Early evolution of glial morphology and inflammatory cytokines following hypoxic-ischemic injury in the newborn piglet brain.

Neuroinflammation is a hallmark of hypoxic-ischemic injury and can be characterized by the activation of glial cells and the expression of inflammatory cytokines and chemokines. Interleukin (IL)-1ß and tumor necrosis factor (TNF)α are among the best-characterized early response cytokines and are often expressed concurrently. Several types of central nervous system cells secrete IL-1ß and TNFα, including microglia, astrocytes, and neurons, and these cytokines convey potent pro-inflammatory actions. Chemokines also play a central role in neuroinflammation by controlling inflammatory cell trafficking. Our aim was to characterise the evolution of early neuroinflammation in the neonatal piglet model of hypoxic-ischemic encephalopathy (HIE). Piglets (< 24 h old) were exposed to HI insult, and recovered to 2, 4, 8, 12 or 24H post-insult. Brain tissue from the frontal cortex and basal ganglia was harvested for assessment of glial cell activation profiles and transcription levels of inflammatory markers in HI piglets with comparison to a control group of newborn piglets. Fluorescence microscopy was used to observe microglia, astrocytes, neurons, degenerating neurons and possibly apoptotic cells, and quantitative polymerase chain reaction was used to measure gene expression of several cytokines and chemokines. HI injury was associated with microglial activation and morphological changes to astrocytes at all time points examined. Gene expression analyses of inflammation-related markers revealed significantly higher expression of pro-inflammatory cytokines tumor necrosis factor-α (TNFα) and interleukin 1 beta (IL-1ß), chemokines cxc-chemokine motif ligand (CXCL)8 and CXCL10, and anti-inflammatory cytokine transforming growth factor (TGF)ß in every HI group, with some region-specific differences noted. No significant difference was observed in the level of C-X-C chemokine receptor (CCR)5 over time. This high degree of neuroinflammation was associated with a reduction in the number of neurons in piglets at 12H and 24H in the frontal cortex, and the putamen at 12H. This reduction of neurons was not associated with increased numbers of degenerating neurons or potentially apoptotic cells. HI injury triggered a robust early neuroinflammatory response associated with a reduction in neurons in cortical and subcortical regions in our piglet model of HIE. This neuroinflammatory response may be targeted using novel therapeutics to reduce neuropathology in our piglet model of neonatal HIE.

Combined hypothermia and mesenchymal stem cells in animal models of neonatal hypoxic-ischaemic encephalopathy: a systematic review.

BACKGROUND: The objective of this study was to systematically review the literature to determine the effect of combined hypothermia (HTH) and mesenchymal stem cell (MSC) therapy (administered during or immediately before or after HTH) compared with HTH alone on brain injury and neurobehavioural outcomes in animal models of neonatal hypoxic-ischaemic encephalopathy. METHODS: Primary outcomes assessed were neuropathological measures and neurobehavioural measures of brain outcome. Secondary outcomes were brain protein proinflammatory cytokine status. Risk of bias (ROB) was assessed with the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) ROB assessment tool. RESULTS: Of 393 studies identified, 3 studies in postnatal day 7 (P7) male Sprague-Dawley rats met the inclusion criteria. Meta-analyses were undertaken for neuropathological measures (apoptotic cells, astrocytes, microglia), neurobehavioral measures (rotarod test and negative geotaxis), and proinflammatory cytokine levels. Two of the three studies scored low or unclear ROB across all measures. Treatment with HTH-MSCs together significantly improved astrocyte optical density by standardised mean difference (SMD) of 0.71 [95% confidence interval (CI) -1.14, -0.28]. No other measures showed significant differences. CONCLUSIONS: There is insufficient preclinical data to confirm the efficacy of combined HTH-MSC therapy over HTH alone. Future studies should utilise a reporting checklist such as in SYRCLE or Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines to improve reporting standards. IMPACT: Very few articles investigating the use of MSCs for the treatment of hypoxic-ischaemic encephalopathy are clinically relevant. Continuing to publish studies in models of hypoxic-ischaemic encephalopathy without the inclusion of HTH therapy does not progress the field towards improved clinical outcomes. This study shows that HTH and MSC therapy improves measures of astrogliosis. More studies are required to establish the efficacy of HTH and MSCs on measures of neuropathology and neurobehavior. The reporting of preclinical data in this space could be improved by using reporting checklists such as the SYRCLE or ARRIVE tools.

Combination of human endothelial colony-forming cells and mesenchymal stromal cells exert neuroprotective effects in the growth-restricted newborn.

The foetal brain is particularly vulnerable to the detrimental effects of foetal growth restriction (FGR) with subsequent abnormal neurodevelopment being common. There are no current treatments to protect the FGR newborn from lifelong neurological disorders. This study examines whether pure foetal mesenchymal stromal cells (MSC) and endothelial colony-forming cells (ECFC) from the human term placenta are neuroprotective through modulating neuroinflammation and supporting the brain vasculature. We determined that one dose of combined MSC-ECFCs (cECFC; 106 ECFC 106 MSC) on the first day of life to the newborn FGR piglet improved damaged vasculature, restored the neurovascular unit, reduced brain inflammation and improved adverse neuronal and white matter changes present in the FGR newborn piglet brain. These findings could not be reproduced using MSCs alone. These results demonstrate cECFC treatment exerts beneficial effects on multiple cellular components in the FGR brain and may act as a neuroprotectant.

IGF-1 concentrations after weaning in young sows fed different pre-mating diets are positively associated with piglet mean birth weight at subsequent farrowing.

Pre-mating diets can influence piglet birth weight and within-litter birth weight variation and thereby piglet survival and development. The major objective of this study was to evaluate the litter characteristics of young sows whose pre-mating diets received different supplementation. The supplements included a top-dressing of 200 g, consisting of either wheat (CON) or wheat plus microfibrillated cellulose, L-carnitine or L-arginine at one of two supplementation levels (low and high) in late lactation and during the weaning-to-oestrus interval (WEI). The second objective was to investigate the role of body condition loss and IGF-1 concentration during the WEI for subsequent litter characteristics. In total, sows after their first (N =41) and second (N =15) lactation were used. One week before weaning, the sows were allocated to the seven treatments based on the number of piglets and BW loss from farrowing until 1 week before weaning. Pre-mating diets did not affect litter characteristics at subsequent farrowing. However, at subsequent farrowing, sows after their first lactation had a lower total number of piglets born per litter (18.3 v. 20.3), higher mean piglet birth weight (1365 v. 1253 g), lower CV of birth weight (20.0 v. 26.1%) and lower percentage of piglets <1000 g (11.5 v. 24.4%) than sows after their second lactation. Litter weight at second parturition was positively related to IGF-1 during the WEI after first lactation (P <0.04). Within parity, piglet mean birth weight was positively related to IGF-1 at oestrus (P <0.02). Surprisingly, within parity, a higher relative loin muscle depth loss during previous lactation was related to lower CV and SD of birth weight (P <0.05, for both). In conclusion, pre-mating diets did not affect litter characteristics at subsequent birth. However, a higher IGF-1 concentration during the WEI was positively associated with subsequent litter weight and piglet mean birth weight. Further studies should elucidate the role of IGF-1 during the WEI for subsequent litter characteristics and dietary interventions to stimulate IGF-1.

IGF-1 concentration patterns and their relationship with follicle development after weaning in young sows fed different pre-mating diets.

Piglet birth weight and within-litter birth weight variation are important for piglet survival and growth. Pre-mating diets may improve IGF-1 and follicle development during the weaning-to-oestrus interval (WEI) and subsequent piglet birth weight. The objective of this study was to modulate IGF-1 concentration during late lactation and the WEI of young sows by using specific pre-mating diets supplemented with microfibrillated cellulose (MF), l-carnitine (LC) or l-arginine (AR). A further objective was to investigate the relationship between IGF-1 and subsequent follicle development and oestrus and ovulation characteristics. In total, 56 first-parity and 20 second-parity sows in three consecutive batches were used for this experiment. Sows received daily either wheat (CON) or wheat plus MF, LC or AR at one of two supplementation levels (low and high) during last week of lactation and WEI. From weaning onwards, follicle and corpus luteum (CL) diameters were repeatedly measured with ultrasound. Blood samples were collected during the WEI for IGF-1 and on day 21 of pregnancy for progesterone analyses, respectively. Insulin-like growth factor-1 concentration, follicle diameter, oestrus and ovulation characteristics and CL diameter were not affected by pre-mating diets. Low IGF-1 class (≤156 ng/ml, N = 22) sows had smaller follicles at weaning (3.5 v. 3.8 mm, P < 0.05) and a longer weaning-to-ovulation interval (147.2 v. 129.8 h, P < 0.05) than high IGF-1 class sows. In first-parity sows, high loin muscle depth (LM) loss sows (≥8%, N = 28) had lower IGF-1 concentrations at weaning (167 v. 214 ng/ml, P < 0.05) compared to low LM loss sows (<8%, N = 28). However, after weaning, IGF-1 concentrations increased and did not differ between high LM loss and low LM loss sows. In conclusion, the different supplemented compounds in pre-mating diets did not improve IGF-1 concentrations around weaning in young sows. Furthermore, high body condition loss caused lower IGF-1 concentrations at weaning, but these levels rapidly recovered after weaning and were related to follicle development and the interval from weaning to ovulation.

Ibuprofen Treatment Reduces the Neuroinflammatory Response and Associated Neuronal and White Matter Impairment in the Growth Restricted Newborn.

Intrauterine growth restriction (IUGR) is a condition where the fetus does not achieve optimal growth, commonly caused by placental insufficiency. The chronic decrease in blood flow restricts oxygen and nutrient supply to the fetus, which can damage numerous organ systems, with the fetal brain being particularly vulnerable. Although white matter and neuronal injury are evident in IUGR infants, the specific mechanisms underlying these changes are poorly understood. Inflammation is considered to be a main driver in exacerbating brain injury. Using a spontaneous piglet model of IUGR, we aim to determine whether administration of the anti-inflammatory drug ibuprofen will decrease inflammation at postnatal day 4 (P4). The treatment group received ibuprofen (20 mg/kg/day on day 1 and 10 mg/kg/day on days 2 and 3) in piglet formula during the morning feed each day and brains examined on P4. Markers of inflammation, apoptosis, cell proliferation, neuronal injury, and white matter injury were examined. Ibuprofen treatment ameliorated the increase in numbers of microglia and astrocytes in the parietal cortex and white matter tracts of the IUGR piglet brain on P4 as well as decreasing proinflammatory cytokines. Ibuprofen treatment prevented the reduction in apoptosis, neuronal cell counts, and myelin index in the IUGR piglets. Our findings demonstrate ibuprofen reduces the inflammatory response in the IUGR neonatal brain and concurrently reduces neuronal and white matter impairment.

Neuropathology in intrauterine growth restricted newborn piglets is associated with glial activation and proinflammatory status in the brain.

BACKGROUND: The fetal brain is particularly vulnerable to intrauterine growth restriction (IUGR) conditions evidenced by neuronal and white matter abnormalities and altered neurodevelopment in the IUGR infant. To further our understanding of neurodevelopment in the newborn IUGR brain, clinically relevant models of IUGR are required. This information is critical for the design and implementation of successful therapeutic interventions to reduce aberrant brain development in the IUGR newborn. We utilise the piglet as a model of IUGR as growth restriction occurs spontaneously in the pig as a result of placental insufficiency, making it a highly relevant model of human IUGR. The purpose of this study was to characterise neuropathology and neuroinflammation in the neonatal IUGR piglet brain. METHODS: Newborn IUGR (< 5th centile) and normally grown (NG) piglets were euthanased on postnatal day 1 (P1; < 18 h) or P4. Immunohistochemistry was utilised to examine neuronal, white matter and inflammatory responses, and PCR for cytokine analysis in parietal cortex of IUGR and NG piglets. RESULTS: The IUGR piglet brain displayed less NeuN-positive cells and reduced myelination at both P1 and P4 in the parietal cortex, indicating neuronal and white matter disruption. A concurrent decrease in Ki67-positive proliferative cells and increase in cell death (caspase-3) in the IUGR piglet brain was also apparent on P4. We observed significant increases in the number of both Iba-1-positive microglia and GFAP-positive astrocytes in the white matter in IUGR piglet brain on both P1 and P4 compared with NG piglets. These increases were associated with a change in activation state, as noted by altered glial morphology. This inflammatory state was further evident with increased expression levels of proinflammatory cytokines (interleukin-1ß, tumour necrosis factor-α) and decreased levels of anti-inflammatory cytokines (interleukin-4 and -10) observed in the IUGR piglet brains. CONCLUSIONS: These findings suggest that the piglet model of IUGR displays the characteristic neuropathological outcomes of neuronal and white matter impairment similar to those reported in the IUGR human brain. The activated glial morphology and elevated proinflammatory cytokines is indicative of an inflammatory response that may be associated with neuronal damage and white matter disruption. These findings support the use of the piglet as a pre-clinical model for studying mechanisms of altered neurodevelopment in the IUGR newborn.

Factors affecting piglet mortality during the first 24 h after the onset of parturition in large litters: effects of farrowing housing on behaviour of postpartum sows.

The present study aimed to identify the factors that affect immediate (within 24 h after farrowing onset) postnatal piglet mortality in litters with hyperprolific sows, and investigate their associations with behaviour of postpartum sows in two different farrowing housing systems. A total of 30 sows were housed in: (1) CRATE (n=15): the farrowing crate closed (0.80×2.20 m) within a pen (2.50×1.70 m), and (2) OPEN (n=15): the farrowing crate open (0.80×2.20×1.80 m) within a pen (2.50×2.40 m) with a provision of 20 ls of hay in a rack. A total of 518 live born piglets, produced from the 30 sows, were used for data analyses during the first 24 h after the onset of parturition (T24). Behavioural observations of the sows were assessed via video analyses during T24. Total and crushed piglet mortality rates were higher in OPEN compared with CRATE (P<0.01, for both). During T24, the OPEN sows tended to show higher frequency of postural changes (P=0.07) and duration of standing (P=0.10), and showed higher frequencies of bar-biting (P<0.05) and piglet trapping (P<0.01), when compared with the CRATE sows. During T24, the mortality rates caused by crushing were correlated with the piglet trapping event (r=0.93, P<0.0001), postural changes (r=0.37, P<0.01), duration of standing (r=0.32, P<0.01) and frequency of bar-biting behaviour (r=0.51, P<0.01) of the sows (n=30). In conclusion, immediate postnatal piglet mortality, mainly due to crushing, may be associated with potential increases in frequency of postural changes, duration of standing and incidence of piglet trapping in postpartum sows in the open crate system with large litters.

The effect of farrowing duration and parity on preovulatory follicular size and oxytocin release of sows at subsequent oestrus.

This study examined the extent to which prolonged farrowing and parity are associated with plasma oxytocin concentrations and follicular development of oestrous sows during subsequent insemination. A total of 30 sows were allocated to two groups based on farrowing duration: (i) SHORT (n = 14): 159 ± 29 min, (ii) LONG (n = 16): 533 ± 190 min. The sows were also divided into two parity classes: (i) YOUNG (n = 14): parity 2.5 ± 0.8, (ii) OLD (n = 16): parity 6.4 ± 2.3. After weaning, the ovaries were examined daily with transrectal ultrasound. On the second day of oestrus, blood samples were collected for oxytocin (OT) assay at -15, -10, -5, 0, +1, +2, +3, +4, +6, +8, +10, +15, +20, +25, +30, +40, +50 and +60 min with a boar contact between 0 and +10 min. Boar presence stimulated an increase in OT concentrations (p < .05). During boar presence, OT in the LONG group was higher than in the SHORT group (p < .01). The sows in the OLD group had a longer farrowing duration than in the YOUNG group (p < .05). OT levels and diameters of follicles were more relevant for parity than was the duration of farrowing. We therefore conclude that the OT levels and follicular development of oestrous sows are associated due to parity but difficult to be predicted from the duration of previous farrowing.

Therapeutic potential to reduce brain injury in growth restricted newborns.

Brain injury in intrauterine growth restricted (IUGR) infants is a major contributing factor to morbidity and mortality worldwide. Adverse outcomes range from mild learning difficulties, to attention difficulties, neurobehavioral issues, cerebral palsy, epilepsy, and other cognitive and psychiatric disorders. While the use of medication to ameliorate neurological deficits in IUGR neonates has been identified as warranting urgent research for several years, few trials have been reported. This review summarises clinical trials focusing on brain protection in the IUGR newborn as well as therapeutic interventions trialled in animal models of IUGR. Therapeutically targeting mechanisms of brain injury in the IUGR neonate is fundamental to improving long-term neurodevelopmental outcomes. Inflammation is a key mechanism in neonatal brain injury; and therefore an appealing target. Ibuprofen, an anti-inflammatory drug currently used in the preterm neonate, may be a potential therapeutic candidate to treat brain injury in the IUGR neonate. To better understand the potential of ibuprofen and other therapeutic agents to be neuroprotective in the IUGR neonate, long-term follow-up information of neurodevelopmental outcomes must be studied. Where agents such as ibuprofen are shown to be effective, have a good safety profile and are relatively inexpensive, they can be widely adopted and lead to improved outcomes.

Identification and expression of a unique neonatal variant of the GABAA receptor α3 subunit.

The GABAA receptor provides the majority of inhibitory neurotransmission in the adult central nervous system but in immature brain is responsible for much of the excitatory drive, a requirement for normal brain development. It is well established that GABAA receptor subunit expression changes across the course of brain development. In the present study, we have identified a splice variant of the GABAA receptor α3 subunit which appears unique to the developing brain, referred to here as the GABAA receptor α3 subunit neonatal variant (GABAA receptor α3N). RT-PCR and sequence analysis revealed splicing of exon 8 of the α3 subunit. Western blot analysis showed expression of GABAA receptor α3N in the cortex of several neonatal species and significantly reduced expression of this splice variant in the corresponding adult brains. Expression was evident in multiple brain regions and decreased across development in the pig. Fractionation revealed differential cellular localisation in the parietal cortex, hippocampus and thalamus of the full-length GABAA receptor α3 and GABAA receptor α3N. Immunoprecipitation showed direct interaction with the GABAA receptor subunits α1 and γ2 but not with gephyrin.

Prolonged parturition and impaired placenta expulsion increase the risk of postpartum metritis and delay uterine involution in sows.

It was hypothesized that prolonged parturition and impaired placenta expulsion increase the risk of postpartum metritis and delay uterine involution. At parturition, for 99 Yorkshire x Large White sows (parity 2-5), we determined the number of liveborn (NLP; 14.8 ± 3.4) and stillborn piglets (NSP; 1.1 ± 1.1), farrowing duration (FAR, time between first and last piglet; 333 ± 249 min), placenta expulsion duration (PLA, time between first and last placental part; 292 ± 241 min) and number of expelled placental parts (PART; 3.0 ± 1.0). FAR was categorized as 'normal' (<300 min; n = 44/99) or 'prolonged' (>300 min; n = 55/99). The relative PLA (rPLA; (PLA * 100)/FAR; 76 ± 101%) and the relative PART (rPART; (PART * 100)/(NLP + NSP); 22 ± 8%) were calculated and placenta expulsion was categorized as 'normal' (rPLA and rPART > 10%; n = 93/99) or 'impaired' (relPLA and relPART < 10%; n = 6/99). We also recorded whether manual palpation occurred (Yes/No) and/or oxytocin was used (Yes/No). After parturition, an ultrasound examination of the uterus was performed once for each sow between the 2nd and 7th day postpartum and the uterine size (mean sectional area of three to five uterine cross-sections) and intrauterine fluid accumulation (Yes/No) were recorded. Uterine size was categorized as 'normal' (n = 55/99) or 'enlarged' (n = 44/99) and used as an indicator of delayed uterine involution. Intrauterine fluid was used as an indicator of metritis. Prolonged FAR (35/54, 2.0 ± 0.5, 13.1, 7.6; n/N, ß ± SE, Wald χ2, Odds; P = 0.001), manual palpation (12/17, 1.5 ± 0.7, 4.4, 4.3; P = 0.036), oxytocin administration (18/31, - 1.5 ± 0.7, 4.7, 0.2, P = 0.040) and NSP ≥ 2 (15/21, 1.4 ± 0.7, 3.8, 3.9; P = 0.052) were associated with increased uterine size (n = 44/99) and NSP ≥ 2 (7/21, 2.6 ± 0.9, 8.7, 13.7; P = 0.003), manual palpation (10/17, 1.8 ± 0.8, 5.0, 6.0; P = 0.025), prolonged FAR (13/15, 1.7 ± 0.8, 4.3, 5.7; P = 0.039) and impaired PLA (4/6, 3.3 ± 1.7, 4.0, 26.9; P = 0.044) with intrauterine fluid accumulation (n = 15/99). The results confirm the hypothesis, indicating that prolonged parturition and impaired placenta expulsion increased the risk for postpartum metritis. Stillborn piglets and manual palpation were also identified as risk factors. Postpartum metritis delays uterine involution whereas the use of exogenous oxytocin supports it.

Serial transvaginal ultrasound-guided biopsy of the porcine corpus luteum in vivo.

The aims of the present study was to develop and describe a transvaginal ultrasound-guided biopsy method for luteal tissue in the porcine and to evaluate the effects of the method on the reproductive tract, ovarian status and pregnancy status. Biopsies were performed in four multiparous sows on Days 9 and 15 of three consecutive oestrous cycles; the size and histological composition of the samples obtained were evaluated and the reproductive tract of the sows was monitored. Furthermore, biopsies were performed in 26 multiparous sows on Days 10 and 13 after insemination, and the pregnancy rate, gestation length and subsequent litter size were evaluated. RNA was extracted from the samples obtained and the quality and quantity were determined. Altogether, 76 biopsies were performed and 38 samples were obtained. Compared with sows from which no samples were obtained (n=6), sows from which one or more samples were obtained (n=24) were older (parity 5.0±2.8 vs 2.2±0.4, mean±s.d.), heavier (290±26 vs 244±27kg) and had higher back fat (11.4±2.7 vs 6.4±2.5mm; P<0.05 for all). No effect of the biopsies (P>0.05) was observed on the cyclicity and reproductive organs of the sows, or on corpus luteum diameter on Day 13 (8.9±1.0 vs 9.2±1.1mm), pregnancy rate (95% vs 96%), gestation length (115±1 vs 115±1 days) and subsequent litter size (12.7±2.5 vs 13.3±2.8) between sows from which samples were obtained and those from which no samples were obtained. The samples obtained had a diameter of 1mm and contained heterogeneous tissue with various cell types. The RNA quantity was 520±160µg per sample and the RNA integrity number was 8.5±1.0. In conclusion, an ultrasound-guided biopsy method for ovarian tissue, which can be used for gene expression studies, was established in the porcine. No effect on corpus luteum function was found.

Maternal hypomagnesemia alters hippocampal NMDAR subunit expression and programs anxiety-like behaviour in adult offspring.

It is well established that maternal undernutrition and micronutrient deficiencies can lead to altered development and behaviour in offspring. However, few studies have explored the implications of maternal Mg deficiency and programmed behavioural and neurological outcomes in offspring. We used a model of Mg deficiency (prior to and during pregnancy and lactation) in CD1 mice to investigate if maternal Mg deficiency programmed changes in behaviour and NMDAR subunit expression in offspring. Hippocampal tissue was collected at postnatal day 2 (PN2), PN8, PN21 and 6 months, and protein expression of NMDAR subunits GluN1, GluN2A and GluN2B was determined. At 6 months of age, offspring were subject to behavioural tasks testing aspects of anxiety-like behaviour, memory, and neophobia. Maternal hypomagnesemia was associated with increased GluN1, GluN2A and GluN2B subunit expression in female offspring at 6 months, but decreased GluN1 and GluN2A expression in males. The GluN2B:GluN2A expression ratio was increased in both sexes. Male (but not female) offspring from Mg-deficient dams showed anxiety-like behaviour, with reduced head dips (Suok test), and reduced exploration of open arms (elevated plus maze). Both male and female offspring from Mg-deficient dams also showed impaired recognition memory (novel object test). These findings suggest that maternal Mg deficiency can result in behavioural deficits in adult life, and that these changes may be related to alterations in hippocampal NMDA receptor expression.

The effect of litter size, parity and farrowing duration on placenta expulsion and retention in sows.

The hypothesis was that a prolonged parturition impairs placenta expulsion and can lead to retained placentas in sows. Furthermore, we hypothesized that application of oxytocin around the time of expulsion of the first placental part improves placenta expulsion. We recorded 142 parturitions of 101 Yorkshire x Large White sows. We determined parity, gestation length, number of liveborn and stillborn piglets, farrowing duration (time between first and last piglet) and the outcome variables: number of expelled placental parts, placenta expulsion duration (time between first and last placental part), first placental part expulsion (time between last piglet and first placental part) and last placental part expulsion (time between last piglet and last placental part). The relationship between farrowing duration and each of the outcome variables was investigated using four distinct multivariable models. Use of oxytocin (used in 44 out of 142 parturitions) increased number of expelled placental parts (3.8 ± 0.2 vs. 2.9 ± 0.3; P = 0.035), decreased the placenta expulsion duration (172 ± 44 vs. 328 ± 26 min; P = 0.011) and time of last placental part expulsion (148 ± 48 vs. 300 ± 24 min; P = 0.025). If oxytocin was not used, farrowing duration obeyed a quadratic relationship with the number of expelled placental parts (P = 0.001), placenta expulsion duration (P = 0.002) and time of last placental part expulsion (P = 0.024). If oxytocin was used, number of expelled placental parts was positively associated with number of liveborn piglets (ß = 0.2 ± 0.1; P = 0.002) and affected by parity. 5th parity sows expelled more placental parts (4.3 ± 0.4) than 4th (3.2 ± 0.3; P = 0.024) and 3rd parity sows (2.7 ± 0.4; P = 0.008). Furthermore, placenta expulsion duration was positively associated with number of liveborn piglets (ß = 18 ± 8 min; P = 0.025). First placental part expulsion was negatively correlated with farrowing duration (ß = 0.3 ± 0.1; P = 0.001). Sows that experienced total (no expulsion of placental parts; n = 4) and partial retained placentas (no expulsion of placental parts after birth of the last piglet; n = 4) had longer farrowing durations (1009 ± 275 and 734 ± 136 min) than sows with no retained placentas (369 ± 202 min; P = 0.021 and P = 0.004). The results show that a prolonged parturition impaired and oxytocin improved placenta expulsion in sows. Furthermore, retained placentas occurred in 3-6% of the sows and was correlated with a prolonged parturition.

Review: The blood-brain barrier; protecting the developing fetal brain.

While placental function is fundamental to normal fetal development, the blood-brain barrier provides a second checkpoint critical to protecting the fetal brain and ensuring healthy brain development. The placenta is considered the key barrier between the mother and fetus, regulating delivery of essential nutrients, removing waste as well as protecting the fetus from potentially noxious substances. However, disturbances to the maternal environment and subsequent adaptations to placental function may render the placenta ineffective for providing a suitable environment for the developing fetus and to providing sufficient protection from harmful substances. The developing brain is particularly vulnerable to changes in the maternal/fetal environment. Development of the blood-brain barrier and maturation of barrier transporter systems work to protect the fetal brain from exposure to drugs, excluding them from the fetal CNS. This review will focus on the role of the 'other' key barrier during gestation - the blood-brain barrier - which has been shown to be functional as early as 8 weeks' gestation.

Review: Neuroinflammation in intrauterine growth restriction.

Disruption to the maternal environment during pregnancy from events such as hypoxia, stress, toxins, inflammation, and reduced placental blood flow can affect fetal development. Intrauterine growth restriction (IUGR) is commonly caused by chronic placental insufficiency, interrupting supply of oxygen and nutrients to the fetus resulting in abnormal fetal growth. IUGR is a major cause of perinatal morbidity and mortality, occurring in approximately 5-10% of pregnancies. The fetal brain is particularly vulnerable in IUGR and there is an increased risk of long-term neurological disorders including cerebral palsy, epilepsy, learning difficulties, behavioural difficulties and psychiatric diagnoses. Few studies have focused on how growth restriction interferes with normal brain development in the IUGR neonate but recent studies in growth restricted animal models demonstrate increased neuroinflammation. This review describes the role of neuroinflammation in the progression of brain injury in growth restricted neonates. Identifying the mediators responsible for alterations in brain development in the IUGR infant is key to prevention and treatment of brain injury in these infants.

Parturition effects on reproductive health in the gilt and sow.

In this review, we address significant characteristics of parturition in the pig and their connection to post-partum reproductive health and fertility. We discuss the normal physiology and behaviour around parturition and the effect of the second phase (expulsion of foetuses) on the third phase of parturition (expulsion of foetal membranes). In addition, we intend to cover retained placenta, and the connection to post-partum uterine health and fertility in the contemporary prolific sow. We also explore factors that support successful parturition or can cause potential problems. Successful parturition in the pig includes the possibility to express adequate maternal behaviour, rapid expulsion of the piglets, complete expulsion of the placenta, neonatal activity and colostrum intake. Abnormal incidents during any phase of parturition can cause subsequent problems. Duration of the expulsion phase of foetuses can be used as a simple measure of whether parturition is considered successful. Prolonged parturition can impair health of the sow and piglet and fertility after weaning. New insights, such as adding more fibre to sow diets during pregnancy, and especially during the period prior to farrowing, may prevent constipation, increase water intake of the sow around parturition and increase milk intake and performance of piglets. Maternal characteristics, including maternal behaviour, ease of parturition, colostrum production and piglet quality parameters, may be utilized to improve success rate of reproductive management during farrowing and early lactation. Additionally, we share some of the recent developments in methods, including ultrasonography in evaluation of post-partum uterine health. In conclusion, successful farrowing is of the greatest importance for reproductive health of the sow and survival of the piglets. We suggest connections exist among prolonged farrowing and yield of colostrum, retained placenta, development of PDS, and impaired involution of the uterus and reduced subsequent fertility.