Foreword

I was once asked to introduce Professor James Belknap and present to him an award at a prestigious International Equine Conference on Laminitis. The award was for scientific excellence in the field of laminitis research, and the venue was a noisy gala dinner in West Palm Beach, USA. I thought it best not to elaborate too grandly about his already numerous and excellent contributions to the science of laminitis, so without much preamble I happily presented the award with acclamation from the audience. That was over 10 years ago and could have been the culmination of his career if he had slipped into university administrative roles as so many top academics do. However, fortunately for us, his hunger to decipher laminitis prevailed and his scientific production continued setting him apart from his peers and placing him at the forefront of the laminitis scientific community. He is the pre-eminent thinker and instigator of cutting-edge laminitis research, so it is entirely appropriate that he contributes to and edits this important first in the laminitis literature. Jim has the historical background and vision to choose the appropriate authors and rigorously oversee their contributions to deliver an historic, first of its kind publication; a multiauthor text with the scope to deliver new information on nearly every aspect of Equine Laminitis. This ranges from the latest molecular perturbations at the cellular level, state-of-the-art radiography, to the effectiveness of various clinical shoeing techniques applied to horse's feet.

I try to keep abreast of the laminitis literature and didn't expect to learn much by reading the chapters of this book, but I was agreeably shocked to discover how little I knew and much that was new and interesting. It was like meeting old friends and colleagues and talking 'laminitis.' In a book of this sort, the rigours of peer review are relaxed a little and the authors are able to not only present the expert details of their specialization, but to speculate and 'think outside the box.' Thus, we learn of visions for future research, why certain procedures failed or succeeded, and exciting - yet to be published - data.

Reading this book will bring you up to date with the latest information on the horse's foot and its major affliction, laminitis. It will help you better understand the disease and thus formulate effective preventive and treatment strategies. It will even help you deliver improved lecture and workshop material. I was recently lecturing internationally and, stuck with the habit of updating my lecture material at the last minute and with early access to the chapters of the book, I was able to quickly add new, pertinent material (referenced of course) to my PowerPoints. Thus, the text is a timely and essential 'must-have' addition to the bookshelf or computer/tablet of all who work with and are fascinated by the horse's foot.

Although long overdue, a book such as this, written after we have struggled with laminitis into the modern era of molecular biology and veterinary diagnostics, can at last capture important progress that has arisen from peer-reviewed, validated basic and clinical research (all of which is presented by the chief investigators and their teams in the chapters that follow). An example is the recognition that three different categories of laminitis exist: sepsis-related; endocrinopathic; and supporting limb laminitis. Knowing that treatment should be anti-inflammatory, insulin-reducing or circulation-promoting, respectively, has translated into more effective clinical management. Another realization is that, regardless of the laminitis category, the essential clinical problem is displacement of the distal phalanx and its wide-ranging anatomical consequences. Chapters devoted to digital radiographic imaging that can be enhanced with contrast media show how to assess the new laminitis case, monitor the effects of therapeutic farriery on the position of the distal phalanx, and follow the progression of laminitis into its chronic phase. It was refreshing to read that nonsteroidal anti-inflammatory drugs (NSAIDs), while having many useful properties for laminitis therapy, likely have little or no efficacy in directly preventing the condition (Dr J Divers, Medical treatment of the laminitic patient - anti-inflammatory therapy; see Chapter 31). Dr Divers' personal insight that prognosis after sepsis-related laminitis can be correlated to the positive or negative analgesic response to initial phenylbutazone dosing is noteworthy, therapeutic prognostication.

Many teachers of laminitis and certain textbooks still hold with some form of blood supply problem being central to the pathophysiology of all types of laminitis. This long-held tenet has endured long after publication of evidence to the contrary, and I anticipate this textbook will accelerate revision towards more evidence-based pathogenesis. Indeed, Professor Belknap in his introduction to this book states "Lamellar ischemia, originally thought to be the driving force behind all types of laminitis, only appears to play a primary role in supporting limb laminitis." Perhaps the documented presence of vasoconstrictive agents that has been the focus of extensive laminitis research plays only a contributing, synergistic role, in combination with the overwhelming inflammatory mechanisms as suggested by Dr Simon Bailey in his chapter, 'Vasoactive drug therapies for laminitis - pharmacological and clinical aspects.' Recent research indicates that drugs used to promote digital vasodilation for decades, including acepromazine (likely the second most commonly used drug in laminitis therapy after phenylbutazone) are ineffective, and that lamellar blood flow is probably more responsive to dynamic loading/unloading of the foot than to any pharmacological intervention.

A novel focus of the book are chapters devoted to a single cell; the lamellar basal epithelial cell (LBEC), the building block of hoof lamellae. Ultimately, layers of LBECs are responsible for the suspension of the distal phalanx by the hoof wall, and these chapters suggest that dysregulation of the LBEC and its intimate attachments to its neighbors and to the lamellar dermis via its basement membrane is at the heart of the laminitis lesion. It is now clear that the LBEC is not just a casualty of the events occurring within the lamellae, but is likely to be an active participant in the events leading to its structural failure (Dr Leise's chapter 'Inflammation'). In other words, any current hierarchical description of laminitis should start with the LBEC and progress to failure of the suspensory apparatus of the distal phalanx. This concept makes the term laminitis redundant, since the only category of laminitis with a proven inflammatory basis is the sepsis-related form. For clarity, laminitis descriptors should be enrolled to ensure meaning (e.g., clinical laminitis, hyperinsulinemic laminitis, histopathologic laminitis, etc.).

Balance is essential in a book such as this, and it is important that readers should be presented with views counter to those generally accepted. This applies particularly to the question of raising the heels of horses with chronic laminitis. This common practice, deemed beneficial to reduce the pull of the deep flexor tendon, is challenged in the chapter 'Digital Biomechanics Relevant to Laminitis' by Professors Merritt and Davies. By increasing the angle of the hoof, more shear loading may be applied to the lamellar junction and despite the force of the deep digital flexor tendon being reduced, this may be more likely to cause tearing of the lamellar junction and promote its failure. Thus, the mechanical benefits of raising or lowering the heels are currently in dispute, and the reader will benefit from reading the complete chapter and that of Dr A. Parks 'Anatomy and Function.' Likewise, deep flexor tenotomy surgical technique is put into perspective as a salvage procedure, rather than a treatment, and an option only likely to increase the comfort of the animal for a variable amount of time, and rarely to allow the animal to return to a low level of athletic activity (Dr W. Waguespack, 'Deep Digital Flexor Tenotomy'). On the other hand. other well-respected authors in this text promote both heel elevation and deep flexor tenotomy. giving the reader the opportunity to question these techniques and formulate therapeutic options for their own laminitis patients based on reasonable hypotheses.

Finally, as the editor points out in his introduction, a thorough understanding of the different parameters of the diseases leading to lamellar injury and the biomechanics of the foot are required to successfully treat the wide variety of clinical scenarios grouped under laminitis. This text will serve Dr Belknap's vision and amply promote an understanding of laminitis and enable clinicians (veterinarians, farriers, and trimmers) to work together with new information at their disposal to approach each individual laminitis case.

At the American Association of Equine Practitioners Annual Convention (New Orleans) in 2003, I concluded my 'Laminitis - In-Depth' presentation by stating: "The biological basis of laminitis has become molecular and the discipline of molecular biology has laminitis in its cross-hairs. These are exciting times to be involved in equine research - we now have...