Cutting edge laminitis treatment?

I'm borrowing this from Fran Jurga's blog. Is this the future of laminitis hoof care?



At least they didn't nail that thing on. What are the stem cells supposed to do exactly?

So many questions for you, Vern Dryden, so many questions...

Laminitis research

As promised here are the links to my sources for the laminitis posts. You'll see a lot of Pollitt on this list, since he's considered the world expert on laminitis I went to his research first.

Microanatomy of the hoof wall (Pollitt)

Recent research into laminitis (Huntington et al)

Equine Laminitis: Current Concepts (Pollitt, 2008) This link sends you to an automatic pdf download

Cryotherapy Reduced the Severity of Laminitis Evaluated 7 Days After Induction With Oligofructose (van Eps and Pollitt, 2006)

Equine Laminitis (Pollitt et al, 2003)

Understanding Laminitis webinar with Jim Belknap and Rustin Moore.

Laminitis diagnosis and treatment webinar

The wooden shoe as an option for treating chronic laminitis (O'Grady and Steward, 2009)

Care and Rehabilitation of the Equine Foot (Pete Ramey, 2011) Specifically the chapters written by Robert Bowker, Eleanor Kellon, and Debra Taylor.

If you only look at one, I highly recommend "Equine Laminitis: Current Concepts." It's long but everything is in there.

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In the meantime, I thought you might be interested in the new developments in Zippy's feet. Look and see what I uncovered yesterday.

Big honking disease pockets where that massive wall separation was. The sole was just peeling off like a scab. Fascinating.

Laminitis: Hoof care

This post is the hardest for me to write because I don't have any personal experience with laminitis. The previous posts were just reporting on research, this one will include some of my own opinions based on my hoof research. This opens me up to criticism, I know, so I will try to clearly label anything that is purely my opinion. Take it with a grain of salt.

Most farriers and vets believe that the hoof wall holds up the coffin bone. When a horse is afflicted with laminitis the connection of the hoof wall to the coffin bone via the laminae is totally lost, leaving the coffin bone floating around willy-nilly inside the capsule. Because of the lack of connection to the toe wall, the deep digital flexor tendon (DDFT) would then be able to pull the toe of the coffin bone downwards, where the bone can pierce the sole.

Severely foundered hoof (founder = chronic laminitis)

Because they believe that the pulley action of the DDFT pulls the toe downwards, they try to find a way to lessen that tension. To do this, they will often prescribe that farriers either let the heels of laminitic horses grow or add pads to lift the heel.


Here's the problem I see with that scenario: The heels are raised to prevent the coffin bone from being pulled down due to stress from the DDFT, yet raising the heels mechanically forces the coffin bone onto its tip, which will then descend straight towards the sole like a spear. They've created the problem they were trying to avoid.



Another option they'll turn to are heart bar shoes, these shoes are designed to contact the frog and make it bear some of the horse's weight. Heart bar shoes are tricky to make and even more tricky to put on, you need a very talented farrier to do it right. Not to mention that if the horse has thrush as well as laminitis this shoe might not be a very good option. Weighting a thrushy frog hurts, a lot.

Heart Bar Shoe

Personally, I cannot understand why you would put shoes on a laminitis horse at all. It simply does not make sense to me to make the horse put all its weight on a failed structure (the laminae). That's what shoes do, they force the weight of the horse onto the hoof wall, and since the hoof wall is connected to the internal structures by the laminae, that means all that weight is transferred from the wall to the laminae- which have either given way or are in the process of doing so. Not to mention that you have to pound nails through the laminae to get the shoes to stay on (how painful must that be to a laminitic horse?).

I think heart bar shoes are terribly ironic, they are designed to take some of the weight off the walls by loading the frogs. Guess what a properly trimmed bare hoof does? Takes the weight off the walls and distributes it between the sole and frogs. So why not just leave the hoof bare and keep the walls from weight bearing at all?

Now I know that farriers have helped laminitic horses, if you've had a horse with laminitis and your farrier has been able to help your horse with shoes (like Dusty), then you've probably got a rather brilliant farrier and you should keep them and never let them get away. The problem is, from what I've heard, those farriers are few and far between.


On a positive note, there is another solution that's been catching on bit by bit with farriers that I will endorse, it's called the Steward Clog. It was created by Dr. Michael Steward of Oklahoma by accident. He had a client come to him with a severely laminitic horse and not much money. At a loss for what to do for her he did the cheapest thing he could think of and screwed a wooden shoe onto the bottom of her foot. The horse came back a few weeks later, much more comfortable and with interesting wear patterns on the wood at the toe and heel. Based on his experience with that horse, Dr. Steward came up with the idea of his clogs and horses have been doing well with them ever since.

Steward Clog

I think the Steward Clog works well for a variety of reasons. For one, you don't have to nail it on- it can be screwed or glued onto the hoof which means no pounding from a hammer is involved; the breakover is under the foot, which greatly reduces the stress and tearing on the laminae at the toe; it covers the entire sole of the foot which allows for a greater dispersion of weight away from the laminae; and they allow the horse flexibility to find a more comfortable stance.

Nicholl's twist on the clog

Here's another good thing about the Steward Clog, the instructions are available for free online. You can make them yourself or you can buy the premade version here. The premade clogs can be nailed, screwed, or glued to the hoof. There's no reason not to try them.

At least that's my opinion, for what it's worth.

Laminitis: Diagnosis and treatment

Here's the hard part: How do you know that your horse has laminitis?

The first signs include:

• shifting the weight from foot to foot
• pounding digital pulse
• heat in the hooves
• reluctance to walk in a circle
• lameness or stiffness of gait

Side comment: Some of you may remember that a while back Coriander went lame and a possible diagnosis was laminitis. Thank goodness it was just an abscess, but it presented much the same way, he was lame with heat and a pounding digital pulse. Sometimes different problems have very similar symptoms.

If you know the horse has had an event that would trigger laminitis, is displaying the signs, and you've caught it within 24 hours of onset you need to ice the hooves. I'm not talking about cold hosing the legs for 20 minutes 2 times a day, I'm talking fill a muck bucket or tank full of ice water and have the horse stand in it for 48 hours straight (keep replenishing the ice).

I'm not kidding.

Chris Pollitt did a lot of research with cryotherapy (ice) and proved that prolonged exposure to the cold works really well to stop laminitis in its tracks. The theory is that vasoconstriction caused by the cold slows down the activity in the hooves enough that it gives the body a chance to right itself before more damage is done.

Now for those of you worried about your horse getting frostbite, Dr. Pollitt says this, "fortunately, cold-induced pain is not a problem in horses; they seem to lack cold nociception in their distal limbs. Horses in the current study showed no cold-induced injury or any clinical signs attributable to cold-induced pain, despite extremely low ice boot and tissue temperatures. Continuous aplication of ice and water to the equine distal limb for 48 h seems safe, effective, and well tolerated by horses."

Fascinating.

I've also heard good things about For Love of the Horse's MMP Stop Solution, if given within 48 hours of the trigger it has also been known to lessen the damage from laminitis.

While you are icing or using something like MMP Stop you also need to treat the cause of the laminitis. If the horse is IR you need to restrict their access to sugar, that means putting the horse on a dry lot, using a muzzle on grass, and soaking your hay if you know it's high in sugar. If you don't know if your horse is IR but you suspect they might be, get them tested. It's a lot better to know now, before they have issues, than to find out later when they do.

If the laminitis was caused by SODS then the horse probably has an infection that will need to be treated with antibiotics and a bunch of other stuff that only a vet can help you with (Always feed probiotics if you have to put your horse on antibiotics- they kill the gut flora.)

Unfortunately if your horse looks like this:

classic laminitis stance

it's already too late to ice or use the MMP Stop, the damage is done. Now you'll need some heavy duty pain killers and anti-inflammatories along with a pretty strict maintenance regimen to get that horse feeling okay again.

At this point in time you'll start hearing about rehabilitative shoeing, but that's for the next post...

If you've seen any other laminitis symptoms please let me know in the comments, if I get enough I'll make another post putting your experiences together. For instance, Kristen said this about when her horse was affected: Laz's laminitis was caused by Potomac which lead to endotoxemia...his sheath was SWOLLEN too during his high fever which is a clue to look for fyi.

Laminitis: Three different paths

One cause of laminitis is physical strain on the laminae due to trauma/injury leading to the horse's weight physically tearing the laminae. This is what happened to Barbaro, his laminae gave out due to excessive weight strain. Personally I think that horseshoes can lead to chronic low-level laminitis since they force all the horse's weight on the laminae (Remember when I said the laminae aren't designed to hold up the entire horse?). I think Dr. Bowker says it best, "any weight-bearing responsibilities the laminae have should be considered their secondary role."

There are two more mechanisms that are found in laminitis that I would call chemical based, one affects the anchoring filaments and the other affects the MMPs. Both have the same result but the causation behind them and how they work is completely different. (Refer to my last post if you don't know what these are.)

Glucose overload- most people know about this cause of laminitis, a lot of them think it is the only cause for laminitis. It isn't. Glucose induced laminitis only happens to horses that are insulin resistant (IR). The horse consumes too much sugar so the body freaks out and shuts down all its sugar uptake mechanisms (similar to diabetes in humans).  Remember how I said anchoring filaments  that attach the hemidesmosomes back onto the basement membrane are made of a glycoprotein molecule? Well the body can't make any if the uptake of sugar (glucose) has been inhibited. That means that the MMPs are still doing their job of popping off the hemidesmosomes but there aren't any anchoring filaments to glue them back on, resulting in the separation of the epidermal laminae from the dermal laminae.

There is another, much more sinister, mechanism for laminitis. This one can be caused by anything that results in an inflammatory response: colic, carbohydrate overload, endotoxemia, septicemia, prolapsed uterus, retained placentas, heat cycles in mares, potomac horse fever- basically anything that ends with -itis and messes with the balance of the hindgut can cause this other kind of laminitis. This can also be referred to as SODS- single organ dysfunction syndrome. When there are bacterial toxins in the bloodstream (which often begin in the hindgut) they activate white blood cells, these toxins and white blood cells eventually migrate down to the hooves and into the lamaella, where they cause the MMPs to go haywire and start popping off the hemidesmosomes at a rate too fast and furious for the anchoring filaments to keep up with, resulting in a separation of the laminae. This action can also result in the death of the secondary epidermal laminae cells. (It's a bit more complicated than this, but I'm trying to make it easier to understand.) Unfortunately, in this case, there is usually some pretty nasty damage done to the basement membrane. 

In the case of IR, it's the failure of the anchoring filaments that lead to laminitis, in the case of SODS it's the MMPs that lead to laminitis. The important thing to remember is that even though they both have the same result they are not caused by the same thing so they cannot be treated the same way. If your horse has laminitis the first thing you need to find out is what caused it.

The hoof wall gives evidence of damage to the basement membrane. It might be the characteristic "rings" that most people think of, but it also looks like these two pictures below. In the case of founder (chronic laminitis) horses will often create a "founder ridge," a place where the hoof wall appears to bunch up. I think the cause of this is damage to the basement membrane, basically the hoof wall cannot be moved down because the foundation that it would attach to is non-functional.

References for this post include Chris Pollitt, Jim Belknap, Rustin Moore, Robert Bowker and Debra Taylor.

Laminitis: Hoof wall growth

The first thing you need to know about the hoof wall is that it is actually composed of three different sections:

• the distal hoof wall/pigmented wall/stratum medium, 
• the water line/unpigmented wall/stratum internum
• the white line/epidermal lamellae

To understand hoof wall growth we also need to focus on the lamellae, of which there are four types:

• Primary Epidermal Lamellae (PEL)
• Secondary Epidermal Lamellae (SEL)
• Primary Dermal Lamellae (PDL)
• Secondary Dermal Lamellae (SDL)

The lamellae from the epidermis (outside of the hoof) interlock with the lamellae from the dermis (inside of the hoof) by means of a basement membrane. "The basement membrane is a thin, unbroken sheet of extracellular material, partitioning the dermis from the epidermis (Pollitt)."

Each one of the SEL (the little fingers hanging off each PEL) is attached to the basement membrane by a hemidesmosome through anchoring filaments. Anchoring filaments are composed of a glycoprotein molecule called laminin-5 and a protein called BP-180.

Following along so far? Okay...

The coronet band is constantly creating new cells for the hoof wall, which means there needs to be a mechanism to move the already existing wall down towards the ground to make room for the new cells. To do that, lamellar remodeling enzymes called matrix metalloproteinases (MMPs) come through and pop the hemidesmosomes off the basement membrane (not all at once, mind you), tissue inhibitors called TIMPs then turn the MMPs off, and the loosened cells then move downward and reattach lower on the basement membrane by the anchoring filaments.

This process happens constantly in order to keep up with the growth from the coronet band. The MMPs, TIMPs, and anchoring filaments are always working in a very delicate balance to keep the hoof wall growing and replace material lost at ground level.

And that's hoof wall growth in a nutshell.

Upon further examination, Bowker's theory of hoof wall growth doesn't differ terribly from this, he just posits that the PELs actually contribute cells to the stratum internum to increase hoof wall thickness closer to the ground. For the purpose of understanding laminitis that isn't terribly important (just interesting).

All the info in this post I learned from reading the work of Chris Pollitt, I'll provide links later on. You'll notice that I've made a few words a little more "obvious." Try to remember those, they'll be important later.