Arterial Cord Research Articles

The impact of intrauterine infection on fetal brain damage assessed by S100B protein concentrations in umbilical cord arteries

Objective: To assess the impact of intrauterine infection on fetal brain damage by measuring S100B protein concentration in umbilical cord arteries. Methods: In the intrauterine infection cases determined by pathology of 25 deliveries (Group I) and non-infection cases of 35 deliveries as control (Group C), we compared gestational age at delivery, birth weight, fetal heart rate monitoring during labor, Apgar score, umbilical cord artery pH and S100B protein concentrations in umbilical arteries measured by two-site immunoradiometric assay kit. Results: (1) There was no significant correlation between pH and concentration of S100B protein. (2) Gestational age at delivery was found to be earlier in Group I, resulting in lower birth weights, when compared with Group C. (3) There was no significant difference between two groups concerning Apgar scores, pH. (4) S100B protein concentrations in Group I was significantly higher than those of Group C (3.9 7 ± 0.66 versus 1.8 9 ± 0.56 μg/L, p < 0.05). (5) The concentration of S100B protein in severe chorioamnionitis (CAM) cases were significantly higher than those of mild CAM and control cases. Conclusion: Higher concentration of S100B protein in Group I suggests that intrauterine infection itself has a serious risk factor on fetal brain damage.

Clinical therapeutic effect of surgery on upper cervical spinal cord tumors.

To evaluate the long-term clinical therapeutic effect of polyaxial screw-rod system for posterior cervical arthrodesis on patients with upper cervical spinal cord tumors. From March 2007 to May 2013, 22 patients with upper cervical spinal cord tumors underwent tumor resection and posterior cervical arthrodesis in our institution. The medical records of these patients were reviewed respectively. There were 10 males and 12 females with ages ranging from 16 to 60 years old. Posterior cervical arthrodesis by polyaxial screw-rod was performed at the upper cervical spine (C1-3). All patients were followed-up clinically and radiographically. The average follow-up was 65.5 months. Twenty-two patients were enrolled and a total of 114 screws were placed in this study. Histopathology revealed neurinoma, meningioma, ganglioneuroma and ganglioglioma in 16, 3, 1 and 1 case (s), respectively. The mixed tumor with component of ganglioneuroma and neurinoma was observed in 1 case. All patients received tumor resection and posterior athrodesis by polyaxial screw-rod system. Cervical kyphosis was encountered in one patient and this patient suffered the recurrence of tumor. Solid fusion was achieved in all patients. The average postoperative Japanese Orthopaedic Association (JOA) score was 13.9 and the average recovery rate was 51.4%. Neurologic deterioration was found in 2 patients. No complications, such as spinal cord or vertebral artery injury, postoperative radiculopathy or instrumentation failure, were observed. The long-term clinical therapeutic effects of posterior cervical arthrodesis using polyaxial screw-rod system on upper cervical spinal cord tumors are satisfactory, with no severe complication.

Predicting Fetal Acidemia Using Umbilical Venous Cord Gas Parameters

OBJECTIVE:To assess the utility of umbilical cord venous blood gas measures for prediction of umbilical artery pH and base deficit acidemia.METHODS:A retrospective cohort study was conducted of all singletons with valid paired arterial and venous cord gas samples delivered at our institution from Ja

2,3,7,8-Tetrachlorodibenzo-p-dioxin differentially suppresses angiogenic responses in human placental vein and artery endothelial cells.

Placental angiogenesis is dramatically increased during pregnancy in association with the elevated placental blood flows to support the rapidly growing fetus. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxicant and a ligand of aryl hydrocarbon receptor (AhR). Herein, we investigated the effects of TCDD on proliferation, migration, and viability of fetoplacental endothelial cells in response to a complete growth medium which contained serum and growth supplement using human umbilical cord vein (HUVECs) and artery (HUAECs) cells as models. We found that TCDD dose- and time-dependently inhibited (p < 0.05) proliferation of HUVECs and HUAECs. Treatment with TCDD at 10 nM for 6 days inhibited (p < 0.05) migration (by ∼ 30%) of HUAECs, but not HUVECs. TCDD at 10nM also decreased (p < 0.05) viability of HUVECs and HUAECs. Interestingly, specific AhR siRNA blocked (p < 0.05) the TCDD-inhibited cellular responses in HUAECs, but not HUVECs. Nonetheless, TCDD at 10nM neither affected the cell cycle progression, nor did it induce cell apoptosis in HUVECs and HUAECs. In addition, TCDD at 10 nM also did not alter activation of ERK1/2 and AKT1 in HUVECs and HUAECs. Collectively, TCDD suppresses proliferation and/or migration (two key steps of angiogenesis) of HUVECs and HUAECs independent and dependent of AhR, respectively. These data suggest that TCDD inhibited growth of HUVECs and HUAECs via decreasing cell viability. Thus, TCDD may inhibit fetoplacental angiogenesis, leading to negative pregnancy outcomes.

Umbilical cord blood concentrations of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) in neonates developing hypoxic-ischemic encephalopathy

Objective: To compare ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) concentrations in umbilical cord blood of neonates who develop Sarnat stage II–III hypoxic-ischemic encephalopathy (HIE) to healthy controls, and to relate the concentrations to the severity of neurology and long-time outcomes.Material and methods: Cord sera of 15 neonates with HIE II–III and 31 matched controls were analyzed for UCH-L1 and GFAP. Comparisons were performed for cord artery pH, amplitude-integrated electroencephalography (aEEG), stage of HIE, and death or sequelae up to an age of 6 years. Parametric and non-parametric statistics were used with a two-sided p < 0.05 considered significant.Results: Among controls no associations between biomarker concentrations and gestational age, birthweight, length of storage of cord sera and degree of hemolysis were found. No significant differences in biomarker concentrations were found between HIE neonates and controls, and no differences were found with regard to HIE stage, cord acidemia, severity of aEEG changes, or persistent sequelae or death.Conclusions: No differences in cord blood UCH-L1 and GFAP concentrations were found between HIE neonates and controls, and no associations were found between the biomarker concentrations and the severity of disease, or whether the condition developed into a permanent or fatal injury.

Treatment of traumatic upper cervical instability with single posterior atlantoaxial pedicle screw system

Objective To investigate the clinical efficacy of atlantoaxial pedicle screw fixation plus bony fusion in treatment of traumatic upper cervical instability. Methods From October 2009 to August 2013, 29 patients with traumatic upper cervical spine instability were treated with posterior atlantoaxial pedicle screws. The patients underwent autografting (n=19) and allografting (n=10) for spinal fusion. Surgical outcomes were recorded including intraoperative blood loss, operation time, with or without nerve, blood vessel and spinal cord injury, wound healing and bone fusion rate. Results All operations were completed smoothly with operation time of 110 minutes (range, 85-135 minutes) and blood loss of 150 ml (range, 80-500 ml). At the follow-up of 10 months to 5 years (mean 18 months), bony fusion was detected for all the patients. Postoperative radiographs verified all patients were bony fusion with satisfactory cervical spine stability. No complications of reduction loss, fixation failure, and spinal cord or vertebral artery injury were observed except for 1 patient with low virulent infection and 2 with delayed wound healing. Conclusion Single posterior atlantoaxial pedicle screw fixation provides security and reliable stability in treatment of upper cervical instability, however wound healing problems should be taken seriously. Key words: Axis; Spinal injuries; Pedicle screws

The clinical classification and surgical treatment choice of irreducible atlantoaxial dislocation

Objective To investigate the clinical classification and surgical options for bone-fused irreducible atlantoaxial dislocation. Methods From November 2002 to December 2013, 20 cases of irreducible atlantoaxial dislocation were treated, including 8 males and 12 females, aged 22 to 57 years (mean 39 years). There were 6 cases without operation history and 14 cases with operation history, including 1 cases of anterior operation, 11 cases of posterior operation, and anterior and 2 cases of posterior combined approach. In 14 patients with surgery history, 13 cases had internal fixation residual, including 1 case of anterior plate and 12 cases of posterior screw rods. Under general anesthesia, the extensive fusion type was decompressed directly without restoration and immobilization, while the point fusion type was performed using soft tissue release, bone-fused point release, restoration, immobilization and fusion. 1 week, 3, 6, 12 months postoperatively and the annual review of the X-ray, CT and MR were checked, in order to evaluate the reduction, internal fixation, bone graft fusion and decompression of the spinal cord. The JOA scores of preoperative, postoperative and outpatient follow-up review were recorded. Results In all 20 patients, the extensive fusion type accounted for 5 cases, point fusion type 15 cases, while spontaneous fusion 6 cases, iatrogenic fusion 14 cases, including 3 cases of extensive fusion type and 11 cases of point fusion. In 5 cases of extensive fusion treated with anterior resection of anterior arch of atlas and the odontoid process decompression, postoperative MR showed that the spinal cord compression were completely eliminated, and reduction were achieved. The spinal cord and vertebral artery injury were not found. 1 case with cerebrospinal fluid leakage was cured after anterior internal fixation removal and posterior internal fixation. 5 cases of extensive fusion type and 14 cases of punctate fusion were followed up, ranged from 6 to 72 months (mean, 38 months). The JOA score was restored from preoperative average of 11 points to the last follow-up of 14 points. Even though no additional internal fixation was added, all 5 patients with extensive fusion showed no atlantoaxial intervertebral instability in follow-up period, and solid bony fusion of lateral atlantoaxial joint was obtained in 14 point fusion patients 6 months later. Conlusion The point fusion irreducible atlantoaxial dislocation can still get reduction after release and thoroughly removal of bony fusion point, while the extensive fusion irreducible atlantoaxialdislocation may still achieve good outcome by decompression. Key words: Atlanto-axial joint; Dislocations; Spinal fusion; Treatment outcome

The clinical effects of atlantoaxial pedicle screw combined with unilateral axial spinous process and lamina screws for atlantoaxial instability

Objective To investigate the clinical effects of the posterior atlantoaxial pedicle screw fixation combined with unilateral axial spinous process and lamina screws and allogeneic bone graft for atlantoaxial instability. Methods From March 2010 to April 2014, data of 10 patients with atlantoaxial instability who had undergone atlanto-axial vertebral pedicle fixation and interbody fusion combined with posterior atlanto-axial spines lamina nails were retrospectively analyzed. There were 6 males and 4 females with an average age of 39 (range, 16-62) years old. The inclusion criteria was atlantoaxial instability together with unilateral vertebral artery segment high cross deformity (7 patients) or atlantoaxial joint break bad involving unilateral pedicle (7 patients). 3 patients have spinal cord disease symptoms and physical signs, both suffered limited neck mobility and pain. The VAS scores were 1-8, with an average of 3.70±2.11. Preoperative X-ray, CT three-dimensional reconstruction and MRI were collected. X-ray and CT examination were performed 7 d and 1, 3, 6, 12 months after operation to evaluate the internal fixation and bone grafting fusion. Results There's no occurrence of cervical spinal cord and vertebral artery injury. Screws were successfully implanted. 1 case's incision occurred infiltration liquid 3 days after operation. For allograft rejection consideration, we changed the plan, and the infiltrating stopped 5 days later. Other incisions were all primary healing. VAS scores were 1.01±0.89 after operation, which was significantly reduced. X-ray showed good recovery of cervical sequence after the operation, and CT revealed 1 patient with atlas pedicle screw in the medial cortex damage. Spinal canal was without infringing, and the other screw positions were normal. 6 months after operation, X-ray or CT examination both showed bony fusion. Conclusion Atlantoaxial pedicle screw fixation combined with unilateral axial spinous process and lamina screws and allograft bone graft fusion for the treatment of atlantoaxial instability can observe good clinical effects. Key words: Cervical atlas; Axis; Joint instability; Internal fixators

Prospect of Using Decellularized Human Placenta and Cow Placentome for Creation of New Organs: Targeting the Liver (Part I: Anatomic Study)

IntroductionThis paper presents anatomic studies of decellularized human placenta and cow placentome and proves that there is a possibility to create a scaffold using the natural microvascular structure for growing organs and tissues. Materials and MethodsThe anatomic studies were conducted on 20 full-term placentas from human donors, and placentomes collected from 8 cows. Before the anatomic studies of human placenta and cow placentome, decellularization was conducted. For visualization of vessels, 50% Latex in water (Nairit L3) through the umbilical cord artery and vein was injected. Corrosion casts were also prepared. ResultsAn important feature in the transplantation of microfragments of the liver tissue is the blood supply system of the piled chorion, which consists of the main vascular trunks, and perivascular and superficial capillary network. Conditionally, based on the degree of difficulty, there are several types of grouping of the capillaries in terminal pile: simple capillary knot, coiled capillary knot, and complexly organized tangle-shaped capillary network with the richly anastomosing crimped microvessels. A similar pattern was observed in the terminal pile of the placentomes of the cow. For the creation of the auxiliary liver and connection of it into the systemic circulation of the recipient, we can use this exclusiveness of the angioarchitechtonics. ConclusionsAnatomic studies demonstrated that decellularized human placenta, as well as cow placentome, can be used as a scaffold for growth of organs and tissues in vitro and in vivo.

Lactate in cord blood and its relation to fetal gluconeogenesis in at term deliveries

BackgroundIn the human fetus, an increased lactate and glucose level can be anticipated when hypoxia and stress are present and is likely to be a function of both anaerobic metabolism and catecholamine-mediated glycogenolysis/glycolysis. AimWe assessed if measurement of lactate in cord artery blood after vaginal and cesarean delivery may predict glucose concentration. Study designUmbilical artery cord blood lactacidemia, acidemia, and glucose concentration was tested by ‘mini-lab’ Radiometer ABL90 FLEX analyzers (Radiometer®, Copenhagen, Denmark) after vaginal delivery (VD), spontaneous (n=493) and by vacuum extractor (n=41) or by cesarean delivery (CD), elective (n=120) and emergency (n=68) in at term, vigorous neonates delivered from March to December 2012 at the 2nd level maternity ward of Policlinico Abano Terme, Abano Terme (Italy). ResultsCord blood lactacidemia and glucose levels were significantly higher in VD by vacuum extractor than in all other groups (5.32±1.96mmol/L, p=0.050 and 103.6±30.5mg/dL, p<0.001, respectively) and significantly lower in elective CD group (1.77±0.99mmol/L, p<0.001 and 69.8±13.0mg/dL, p<0.001). The cord blood lactate concentration was significantly and positively correlated with glucose levels (r=0.434, p<0.001), but significantly and negatively correlated with pH (r=−0,662, p<0.001), NaHCO3− (r=−0,802, p<0.001), and base excess (BE) (r=−0,698, p<0.001). However, in multivariate linear regression analysis, only BE, PaCO2 and cord blood lactate were significant predictive variables (R2=0.410; p<0.001) of glucose levels at birth. ConclusionCord blood artery lactate and glucose concentration are significantly and positively correlated at birth in healthy, at term vaginally and cesarean delivered neonates, but BE is the best indicator of activated fetal gluconeogenesis.

An anatomic study to determine the optimal entry point, medial angles, and effective length for safe fixation using posterior C1 lateral mass screws.

Anatomic study of the C1 lateral mass using fine-cut computed tomographic scans and Mimics software. To investigate the optimal entry point, medial angles, and effective length for safe fixation using posterior C1 lateral mass screws. Placing posterior C1 lateral mass screws is technically demanding, and a misplaced screw can result in injury to the vertebral artery, spinal cord, or internal carotid artery. Although various insertion angles have been proposed for posterior C1 lateral mass screw, no clear consensus has been reached on the ideal medial angle of the C1 lateral mass. The C1 lateral masses were evaluated using computed tomographic scans and Mimics software in 70 patients. The effective width and effective screw length of posterior C1 lateral mass screws were measured at different medial angulations relative to the midline sagittal plane. The height (H) for screw entry point on the posterior surface of C1 lateral mass and the distance (D) between screw entry point and the intersection of the midline sagittal plane and the posterior arch of the atlas were also measured. The mean height (H) for screw entry on the posterior surface of the lateral mass was 4.25 mm, the mean distance (D) between screw entry point and the intersection of the midsagittal plane and the posterior arch of the atlas was 27.62 mm. The optimal medial angle was 20.86° with a corresponding effective width of 10.56 mm and effective screw length of 21.87 mm. This study helps to define the specific anatomy related to C1 posterior lateral mass screw placement in an effort to facilitate instrumentation. However, variation is seen in lateral mass anatomy, and this study must be combined with customized surgical planning that includes advanced imaging for safe and effective instrumentation. 1.

65-OR

Objectives To investigate total bile acid (TBA) levels in maternal and umbilical cord blood in normotensive and preeclamptic pregnancies in the context of ABCG2 placental gene expression levels, a recently reported placental bile acid transporter. Methods TBA levels were determined in 83 paired maternal blood (MB) and umbilical cord blood (UCB) samples of normotensive and preeclamptic pregnancies and in 22 paired arterial and venous umbilical cord blood samples from uncomplicated term pregnancies. ABCG2 gene expression was measured in 104 human placentas by reverse transcriptase quantitative polymerase chain reaction. Results Both in normotensive and in preeclamptic pregnancies, TBA levels in the maternal compartment are higher than in the fetal compartment. This effect is more pronounced in preeclamptic pregnancies ( p = 0.007 and p p = 0.016). TBA levels in arterial and venous UCB from 22 normotensive pregnancies are not statistically different. ABCG2 expression is reduced in pregnancies where preeclampsia is further complicated by Hemolysis Elevated Liver Enzymes and Low Platelets syndrome ( p = 0.033). ABCG2 expression in human placenta is not correlated with maternal or umbilical cord TBA levels. Conclusions Increased maternal TBA levels in preeclamptic pregnancies indicate a relation between bile acids in the maternal circulation and preeclampsia. The fact that TBA levels in the fetal compartment do not differ between normotensive and preeclamptic pregnancies combined with the fact that arterial and venous umbilical cord blood TBA levels are comparable suggests that the placenta functions as a bile acid barrier. Disclosures J.M. Jebbink: None. G.J. Veenboer: None. S. Boussata: None. A.E. Kremer: None. R.P. Oude-Elferink: None. J.A. van der Post: None. G.B. Afink: None. C. Ris-Stalpers: None.

A new approach to oxidative stress and inflammatory signaling during labour in healthy mothers and neonates.

The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates. 56 mothers with normal gestational course and spontaneous delivery were selected. Blood samples were taken from mother (before and after delivery) both from vein and artery of umbilical cord. Lower antioxidant enzymes activities were observed in neonates compared with their mothers and lower oxidative stress in umbilical cord artery with respect to vein. There was an overexpression of inflammatory cytokines in the mother, such as IL-6 and TNF-α, and, in addition, PGE2 was also increased. Neonates showed lower levels of IL-6 and TNF-α and higher values of sTNF-RII and PGE2 in comparison with their mothers. Parturition increases oxidative damage in the mother, although the indicators of oxidative damage were lower in umbilical cord artery with respect to umbilical vein. The overexpression of inflammatory cytokines reveals that fetus suffers its own inflammatory process during parturition.

Evaluation of erythromycin concentration in the umbilical artery serum

The aim of the study was to investigate the effectiveness of erythromycin in preventing intrauterine infection caused by group B streptococcus (GBS). The study included 20 pregnant women with GBS-positive screening or whose laboratory screening was not available, who delivered between April 17, 2013 and July 22, 2013. The women were given 600 mg of erythromycin intravenously After delivery blood was drawn in parallel from maternal antecubital vein and umbilical cord artery Serum erythromycin concentrations were evaluated using enzyme-linked immunosorbent assay (ELISA) kit. Statistical analysis for measurable and non-measurable characteristics were performed, correlation coefficients for each pair of variables were calculated in order to investigate the sought dependence. Mean placental transfer of erythromycin was 2.04%. There was a high correlation between umbilical artery serum and maternal serum erythromycin concentration. Selected variables of mothers in the control group had no effect on serum erythromycin concentration in the umbilical artery Transplacental transfer of erythromycin is limited (2.04%). Intravenous application of erythromycin at a dose of 600 mg does not allow to achieve the value of MIC50 and MIC90 for erythromycin against strains S. agalactiae in umbilical artery serum, what suggests a compromised efficacy in the treatment of intrauterine fetal infections. At the same time, the placenta seems to be an effective barrier reducing fetal exposure when this macrolide is used to treat maternal infections.

Marker profile for the evaluation of human umbilical artery smooth muscle cell quality obtained by different isolation and culture methods.

Even though umbilical cord arteries are a common source of vascular smooth muscle cells, the lack of reliable marker profiles have not facilitated the isolation of human umbilical artery smooth muscle cells (HUASMC). For accurate characterization of HUASMC and cells in their environment, the expression of smooth muscle and mesenchymal markers was analyzed in umbilical cord tissue sections. The resulting marker profile was then used to evaluate the quality of HUASMC isolation and culture methods. HUASMC and perivascular-Wharton's jelly stromal cells (pv-WJSC) showed positive staining for α-smooth muscle actin (α-SMA), smooth muscle myosin heavy chain (SM-MHC), desmin, vimentin and CD90. Anti-CD10 stained only pv-WJSC. Consequently, HUASMC could be characterized as α-SMA+, SM-MHC+, CD10- cells, which are additionally negative for endothelial markers (CD31 and CD34). Enzymatic isolation provided primary HUASMC batches with 90-99% purity, yet, under standard culture conditions, contaminant CD10+cells rapidly constituted more than 80% of the total cell population. Contamination was mainly due to the poor adhesion of HUASMC to cell culture plates, regardless of the different protein coatings (fibronectin, collagen I or gelatin). HUASMC showed strong attachment and long-term viability only in 3D matrices. The explant isolation method achieved cultures with only 13-40% purity with considerable contamination by CD10+cells. CD10+cells showed spindle-like morphology and up-regulated expression of α-SMA and SM-MHC upon culture in smooth muscle differentiation medium. Considering the high contamination risk of HUASMC cultures by CD10+neighboring cells and their phenotypic similarities, precise characterization is mandatory to avoid misleading results.

58: Brain injury in term-born infants: does acidemia select those at risk?

Cerebral magnetic resonance imaging (MRI) is a power tool, used in infants born preterm and those with hypoxic-ischemic encephalopathy (HIE) to identify risk for long-term neurologic morbidity. The tool remains unused in the well, term-born population, despite the fact that they represent the majority of morbidity. To use MRI in this population, we require clinical measures to select infants for imaging. We aimed to estimate the risk of MRI-identified brain injury, stratified by arterial cord pH.

Muscarinic-mediated vasoconstriction in human, rat and sheep umbilical cords and related vasoconstriction mechanisms.

The umbilical cord provides nutrition and oxygen to the fetus. The aim of this study was to determine the effects of acetylcholine (ACh) on umbilical cords from humans and other mammals, and the mechanisms of ACh-mediated vasoconstriction in the human umbilical cord. Human and animal umbilical cords used in vascular and cellular experiments. Institute for Fetology, First Hospital of Soochow University, Suzhou, China. A total of 85 pregnant women, 16 Sprague Dawley rats and seven pregnant sheep. Umbilical cord veins and arteries from humans, rats and sheep, aortas and mesenteric arteries from rats, and mesenteric, carotid and femoral arteries from ovine fetuses were used to compare vascular functions in response to ACh and to determine the mechanisms of ACh-mediated umbilical vasoconstriction. Vascular tension and ion channel currents were measured on isolated vessels and smooth muscle cells from human umbilical cords. Provision of new evidence to conclude that ACh-stimulated vasoconstriction is common to all umbilical cords, and cellular mechanisms are linked to potassium channels. ACh caused reliable vasoconstriction in umbilical veins/arteries in humans, rats and sheep, but not in any other vessels, including fetal vessels. Atropine inhibited the effects of ACh. The mRNA of ACh-muscarinic receptor subtypes M1 -M5 was expressed in human umbilical vessels. The protein kinase C antagonist GF109203X and the calcium inhibitor nifedipine decreased ACh-induced vasoconstriction in human umbilical vessels. ACh also caused a reduction in whole-cell potassium channel currents and the single-channel current of large-conductance calcium-activated potassium (BKca) channels. Umbilical vessels are significantly different from other vessels in their response to ACh. BKca channels in smooth muscle cells may play important roles in ACh-mediated vasoconstriction in human umbilical cords. This information may be important for fetal medicine and practice with regard to the effect on fetal development of umbilical vascular functions.

Is acetylcholine constriction of umbilical vessels clinically relevant?

Umbilical cord vessels lack innervation, yet they constrict immediately following delivery. This is obviously an important response and is observed across many mammalian species. The precise mechanism of the vasoconstriction is unknown, but temperature changes, changes in oxygen tension and mechanical traction on the cord are generally accepted stimuli which elicit this vasoconstriction response. It is also widely believed that the regulation of vascular smooth muscle tension is mediated via vasoactive substances within the circulation or through local production of these substances within the vessel wall. Acetylcholine, a vasodilator, has been shown to induce endothelium-dependent vascular smooth muscle relaxation in different species and in different vascular beds (Furchgott and Zawadski, Nature 1980;288:373–6). In contrast, other investigators have shown that acetylcholine induces vasoconstriction of human umbilical cord arteries and veins (Altura et al. Am J Physiol 1972;222:345–55). Although other autacoids induced more potent constriction than acetylcholine in most vascular beds, the finding that acetylcholine exerted a vasoconstrictive effect on umbilical cord vessels raises the question of whether such a vasoactive effect may have clinical implications. In a series of elegant experiments, the present authors investigated the potential mechanisms through which this effect may be mediated. They confirmed the contrasting vasodilatory and constrictive properties of acetylcholine in human, sheep and rat umbilical cord preparations, and, more importantly, they unravelled some of the physiological mechanisms involved, including a role for potassium and calcium currents, and muscarinic receptor subtypes. Their findings are preliminary and yet to be corroborated by others; however, they raise the question of whether acetylcholine-induced vasoconstriction of umbilical cord vessels may be conserved across mammalian species. Although the investigators also examined umbilical cord vessels from pregnancies complicated by diabetes and hypertension, they provided no data nor speculated on any differences in cord vessel responses between these complicated pregnancies and their normal counterparts. Their elaboration of the mechanisms involved in acetylcholine-induced vasoconstriction also highlights another layer of complexity. For example, acetylcholine induced further vasoconstriction in preparations which were pre-constricted with potassium chloride, serotonin or prostaglandin E2. In spite of this, the situation is likely to be different in vivo. The umbilical cord vessels are believed to be almost maximally dilated in vivo and it is unknown to what extent acetylcholine maintains smooth muscle tone in the umbilical cord vessels. Therefore, these results should be interpreted with caution. A major part of the vascular resistance in the feto-placental circulation is presumed to be located in the resistance vessels of the placental villi. Acetylcholine induced a relaxant response in vascular preparations from human stem villi arteries in vitro (Sabry et al. Fundam Clin Pharmacol 1995;9:46–51), but did not induce changes in the perfusion pressure of isolated and perfused human placental cotyledons (Amarnani et al. Am J Physiol 1999;277:H842–7). Furthermore, in vitro preparations of human umbilical cord vessels used in experiments on autacoid responsiveness are unavoidably sampled after birth when the preparations are already constricted. These preparations are therefore not necessarily representative of the in vivo situation. In summary, the current study provides valuable data on the physiology and regulation of umbilico-placental blood flow; however, the jury is still out on the clinical importance of acetylcholine in human umbilical cord circulation. The author has no conflicts of interest.

Automated auditory brainstem response in preterm newborns with histological chorioamnionitis

Objective: We investigated whether histological chorioamnionitis is associated with an adverse neonatal hearing outcome.Methods: Two cohorts of very preterm newborns (n = 548, gestational age ≤ 32.0 weeks) were linked to placental histology and automated auditory brainstem response (AABR) outcome.Results: In multivariable analyses, an abnormal AABR was not predicted by the presence of histological chorioamnionitis, either with or without fetal involvement (OR 1.4, 95% CI 0.5 – 3.8, p = 0.54 and OR 1.1, 95% CI 0.4–3.0, p = 0.79, respectively). Significant predictors of abnormal AABR included, e.g. birth weight (per kg increase: OR 0.2, 95% CI 0.0–0.6, p = 0.006), umbilical cord artery pH (per 0.1 increase: OR 0.7, 95% CI 0.5–0.9, p = 0.005) and mechanical ventilation (OR 3.7, 95% CI 1.2–11.6, p = 0.03).Conclusions: Histological chorioamnionitis was not associated with an adverse neonatal hearing outcome in two cohorts of very preterm newborns. Indicators of a complicated neonatal clinical course were the most important predictors of an abnormal hearing screening.

Evaluation of Decellularization in Umbilical Cord Artery

Major achievements in creating decellularized whole tissue scaffolds have drawn considerable attention to decellularization as a promising approach for tissue engineering. Developing a tissue-engineered small-diameter (≤2 mm) vascular graft, using decellularized human umbilical arteries (hUAs), for reconstructive surgery is a challenging task. Polymers used in the past, proved unsuitable due to serious adverse effects and autologous vessels are available only in 40% of patients. In this study, histological and proteomic analysis was performed to evaluate the efficiency of two decellularization protocols. In decellularization protocol A, hUAs were incubated in 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) followed by incubation in alpha minimal essential medium (α-MEM) with foetal bovine serum (FBS) while in decellularization protocol B the hUAs were incubated in Hypotonic Tris and SDS followed by incubation in nuclease solution. Histological analysis of decelullarised hUA with both protocols revealed good preservation of extracellular cell matrix (ECM) proteins and immunofluorescent staining detected collagen I and fibronectin. The DNA content within the hUAs after decellularization with protocol A was 6.2% and with protocol B 17.3%. Proteomic analysis identified cytoplasmic enzymes such as, dehydrogenase X, α-enolase and peptidyl-prolyl cis-trans isomerase A only in native samples, while, cytoskeletal proteins such as a-actin, filamin and ECM proteins like collagens were found both in native and decellularised hUA. In conclusion, both decellularization protocols effectively removed the cellular material while the ECM remained intact. Future studies are warranted to elucidate the specific effects of altered structure–function relationships on the overall fate of decellularized hUAs.