Objectives The umbilical cord (UC) plays an essential role in the exchange between the mother and the foetus, allowing the latter to receive oxygen and nutrients necessary for survival and development. The UC intervascular stroma consists of mucous connective tissue, also called Wharton's jelly (WJ). It develops from extraembryonic mesoderm, binds and encases the umbilical vessels, protecting them from twisting and compression during pregnancy. WJ also has angiogenic and metabolic roles for the umbilical circulation. Some authors demonstrated that in human, an alteration of its composition could be related to fetal pathologic condition (Ferguson et al 2009). The aims of the study were to macroscopically describe the equine UC, and, for the first time in the horse, to evaluate the weight and the microscopic composition of WJ. Materials and Methods Twenty-four mares with normal pregnancy and parturition have been enrolled. The following data were registered for each mare: age, parity, length of pregnancy, total length of UC, length of UC amniotic and allantoic portion, total number of UC coils and their number in each segment, sex and weight of the foal at birth. There was no control of mare breeding. The Kolmogorov-Smirnov test was used to evaluate the distribution of continuous variables; the presence of differences in the UC macroscopic structure between gender was evaluated by T Student, considering significant a P value <0.05. Pearson’s correlation test was used to assess the presence of correlations between the data registered. Immediately after breaking the UC, the part closest to the foal (~15 cm), characterized by an abundant amount of WJ, was severed and transported to the lab, where WJ was separated from vessels, weighted, and fixed in 4% paraformaldehyde for microscopic examinations. Fixed tissue sections were labelled with antibodies anti-type I, IV and V collagen, and anti-fibrillin. Furthermore fibroblast cells were highlighted using Masson's trichrome staining. To verify the presence of elastic, reticular and nervous fibers, orcein staining and silver impregnation were used. Results and Discussion The mean total length of UC was 58.3 ±17 cm; the mean length of amniotic portion was 33.2 ±10.6 cm, while the allantoic segment was 27.0 ±10.5 cm. These data confirmed those previously reported (Whitwell et al., 1975). The total UC length and the allantoic portion length resulted statistically higher in males (n=10) than in females (n=14; P<0.05). As in humans, this could be due to the higher weight at birth in males (Naeye, 1985). The mean total number of UC coils was 5.1 ±2.8, with 2.7 ±0.9 coils in the amniotic portion and 3.0 ±1.8 coils in the allantoic portion, respectively. Our study revealed that total number of coils (R=0.43, P<0.05) and coils number of the allantoic portion (R=0.67, P<0.05) were positively related with parity. A positive correlation was also observed between the length of the allantoic portion and its coils (R=0.58, P<0.05). Coils formation is the result of rotations given by the foetus. Since in the horse from the eighth month of gestation foetal movements occur only along the longitudinal axis, the number of coils observed is lower than that reported in human. This could also be related to the mean UCI value registered in the present study (0.10 ±0.04), lower than that reported in babies (van Dick et al., 2002). Different from humans, we did not observe any correlation between UCI and age of the mare, length of pregnancy, sex and weight of the foal, but UCI was positively related with the total number of coils (R=0.448, P<0.05) and with their number in the amniotic portion (R=0.699, P<0.05). On the contrary, the UCI resulted negatively related to the total UC length (R=-0.526, P<0.05) and to the amniotic portion UC length (R=-0.499, P<0.05). From each UC sample, 4.5 ±3.45 g of WJ were isolated. As in humans (Takeki, 1993), the immunohistochemical analysis revealed the presence of fibroblast cells positive for antibodies anti-type II, IV and V collagen, anti-fibrillin, surrounded by a dense network of reticular fibers. Given their abundance, we could not confirm the presence of nervous fibers. Different from humans, in the horse UC, elastic fibers are less concentrated, with an uneven pattern around the vessels. Conclusion In this study we highlighted similarities and differences between equine and human macroscopic and microscopic characteristics of the umbilical cord. Given the presence in human species of a strong correlation between these and specific pathological conditions of newborn and mother, further studies are needed, both on normal and high risk pregnancies, to verify the presence of these correlations also in the equine species.
Lanci, A., Iacono, E., Palermo, C., Grandis, A., Pirrone, A., Merlo, B., et al. (2015). Study of umbilical cord in the equine species.
Study of umbilical cord in the equine species
LANCI, ALIAI;IACONO, ELEONORA;GRANDIS, ANNAMARIA;PIRRONE, ALESSANDRO;MERLO, BARBARA;CASTAGNETTI, CAROLINA
2015
Abstract
Objectives The umbilical cord (UC) plays an essential role in the exchange between the mother and the foetus, allowing the latter to receive oxygen and nutrients necessary for survival and development. The UC intervascular stroma consists of mucous connective tissue, also called Wharton's jelly (WJ). It develops from extraembryonic mesoderm, binds and encases the umbilical vessels, protecting them from twisting and compression during pregnancy. WJ also has angiogenic and metabolic roles for the umbilical circulation. Some authors demonstrated that in human, an alteration of its composition could be related to fetal pathologic condition (Ferguson et al 2009). The aims of the study were to macroscopically describe the equine UC, and, for the first time in the horse, to evaluate the weight and the microscopic composition of WJ. Materials and Methods Twenty-four mares with normal pregnancy and parturition have been enrolled. The following data were registered for each mare: age, parity, length of pregnancy, total length of UC, length of UC amniotic and allantoic portion, total number of UC coils and their number in each segment, sex and weight of the foal at birth. There was no control of mare breeding. The Kolmogorov-Smirnov test was used to evaluate the distribution of continuous variables; the presence of differences in the UC macroscopic structure between gender was evaluated by T Student, considering significant a P value <0.05. Pearson’s correlation test was used to assess the presence of correlations between the data registered. Immediately after breaking the UC, the part closest to the foal (~15 cm), characterized by an abundant amount of WJ, was severed and transported to the lab, where WJ was separated from vessels, weighted, and fixed in 4% paraformaldehyde for microscopic examinations. Fixed tissue sections were labelled with antibodies anti-type I, IV and V collagen, and anti-fibrillin. Furthermore fibroblast cells were highlighted using Masson's trichrome staining. To verify the presence of elastic, reticular and nervous fibers, orcein staining and silver impregnation were used. Results and Discussion The mean total length of UC was 58.3 ±17 cm; the mean length of amniotic portion was 33.2 ±10.6 cm, while the allantoic segment was 27.0 ±10.5 cm. These data confirmed those previously reported (Whitwell et al., 1975). The total UC length and the allantoic portion length resulted statistically higher in males (n=10) than in females (n=14; P<0.05). As in humans, this could be due to the higher weight at birth in males (Naeye, 1985). The mean total number of UC coils was 5.1 ±2.8, with 2.7 ±0.9 coils in the amniotic portion and 3.0 ±1.8 coils in the allantoic portion, respectively. Our study revealed that total number of coils (R=0.43, P<0.05) and coils number of the allantoic portion (R=0.67, P<0.05) were positively related with parity. A positive correlation was also observed between the length of the allantoic portion and its coils (R=0.58, P<0.05). Coils formation is the result of rotations given by the foetus. Since in the horse from the eighth month of gestation foetal movements occur only along the longitudinal axis, the number of coils observed is lower than that reported in human. This could also be related to the mean UCI value registered in the present study (0.10 ±0.04), lower than that reported in babies (van Dick et al., 2002). Different from humans, we did not observe any correlation between UCI and age of the mare, length of pregnancy, sex and weight of the foal, but UCI was positively related with the total number of coils (R=0.448, P<0.05) and with their number in the amniotic portion (R=0.699, P<0.05). On the contrary, the UCI resulted negatively related to the total UC length (R=-0.526, P<0.05) and to the amniotic portion UC length (R=-0.499, P<0.05). From each UC sample, 4.5 ±3.45 g of WJ were isolated. As in humans (Takeki, 1993), the immunohistochemical analysis revealed the presence of fibroblast cells positive for antibodies anti-type II, IV and V collagen, anti-fibrillin, surrounded by a dense network of reticular fibers. Given their abundance, we could not confirm the presence of nervous fibers. Different from humans, in the horse UC, elastic fibers are less concentrated, with an uneven pattern around the vessels. Conclusion In this study we highlighted similarities and differences between equine and human macroscopic and microscopic characteristics of the umbilical cord. Given the presence in human species of a strong correlation between these and specific pathological conditions of newborn and mother, further studies are needed, both on normal and high risk pregnancies, to verify the presence of these correlations also in the equine species.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
