WHAT BONE MAR­ROW AB­NOR­MAL­I­TIES MAY MEAN

EQUUS - - Eq Medicalfro­nt -

Although bone mar­row ab­nor­mal­i­ties of the can­non bone may ap­pear alarm­ing on di­ag­nos­tic images, many are not associated with lame­ness, ac­cord­ing to a new study from France.

Re­searchers at the Uni­ver­sity of Lyon re­viewed the records of 166 sport and plea­sure horses who un­der­went a stand­ing mag­netic res­o­nance imag­ing (MRI) ex­am­i­na­tion be­tween 2009 and 2016. Based on clin­i­cal ex­ams, the horses were di­vided into three groups: horses lame in the foot, horses lame in the fet­lock and horses who were not lame. Next, an in­de­pen­dent clin­i­cian ex­am­ined the MRI images and clas­si­fied the horses based on the pres­ence and sever­ity of le­sions seen at the lower (dis­tal) end of the can­non bone, at the level of the fet­lock joint. The re­searchers found such le­sions in 76.5 per­cent of the study horses.

When the in­for­ma­tion from the clin­i­cal ex­ams and MRI analy­ses were com­pared, the re­searchers could find no cor­re­la­tion be­tween the pres­ence or sever­ity of the bone mar­row le­sions and the

STUDY: EQUINE SKIN HOSTS MANY MI­CROBES

de­gree of lame­ness in in­di­vid­ual horses. Nor was the sever­ity of bone mar­row ab­nor­mal­i­ties associated with any par­tic­u­lar type or level of ac­tiv­ity.

The group calls for fur­ther study to de­ter­mine the clin­i­cal sig­nif­i­cance, if any, of bone mar­row le­sions of the dis­tal end of the can­non bone, vis­i­ble on MRI in horses.

Ref­er­ence: “Bone mar­row le­sions of the dis­tal condyles of the third metacarpal bone are com­mon and not al­ways re­lated to lame­ness in sports and plea­sure horses,” Vet­eri­nary Ra­di­ol­ogy & Ul­tra­sound, Novem­ber 2018

High-tech anal­y­sis has re­vealed that a horse’s skin, like his gut, is home to var­ied but sta­ble bac­te­rial com­mu­ni­ties, a find­ing that may have im­pli­ca­tions for wound-treat­ment de­ci­sions.

Work­ing at the Uni­ver­sity of Mon­treal, the re­searchers used DNA se­quenc­ing to iden­tify bac­te­ria in wounds on equine limbs and flanks dur­ing var­i­ous stages of healing. This ad­vanced tech­nol­ogy en­ables re­searchers to iden­tify or­gan­isms that might oth­er­wise es­cape de­tec­tion, ac­cord­ing to Mar­cio Costa

DVM, PhD, and Chris­tine The­o­ret, DVM, PhD, DACVS. “Only be­tween 5 to 20 per­cent of bac­te­ria can grow on tra­di­tional cul­tur­ing me­dia,” says Costa. “There­fore, they re­mained un­known for a long time. [With DNA se­quenc­ing], we now have a bet­ter pic­ture of a bac­te­rial com­mu­nity.”

For the study, iden­ti­cal sur­gi­cal wounds were cre­ated on the lower front legs and a flank of four horses. On each horse, one leg wound was ban­daged and the other was left un­cov­ered, as was the flank wound. The dress­ing on the ban­daged wounds was changed ev­ery two to three days. Re­searchers took biop­sies of all wounds af­ter one, two and three weeks of healing. No sys­temic or top­i­cal med­i­ca­tions were ad­min­is­tered dur­ing the study pe­riod.

The data showed that each in­di­vid­ual’s skin had unique mi­cro­biota pro­files, but there was some con­sis­tency in the types of bac­te­ria found at par­tic­u­lar wound lo­ca­tions on all of the horses. For in­stance, bac­te­ria from the gen­era Fu­sobac­terium and Acti­nobacil­lus were more abun­dant in limb wounds than in wounds on the flanks. The rea­son for this isn’t clear, says Costa, but dif­fer­ing bac­te­rial pop­u­la­tions could have prac­ti­cal con­se­quences: “Fu­sobac­terium, for ex­am­ple, has been associated with skin ul­cers in hu­mans and dig­i­tal der­mati­tis in cat­tle, so its pres­ence on equine limbs might also make healing more dif­fi­cult.”

The re­searchers also found that un­ban­daged wounds har­bored a greater va­ri­ety of mi­croor­gan­isms than did ban­daged wounds. “I can­not say whether this is good or bad,” says Costa, “but in gen­eral, di­ver­sity is associated with a health­ier com­mu­nity.”

He adds that all four of the ban­daged limbs de­vel­oped ex­u­ber­ant gran­u­la­tion tis­sue (proud flesh) but, given the small sam­ple size, this doesn’t nec­es­sar­ily mean that ban­dag­ing con­trib­uted to the prob­lem. “Maybe in the fu­ture we can use this in­for­ma­tion for other re­search,” he says, “for ex­am­ple, to de­velop a pro­bi­otic that is proven to im­prove healing---you can ban­dage the wound with this ‘med­i­ca­tion.’”

In each study horse, the micro­organ­ism pro­file of healed wounds was sim­i­lar to the pro­file found on the in­tact skin sam­ples col­lected from healthy con­trol horses. This, the re­searchers say, is a sign of the sta­bil­ity and re­silience of mi­cro­biota com­mu­ni­ties on equine skin.

Ref­er­ence: “Use of next gen­er­a­tion se­quenc­ing to in­ves­ti­gate the mi­cro­biota of ex­per­i­men­tally in­duced wounds and the ef­fect of ban­dag­ing in horses,” PLOS One, Novem­ber 2018

The va­ri­ety and sta­bil­ity of the bac­te­ria liv­ing on a horse’s skin may have im­pli­ca­tions for wound treat­ment.

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