Canine Placenta Histological Findings and Microvascular Density: The Histological Basis of a Negative Neonatal Outcome?

Multicentric aggressive unclassified hematopoietic neoplasm involving the placenta in a pregnant bitch

Hematopoietic neoplasms are common in dogs; however, their association with pregnancy has not been previously reported in veterinary medicine. This rare occurrence presents a variety of diagnostic, therapeutic, prognostic, and ethical challenges. We report a case of a 3-year-old pregnant Bernese Mountain Dog diagnosed with multicentric aggressive unclassified hematopoietic cancer associated with paraneoplastic hypercalcemia during pregnancy. The dog died 7 days after diagnosis, and at Day 36 of pregnancy before any treatment decision could be made. Post-mortem evaluation, including histology, immunohistochemistry, and clonality analysis, led to the diagnosis of an unclassified hematopoietic cancer affecting the uterus and placenta, with no evidence of fetal involvement. The placenta likely acted as a barrier, preventing neoplastic involvement of the fetuses. Alternatively, the pregnancy might have been too early for the hematopoietic neoplasm to affect the labyrinth zone of the placenta and the fetuses. The dramatic disease progression could be explained by compromised cell-mediated immunity during pregnancy. This immunodeficient state is induced by embryonic, maternal, and hormonal factors, which suppress the response to mitogens to prevent rejection of the placenta and the conceptuses. Thus, pregnant dogs might exhibit increased vulnerability to cancer and infectious diseases that rely on cell-mediated immunity for host defense.

Proliferation and apoptosis studies of interplacental areas after aglepristone treatment for planned cesarean section in pregnant bitches

Background and Aim

Progesterone (P4) is the main hormone for pregnancy maintenance, occurring approximately 62-64 days after ovulation in bitches. Progesterone acts by binding to specific receptors. Aglepristone is a progesterone receptor (PR) antagonist with a higher affinity for PR binding. There are no published studies on cell proliferation and apoptosis in the canine uterus at the time of parturition. Therefore, this study aimed to determine the local effects of aglepristone on cell proliferation and apoptosis of interplacental uterine tissue during planned cesarean section (C-section) in bitches.

Materials and Methods

In this study, 13 client-owned French bulldogs were examined. Bitches were divided into treatment (n = 8) and control (n = 5) groups. Ovulation timing was predicted based on the serum P4 level on 62-64 days post-ovulation for parturition. Serum P4 levels were measured before (on 60-day post-ovulation) and on C-section day (on 61-day post-ovulation). Aglepristone (Alizine®), 15 mg/kg subcutaneously (SC), was administered on 60 days post-ovulation in the treatment group. A C-section was planned 20-24 h later, and interplacental uterine areas were collected from both groups during the C-section. Immunohistochemistry based on Ki-67 and TUNEL assay was used to evaluate cell proliferation and apoptosis in four different interplacental uterine tissue layers (epithelium, stroma, glandular epithelium, and myometrium). Data are reported as mean ± standard deviation. Kruskal-Wallis test was used for comparisons of more than two independent groups. P value of 0.05 was considered statistically significant.

Results

One bitch in the treatment group was excluded due to emergency C-section 8 h after aglepristone administration. Serum P4 levels (ng/mL) at 20-24 h before and at C-section were 6.09 ± 2.72 and 4.32 ± 2.2 in the treatment group (n = 7) and 5.45 ± 1.28 and 3.67 ± 1.89 in the control group (n = 5), respectively. Proliferation (PI) and apoptotic (AI) indices were <5% and >45%, respectively, in both the treatment (n = 5) and control (n = 3) groups. PI and AI were detected at interplacental areas.

Conclusion

There were no significant differences in serum P4 levels or PI and AI indices between the groups. The PI <5% and AI was higher than 45% in both groups. Aglepristone did not have a direct effect on the serum P4 levels in both groups. These results correlated with the natural physiology of parturition preparation. Aglepristone 15 mg/kg SC injected 20-24 h before parturition had no effect on the P4 level, nor were any harmful effects observed for a planned C-section in pregnant bitches.

Animal models of postpartum hemorrhage

Postpartum hemorrhage (PPH)-heavy bleeding following childbirth-is a leading cause of morbidity and mortality worldwide. PPH can affect individuals regardless of risks factors and its incidence has been increasing in high-income countries including the United States. The high incidence and severity of this childbirth complication has propelled research into advanced treatments and alternative solutions for patients facing PPH; however, the development of novel treatments is limited by the absence of a common, well-established and well-validated animal model of PPH. A variety of animals have been used for in vivo studies of novel therapeutic materials; however, each of these animals differs considerably from the anatomy and physiology of a postpartum woman, and the methods used for achieving a postpartum hemorrhagic condition vary widely. Here we critically evaluate the various animal models of PPH presented in the literature and propose additional and alternative methods for modeling PPH in in vivo studies. We highlight how current animal models successfully or unsuccessfully mimic the anatomy and physiology of a postpartum woman and how this may impact treatment development. We aim to equip researchers with the necessary background information to select appropriate animal models for their research related to PPH solutions, while supporting the goals of refinement, reduction and replacement (3Rs) in preclinical animal studies.

Does Placental Efficiency and Vascularization Affect Puppy Health? A Study in Boxer and Dobermann Dogs

BACKGROUND

The anatomical and functional characteristics of the placenta influence the adaptive ability of the fetus to the extrauterine environment. Placental efficiency, measured as the gram of neonate produced by each gram of placenta, summarizes these characteristics. In the present study, placental efficiency and its impact on the 7-day postpartum life of the puppies were studied in canine large breeds.

METHODS

Placental efficiency (PE) was computed using chorioallantois weight (WPE) and surface (SPE) efficiency for puppies born from natural delivery or elective cesarean section. Capillary density was also histologically determined. Neonate viability was estimated by the APGAR score and the daily weight gain (DWG) was recorded on day 7 after delivery.

RESULTS

from 15 large-breed bitches, 69 live puppies were born by natural delivery (24 puppies) and elective cesarean section (45 puppies). Cluster analysis detected a group of neonates for which reduced placental efficiency (8 for the WPE, 9 for the SPE) was identified, despite a placental weight and surface within the mean and no difference in capillary density. In this group, the DWG was lower and the mortality within 7 days was higher.

CONCLUSIONS

the results suggest that placental efficiency could be an additional tool for the evaluation of a puppy in the first 7 days after delivery.

Neonatal-Maternal Bodyweight Ratio at Birth: An Indicator for First-Week Survival Prognosis in Canine Newborns

Objectives. In dogs, neonatal bodyweight (NBW) varies at birth. Size-specific reference values for NBW are essential to correctly manage newborns. The present study aimed to define a new tool to evaluate NBW that could be routinely applied in canine neonatology, promptly identifying puppies requiring more care. Methods. The records of 89 litters were retrospectively evaluated. Data were grouped according to maternal bodyweight (MBW) in five categories: toy (≤5 kg), small (5.1-9.9 kg), medium (10-24.9 kg), large (25-39.9 kg), and giant (≥40 kg) dogs. At birth, the NBW of 412 puppies, alongside their litter size (LS) and gender (G), were recorded. Neonatal mortality within the first week was considered. The influence of MBW, LS, and G on NBW and the effect of NBW on the 1-week outcome were evaluated using ANOVA (p < 0.05). The ratio between NBW and MBW expressed as a percentage (N-MBW%), was assessed for each puppy. Through Receiver-Operating Characteristic (ROC) curves, N-MBW% thresholds between puppies alive or dead at one week of age were calculated in each group. Results. The LS was different among groups, except for small vs. medium dogs. In small litters, N-MBW% was lower in medium-, large- and giant-sized dogs than in toy and small dogs. In medium and large litters, N-MBW% differed among the five groups. Male and female N-MBW% differed among the five groups. Only in large and giant sizes did LS affect N-MBW%, which was lower in a large LS. The N-MBW% was higher in healthy puppies than in those who died within one week. The ROC-derived N-MBW% thresholds were as follows: 4.5% in toy-, 3.2% in small-, 1.5% in medium-, 1.2% in large-, and 1% in giant dogs. Clinical significance. The ROC-derived N-MBW% thresholds can be used to cautiously identify puppies at increased risk for one-week mortality and may be helpful in clinical practice, representing a suitable parameter to give a prognosis on 1-week survival immediately at birth.

Emergency cesarean section in dogs: Usefulness of amniotic fluid biochemical parameters and placental morphology as indicators of neonatal viability

In recent years, special attention has been paid to the analysis of fetal fluids and placental histopathology to identify parameters that can be used as indicators of maternal reproductive quality, embryonic viability, and fetal and neonatal health. Newborn health reflects the functioning of the fetal adnexa and its relationship with maternal tissues. Therefore, evaluating these components is promising for the early detection of newborns at risk. This study aimed to detect the biochemical characteristics of the amniotic fluid (AF) and histopathological characteristics of the placenta for comparison between canine neonates born by elective (EL) and emergency (EM) cesarean sections (CSs) and associate the results with neonatal viability in the first 24 h. A total of 38 neonates born by ELCS (n = 19) and EMCS (n = 19) were selected. AF was collected to analyze the concentration of its biochemical components [alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatinine, urea, total protein, albumin, total and direct bilirubin, lactate, glucose, potassium, chloride, calcium, and sodium]. Histopathological processing of the placenta was used to describe the lesions and identify the arrangement of collagen fibers using hematoxylin-eosin and picrosirius staining. There was an increase in ALP activity (P = 0.035) and the concentrations of lactate (P < 0.001) and potassium (P = 0.031), and a decrease in chlorides (P < 0.001) in the AF of neonates in the EMCS group. The comparisons between the groups did not show differences between the presence and extent of lesions in the placenta; however, a difference was observed in the arrangement of collagen fibers in the placental structure. A comparison between AF and histopathological findings showed a negative correlation (r = -0.609, P = 0.003) between glucose concentration and the presence of necrosis in the placental labyrinth. It was observed that the composition of the AF changed owing to the influence of the type of cesarean, possibly caused by prolonged hypoxia in cases of dystocia. ALP activity and lactate, potassium, and chloride concentrations in the AF might be explored as markers of neonatal health in EMCS. Under the conditions of this study, no correlations were found between the placenta's histopathological characteristics and the neonates' viability.

Macro and microscopic characteristics of the placenta and its relationship with the weight and the Apgar score of canine neonates

The placenta is the main organ of pregnancy and is directly related to the proper development of the fetus. The correlation among some placental measurements and their respective neonates is widely studied in the human species. However, the studies regarding bitches are still limited. Therefore, the aim of this work was to evaluate if there is a relationship between placental weight and volume and the weight of neonates at birth in the canine species, as well as its influence on their viability. In this work, 7 bitches, 18 neonates and their placentas were evaluated. The weight of the placentas was measured using an analytical balance and the volume was calculated by measuring the volume of water displaced after placing it in a container of water. The neonates were weighed and classified according to the Apgar score after birth. Samples from each placenta were fixed in formalin and embedded in paraffin, then placed on slides and stained in hematoxylin and eosin. From these samples, the microvascular density (MVD) was calculated, as well as the presence or absence of necrosis, calcification and haemorrhage, classified in scores from 0 to 2. Data were analyzed using Kendall's test. The mean weight of the placentas was 29.11 ± 11.06 g and the volume was 21.33 ± 10.65 cm³. The mean weight of the neonates was 282.94 ± 123.28 g and the Apgar score was 8.83 ± 2.06. The mean MVD of the placentas was 0.04 ± 0.01. A positive correlation was observed between birth weight and placental weight and volume. Placental weight also positively correlated with placental volume. Also, no significant correlation was found between MVD and alterations with placental weight and volume and with the weight and Apgar score of neonates. Among the microscopic changes, only necrosis showed a moderate correlation with placental weight and volume. It can be concluded that the placenta has an influence on the weight of neonates, which is essential for its development in intra and extrauterine life. However, more studies are required in the described species, to better elucidate these questions.

Dead or Alive? A Review of Perinatal Factors That Determine Canine Neonatal Viability

Simple Summary

The article summarizes the current knowledge on factors related to pregnancy, parturition, and newborns that affect the health status of a puppy and determine its chances for survival and development. The detailed information is provided in terms of breed predispositions, objectives of pregnancy monitoring, potential sources of complications, and veterinary advances in care and treatment of perinatal conditions. Successful pregnancy outcomes still pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Abstract

The perinatal period has a critical impact on viability of the newborns. The variety of factors that can potentially affect the health of a litter during pregnancy, birth, and the first weeks of life requires proper attention from both the breeder and the veterinarian. The health status of puppies can be influenced by various maternal factors, including breed characteristics, anatomy, quality of nutrition, delivery assistance, neonatal care, and environmental or infectious agents encountered during pregnancy. Regular examinations and pregnancy monitoring are key tools for early detection of signals that can indicate disorders even before clinical signs occur. Early detection significantly increases the chances of puppies’ survival and proper development. The purpose of the review was to summarize and discuss the complex interactions between all elements that, throughout pregnancy and the first days of life, have a tangible impact on the subsequent fate of the offspring. Many of these components continue to pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Collagen and Microvascularization in Placentas From Young and Older Mares

In older mares, increasing collagen fibers (fibrosis) in the endometrium and oviduct predisposes to sub-fertility and infertility. In this study, (i) gene transcription of collagen (qPCR: COL1A1, COL1A2, COL3A1, COL5A1); (ii) total collagen protein (hydroxyproline); (iii) collagen distribution (Picrosirius red staining; polarized light microscopy); and (iv) microvascular density (Periodic acid-Schiff staining), were evaluated in mares' placenta, and related to mares age, and placenta and neonate weights. Samples were collected from the gravid horn, non-gravid horn, and body of the placenta from younger (n = 7), and older mares (n = 9) of different breeds. Transcripts of COL1A1, COL3A1 and COL5A1, total collagen protein, chorionic plate connective tissue thickness, and microvascularization increased in the gravid horn of older mares' placentas, compared to the youngest (P < 0.05). Although in other species placenta fibrosis may indicate placental insufficiency and reduced neonate weight, this was not observed here. It appears that older fertile mares, with more parities, may develop a heavier, more vascularized functional placenta with more collagen, throughout a longer gestation, which enables the delivery of heavier foals. Thus, these features might represent morphological and physiological adaptations of older fertile mares' placentas to provide the appropriate nutrition to the equine fetus.