Large Colon Volvulus Research Articles

Flowmetry and spectrophotometry can detect reduced intestinal microperfusion in nonsurvivors during equine colic surgery for large intestinal strangulation.

To evaluate the use of laser Doppler flowmetry and spectrophotometry (LDFS) for large intestinal viability assessment in horses with naturally occurring large intestinal strangulations. By use of LDFS, intestinal microperfusion was quantified as tissue oxygen saturation (tSo2), hemoglobin (tHB), and blood flow (tBF) in cases with large colon volvulus and small colon strangulations undergoing colic surgery (n = 17). Intestinal biopsies were taken from the pelvic flexure in all large colon cases and in small colon cases that underwent intraoperative euthanasia. Measurements were compared between survivors and nonsurvivors, and the correlation between LDFS and (immuno)histology was tested (P < .05). The tSo2 and tBF were clearly lower and tHB was higher than previously reported in healthy horses. Following correction of the lesion, pelvic flexure tBF was significantly lower than that of the left ventral colon. Prior to correction of the lesion, microperfusion did not differ between survivors and nonsurvivors, but following release of the strangulation the survivors had a significantly higher tSo2 and tBF compared to the nonsurvivors. There was a negative correlation between tBF and interstitium-to-crypt ratio and a positive correlation between tHB and the histological hemorrhage score. There were no significant correlations between LDFS measurements and inflammatory cell counts or hypoxia-inducible factor-1α immunoreactivity. Large intestinal microperfusion was decreased in nonsurvivors compared to survivors and was correlated with histological injury, suggesting that LDFS has the potential to predict tissue injury and postoperative survival. The use of LDFS as an ancillary diagnostic aid may improve intraoperative viability assessment during colic surgery.

Dexmedetomidine preconditioning reduces ischaemia-reperfusion injury in equine model of large colon volvulus.

Large colon volvulus is a cause of colic in horses with high morbidity and mortality when not promptly treated. More treatment options are needed to improve the outcome of these cases by protecting against the damage caused by ischaemia and reperfusion injury. To determine the effect of preconditioning with dexmedetomidine prior to induction of ischaemia-reperfusion (IR) injury in a large colon volvulus model in the horse. Randomised blinded in vivo experiments. Horses received either a dexmedetomidine (DEX) or saline (CON) constant rate infusion (CRI) immediately following induction of anaesthesia. Venous, arterial, and transmural occlusion of a section of the large colon was performed for 3 h, after which the ligatures and clamps were removed to allow for reperfusion for 3 h. Biopsies of the large colon were taken at baseline, 1 and 3 h of ischaemia, and at 1 and 3 h of reperfusion. The severity of crypt epithelial loss (DEX = 2.1 [0.8-2.8], CON = 3.1 [2.5-4], p = 0.03) and mucosal haemorrhage was decreased (DEX = 2.1 [1.3-3], CON = 3.5 [2.5-4], p = 0.03) in group DEX compared to group CON when graded on a scale of 0-4. Crypt length remained longer (DEX = 369.5 ± 91.7 μm, CON = 238.5 ± 72.6 μm, p = 0.02) and interstitium to crypt (I:C) ratio remained lower (DEX = 1.4 (1-1.7), CON = 2.6 [1.8-5.9], p = 0.03) in group DEX compared to group CON during reperfusion. Clinical applicability of pharmacologic preconditioning is limited. Preconditioning with a dexmedetomidine CRI prior to IR injury demonstrated a protective effect histologically on the large colon in the horse. Further investigation into postconditioning with dexmedetomidine is warranted as a possible intervention in colic cases suspected of being large colon volvulus.

Factors associated with development of post-operative reflux in horses with large colon volvulus and association with complications and outcomes.

Post-operative reflux (POR) is rare following large colon volvulus (LCV) but does occur despite the absence of a small intestinal lesion. The prevalence, risk factors and association with survival of POR after LCV are currently unknown. To determine the prevalence of POR in horses with an LCV and its association with survival. A further objective was to assess factors which may predict POR. The hypothesis was that horses with POR following LCV surgery have a worse outcome for survival compared to those without POR. A retrospective cross-sectional study. Clinical data of client owned horses which underwent colic surgery at a single UK referral hospital between 2008 and 2021, where LCV was the primary finding, were retrieved from hospital records. Statistical analyses included chi-squared, t-tests and odds ratios (ORs). Horses with concurrent lesions, and those that did not survive past anaesthetic recovery, were excluded from analysis. POR was defined as ≥2 L of gastric reflux on at least one occasion. A total of 128 horses were included in the study, 23 of which had POR (18%). Overall survival to hospital discharge was 86%, 95% in the non-POR and 44% in the POR group. Horses with POR were less likely to survive to discharge than those without (OR = 26, 95% confidence interval [CI] [7.68-88.0], p < 0.001), and less likely to be alive 3 years after surgery (OR = 13.4, 95% CI [2.78-64.8], p < 0.001). Due to the retrospective study design, full data sets were not available for every case because clinical records were incomplete or, at that time, certain tests were not performed or clinical variables were not measured. POR in LCV cases is a negative prognostic indicator for survival.

Small Colon Faecalith with Large Colon Displacement in Ten Cases (2015-2023): A Detailed Case Description and Literature Review.

Small colon impaction can result in accumulation of ingesta, gas, and fluid orally to the impaction site in horses. Large colon tympany, which is caused by ingesta fermentation, can be a predisposing factor for intestinal displacement. The aim of this study is to report the history, clinical, and surgical findings of horses and ponies referred for abdominal pain not responsive to drugs where a right dorsal displacement (RDD) or large colon volvulus (LCV), together with a small colon faecalith (SCF), were diagnosed during surgery. This study included a total of five horses and five ponies. Based on clinical features, ultrasonographic examination, and rectal palpation, an initial suspected diagnosis of RDD, LCV or severe large colon and caecum distension was made in all clinical cases. Due to the lack of response to medical treatment or worsening of colic symptoms, surgery was performed in all horses: diagnosis of RDD or LCV was made and a SCF was incidentally detected in all cases. While exploratory laparotomy was carried out in all the patients for the presence of a large colon issue, it was probably subsequent to an obstruction of the small colon caused by the presence of an SCF, which is generally difficult to diagnose. This study reported the presence of SCF as a possible cause of secondary RDD or LCV in horses and ponies that, to the authors' knowledge, has never been reported.

Strangulating Large Colon Volvulus: A Diagnostic and Surgical Challenge in a Post-Partum Thoroughbred Mare

Strangulating Large Colon Volvulus: A Diagnostic and Surgical Challenge in a Post-Partum Thoroughbred Mare

Caecocolic ligament hypoplasia in a Thoroughbred filly with volvulus of the large colon

SummaryAn 11‐month‐old Thoroughbred filly was referred to the hospital with signs of severe abdominal pain unresponsive to medical treatment. Upon arrival, the filly had a heart rate of 60 beats/min, pink mucous membranes and continued to show severe colic signs despite sedation. Due to the severity of colic signs, general anaesthesia was induced immediately. Exploratory celiotomy revealed a large colon volvulus of more than 360 degrees and hypoplasia of the caecocolic ligament between the caecum and right dorsal colon. The large colon volvulus was corrected, and the filly recovered uneventfully from general anaesthesia. Post‐operative treatment included intravenous fluids and intravenous lidocaine continuous rate infusion, parenteral nutrition, systemic antibiotics, nonsteroidal anti‐inflammatories, gastroprotectants and restricted feeding. The filly experienced several post‐operative complications associated with severe enterocolitis including pyrexia, leukopenia and diarrhoea but made a full recovery and was discharged to the farm after 16 days of hospitalisation. Long‐term follow‐up was available for 22 months after surgery without further reports of colic and the filly had entered race training. Hypoplasia of the caecocolic ligament in association with colic in horses has rarely been reported in the equine literature. To date, only two further case reports of young horses with large colon volvulus and hypoplasia of the caecocolic ligament have been published. In contrast to the presenting case, several other mesenteric abnormalities were present in these two cases in addition to the hypoplastic caecocolic ligament and both horses were eventually euthanised. The pathogenesis of hypoplasia of the caecocolic ligament remains unclear but may include the disruption of early stages of embryogenesis. An abnormal caecocolic ligament has been suggested to potentially predispose horses to large colon volvulus. The presenting case indicates that as an isolated abnormality, a hypoplastic caecocolic ligament may not result in reduced long‐term survival in horses with large colon volvulus.

Effect of post‐operative reflux on horses following large colon volvulus

Effect of post‐operative reflux on horses following large colon volvulus

A retrospective study of gastrointestinal disorders in a predominantly Austrian leisure horse referral hospital population

SummaryThe aim of our retrospective study was to produce and analyse epidemiological data on gastrointestinal (GI) disorders of Austrian leisure horses. Case records of horses referred to the Equine Clinic of the Veterinary University of Vienna were collected from an electronic hospital information system using its search options. All cases reported to have suffered a GI disorder between March 2003 and February 2015 were selected. In this period of 4314 days, data of 1833 GI cases, mostly accompanied by colic signs, were analysed. The vast majority of our GI cases appeared in the abdominal parts of the GI tract 96% (1760/1833) while just 1.3% (24/1833) could be definitively attributed to oesophageal disorders, whereas in 2.7% (49/1833) of the cases a definitive diagnosis could not be made. The highest prevalence of GI disorders was seen in July and October/November. A breakdown of figures for cases clustered under the colic syndrome showed that colon impactions in left ventral large and/or pelvic flexure (35%) were the major problem followed by gastric disorders (18%), spasmodic colic (9%), enteritis (7%), caecal tympany (6%); caecal impaction (4%), colitis (3%), abnormal anatomical positions of large colon including complete and partial strangulation/volvulus, nephrosplenic entrapment of the left ventral and dorsal colon and right dorsal displacement of the large colon (3%) and small intestinal volvulus (2.7%). In 12% of the cases, the cause of the abdominal discomfort was likely idiopathic paralytic ileus. The searching tool of the electronic patient data also brought up cases with malabsorbtion/IBD syndrome and GI ruptures, both these contributed less than 1% of the referred GI cases. Results suggested that the causes of colic are diverse, but the major reasons for referred cases of colic in the east Austrian horse population are large colon impaction or displacements. Seasonal distribution and specific causes of gastrointestinal disorders should be considered essential components of the initial clinical assessment of horses presenting with colic.

Evaluation of Clinical, Laboratory and Ultrasonography Variables as Prognostic Indicators in Equine Colic Surgery

Background: Equine colic surgery is an expensive procedure and availability of reliable prognostic indicators aid in decision making process. This study aimed to evaluate clinical, hemato-biochemistry, ultrasonography, surgery and peritoneal cytology / intestinal histology as prognostic indicators (based on strangulating vs non-strangulating lesion) for equine colic surgery. Methods: Fifteen equines {13 females and 2 males; 5 Thoroughbred, 9 Marwari and one mule} operated for intestinal colic were investigated. The feeding history, pre and post-surgery clinical, hematological and biochemical findings were recorded. Pre and post-surgery ultrasonography, peritoneal cytology and intestinal histology were done. Three equine were euthanized intra-operatively and 12 were followed for short and long term outcome. Result: On surgery, three equine were diagnosed for strangulating (right dorsal displacement of large colon, large colon volvulus and small colon strangulation) and 12 for non-strangulating colic {impaction (3), fecalith (5), sand colic (2), foreign body (1) and small intestine ileus (1)}. Detection of polymorphonuclear cells alone or with lymphocytes on peritoneal fluid cytology was indicator of good prognosis. Feeding of wheat straw is major predisposing factor for non-strangulating colic in Marwari breed but had favorable surgical prognosis (7/9=77.78%). While Thoroughbreds, not on wheat straw, are susceptible to strangulating colic that require early referral for favorable surgical outcome. Prolonged capillary refill time, injected mucous membranes, absent borborygymi, high serum creatine kinase and glucose are poor prognostic indicators for colic surgery. Thoroughbred equine with severe pain, elevated levels of Hb, neutrophils, packed cell volume (PCV), serum glucose and low peritoneal total protein are indicators of strangulating lesion. The equine colic surgery bears a very good short term (10/12=83.33%) and excellent (10/10=100%) long term outcome.

Expression of Proteinase-Activated Receptor 2 During Colon Volvulus in the Horse.

Large colon volvulus in horses is associated with a poor prognosis, especially when ischemic-reperfusion injury of the affected intestinal tract develops. Proteinase-activated receptor 2 (PAR2) plays an important role in the pathogenesis of inflammation in the gastrointestinal tract. The aim of this study was to evaluate the distribution and expression of PAR2 in colonic pelvic flexure of horses spontaneously affected by large colon volvulus (CVH group). Eight horses admitted for severe abdominal colon volvolus and which underwent surgery were included. Colon samples were collected after enterotomy. Data previously obtained from healthy horses were used as a control group. Histologic evaluation was carried out to grade the severity of the colon lesions. Immunofluorescence, western blot and quantitative polymerase chain reaction (RT-qPCR) were carried out on colon samples to evaluate PAR2 expression. In addition, the transcriptional profile of cytokines and chemokines was evaluated using RT2 Profiler™ PCR Array Horse Cytokines & Chemokines. Three out of the eight patients were euthanised due to clinical deterioration. Immunostaining for PAR2 was observed in the enterocytes, intestinal glands and neurons of the submucosal and myenteric plexi. In the CVH horses, the expression of PAR2 mesenger RNA (mRNA) did not differ significantly from that of the healthy animals; western blots of the mucosa of the colon tracts showed a clear band of the expected molecular weight for PAR2 (~44 kDa) and a band smaller than the expected molecular weight for PAR2 (25kDa), suggesting its activation. The gene expressions for C-X-C motif ligand 1 (CXCL1); interleukin 8 (IL8), macrophage inflammatory protein 2 beta (MIP-2BETA) were upregulated in the colic horses as compared with the colons of the healthy horses. Therefore, in the present study, the expression and activation of PAR2 in the colons of horses in the presence of an inflammatory reaction like that occurring in those with spontaneous colon volvulus was confirmed.

Comparison of histomorphometric characteristics of dorsal colon and pelvic flexure biopsy specimens obtained from horses with large colon volvulus that underwent resection.

To determine the degree of histomorphometric damage in dorsal colon and pelvic flexure biopsy specimens (DCBSs and PFBSs, respectively) obtained from horses with large colon volvulus (LCV) and assess the accuracy of predicting short-term outcome for those horses on the basis of DCBS or PFBS characteristics. 18 horses with ≥ 360° LCV that underwent large colon resection. During surgery, biopsy specimens from the dorsal colon resection site and the pelvic flexure (when available) were collected from each horse. Interstitial-to-crypt (I:C) ratio (ratio of the lamina propria space occupied by the interstitium to that occupied by crypts), hemorrhage within the lamina propria (mucosal hemorrhage score [MHS] from 0 to 4), and percentage losses of glandular and luminal epithelium were determined in paired biopsy specimens and compared to determine optimal cutoff values for calculating the accuracy of DCBS and PFBS characteristics to predict short-term outcome (survival or nonsurvival after recovery from surgery). Paired biopsy specimens were obtained from 17 of the 18 horses. The I:C ratio and percentage glandular epithelial loss differed between DCBSs and PFBSs. For DCBSs, an I:C ratio ≥ 0.9 and MHS ≥ 3 each predicted patient nonsurvival with 77.8% accuracy. For PFBSs, an I:C ratio ≥ I and MHS ≥ 3 predicted patient nonsurvival with 70.6% and 82.4% accuracy, respectively. Although different, histomorphometric measurements for either DCBSs or PFBSs could be used to accurately predict short-term outcome for horses with LCV that underwent large colon resection, and arguably PFBSs are easier to collect.

Ultrasonographic visualisation of the mesenteric vasculature in horses with large colon colic.

Ultrasonographic visualisation of the mesenteric vasculature of the large colon (LC) from the right side of the abdomen in cases of displacement and volvulus has been described. However, the LC can move freely within the abdomen and its mesentery can potentially contact both sides of the abdominal wall. Thirty-four horses presented with LC-related colic that had visible LC mesenteric vasculature visible on abdominal ultrasound were included. A control group was made including horses with confirmed small intestinal-related colic. The objective of this study was to evaluate the visibility of LC mesenteric vasculature with transabdominal ultrasonography in horses with LC-related colic and to determine its diagnostic value. The LC mesenteric vasculature was identified on the right side of the abdomen in 16/34 horses with right dorsal displacement of the LC (RDDLC), 180° LC volvulus (LCV), 540° LCV or LC impaction. On the left side of the abdomen, LC mesenteric vessels were identified in 17/34 horses with left dorsal displacement of the LC (LDDLC), 180° LCV or RDDLC. Vessels were visualised on both sides in one horse with a 180° LCV. Presence of LC mesenteric vasculature in the dorsal aspect on the left side of the abdomen was significantly associated with LDDLC. LC mesenteric vasculature can be visualised on transabdominal ultrasound from either side of the abdomen in horses with different forms of LC-related colic.

Prognostic value of colonic and peripheral venous lactate measurements in horses with large colon volvulus.

To determine the prognostic value of (1) colonic venous lactate or peripheral lactate values obtained before and after manual correction of a large colon volvulus and (2) a combination of variables including pelvic flexure biopsy. Prospective clinical study. Forty adult horses in which large colon volvulus was diagnosed intraoperatively. Colonic venous, peripheral venous, and arterial blood samples were collected to measure lactate values before and after manual correction. Mucosal biopsy samples were obtained in cases that underwent enterotomy or colonic resection and anastomosis. Interstitium to crypt (I:C) ratio and hemorrhage scores were measured. Optimal cutoff values were determined by receiver operator curve analysis, and associations between variables and short-term outcome were determined by univariable regression. Short-term survival was defined as horses being discharged from the hospital. P ≤ .05 was considered significant. No association was found between colonic venous lactate values before (P = .011) or after (P = .201) manual correction of large colon volvulus and determination of short-term outcome. Peripheral venous lactate at admission ≥3.2 mmol/L and after manual correction ≥5 mmol/L, arterial lactate postmanual correction ≥3.53 mmol/L, and histomorphometric measurements of mucosal hemorrhage ≥3 and I:C ratio > 1 were associated with poor short-term outcome. Peripheral lactate values, histomorphometric measures of I:C ratio, and hemorrhage score provided prognostic information that could help guide recommendations made to owners. Peripheral lactate values after manual correction provide important intraoperative diagnostic information to assist in predicting case outcome in the operative and immediately postoperative period.

Resumption of Athletic Performance Following Emergency Surgical Correction of Strangulating Large Colon Volvulus in a Thoroughbred Mare

This report describes a case of large colon volvulus in a 6 year old Thoroughbred mare used for tent pegging sport by the Police department. The mare was presented in severe and acute pain from the last 5-6 hours (while returning after national games) with injected mucous membrane and capillary refill time >3secs. The mare was immediately anaesthetized and subjected to surgery. Sub-serosal hemorrhages and edema was evident on the mesentery of left ventral and dorsal colons. The condition was diagnosed as volvulus (>360⁰) of the left ventral colon. The volvulus was corrected and pelvic flexure was emptied and flushed. The mare recovered from anesthesia but experienced moderate pain for the next 5-6 hours. Uneventful recovery was reported on the next day with no pain, passed feces and took some green fodder. The mare recovered and resumed athletic performance in the subsequent7-8 months. The report recommends early referral for surgery in large colon volvulus for favourable prognosis and also highlights the pre and post surgery serial monitoring of clinical, haematological and biochemical parameters.

Preliminary heritability of complete rotation large colon volvulus in Thoroughbred broodmares

Large colon volvulus (LCV) is a life-threatening form of colic that occurs when the large colon rotates 360° or more on its axis, resulting in colonic distention and ischaemia. Any...

A longitudinal study of the faecal microbiome and metabolome of periparturient mares.

BackgroundPeriparturient mares are at increased risk of colic including large colon volvulus, which has a high mortality rate. Alterations in colonic microbiota related to either physiological or management changes, or both, that occur at this time have been suggested as potential causes for increased colic risk in this population of horses. Although the effect of management changes on the horse faecal microbiota has been investigated, limited work has been conducted to investigate changes in faecal microbiota structure and function in the periparturient period. The objectives of the current study were to investigate temporal stability of the faecal microbiota and volatile organic compounds (VOCs) of the faecal metabolome in periparturient mares.MethodsFaecal samples were collected weekly from five pregnant mares from 3 weeks pre-foaling to 7 weeks post-foaling. The microbiome data was generated by PCR amplification and sequencing of the V1–V2 regions of the bacterial 16S rRNA genes, while the VOC profile was characterised using headspace solid phase microextraction gas chromatography mass spectrometry.ResultsThe mare faecal microbiota was relatively stable over the periparturient period and most variation was associated with individual mares. A small number of operational taxonomic units were found to be significantly differentially abundant between samples collected before and after foaling. A total of 98 VOCs were identified. The total number of VOCs did not vary significantly between individual mares, weeks of sample collection and feeds available to the mares. Three VOCs (decane, 2-pentylfuran, and oct-2-ene) showed significant increase overtime on linear mixed effects modelling analysis. These results suggest that the mare faecal microbiota is structurally and functionally stable during the periparturient period. The findings also suggest that if changes in the gut microbiota are related to development of colic postpartum, altered risk may be due to inherent differences between individual mares. VOCs offer a cost-effective means of looking at the functional changes in the microbiome and warrant further investigation in mares at risk of colic.

Is a standardised approach to colopexy justified?

SummaryEquine colopexy techniques vary according to surgeon preference and there is no clear evidence of the superiority of any one technique. Complications secondary to colopexy are varied, but dehiscence of the colopexy site is rare, with less than 1% of horses reported to have a repeat large colon volvulus after dehiscence of the colopexy. Considerations of how and when to perform a surgical fixation of the colon to the body wall include position of the colon, length of the colopexy, and suture material and pattern. Little evidence exists regarding best practice outside of experimental studies and retrospective studies of Thoroughbred broodmares. Therefore, more work must be done to standardise a colopexy technique to apply to a broad spectrum of horses suffering from large colon volvulus and displacement.

Colopexy dehiscence preceding an episode of large colon volvulus, followed by repeat colopexy, in three Thoroughbred broodmares

SummaryThree Thoroughbred mares that had undergone previous colopexy following surgical correction of a large colon volvulus presented for colic signs unresponsive to medical management. Exploratory laparotomy was elected and a midline celiotomy was performed in the caudal aspect of the ventral abdomen in each mare. Examination of the cranial abdomen revealed the large colon was not adhered to the ventral body wall, indicating dehiscence of the previous colopexy. Further examination of the abdomen in each mare revealed a 360‐degree large colon volvulus. The previous colopexy site appeared as a linear haemorrhagic area of fibrosis in one mare and a pale area of fibrosis in two mares. The large colon volvulus was corrected and a second colopexy was then performed using the same technique as the first colopexy – by incorporating 10–12 cm of the lateral free band of the left ventral colon into the midline linea alba closure using number 3 polyglactin 910 (Vicryl®). The mares each recovered uneventfully from anaesthesia and were discharged 2–10 days later. Two of the mares are still alive at the time of manuscript submission, 475 and 789 days post‐operatively. The third mare survived 4 years post‐operatively, following which she was lost to follow‐up. Data available from our clinic indicate an incidence rate of 0.79% for colopexy dehiscence followed by a repeat episode of large colon volvulus. This phenomenon should be considered as a differential diagnosis when a mare that previously underwent a colopexy presents with severe signs of colic.

Clinical outcomes after colopexy through left ventral paramedian incision in 156 thoroughbred broodmares with large colon disorders (1999‐2015)

To describe a technique for colopexy via a left ventral paramedian incision and report postoperative clinical outcomes. Retrospective case series. One hundred fifty-six thoroughbred broodmares treated with a colopexy through a left ventral paramedian incision between 1999 and 2015. Medical records were reviewed for postoperative complications and survival to discharge. The survival rate at 1 year after surgery was based on the medical record, progeny record, or client telephone conversation. Progeny records were reviewed to assess reproductive performance. T tests, χ2 tests, logistic regression, and Kaplan-Meier survival curves were used to identify prognostic factors. The rates of postoperative recurrence of large colon volvulus and colon rupture were 1.2% and 3%, respectively. Ninety-three percent of mares that were treated were discharged alive from the hospital, and 78% were alive 1 year after surgery. The diagnosis of 1 of the following complications increased the risk of death within 1 year: systemic inflammatory response syndrome (SIRS), diarrhea, and/or thrombophlebitis (odds ratio [OR] 4.76). Sixty-six percent of mares that were pregnant at the time of colopexy and discharged alive from the hospital produced a live foal. The percentage of live foals produced each year that the mare was bred after colopexy was 67%. Thoroughbred mares treated with colopexy via a left paramedian incision had a good prognosis for survival and continued use as a broodmare. SIRS, diarrhea, or jugular thrombophlebitis affected long-term survival in this population. Colopexy via a left paramedian incision is a suitable alternative to colopexies requiring a second incision or creating adhesions between the colon and the linea alba in thoroughbred mares.

Protein biomarker of cell proliferation determines survival to discharge in cases of equine large colon volvulus

Progenitor cells play critical roles in epithelial repair following ischaemic injury. Protein biomarkers have been used to identify intestinal progenitor cell subpopulations. This study aims to determine if a critical number of intestinal progenitor cells can predict tissue viability and survival to discharge of large colon volvulus (LCV) cases. The objectives were to 1) identify intestinal progenitor cell subpopulations using biomarkers: proliferating cell nuclear antigen (PCNA), sex determining region Y box 9 (SOX9), phospho-histone H3 (PHH3) and Ki-67, 2) define cut-off values for critical numbers of positive cells and 3) determine if survival to discharge is associated with cut-off values. Retrospective cohort study. Adult horses admitted to the Farm and Equine Veterinary Medical Center at NC State's Veterinary Hospital and Peterson and Smith Equine Hospital between 2006 and 2016 that underwent an exploratory coeliotomy with a diagnosis of LCV of ≥360 degrees, had pelvic flexure biopsy and that recovered from general anaesthesia were selected for inclusion in the study. Immunohistochemical analyses were performed and positive cells were counted. Optimal cut-off values were determined using receiver operator curves. A Fisher's exact test was used to associate cut-off values with survival to discharge. In this study, 23 cases of LCV ≥360° were included. Of 23 horses, 13 (57%) survived to discharge. A cut-off value of <2.1 PHH3 positive cells per crypt correctly predicted death with 100% sensitivity (95% CI; 69.15-100%) and 84.62% specificity (95% CI; 54.55-98.08%). LCV cases with <2.1 PHH3 positive cells per crypt were 96.6 times more likely to die (95% CI; 4.14-2255 and P<0.0001). Biomarkers PCNA, SOX9 and Ki-67 did not predict short-term survival. The population size was small. PHH3 immunohistochemical analysis may assist in more accurate prediction of survival to hospital discharge of LCV cases. The summary is available in Spanish - see Supporting Information.