The putative role of ovary removal and progesterone when considering the effect of formaldehyde exposure on lung inflammation induced by ovalbumin

OBJECTIVE: Formaldehyde exposure during the menstrual cycle is known to affect the course of allergic lung inflammation. Because our previous data demonstrated that formaldehyde combined with an ovariectomy reduced allergic lung inflammation, we investigated the putative role of ovary removal and progesterone treatment when considering the effect of formaldehyde on allergic lung inflammation. METHOD: Ovariectomized rats and their matched controls were exposed to formaldehyde (1%, 3 days, 90 min/day) or vehicle, and immediately after exposure, the rats were sensitized to ovalbumin by a subcutaneous route. After 1 week, the rats received a booster by the same route, and after an additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability, ex vivo tracheal reactivity to methacholine and mast cell degranulation were determined 24 h later. RESULTS: Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure on ex vivo tracheal reactivity, cell influx into the lungs and mast cell degranulation. CONCLUSION: In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation

Farmacocinetica della buprenorfina, e del suo metabolita norbuprenorfina, somministrata come infusione costante nel periodo post-operatorio in cagne sane sottoposte ad ovariectomia

Il dolore non è solo una conseguenza della malattia ma un fattore patogeno che è di per se stesso in grado di perpetuare il danno all’organismo. Il suo trattamento non è quindi solo un atto di umanità ma un contributo ad arrestare la malattia e restituire la salute al paziente. Tra i farmaci più popolari per la terapia del dolore negli animali da affezione si trova la buprenorfina. Questa molecola viene impiegata con successo da anni nel cane e nel gatto per motivi riconducibili, oltre che alla sua efficacia (la sua potenza è diverse volte quella della morfina), alla lunga durata d’azione e alla scarsità degli effetti collaterali. Nonostante l’ampia diffusione e longevità del suo utilizzo, però, sappiamo poco della farmacocinetica di questa molecola negli animali da affezione; i dosaggi clinicamente impiegati sono di fatto estrapolati dagli studi nell’uomo oppure basati su semplici osservazioni degli effetti; i pochi dati farmacocinetici ottenuti nel cane fanno riferimento a singoli boli di dosi che non sempre corrispondono a quelle clinicamente impiegate. Nonostante la buprenorfina trovi il suo principale impiego nelle somministrazioni protratte a lungo (durante il periodo post-operatorio o la degenza ospedaliera) non è mai stato indagato il profilo farmacocinetico della molecola somministrata a boli ripetuti o come infusione continua. Il nostro studio si pone come obiettivo di indagare la farmacocinetica della buprenorfina somministrata come bolo di carico seguito da un’infusione costante a dosaggi considerati clinici in cani sani nel periodo post operatorio. Lo scopo ultimo è quello di sviluppare un protocollo per la somministrazione di questa molecola in modo prolungato in pazienti degenti ed addolorati per poi, in futuro, confrontare la somministrazione come infusione continua con i tradizionali boli ripetuti. Per lo studio sono state utilizzate giovani cagne adulte di taglia media o grande sottoposte ad intervento di ovariectomia.

Studio sull'applicazione della piattaforma ForcetriadTM con sistema LigasureTM nella chirurgia oncologica e dei tessuti molli nel cane

Questo studio prospettico valuta l’efficacia e i vantaggi del sistema LigasureTM rispetto alle tecniche chirurgiche tradizionali, in quattro differenti procedure eseguite su 77 cani. I soggetti sono stati suddivisi in 4 gruppi, a seconda della chirurgia eseguita: Gruppo 1, 25 pazienti sottoposti a Splenectomia “aperta” semplice; Gruppo 2, 15 pazienti sottoposti a Splenectomia “aperta” complessa; Gruppo 3, 22 pazienti sottoposti ad Ovariectomia “aperta”. Gruppo 4: 18 pazienti sottoposti a Linfoadenectomia. Ciascun gruppo è stato a sua volta suddiviso in due sottogruppi: a (LigasureTM) e b (Tradizionale), a seconda della metodica utilizzata. Sono stati analizzati: il segnalamento, i parametri ematologici, le condizioni cliniche, le informazioni riguardanti l’intervento chirurgico e l’outcome. In tutti i gruppi il ricorso all’utilizzo di garze nonché dei fili da sutura sono risultati statisticamente inferiori nei pazienti operati con il sistema a radiofrequenza (Gruppo 1, P < 0.0001; Gruppo 2, P < 0,0014; Gruppo 3, P = 0,0001; Gruppo 4, P = 0,0148). Anche i tempi per la rimozione dell’organo sono significativamente ridotti in tutti i gruppi in cui è stato utilizzato il sistema LigasureTM (Gruppo 1 P < 0.0001; Gruppo 2 P < 0,0014; Gruppo 3 P = 0,0009; Gruppo 4 P = 0,0008), come i tempi chirurgici nei gruppi 1, 2 e 3 (P = 0,0287; P = 0,0064; e P = 0,0124) ed anestesiologici nei gruppi 1a e 2a (P = 0,0176; P = 0,0043). Tra le variabili analizzate, l’utilizzo del sistema di sintesi vascolare a radiofrequenza, è l’unico ad influenzare i tempi necessari per l’esecuzione della procedura. Questo studio dimostra, quindi, come il sistema LigasureTM sia sicuro ed efficace per le procedure chirurgiche esaminate, riducendo i tempi della chirurgia e limitando, quindi, i rischi per il paziente, indipendentemente dall’operatore, dall’esecuzione di altre procedure contemporanee e dalla natura della patologia splenica o linfonodale.

Endogenous estrogens, through estrogen receptor , constrain autoimmune inflammation in female mice by limiting CD4(+) T-cell homing into the CNS

Sex hormones influence immune responses and the development of autoimmune diseases including MS and its animal model, EAE. Although it has been previously reported that ovariectomy could worsen EAE, the mechanisms implicated in the protective action of endogenous ovarian hormones have not been addressed. In this report, we now show that endogenous estrogens limit EAE development and CNS inflammation in adult female mice through estrogen receptor expression in the host non-hematopoietic tissues. We provide evidence that the enhancing effect of gonadectomy on EAE development was due to quantitative rather than qualitative changes in effector Th1 or Th17 cell recruitment into the CNS. Consistent with this observation, adoptive transfer of myelin oligodendrocyte glycoprotein-specific encephalitogenic CD4(+) T lymphocytes induced more severe EAE in ovariectomized mice as compared to normal female mice. Finally, we show that gonadectomy accelerated the early recruitment of inflammatory cells into the CNS upon adoptive transfer of encephalitogenic CD4(+) T cells. Altogether, these data show that endogenous estrogens, through estrogen receptor , exert a protective effect on EAE by limiting the recruitment of blood-derived inflammatory cells into the CNS.

Topical application of 17β-estradiol (E2) improves skin flap survival through activation of endothelial nitric oxide synthase in rats

This study investigates the influence of 17β-estradiol (E2) on nitric oxide (NO) production in endothelial cell cultures and the effect of topical E2 on the survival of skin flap transplants in a rat model. Human umbilical vein endothelial cells were treated with three different E2 concentrations and nitrite (NO2) concentrations, as well as endothelial nitric oxide synthase (eNOS) protein expressions were analyzed. In vivo, random-pattern skin flaps were raised in female Wistar rats 14 days following ovariectomy and treated with placebo ointment (group 1), E2 as gel (group 2), and E2 via plaster (group 3). Flap perfusion, survival, and NO2 levels were measured on postoperative day 7. In vitro, E2 treatment increased NO2 concentration in cell supernatant and eNOS expression in cell lysates (p < 0.05). In vivo, E2 treated (gel and plaster groups) demonstrated significantly increased skin flap survival compared to the placebo group (p < 0.05). E2 plaster-treated animals exhibited higher NO2 blood levels than placebo (p < 0.05) paralleling the in vitro observations. E2 increases NO production in endothelial cells via eNOS activation. Topical E2 application can significantly increase survival of ischemically challenged skin flaps in a rat model and may augment wound healing in other ischemic situations via activation of NO production.

Osseointegration of hollow cylinder based spinal implants in normal and osteoporotic vertebrae: a sheep study

INTRODUCTION: Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based implant takes place in normal or osteoporotic bone of sheep under functional loading conditions during anterior stabilization of the lumbar spine. MATERIALS AND METHODS: Osseointegration of the cylinders and status of the fused segments (ventral corpectomy, replacement with iliac strut, and fixation with testing implant) were investigated in six osteoporotic (age 6.9 +/- 0.8 years, mean body weight 61.1 +/- 5.2 kg) and seven control sheep (age 6.1 +/- 0.2 years, mean body weight 64.9 +/- 5.7 kg). Osteoporosis was introduced using a combination protocol of ovariectomy, high-dose prednisone, calcium and phosphor reduced diet and movement restriction. Osseointegration was quantified using fluorescence and conventional histology; fusion status was determined using biomechanical testing of the stabilized segment in a six-degree-of-freedom loading device as well as with radiological and histological staging. RESULTS: Intact bone trabeculae were found in 70% of all perforations without differences between the two groups (P = 0.26). Inside the cylinders, bone volume/total volume was significantly higher than in the control vertebra (50 +/- 16 vs. 28 +/- 13%) of the same animal (P<0.01), but significantly less (P<0.01) than in the near surrounding (60 +/- 21%). After biomechanical testing as described in Sect. "Materials and methods", seven spines (three healthy and four osteoporotic) were classified as completely fused and six (four healthy and two osteoporotic) as not fused after a 4-month observation time. All endplates were bridged with intact trabeculae in the histological slices. CONCLUSIONS: The high number of perforations, filled with intact trabeculae, indicates an adequate fixation; bridging trabeculae between adjacent endplates and tricortical iliac struts in all vertebrae indicates that the anchorage is adequate to promote fusion in this animal model, even in the osteoporotic sheep.

Optimization of corticosteroid induced osteoporosis in ovariectomized sheep. A bone histomorphometric study

During osteoporosis induction in sheep, side effects of the steroids were observed in previous studies. The aim of this study was to improve the induction regimen consisting of ovariectomy, calcium/vitamin D- restricted diet and methylprednisolone (-MP)- medication with respect to the bone metabolism and to reduce the adverse side effects. Thirty-six ewes (age 6.5 +/- 0.6 years) were divided into four MP-administration groups (n = 9) with a total dose of 1800 mg MP: group 1: 20 mg/day, group 2: 60 mg/every third day, group 3: 3 x 500 mg and 1 x 300 mg at intervals of three weeks, group 4: weekly administration, starting at 70 mg and weekly reduction by 10 mg. After double-labelling with Calcein Green and Xylenol Orange, bone biopsy specimens were taken from the iliac crest (IC) at the beginning and four weeks after the last MP injection, and additionally from the vertebral body (VB) at the end of the experiment. Bone samples were processed into stained and fluorescent sections, static and dynamic measurements were performed. There were no significant differences for static parameters between the groups initially. The bone perimeter and the bone area values were significantly higher in the VB than in the IC (Pm: 26%, p < 0.0001, Ar: 11%, p < 0.0166). A significant decrease (20%) of the bone area was observed after corticosteroid-induced osteoporosis (p < 0.0004). For the dynamic parameters, no significant difference between the groups was found. Presence of Calcein Green and Xylenol Orange labels were noted in 50% of the biopsies in the IC, 100% in the VB. Group 3 showed the lowest prevalence of adverse side effects. The bone metabolism changes were observed in all four groups, and the VB bone metabolism was higher when compared to the IC. In conclusion, when using equal amounts of steroids adverse side effects can be reduced by decreasing the number of administrations without reducing the effect regarding corticosteroid-induced osteoporosis. This information is useful to reduce the discomfort of the animals in this sheep model of corticosteroid-induced osteoporosis.

Comparative quantitative assessment of GnRH- and LH-receptor mRNA expression in the urinary tract of sexually intact and spayed female dogs

Ovariectomy interrupts the regulatory loop in the hypothalamus-pituitary-gonad axis, leading to a several-fold increase in gonadotropin levels. This rise in hormonal secretion may play a causal role in ovariectomy-related urinary incontinence. The purpose of this study was to examine the effect of ovariectomy in bitches on the expression of GnRH- and LH-receptors in the lower urinary tract, and assess the relationship between receptor expression and plasma gonadotropin concentrations. Plasma gonadotropins were measured in 37 client-owned bitches. Biopsies were harvested from the mid-ventral bladder wall in all dogs, and from nine further locations within the lower urinary tract in 17 of the 37 animals. Messenger RNA of the LH and GnRH receptors was quantified using RT-PCR with the TaqMan Universal PCR Master Mix. Gonadotropins were measured with a canine-specific FSH-immunoradiometric assay and LH-radioimmunoassay. The hierarchical mixed ANOVA model using MINITAB, Mann-Whitney U-test, unpaired means comparison and linear regressions using StatView were applied for statistical analyses. Messenger RNA for both receptors was detected in all biopsy samples. Age was negatively correlated to mRNA expression of the LH and the GnRH receptors. A relationship between the mRNA values and the plasma gonadotropin concentrations was not established. Evaluation of results within each of the biopsy locations revealed greater LH-receptor expression in the proximal second quarter of the urethra in spayed bitches than in intact bitches (P=0.0481). Increased mRNA expression of LH receptors in this location could possibly play a role in the decrease in closing pressure of the urethra following ovariectomy.

Correspondence of Gonadotropin-Releasing Hormone and Luteinizing Hormone Secretion during Suckling in Postpartum Cows

The hypothalamus in the lower part of the brain contains neurons that produce a small peptide, gonadotropin- releasing hormone (GnRH, LHRH), that regulates luteinizing hormone (LH) secretion by the anterior pituitary gland. Important functions of LH include induction of ovulation in preovulatory follicles during estrus and the luteinization of granulosa cells lining those collapsed follicles to form corpora lutea that produce progesterone during the luteal phase of the estrous cycle or during pregnancy. The production of progesterone by the corpus luteum conveys a negative feed-back action at the central nervous system (CNS) for further episodic secretion of GnRH and in turn, LH secretion. Gonadal removal (i.e., ovariectomy) allows a greater amount of LH secretion to occur during a prolonged period. The objectives of this study were to characterize the pattern of GnRH secretion in the cerebrospinal fluid (CSF) of the bovine third ventricle region of the hypothalamus, determine its correspondence with the tonic and surge release of LH in ovariectomized cows, and examine the dynamics of GnRH pulse release activity in response to known modulators of LH release (suckling, neuropeptide-Y [NPY]). In ovariectomized cows, both tonic release patterns and estradiol-induced surges of GnRH and LH were highly correlated. A 500-microgram dose of NPY caused an immediate cessation of LH pulses and decreased plasma concentrations of LH for at least 4 hours. This corresponded with a decrease in both GnRH pulse amplitude and frequency. In anestrous cows, GnRH pulse frequency did not change before and 48 to 54 hours after weaning on day 18 postpartum, but GnRH concentration and amplitudes of GnRH pulses increased in association with weaning and heightened secretion of LH. It is clear that high-frequency, highamplitude pulses of LH are accompanied by similar patterns of GnRH in CSF of adult cattle. Yet strong inhibitors of LH pulsatility, putatively acting at the level of the central nervous system (i.e., suckling) or at both the central nervous system and pituitary (NPY) levels, produced periods of discordance between GnRH and LH pulses.

Genetic and hormonal factors modulate spreading depression and transient hemiparesis in mouse models of familial hemiplegic migraine type 1.

Familial hemiplegic migraine type 1 (FHM1) is an autosomal dominant subtype of migraine with aura that is associated with hemiparesis. As with other types of migraine, it affects women more frequently than men. FHM1 is caused by mutations in the CACNA1A gene, which encodes the alpha1A subunit of Cav2.1 channels; the R192Q mutation in CACNA1A causes a mild form of FHM1, whereas the S218L mutation causes a severe, often lethal phenotype. Spreading depression (SD), a slowly propagating neuronal and glial cell depolarization that leads to depression of neuronal activity, is the most likely cause of migraine aura. Here, we have shown that transgenic mice expressing R192Q or S218L FHM1 mutations have increased SD frequency and propagation speed; enhanced corticostriatal propagation; and, similar to the human FHM1 phenotype, more severe and prolonged post-SD neurological deficits. The susceptibility to SD and neurological deficits is affected by allele dosage and is higher in S218L than R192Q mutants. Further, female S218L and R192Q mutant mice were more susceptible to SD and neurological deficits than males. This sex difference was abrogated by ovariectomy and senescence and was partially restored by estrogen replacement, implicating ovarian hormones in the observed sex differences in humans with FHM1. These findings demonstrate that genetic and hormonal factors modulate susceptibility to SD and neurological deficits in FHM1 mutant mice, providing a potential mechanism for the phenotypic diversity of human migraine and aura.

Nonclassical mechanisms of progesterone action in the brain: I. Protein kinase C activation in the hypothalamus of female rats.

The modulation of gene regulation by progesterone (P) and its classical intracellular regulation by progestin receptors in the brain, resulting in alterations in physiology and behavior has been well studied. The mechanisms mediating the short latency effects of P are less well understood. Recent studies have revealed rapid nonclassical signaling action of P involving the activation of intracellular signaling pathways. We explored the involvement of protein kinase C (PKC) in P-induced rapid signaling in the ventromedial nucleus of the hypothalamus (VMN) and preoptic area (POA) of the rat brain. Both the Ca2+-independent (basal) PKC activity representing the activation of PKC by the in vivo treatments and the Ca+2-dependent (total) PKC activity assayed in the presence of exogenous cofactors in vitro were determined. A comparison of the two activities demonstrated the strength and temporal status of PKC regulation by steroid hormones in vivo. P treatment resulted in a rapid increase in basal PKC activity in the VMN but not the POA. Estradiol benzoate priming augmented P-initiated increase in PKC basal activity in both the VMN and POA. These increases were inhibited by intracerebroventricular administration of a PKC inhibitor administered 30 min prior to P. The total PKC activity remained unchanged demonstrating maximal PKC activation within 30 min in the VMN. In contrast, P regulation in the POA significantly attenuated total PKC activity +/- estradiol benzoate priming. These rapid changes in P-initiated PKC activity were not due to changes in PKC protein levels or phosphorylation status.

Expression and hormonal regulation of Muc-1 at the apical surface of mouse uterine epithelial cells and its role in modulating embryo implantation

Previous studies from our lab have established that large molecular weight mucin glycoproteins are major apically-disposed components of mouse uterine epithelial cells in vitro (Valdizan et al., (1992) J. Cell. Physiol. 151:451-465). The present studies demonstrate that Muc-1 represents one of the apically-disposed mucin glycoproteins of mouse uterine epithelia, and that Muc-1 protein and mRNA expression are regulated in the peri-implantation stage mouse uterus by ovarian steroids. Muc-1 expression is high in the proestrous and estrous stages, and decreases during diestrous. Both Muc-1 protein and mRNA levels decline to barely detectable levels by day 4 of pregnancy, i.e., prior to the time of blastocyst attachment. In contrast, Muc-1 expression in the cervix and vagina is maintained during this same period. Delayed implantation was established in pregnant mice by ovariectomy and maintained by administration of exogenous progesterone. Initiation of implantation was triggered by coinjection of progesterone maintained mice with a nidatory dose of 17$\beta$-estradiol. Muc-1 levels in the uterine epithelia of progesterone maintained mice declined to similar low levels as observed on day 4 of normal pregnancy. Coinjection of estradiol did not alter Muc-1 expression suggesting that down-regulation of Muc-1 is a progesterone dominated event. This was confirmed in ovariectomized, non-pregnant mice which displayed stimulation of Muc-1 expression following 6 hr of estradiol injection. Estradiol stimulated Muc-1 expression was inhibited by the pure antiestrogen, ICI 164,384. While progesterone alone had no effect on Muc-1 expression, it antagonized estradiol action in this regard. Injection of pregnant mice with the antiprogestin, RU 486, a known implantation inhibitor, on day 3 of pregnancy restored high level expression of Muc-1 mRNA on day 4, indicating that down-regulation of Muc-1 is progesterone receptor-mediated. Muc-1 appears to function as an anti-adhesive molecule at the apical cell surface of mouse uterine epithelial cells. Treatment of polarized cultures of mouse uterine epithelial cells with O-sialoglycoprotein endopeptidase reduced mucin expression in vitro, by about 50%, and converted polarized uterine epithelia to a functionally receptive state. Similarly, ablation of Muc-1 in Muc-1 null mice resulted in polarized uterine epithelia that were functionally receptive as compared to their wild-type counterparts in vitro. Collectively, these data indicate that Muc-1 and other mucins function as anti-adhesive molecules and that reduction or removal of these molecules is a prerequisite for the generation of a receptive uterine state. ^

A novel form of CYP3A from rat brain: cDNA cloning, protein characterization and gene regulation of cytochrome P450 3A9

One full length cDNA clone, designated 3aH15, was isolated from a rat brain cDNA library using a fragment of CYP3A2 cDNA as a probe. 3aH15 encoded a protein composed of 503 amino acid residues. The deduced amino acid sequence of 3aH15 was 92% identical to mouse Cyp3a-13 and had a 68.4% to 76.5% homology with the other reported rat CYP3A sequences. Clone 3aH15 was thus named CYP3A9 by Cytochrome P450 Nomenclature Committee. CYP3A9 seems to the major CYP3A isozyme expressed in rat brain. Sexual dimorphism of the expression of CYP3A9 was shown for the first time in rat brain as well as in rat liver. CYP3A9 appears to be female specific in rat liver based on the standards proposed by Kato and Yamazoe who defined sex specific expression of P450s as being a 10-fold or higher expression level in one sex compared with the other. CYP3A9 gene expression was inducible by estrogen treatment both in male and in female rats. Male rats treated with estrogen had a similar expression level of CYP3A9 mRNA both in the liver and brain. Ovariectomy of adult female rats drastically reduced the mRNA level of CYP3A9 which could be fully restored by estrogen replacement. On the other hand, only a two-fold induction of CYP3A9 expression by dexamethasone was observed in male liver and no significant induction of CYP3A9 mRNA was observed in female liver or in the brains. These results suggest that estrogen may play an important role in the female specific expression of the CYP3A9 gene and that CYP3A9 gene expression is regulated differently from other CYP3A isozymes. ^ P450 3A9 recombinant protein was expressed in E. coli using the pCWOri+ expression vector and the MALLLAVF amino terminal sequence modification. This construct gave a high level of expression (130 nmol P450 3A9/liter culture) and the recombinant protein of the modified P450 3A9 was purified to electrophoretic homogeneity (10.1 nmol P450/mg protein) from solubilized fractions using two chromatographic steps. The purified P450 3A9 protein was active towards the metabolism of many clinically important drugs such as imipramine, erythromycin, benzphetamine, ethylmorphine, chlorzoxazone, cyclosporine, rapamycin, etc. in a reconstituted system containing lipid and rat NADPH-P450 reductase. Although P450 3A9 was active towards the catabolism of testosterone, androstenedione, dehydroepiandrosterone (DHEA) and 17β-estradiol, P450 3A9 preferentially catalyzes the metabolism of progesterone to form four different hydroxylated products. Optimal reconstitution conditions for P450 3A9 activities required a lipid mixture and GSH. The possible mechanisms of the stimulatory effects of GSH on P450 3A9 activities are discussed. Sexually dimorphic expression of P450 3A9 in the brain and its involvement in many neuroactive drugs as well as neurosteroids suggest the possible role of P450 3A9 in some mental disorders and brain functions. ^

Noncitrated blood transfusions used as adjunctive treatment in a 7-year-old Shetland Pony with haemoperitoneum due to a ruptured corpus haemorrhagicum

Chronic bleeding due to extensive haemorrhage from a ruptured corpus haemorrhagicum developed 2–4 weeks after parturition and was identified as the cause for a haemoperitoneum in a 7-year-old Shetland Pony mare, leading to anaemia. Diagnosis was made upon exploratory coeliotomy and a unilateral ovariectomy was performed. Intra- and post operatively, the mare received autologous blood transfusions of noncitrated blood. To our knowledge, this is the first report of an autologous blood transfusion accomplished using noncitrated blood collected from the abdominal cavity.

Osseointegration of biochemically modified implants in an osteoporosis rodent model

The present study examined the impact of implant surface modifications on osseointegration in an osteoporotic rodent model. Sandblasted, acid-etched titanium implants were either used directly (control) or were further modified by surface conditioning with NaOH or by coating with one of the following active agents: collagen/chondroitin sulphate, simvastatin, or zoledronic acid. Control and modified implants were inserted into the proximal tibia of aged ovariectomised (OVX) osteoporotic rats (n = 32/group). In addition, aged oestrogen competent animals received either control or NaOH conditioned implants. Animals were sacrificed 2 and 4 weeks post-implantation. The excised tibiae were utilised for biomechanical and morphometric readouts (n = 8/group/readout). Biomechanical testing revealed at both time points dramatically reduced osseointegration in the tibia of oestrogen deprived osteoporotic animals compared to intact controls irrespective of NaOH exposure. Consistently, histomorphometric and microCT analyses demonstrated diminished bone-implant contact (BIC), peri-implant bone area (BA), bone volume/tissue volume (BV/TV) and bone-mineral density (BMD) in OVX animals. Surface coating with collagen/chondroitin sulphate had no detectable impact on osseointegration. Interestingly, statin coating resulted in a transient increase in BIC 2 weeks post-implantation; which, however, did not correspond to improvement of biomechanical readouts. Local exposure to zoledronic acid increased BIC, BA, BV/TV and BMD at 4 weeks. Yet this translated only into a non-significant improvement of biomechanical properties. In conclusion, this study presents a rodent model mimicking severely osteoporotic bone. Contrary to the other bioactive agents, locally released zoledronic acid had a positive impact on osseointegration albeit to a lesser extent than reported in less challenging models.