolomics is a fast track to discovering underlying causes and mechanisms of disease in humans and horses. This technique is a rapidly growing area simply because of the technology available to detect and identify the signaling and inflammatory chemicals that are released during a disease process. Many of you are in a state of complete shock when a previously completely well horse suddenly develops a devastating laminitic attack often causing death and certainly causing devastation, these attacks occur even when the diet is strictly managed and every care is taken to avoid the event. In a very recent paper scientists have recreated the ‘food poisoning’ event that occurs in the hind gut which allows toxins to flood through the gastro intestinal tract, leading to multi organ failure which eventually causes the failure of the sensitive laminae in the feet but which originally occurs during a failure event in the gut. It is very important to understand that this type of laminitis is different to endocrinopathic laminits relating to EMS which appears to have a build- up time and relates to adipose tissue raised insulin/glucose levels and the release of inflammatory chemicals from the fat pad deposits. It is entirely possible to have both of course.
The scientists found that ‘well’ horses release one chemical signaling marker ( determinable by blood testing) in the small intestine which remains stable, but the level of this chemical falls prior to an attack of the ‘food poisoning’ type of laminitis which also precedes the failure of the gut barrier prior to the laminitis/ colic event. There appears to be a correlation between the production of this chemical, the level to which it falls and the symptoms which occur after. Making it possible for the first time to predict whether the horse is likely to have multiple organ failure, ie if the levels drop below a certain measurable amount the horse will develop colic like symptoms followed by a devastating attack of laminitis, it can also predict those horses which will survive and those which are likely to die. This means that owners will be able to know and understand that there apparently ‘well’ looking horse is in fact ‘sick’ with the potential for a life threatening ‘food poisoning’ event
This also means that there is a potential window of opportunity to manage the gastro intestinal event before it hits the feet. Very surprisingly it was also discovered that a horse will produce two chemicals that are identical to compounds occurring in white willow and one other common hedgerow plant both prior and during the devastating inflammatory event without being fed either plant. This was a completely unexpected result and one which may present an opportunity for prevention and intervention. As the science is going to take some time to trickle through from the research labs to the stable yard, it may be worth examining the subject of prevention more closely, the doses of both compounds are very small and if given as an oral supplementation require both careful management and purity of compounds. If anyone is interesting in knowing more please let me know as the area of inflammation is complex and will require some unravelling before safe doses can be recommended. We are currently funded for research in the area of metabolomics/ respiratory bleeding in racehorses but have been offered a follow on year if enough of you are interested it may be possible to include or put together another study. With the technology available it might also be possible to develop a test using saliva rather than blood which would make management much easier and would serve to test whether the dose of the two natural compounds are doing the job.
Even in the middle of this very wet winter plantago is still growing well, we have the smaller version Plantago lanceolata, it grows close to the ground and has thin spear like leaves that form a rosette. Both the larger, Plantago Major and smaller, Plantago Lanceolata contain very high levels of anti-oxidants that have a positive effect on the health of the horse. Flavonoids and hydroycinnamic acids are two of the major anti- oxidants, both work to restore health and aid in recovery, both protect cells against oxidative damage by free radicals and activate antioxidant enzymes with anti-inflammatory properties, phenolic compounds have been identified as being the main ingredients of many ethno-medical plants, it’s great to have such a powerful one growing wild in the field that the horses can self-select if required.
The roots are high in phenolic anti- oxidants, these are water soluble so if you are making up a mash, soak the plantago in hot/boiling water first, then use the water to make the mash to ensure the horse is receiving his medicine!
The other benefit to a bit of plantago are the high levels of beta carotene a precursor of vitamin A. Synthetic Vitamin A is often added to processed pelleted feeds but between 30-40% of the vitamin A added can be lost in the pelleting process or degraded if stored badly or as the food ages. For those processed foods with added minerals the loss of vitamin A may be even greater as the minerals cause degradation of the vitamin A. Humidity and high temperatures can reduce the content to 2%. A 500kg horse needs around 15,000 IU of vitamin a per day and 100g of plantago will supply 11,000 IU’s, of beta carotene that’s around seven very small plants or one the size of the plant in the image, the beta carotene is converted to vitamin A in the digestion process.
The information on vitamin A in literature seems to be confusing, for instance vitamin A is recommended to be added as a supplement to the equine diet especially for horses stabled, but in a trial, mares fed a low beta carotene hay for 22 months, showed no signs of deficiency. The horse must be manufacturing its own, from food given, as there are over 10 known carotenes apart from beta carotene which may be used to convert into vitamin A without the need for synthetic added extras.