Source: MISSISSIPPI STATE UNIV submitted to
PREVENTION OF PLACENTITIS AND PRETERM BIRTH IN HORSE AND SHEEP
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0207250
Grant No.
(N/A)
Project No.
MIS-381020
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jun 1, 2006
Project End Date
Jun 30, 2011
Grant Year
(N/A)
Project Director
Ryan, P.
Recipient Organization
MISSISSIPPI STATE UNIV
(N/A)
MISSISSIPPI STATE,MS 39762
Performing Department
Animal & Dairy Science
Non Technical Summary
Uterine infections are a major cause of preterm labor and fetal death in mares leading to serious economic loss to the equine industry. The purpose of this project is threefold: 1) to evaluate the efficacy of a combination of antibiotics and immunomodulators in the prevention of uterine infection-induced preterm labor in horses, 2) to determine the incidence of periventricular leukomalacia in preterm foals, and 3) to understand pathogen progression during placentitis using lux-modified organisms and biophotonics imaging.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3013610102025%
3013810102025%
3113610102025%
3113810102025%
Knowledge Area
311 - Animal Diseases; 301 - Reproductive Performance of Animals;

Subject Of Investigation
3610 - Sheep, live animal; 3810 - Horses, ponies, and mules;

Field Of Science
1020 - Physiology;
Goals / Objectives
Objective 1. Determine if antibiotic/dexamethasone, antibiotic/interleukin-10 or antibiotic/ progestin therapy is more effective in preventing uterine infection-induced (pro-inflammatory cytokine-mediated) preterm birth in mares than antibiotics alone. Objective 2. Determine the relationship between the incidence of white matter brain lesions and neurological abnormalities seen in premature foals born to dams with uterine infections (i.e., placentitis). Objective 3. Determine pathogen progression and fetal tissue localization during placentitis disease process using lux gene-modified organisms (i.e., E. coli; S. equi zooepidemicus) and bioluminescence imaging technology.
Project Methods
Pregnant mares (~295 days gestation) will be infected intra-cervically with 1 to 2 million colony forming units (CFU) with a clinical strain of S. equi zooepidemicus to initiate placental infection. Once established, mares will be assigned to receive one of three treatments: 1)the antibioitc trimethroprim sulfamethoxazole (TMS; 30 mg/kg BW, BID) alone, 2) antibiotic with RegumateTM (altrenogest; TMS+R; 2.0 mg/50 kg BW, SID), and 3) antibiotic with dexamethasone administered daily over a six-day period with decreasing doses every two days from 40, 35 to 25 mg (TMS+DEX). Blood samples will be collected prior to infection and at 12, 24, 48, 72 h post infection and 3x/week thereafter until delivery for macrophage cytokine mRNA, relaxin and progesterone (P4) analysis. Fetal and placental well-being will be evaluated daily by transrectal ultrasonography. The efficacy of the differe(t therapeutic approaches will be examined. Preterm foals that do not survive will be evaluated for white matter tissue trauma. Finally, a separate group of pregnant mares ~300 days) and ewes (~120 days) will be infected via injection into the amniotic fluid with lux-gene modified organisms and the progression of the pathogen monitored using biophotonic imaging.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Student training; three sophomore DVM studenst participated in various aspects of this project as part of a DVM reseach program at Mississippi State Univeristy, College of Veterinary Medicine. The studies also were part of two graduate students (bothe CVM faculty) research programs. Findings from these studies were presented at the Society for Theriogenology annual meeting in Albuquerque, NM and at seminars on campus as part of the graduate academic programs. Data was published in peer-reviewed journals. PARTICIPANTS: Dr. David Christiansen, Clinical Professor, Mississippi State University Dr. Kevin Walters, Clinical Instructor, Mississippi State University Ryan Black, Jarrod Harney, Youry Dupre - summer research experience students Dr. Keesla Moulton and Dr. Jean Feugang, Postdoctoral fellows at Mississippi State University TARGET AUDIENCES: The target audience in this instance are equine practitioners and owners and mangers of brood mare farms. The incidence of pre-term pregnancy loss associated with uterine infections in the equine industry acconts for approximately 33% of all pregnancy losses. Thus, developing new and efficacious therapeutic strategies to prevent pre-term delivery in late term pregnant mares presented with symptoms consistent with uterine infections is of paramount importance for the industry. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The objective of these studies are to evaluate the efficacy of using antibiotics alone or in combination with immunomodulators to prevent pre-term birth and increase foal viability/survivability in mares experimentally infected with Streptoccocus equi subspecies zooepidemicus to induce ascending placentitis. The hypothesis is that immunomodulators in combination with appropriate antibiotic therapy will markedly improve pregnacny outcome in mares presented with signs of ascending placentitis in late gestation. The overall finding to date is that aggressive therapy with antibiotics alone results in a very favorable outcome, but the addition of immunomodulators such as acetylsalicylic acid, reduces the interval between pre-term delivery and the normal due date of mares. The study is continuing to look at additional combinatorial therapies to enhance neonatal survival of foals born to dams with uterine infections.

Publications

  • Ryan P, Christiansen D, Crouch J, Hopper R, Cooley J, Moulton K, S. Willard S. 2009. Evaluation of pathogen progression during induced placentitis in mares using lux-modified Escherichia coli and novel bioluminescence imaging technology. Annual Meeting Society for Theriogenology, Albuquerque, NM, August 25th to 29th 2009.
  • Al-Rashed HA, Christiansen DL, Walters FK, Hopper RM, Musselwhite A, Schenck EL, Ryan PL. 2009. Evaluation of a novel, non-toxic, endophyte-infected tall fescue cultivar, AGRFA-144, as a safe forage for pregnant mares. ASAS Southern Section, Atlanta, GA, February 2009. Abst. 30, pp 10.
  • Brookshire WC, Necaise KW, Moulton K, Christiansen DL, Crenshaw M, Scanes CG, Ryan PL. 2009. Changes in thermal gradients of the external genitalia of neonatal pigs after oral exposure to soy-derived phytoestrogen, genistein and estradiol. American Association of Swine Veterinarians. Dallas, TX, March, 2009
  • Moulton K, Ryan P, Lay Jr. D, Willard S. 2009. Photonic plasmid stability of transformed Salmonella typhimurium: a comparison of three unique plasmids. BMC Microbiology 9: 152-159.
  • Moulton K, Ryan P, Lay D, Willard S. 2009. Postmortem photonic imaging of lux-modified Salmonella Typhimurium within the gastrointestinal tract of swine following oral inoculation in vivo. J Anim Sci 87:2239-2244.
  • Bowers S, Gandy S, Anderson B, Ryan P, Willard T. 2009. Assessment of pregnancy in the late gestation mare using digital infrared thermography. Theriogenology 72:372-377.
  • Moulton K, Ryan PL, Christiansen D, Hopper R, Klauser C, Bennett W, Rodts-Palenik S, Willard S. 2009. Hormonal profiles of late gestation ewes following intra-uterine inoculation with and without lux-modified Escherichia coli. J Reprod Dev 55:55-62.
  • Ryan PL, Christiansen DL, Hopper RM, Bagnell CA, Vaala WE, LeBlanc MM. 2009. Evaluation of relaxin blood profiles of horses as a means of assessing placental function in high-risk pregnancies and responsiveness to therapeutic strategies. Ann NY Acad Sci 1160:169-178.
  • Borazjani A, Weed B, Chen J, Feugang J, Ryan P, Liao J. 2009. Cross-Species Comparison of Fetal Membrane Structural Properties. Biomedical Engineering Society Annual Meeting Pittsburg, PA, October, 2009
  • Dupre Y, Strohm A, Schenck E, Harney J, Moulton K and Ryan P. Assessment of heat load and dissipation using infrared thermography and serum cortisol profiles in horses during the summer months. NIH-Merial Summer Veterinary Student Research Experience Program Symposium, University North Carolina, Raleigh, NC, August, 2009.
  • Borazjani A, Weed B, Chen J, Feugan J, Ryan P, Liao J. 2009. Cross-species analysis of fetal membrane mechanics. Twenty Second Congress of the International Society of Biomechanics, South Africa
  • Christiansen DL, Crouch J, R.M. Hopper RM, Moulton K, LeBlanc MM, Ryan PL. 2009. Experimentally induced placentitis in late gestation mares with Streptococcus equi zooepidemicus: therapeutic prevention of preterm birth. Annual Meeting Society for Theriogenology, Albuquerque, NM, August 25th to 29th 2009.


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: A series of experiments were performed to investigate efficacy of different drug combinations for use in treatment of placentitis and prevention of preterm labor in late gestation (>280 days) mares. Eighteen mares were inoculated with ~1 million CFU of Streptococcus equi zooepidemicus transcervically and upon signs of vaginal discharge (24-48 h post inoculation) were assigned to one of three treatment groups (n=6/group): trimethroprim sulfamethoxazole (TMS; 30 mg/kg, q 12 h, PO) alone; TMS with dexamethasone (D) given over 6 d with decreasing doses every two days (TMS+D; 40, 35, 25 mg, respectively, q 24 h, IV) or TMS with acetylsalicylic acid (TMS+A; aspirin 150 mg/kg, q 12 h, PO for 6 d). Six non-inoculated mares served as naive controls. Mares were blood sampled for hormonal and pro-inflammatory cytokine analyses. The outcome of the study demonstrated that regardless of treatment approach, timely intervention with therapeutics had a high success rate in resulting in near-term delivery of viable foals. The findings have been presented at national and international equine veterinary sciences meetings. PARTICIPANTS: Dr. Michelle LeBlanc, Rood and Riddle Equine Veterinary Hospital, Lexington, Kentucky was instrumental in providing expertise and guidance in design, implementation and interpretation of study outcomes. Dr. David Christiansen, College of Veterinary Medicine, Mississippi State University was a co-investigator and provided valuable clinical expertise. Dr. Richard Hopper, College of Veterinary Medicine, Mississippi State University, was a co-investigator and provided valuable clinical expertise. Dr. William Bennett, University of Mississippi Medical Center, was a collaborator and provided expertise and guidance regarding role of inflammatory cytokines and pre-term delivery in animals with uterine infections. TARGET AUDIENCES: The primary target audience is the equine veterinary practitioner and data was presented at appropriate national (Annual Society for Theriogenology; Havemeyer Foundation Workshops) and international (World Congress of Equine Veterinary Association) meetings to ensure dissemination of the study outcomes. PROJECT MODIFICATIONS: No modifications.

Impacts
The objective of these studies was to evaluate therapeutic strategies that might best serve veterinarians in obtaining the best possible outcome in the treatment of mares presented with placentitis in late pregnancy. While different approaches for treatment of this condition are practiced most are based on anecdotal information or experience. These studies attempted to use the evidence-based medicine approach to evaluate the efficacy of therapeutic strategies that employ not only antibiotics but also immune-modulators to maintain pregnancy. Fetal maturation in the equine does not occur until the last 5-7 days of in utero life and stimulation of precocious fetal maturation is difficult to achieve. Thus, treatment of the infection along with stabilizing the pregnancy to near-term as is possible is the most desirable course of action. Our data in these preliminary studies demonstrate that timely therapeutic intervention increases the chances of a viable foal and that the combination of antibiotics with immune-modulators, particularly aspirin, increases the chances of a delivering a viable foal.

Publications

  • Ryan P, Crouch J, Sykes D, Moulton K, Christiansen D, Hopper R, Read R, Bennett W, LeBlanc M. 2008. Experimentally induced placentitis in late gestation mares with streptococcus equi zooepidemicus: prevention of pre-term birth. In: Uterine infections in Mares and Women: A comparative Study II, eds M. LeBlanc, J.F. Wade and L. Foster, Havemeyer Foundation Monograph Series #19, R and W Communications, Newmarket, UK, pp 13-14.
  • Ryan P, Moulton K, Willard S, Crouch J, Sykes D, Christiansen D, Bennett W. 2008. Experimentally-induced placentitis in late gestation ewes and mares: evaluation of pathogen progression using lux-modified bacteria and bioluminescence imaging. In: Uterine infections in Mares and Women: A comparative Study II, eds M. LeBlanc, J.F. Wade and L. Foster, Havemeyer Foundation Monograph Series #19, R and W Communications, Newmarket, UK, pp 35-36.
  • Christiansen D, Olsen G, Smith J. Hopper R, Leblanc MM. Ryan P. 2008. The use of bethamethasone to advance fetal maturation in the equine. In: Uterine infections in Mares and Women: A comparative Study II, eds M. LeBlanc, J.F. Wade and L. Foster, Havemeyer Foundation Monograph Series #19, R and W Communications, Newmarket, UK, pp 19-20.
  • Ryan P, Christiansen D, Smith J, Hopper R, Read R, Crouch J, Moulton K, Bennett W, LeBlanc M. 2008. Experimentally induced placentitis with streptococcus equi zooepidemicus in late gestation mares: prevention of preterm birth. Procd 10th Congress World Equine Vet. Assoc, Moscow, Russia, 1/28/2008 to 2/1/2008. pp 557-580.
  • Christiansen DL, Crouch J, Hopper R, Read R, Moulton K, Bennett W, LeBlanc, Ryan PL. 2008. Efficacy of antibiotics with Regu-mate on experimentally-induced placentitis with Streptococcus equi zooepidemicus in late gestation Hackney pony mares. Procd 10th Congress World Equine Vet. Assoc., Moscow, Russia, 1/28/2008 to 2/1/2008. pp 59-560.
  • Fitzgerald BP, Horohov DW, Lang D, Christiansen DL, Hopper RM, Ryan PL. 2007. Perturbations in macrophage inflammatory cytokine mRNA expression in mares exposed to endophyte-infected tall fescue pastures. Society for Theriogenology, Monterey, CA, 8/7/200 to 8/11/2007. Theriogenology, 68:496-497.
  • Christiansen DL, Hopper RM, Filipov NM, Hill NS, Ryan PL. 2007. Effects of dietary FEB-200 in late gestation mares grazing endophyte-infected tall fescue. Society for Theriogenology, Monterey, CA, 8/7/200 to 8/11/2007. Theriogenology, 68:495.
  • Pelczer I, Lloyd TL, Shutt C, Sahulhameed F, Ralston R, Bagnell CA, Christiansen DL, Walters K, Ryan PL. 2007. NMR-based metabonomic analysis of pregnant mares serum as a reflection of fescue toxicosis onset and its outcome. SERA-IEG-8 Tall Fescue/Endophyte Workshop, 10/14/2007 to 10/16/2007, Wildersville, TN, pp 75-82.
  • Ryan PL, Christiansen DL, Walters K, Hopper RM, Lang D, Fitzgerald BP, Horohov DW, Lehner AF, Camargo FC, C. Hughes C, Tobin T. 2007. Identification and role of inflammatory cytokines and ergot alkaloids on pregnancy outcome in mares exposed to endophyte-infected tall fescue. SERA-IEG-8 Tall Fescue/Endophyte Workshop, 10/14/2007 to 10/16/2007, Wildersville, TN, pp 83-93.