Cortical plasticity after hand prostheses use: Is the hypothesis of deafferented cortex "invasion" always true?

OBJECTIVE

To study motor cortex plasticity after a period of training with a new prototype of bidirectional hand prosthesis in three left trans-radial amputees, correlating these changes with the modification of Phantom Limb Pain (PLP) in the same period.

METHODS

Each subject underwent a brain motor mapping with Transcranial Magnetic Stimulation (TMS) and PLP evaluation with questionnaires during a six-month training with a prototype of bidirectional hand prosthesis.

RESULTS

The baseline motor maps showed in all three amputees a smaller area of muscles representation of the amputated side compared to the intact limb. After training, there was a partial reversal of the baseline asymmetry. The two subjects affected by PLP experienced a statistically significant reduction of pain.

CONCLUSIONS

Two apparently opposite findings, the invasion of the "deafferented" cortex by neighbouring areas and the "persistence" of neural structures after amputation, could vary according to different target used for measurement. Our results do not support a correlation between PLP and motor cortical changes.

SIGNIFICANCE

The selection of the target and of the task is essential for studies investigating motor brain plasticity. This study boosts against a direct and unique role of motor cortical changes on PLP genesis.

Characterization of multi-channel intraneural stimulation in transradial amputees

Although peripheral nerve stimulation using intraneural electrodes has been shown to be an effective and reliable solution to restore sensory feedback after hand loss, there have been no reports on the characterization of multi-channel stimulation. A deeper understanding of how the simultaneous stimulation of multiple electrode channels affects the evoked sensations should help in improving the definition of encoding strategies for bidirectional prostheses. We characterized the sensations evoked by simultaneous stimulation of median and ulnar nerves (multi-channel configuration) in four transradial amputees who had been implanted with four TIMEs (Transverse Intrafascicular Multichannel Electrodes). The results were compared with the characterization of single-channel stimulation. The sensations were characterized in terms of location, extent, type, and intensity. Combining two or more single-channel configurations caused a linear combination of the sensation locations and types perceived with such single-channel stimulations. Interestingly, this was also true when two active sites from the same nerve were stimulated. When stimulating in multi-channel configuration, the charge needed from each electrode channel to evoke a sensation was significantly lower than the one needed in single-channel configuration (sensory facilitation). This result was also supported by electroencephalography (EEG) recordings during nerve stimulation. Somatosensory potentials evoked by multi-channel stimulation confirmed that sensations in the amputated hand were perceived by the subjects and that a perceptual sensory facilitation occurred. Our results should help the future development of more efficient bidirectional prostheses by providing guidelines for the development of more complex stimulation approaches to effectively restore multiple sensations at the same time.

Alpha Lipoic Acid (ALA) effects on subchorionic hematoma: preliminary clinical results

OBJECTIVE

The clinic use of alpha Lipoic Acid (ALA) is linked to its capability to exert antioxidant effects and, more interestingly, to counteract the pathologic changes of complex networks of cytokines, chemokines and growth factors, restoring their physiological state. The aim of this randomized controlled clinical trial was to test the contribution of oral supplementation of ALA to the standard treatment with Progesterone vaginal suppositories, in healing subchorionic hematomas in patients with threatened miscarriage. Controls were administered only Progesterone suppositories.

PATIENTS AND METHODS

Nineteen pregnant women in the first trimester of gestation, with threatened miscarriage and ultrasound evidence of subchorionic hematoma, were included in the trial and randomly divided in two groups: controls, treated with 400 mg Progesterone (200 mg 2 times per day), given by vaginal suppositories, and case study treated with the same Progesterone dosage, plus ALA, given orally at the dose of 600 mg (300 mg 2 times per day, DAV®, Lo.Li. Pharma srl, Italy). Sixteen patients completed the trial. Treatment was performed until complete resolution of the clinical picture.

RESULTS

In both groups, the subjects improved significantly but, in general, a better and faster evolution in the major signs of threatened miscarriage was observed in the subjects treated with ALA and Progesterone. In these patients, the speed of resorption of subchorionic hematoma was significantly (p ≤ 0.05) superior compared to controls. The ALA and Progesterone group showed a faster decrease or disappearance of all symptoms than that observed in the control group, however the difference was not significant.

CONCLUSIONS

These preliminary results suggest that ALA supplementation significantly contributes to speed up the process of restoration of physiological conditions in threatened miscarriage and ameliorates the medical conditions of both the mothers and the foetus, probably modulating the networks of cytokines, growth factors and other molecules.

Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: Basic principles and procedures for routine clinical and research application. An updated report from an I.F.C.N. Committee

These guidelines provide an up-date of previous IFCN report on “Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application” (Rossini et al., 1994). A new Committee, composed of international experts, some of whom were in the panel of the 1994 “Report”, was selected to produce a current state-of-the-art review of non-invasive stimulation both for clinical application and research in neuroscience.

Since 1994, the international scientific community has seen a rapid increase in non-invasive brain stimulation in studying cognition, brain–behavior relationship and pathophysiology of various neurologic and psychiatric disorders. New paradigms of stimulation and new techniques have been developed. Furthermore, a large number of studies and clinical trials have demonstrated potential therapeutic applications of non-invasive brain stimulation, especially for TMS. Recent guidelines can be found in the literature covering specific aspects of non-invasive brain stimulation, such as safety (Rossi et al., 2009), methodology (Groppa et al., 2012) and therapeutic applications (Lefaucheur et al., 2014).

This up-dated review covers theoretical, physiological and practical aspects of non-invasive stimulation of brain, spinal cord, nerve roots and peripheral nerves in the light of more updated knowledge, and include some recent extensions and developments.

Neurotrophic keratitis

Neurotrophic keratitis (NK) is a rare degenerative corneal disease that occurs as a result of partial or total impairment of trigeminal innervations, leading to a reduction (hypoesthesia) in or loss (anaesthesia) of corneal sensitivity. The impairment of sensory innervation causes a reduction in the lacrimation reflex and the vitality, metabolism and mitosis of epithelial cells, with subsequent deficiency in epithelial repair, stromal and intracellular oedema, loss of microvilli, and abnormal development of the basal lamina. Several recent studies have proposed different therapies based on different aetiopathogenetic theories. The aim of the therapy is to treat aetiopathogenesis and, at the same time, promote corneal healing. In this paper, we report the aetiology, diagnosis, management, and medical and surgical treatment of NK, also indicating future treatments based on the most recent studies.

Behaviour of lab parameters and neonatal weight loss in relation to neonatal breathing movements and cord clamping time

BACKGROUND

To date, delaying cord clamping two to three minutes after birth is considered effective for newborn well-being. This time does not consider the newborn's breathing movements, which may also condition neonate well-being.

AIM

To investigate the behaviour of neonatal weight loss and of some umbilical vein lab parameters, in relation to timing of newborn breathing and cord clamping.

MATERIALS AND METHODS

Time from birth to cord clamping and time from birth to first cry of the newborn were collected in 87 full-term healthy women. First cry is a sign of effective breathing. Birth weight loss at the first, second, and third day from birth and lab parameters were assessed in relation to: time from birth to cord clamping, time from birth to first cry, and cord clamping before or after the first cry.

RESULTS

Partial pressure of carbon dioxide (pCO2) decreased if cord clamping was performed after first cry and increased if first cry occurred after cord clamping, independently from the time elapsed from birth to first cry (p = 0.012). Calcium (Ca(2+)) concentration decreased if cord clamping was performed after the first cry and increased if first cry of the baby after birth was delayed (p = 0.021). Each second of delay from birth to cord clamping resulted in an increase in Cl- concentration (p <0.001). Each second of delay in cord clamping resulted in a reduction in the percentage of weight loss at the first day (p = 0.024), at the second day (p = 0.007), and at the third day (p = 0.028) after birth.

CONCLUSIONS

Neonate breathing after birth should induce umbilical vein flow from placenta to lungs, conditioning the reduction of birth weight loss after birth and umbilical lab parameters modifications.

The pathogenesis of endometrial polyps: a systematic semi-quantitative review

The pathogenesis and natural history of endometrial polyps are not very clear. The objective of this study was to assess the opinions of international medical literature regarding the factors involved in the pathogenesis of endometrial polyps and to organize the results consistently with what is known about endometrial physiology.

MATERIALS AND METHODS

A systematic review was carried out with the following search engines: PubMed, OVID, Scopus, SCIELO, and AJOL. Two hundreds forty-six abstracts were selected from the literature; of these abstracts, 58 factors were extracted and set as causative, non-causative, unclear or protective link with endometrial polyps. This relation is described through a correspondence analysis and tested with a main effect hierarchical log-linear model.

RESULTS

The log-linear model resulted significant for the correspondence found with the following factors: (i) causative link (ageing, bcl-2 protein, excess weight/obesity, tamoxifen regardless of timing, relationship between estrogen receptors and prog-estinics, unbalanced estrogen therapy, estrogen-like effect, and unbalance between estrogens and progestinics), (ii) protective link (progestinics, antiestrogenic action), (iii) unclear link (menopause, ki-67 protein, angiogenesis, tamoxifen for a short time, tamoxifen for a long time, hormone replacement therapy (HRT), endometritis/inflammation), and (iv) non-causative link (none of the factors specifically).

DISCUSSION

Subsequently to a review of the physiology of the endometrium, the onsetting of endometrial polyps was suggested through estrogen-related and non-estrogen related ways; the two ways can overlap. The most implied factors in the development of endometrial polyps are linked with one of these or both ways.

Synaptic plasticity in neurodegenerative diseases evaluated and modulated by in vivo neurophysiological techniques

Several studies demonstrated in experimental models and in humans synaptic plasticity impairment in some neurodegenerative and neuropsychiatric diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and schizophrenia. Recently new neurophysiological tools, such as repetitive transcranial magnetic stimulation and transcranial direct current stimulation, have been introduced in experimental and clinical settings for studying physiology of the brain and modulating cortical activity. These techniques use noninvasive transcranial electrical or magnetic stimulation to modulate neurons activity in the human brain. Cortical stimulation might enhance or inhibit the activity of cortico-subcortical networks, depending on stimulus frequency and intensity, current polarity, and other stimulation parameters such as the configuration of the induced electric field and stimulation protocols. On this basis, in the last two decades, these techniques have rapidly become valuable tools to investigate physiology of the human brain and have been applied to treat drug-resistant neurological and psychiatric diseases. Here we describe these techniques and discuss the mechanisms that may explain these effects.

Effect of epidural analgesia on labor times and mode of delivery: a prospective study

PURPOSE

To assess changes in labor times and delivery outcome in low-risk women requesting pain relief and undergoing epidural analgesia, according to the epidural analgesia schemes.

MATERIALS AND METHODS

Prospective observational study of 499 low-risk women with epidural analgesia. Speed of dilatation (SD) (centimeters of dilatation / hours), speed of lowering of the fetal head through maternal pelvis (SL) (centimeters in lowering / hours), time of active phase of labor (TA), cesarean section (CS), vacuum application (VA) were dependent variables in multivariable linear and logistic regressions.

RESULTS

Dilution of ropivacain, fentanyl amount, and volume of the first dose of epidural analgesia did not seem to affect labor times. Epidural analgesia with schemes used in this study favored both the dilatation and the fetal head lowering through maternal pelvis. Every five minutes from the first dose of epidural to the last top-up, SD decreased by about 13% (p=0.002), SL decreased by about 14% (p<0.001), and TA increased by about 40% (p<0.001). Additionally, every five minutes from the first dose of epidural to the last top-up, the odds of an operative vaginal birth (vacuum) increased by 0.7% (p<0.001). Increasing of number of top-ups independently caused a reduction in odds of undergoing CS (odds ratio 0.434; C.I. 95% 0.219-0.859, p=0.017), without influencing labor times.

CONCLUSION

Epidural analgesia in patients requesting pain relief favors normal course of labor if it is not discontinued or delayed.

Pain and breastfeeding: a prospective observational study

OBJECTIVE

To demonstrate that pain affects the goodness of breastfeeding.

MATERIALS AND METHODS

Seventy-nine patients were interviewed regarding satisfaction in breastfeeding, tiredness, uterine pain, nipple and other pain, and analgesic use at day three and at first, second, third, and fourth week after birth. Data regarding the mode of delivery were recorded from medical charts. Milk formula supplements, bottle use, pacifier use, and nipple shields use were considered as variables suggesting unsuccessful breastfeeding.

RESULTS

At third day after delivery, it appeared that analgesic use was significantly associated with milk formula supplementing, bottle use, less satisfaction in breastfeeding, and more tiredness. At first week after delivery, the presence of pain differing from nipple and uterine pain, was more likely associated with milk formula supplementing, bottle use, pacifier use, less satisfaction in breastfeeding, and more tiredness. At third week after delivery, nipple pain was directly related to tiredness, while it increased the odds of adding milk formula and using a bottle.

CONCLUSION

Pain affects the goodness of breastfeeding.

Could endometrial cytology be helpful in detecting endometrial malignancies?

This short communication assesses the concordance indexes between hysteroscopic biopsies and endometrial cytology for each endometrial pattern found in a sample of 37 women. Patients underwent endometrial cytology under sonographic guidance. The specimens were obtained with an endocervical brush and were fixed on slides (no liquid-based methods). After endometrial cytology, hysteroscopy with biopsy was performed. The best concordance index was found for endometrial malignancies, suggesting that endometrial cytology is able to detect cancers but not other endometrial diseases, as compared with endometrial hysteroscopic biopsies. Therefore, the overall concordance index suggests a fair concordance between histological and cytological findings. This leads us to conclude that usual endometrial cytology should not be recommended to screen endometrial diseases, but it may be used as an alternative diagnostic tool when hysteroscopic biopsies or other blinded procedures for endometrial sampling are unwanted, because it allows malignancies to be detected as well as hysteroscopic-guided biopsies.

Modulation of motor cortex neuronal networks by rTMS: comparison of local and remote effects of six different protocols of stimulation

Repetitive transcranial magnetic stimulation (rTMS) of human motor cortex can produce long-lasting changes in the excitability of excitatory and inhibitory neuronal networks. The effects of rTMS depend critically on stimulus frequency. The aim of our present study was to compare the effects of different rTMS protocols. We compared the aftereffects of 6 different rTMS protocols [paired associative stimulation at interstimulus intervals of 25 (PAS25) and 10 ms (PAS10); theta burst stimulation delivered as continuous (cTBS) or intermittent delivery pattern (iTBS); 1- and 5-Hz rTMS] on the excitability of stimulated and contralateral motor cortex in 10 healthy subjects. A pronounced increase of cortical excitability, evaluated by measuring the amplitude of motor evoked potentials (MEPs), was produced by iTBS (+56%) and PAS25 (+45%). Five-hertz rTMS did not produce a significant increase of MEPs. A pronounced decrease of cortical excitability was produced by PAS10 (−31%), cTBS (−29%), and 1-Hz rTMS (−20%). Short-interval intracortical inhibition was suppressed by PAS10. Cortical silent period duration was increased by 1-Hz stimulation. No significant effect was observed in the contralateral hemisphere. Head-to-head comparison of the different protocols enabled us to identify the most effective paradigms for modulating the excitatory and inhibitory circuits activated by TMS.

Effect of epidural analgesia on operative vaginal birth rate

The aim of the study was to investigate if epidural analgesia may affect the operative vaginal birth rate. An observational study was carried out on 1,158 in low-risk patients who delivered vaginally; 46.9% of these patients underwent epidural analgesia using different doses and drugs. Overall, epidural analgesia enhanced the probability of vacuum delivery (OR 2.70 95% CI 1.88-3.89, p < 0.001). Vacuum application was increased about seven times by administration of fentanyl alone at the first dose, while it was reduced if ropivacaine was added to fentanyl. In patients undergoing epidural analgesia, increasing the amount of ropivacaine at the first dose reduced the probability of vacuum delivery (OR 0.82; 95% CI 0.67-1.00, p = 0.05). Moreover, increasing the number of top-ups reduced the probability of vacuum delivery (OR 0.49 95% CI 0.27-0.93, p = 0.029) and the time of the second stage of labor. On the other hand, increasing time from the first dose of epidural to the last top-up increased the risk of operative vaginal delivery (OR 1.33 95% CI 1.03-1.72, p = 0.031) and the time of the second stage of labor. Epidural analgesia seems to favor spontaneous delivery when it is properly carried on.

Repetitive transcranial magnetic stimulation for ALS

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease affecting upper and lower motor neurons characterized by progressive weakness, respiratory failure and death within 3-5 years. It has been proposed that glutamate-related excitotoxicity may promote motor neuron death in ALS. Glutamatergic circuits of the human motor cortex can be activated noninvasively using transcranial magnetic stimulation (TMS) of the brain, and repetitive TMS (rTMS) can produce changes in neurotransmission that outlast the period of stimulation. In recent years a remarkable number of papers about the potential effects of rTMS in several neurological disorders including ALS has been published. Preliminary studies have shown that rTMS of the motor cortex, at frequencies that decrease cortical excitability, causes a slight slowing in the progression rate of ALS, suggesting that these effects might be related to a diminution of glutamate-driven excitotoxicity. RTMS could also interfere with motor neuron death through different mechanisms: rTMS could modulate the production of brain-derived neurotrophic factor (BDNF), a potent survival factor for neurons, that in turn might represent a promoter of motor neuron sparing in ALS. Despite some promising preliminary data, recent studies have demonstrated a lack of significant long-term beneficial effects of rTMS on neurological deterioration in ALS. However, further studies are warranted to evaluate the potential efficacy of different protocols of motor cortex stimulation (in terms of technique, duration and frequency of stimulation), particularly during the early stages of the disease when the progression rate is more pronounced.

Enhanced human brain associative plasticity in Costello syndrome

Costello syndrome (CS) is a rare multiple congenital anomaly disorder which is caused by germline mutations in the v-Ha-ras Harvey rat sarcoma viral oncogene homologue (HRAS) proto-oncogene. Experimental data suggest perturbing effects of the mutated protein on the functional and structural organization of networks of cerebral cortex and on the activity-dependent strengthening of synaptic transmission known as long term potentiation (LTP). In five patients with molecularly proven diagnosis of CS and in a group of 13 age-matched control subjects we investigated activity-dependent synaptic plasticity. To this end, we used a paired associative stimulation (PAS) protocol, in which left ulnar nerve stimuli were followed by transcranial magnetic stimulation (TMS) pulses to right cortical hand area, and recorded motor evoked potentials (MEPs) by single pulse TMS from left first dorsal interosseus (FDI) muscle before and after PAS. In 4 out of 5 CS patients and in a subgroup of nine control subjects we also evaluated the time course and the topographical specificity of PAS after-effects. In these two subgroups, MEPs were measured before, immediately after and 30 min after PAS in the left FDI and left abductor pollicis brevis (APB). While the PAS protocol led to a 65% increase of the FDI MEP amplitude in controls, the LTP-like phenomenon was significantly more pronounced in CS patients, with motor responses increased by 230%. In addition, CS patients showed a similar MEP increase in both muscles while control subjects showed a slight increase in APB and only immediately after PAS. We hypothesize that the extremely enhanced PAS after-effects could be due to the influence of HRAS activity on the susceptibility of synapses to undergo LTP.

Impact of the medicalization of labor on mode of delivery

AIMS

To evaluate whether routine medical interventions during labor (oxytocin augmentation, induction, amniotomy, epidural analgesia) condition the outcome of delivery independently of each other and of obstetric risk (calculated in an objective manner). Moreover, to evaluate whether there is an ideal window for initiating such interventions.

METHODS

Prospective, observational study with 1,047 patients enrolled.

RESULTS

Medical interventions were high, whether in low-, medium- or high-risk pregnancies. Oxytocin augmentation (odds ratio 4.678) labour induction (odds ratio 1.717) amniotomy (odds ratio 1.403) and obstetric risk (intermediate-risk odds ratio 1.889, high-risk odds ratio 2.008) increase the probability of an operative delivery. Oxytocin augmentation increases both the probability of a Cesarean delivery and vacuum extraction. Epidural analgesia reduces the probability of cesarean delivery and increases the probability of vacuum extraction. The greater the cervical dilation when oxytocin infusion is initiated, the lower the probability of an operative delivery. The more advanced the cervical dilation and the lower the station when amniotomy or epidural analgesia are carried out, the lower the probability of an operative delivery. Obstetric risk and oxytocin augmentation appear to increase the probability of operative delivery in patients who have undergone amniotomy or epidural analgesia. In addition, labor induction in patients who undergo epidural analgesia increases the risk of operative delivery.

CONCLUSIONS

Medical interventions during labor are high and cause a rise in operative delivery. Therefore, practitioners should defer it as much as possible. The exception is epidural analgesia because it seems to reduce the number of cesarean sections.

Stroke in critically ill patients

Advances in critical care medicine have led to improved survival rates among patients admitted to the Intensive Care unit (ICU), but complications experienced during admittance in an ICU may influence long-term outcome and the neurocognitive state of these patients. Coagulation disorders, glucose intolerance, diabetes, pro-inflammatory state and underlying severe pathologies are common risk factors for stroke development in ICU patients. Stroke may result in very serious consequences like motor function impairment, neglect and aphasia, but in some cases, stroke may not result in any clinical sign in acute phase. Recently, more attention has been given to this condition called ''silent stroke.'' ''Silent stroke'' could be the foundation of the development of neurocognitive impairment and vascular dementia. In ICU survivors, approximately 1/3 of patients or more will develop chronic neurocognitive impairment. With the advent of sensitive techniques for brain imaging, silent brain lesions, including brain infarct and white matter changes, have been frequently recognized. Until now, epidemiological studies in this field evaluating incidence and consequences of stroke in ICU setting are lacking, and prospective studies are required to evaluate the impact of this condition on the quality of life, neurocognitive outcome and mortality of ICU patients. We believe that when stroke occurs in critically ill patients, more attention is typically given to the underlying pathologies than stroke, and this may influence the long-term outcome. Guidelines for the early management of stroke, commonly used in Stroke Units, should be followed, even in critically ill patients in an ICU setting.

Circulating adrenomedullin is increased in preterm newborns developing intraventricular hemorrhage

Adrenomedullin is a novel vasoactive peptide that participates in cerebral blood flow regulation and circulates in human plasma. To verify whether plasma adrenomedullin is able to identify preterm newborns at risk of intraventricular hemorrhage (IVH), we performed a case-control study. Plasma samples collected within 6 h after birth in 24 preterm newborns who developed IVH, as diagnosed at 72 h, were assessed for adrenomedullin and compared with those obtained from 48 preterm newborns, matched for gestational age, who did not develop IVH. Cerebral ultrasound and Doppler velocimetry waveform patterns in the middle cerebral artery were also recorded at the time of blood sampling. Adrenomedullin blood concentrations and middle cerebral artery pulsatility index values were significantly higher in infants developing IVH (20.1 +/- 4.5 fmol/mL and 1.71 +/- 0.21 fmol/mL, respectively) than in controls (7.5 +/- 3.0 fmol/mL and 1.49 +/- 0.19 fmol/mL, respectively). Adrenomedullin blood concentrations correlated with middle cerebral artery pulsatility index (r = -0.77, p < 0.01) and with the grade of IVH extension (r = 0.83, p < 0.01). This study suggests that adrenomedullin blood concentration might be a promising tool for identifying preterm infants at risk of IVH immediately after birth, when imaging assessment and clinical symptoms of hemorrhage are still silent.

Influence of labor on fetoplacental adrenomedullin concentrations

OBJECTIVE

Circulating adrenomedullin is increased in pregnancy, and placental and fetal membranes participate significantly in its secretion. Recent studies have suggested a potential role for this peptide in the regulation of fetoplacental circulation and placental hormonal secretion. Because adrenomedullin acts also as a uterorelaxant in rats, this study was designed to investigate whether fetoplacental adrenomedullin production changes with human labor, either at term or preterm.

STUDY DESIGN

Eighty pregnant women grouped according to gestational age and presence of labor were studied. Adrenomedullin concentrations in plasma, amniotic fluid, and placental tissue extracts were measured by means of radioimmunoassay and immunohistochemistry. In addition, the ability of amnion and chorion-decidua to secrete adrenomedullin was investigated in vitro.

RESULTS

Adrenomedullin concentrations in amniotic fluid were higher in preterm labor, whereas no differences were found in adrenomedullin expression or concentrations in tissues or in maternal and fetal plasma between vaginal delivery or elective cesarean section, both at term and preterm. During term labor (8 patients), maternal plasma adrenomedullin concentration decreased with advancing cervical dilatation, being 173 pg/mL at the beginning of the active stage of labor and 57 pg/mL at the time of delivery. Adrenomedullin concentration in the medium of amnion- and chorion-decidua-cultured cells was higher after vaginal delivery.

CONCLUSION

These results suggest that a decrease in adrenomedullin production is not involved in the onset of labor in human subjects but rather that it may play a role other than that of a myometrial relaxant in human parturition.

Fetomaternal adrenomedullin levels in diabetic pregnancy

We investigated whether maternal and fetoplacental adrenomedullin, a newly discovered hypotensive peptide involved in the insulin regulatory system, is modified in diabetic pregnancy. We studied its correlation with pregnancy complications associated with this disease. Thirty-six pregnant women with diabetes (13 with type I and 23 with gestational diabetes mellitus) and in 40 uncomplicated pregnancies were included. 10 out of 36 diabetic pregnancies were complicated by gestational hypertension. In each woman, adrenomedullin concentration in maternal and fetal plasma and in amniotic fluid was assessed by specific radioimmunoassay. We found that overall mean amniotic fluid adrenomedullin concentration was higher (p < 0.05) in diabetic (14.7 +/- 1.6 fmol/ml) than in uncomplicated pregnancies (10.8 +/- 0.9 fmol/ml), whereas no differences were present in maternal and fetal plasma adrenomedullin levels between diabetic and uncomplicated pregnant women. High levels of amniotic fluid adrenomedullin were found in both type I and gestational diabetes mellitus pregnancies (13.7 +/- 1.4 and 15.6 +/- 2.2 fmol/ml, respectively). Diabetic pregnancies complicated by gestational hypertension showed lower (p < 0.05) amniotic fluid adrenomedullin concentrations than normotensive diabetic patients. These findings suggest that placental adrenomedullin production is upregulated in diabetic pregnancy, and it may be important to prevent excessive vasoconstriction of placental vessels.

New placental factors: Between implantation and inflammatory reaction

The trophoblast invasion is a dynamic changes in cell-cell and cell matrix interaction and it create in the endometrio a reaction similar to the inflammatory reaction. In the recent past most of the investigator in this field had focus on the mediator of this process especially on cytokine and on vasoactive agent. We have studied the inducible isoform of nitric oxide synthase (iNOS), adrenomedullin (AM), fatty acid synthase (FAS), and S-100 protein. Several evidences had lead our choice: the two first factors are essentially local mediator of vasospasm which works in synergy during the inflammatory reaction, but the AM I addition stimulates the DNA synthesis and cell proliferation of Swiss 3T3 fibroblasts, induces the cell cycle progression from G0 to G1 phase and the malignant cell lines express AM mRNA and mRNA for its receptor and the pattern of distribution of ir-AM and its mRNA during murine development is similar to that of other growth factors (TGFb isoforms, PDGF, FGF, IGF 1 and 2); Fatty acid synthase (FAS) is a major biosynthetic enzyme of intracellular fatty acid synthesis, its expression and activity is enhanced in proliferative tissues, such as malignant cells; S-100 is an acid calcium binding protein present in central nervous system where it is in mainly concentrated in the glial cells, astrocytes, Schwann cells, and neurons. It regulates several functions such as cell-cell communication, cell growth, cell structure, energy metabolism, contraction, and intracellular signal transduction. Recently the appearance in blood of S100 in preterm infants has been used as a marker of brain damage in perinatal period. The iNOS, AM, S100 and FAS are localized in both decidual and trophoblastic cells in early pregnancy, but we found that changes in iNOS, S100, AM, and FAS are different in spontaneous abortion (SA) versus voluntary pregnancy termination (VPT). Considering the VPT as non pathologic pregnancy, this difference may reflect functional modifications of placental tissues. Our result shown that AM and NO are increased in VPT vs SA showing that when the process of implantation is on course we found an higher expression that we have during the inflammatory reaction. [Table: see text]

Circulating adrenomedullin is increased in patients with corticotropin-dependent Cushing's syndrome due to pituitary adenoma

It has been demonstrated that adrenomedullin, a newly discovered peptide with structural similarity to calcitonin gene-related peptide (CGRP), is expressed in pituitary gland and affects basal and corticotropin (ACTH)-releasing factor (CRF)-stimulated ACTH release in animals, thus suggesting its potential role in regulating the hypothalamus-pituitary-adrenal axis. To evaluate whether ACTH and cortisol levels affect adrenomedullin production in humans, we studied 14 patients with Cushing's syndrome due to pituitary adenoma and 8 patients with Cushing's syndrome due to adrenal tumor, with measurement of circulating adrenomedullin by a specific radioimmunoassay (RIA). Adrenomedullin concentrations were significantly higher in patients with pituitary adenoma (37.6 +/- 17.8 pg/mL) versus controls (13.7 +/- 6.1 pg/mL) and patients with adrenal adenoma (17.8 +/- 2.2 pg/mL). After pituitary surgical treatment, plasma adrenomedullin decreased significantly. In one patient with Cushing's syndrome due to pituitary adenoma who underwent simultaneous sampling of the inferior petrosal venous sinuses, the adrenomedullin concentration was significantly higher in plasma collected from the side with the adenoma and increased after CRF administration (delta increase, 42.6%), according to ACTH levels. Our findings indicate that circulating adrenomedullin is increased in Cushing's disease, and the pituitary gland may represent the site of the elevated production of adrenomedullin in this condition.

Amniotic fluid nitric oxide metabolite levels and nitric oxide synthase localization in feto-placental tissues are modified in association with human labor

Nitric oxide (NO) has a relaxant effect on uterine smooth muscle and may be implicated in maintaining uterine quiescence during pregnancy. In order to investigate the role of nitric oxide in human parturition, we have measured NO metabolite levels in maternal and fetal compartments in association with labor, both at term and preterm. We have also examined the localization and distribution of NO synthase (NOS) isoforms in placentas and fetal membranes after term and preterm delivery by means of immunohistochemistry. Although no differences were present in maternal and fetal blood and in maternal urine among groups, we found that NO metabolite concentrations were higher in amniotic fluid collected from women in labor than in non-laboring patients, both at term (15.4+/-1.6 vs. 6.8+/-0.6 microM/mg creatinine) and preterm (16.7+/-2.0 vs. 7.0+/-0.8 microM/mg creatinine). Ir-bNOS staining appeared to be decreased in fetal membranes collected after spontaneous labor at term and preterm. In contrast, a stronger staining for iNOS was detected in trophoblast cells of fetal membranes from women in labor than in those from non-laboring women. We suggest that NOS isoenzymes in fetal placental tissues are differently regulated and might play different roles during pregnancy.

Adrenomedullin is increased in the fetoplacental circulation in intrauterine growth restriction with abnormal umbilical artery waveforms

OBJECTIVE

To examine whether adrenomedullin, a novel vasoactive peptide produced by the placenta, participates in the uteroplacental hemodynamic alterations in intrauterine growth restriction, we studied the correlation between adrenomedullin levels and fetoplacental blood flow.

STUDY DESIGN

Maternal and umbilical blood samples were collected in pregnancies complicated by intrauterine growth restriction with abnormal umbilical artery Doppler findings and in control pregnancies. Adrenomedullin levels were measured by means of a specific radioimmunoassay, and flow velocimetry waveforms were recorded from uterine, umbilical, and fetal middle cerebral arteries.

RESULTS

Mean adrenomedullin values in umbilical plasma were higher (P <.05) in patients with intrauterine growth restriction (63.7 +/- 34.2 pg/mL; n = 16) than in control subjects (38.1 +/- 14.8 pg/mL; n = 16). A significant correlation was found between maternal adrenomedullin levels and umbilical artery pulsatility index. Moreover, fetal adrenomedullin concentrations correlated negatively with middle cerebral artery pulsatility index and positively with umbilical artery pulsatility index/middle cerebral artery pulsatility index ratio.

CONCLUSION

This study provides evidence that adrenomedullin is increased in fetuses with intrauterine growth restriction in response to reduced uteroplacental blood flow and suggests that it may participate in the fetal hemodynamic modifications.

Changes in plasma adrenomedullin levels during the menstrual cycle

We investigated whether the levels of adrenomedullin, a novel peptide produced by several tissues, including the pituitary gland, change during the ovarian cycle. We studied 13 healthy women with regular menstrual cycles. Plasma samples were collected at 7, 14, 21 and 28 days of the ovarian cycle and assayed for adrenomedullin 1-52 using a specific RIA. LH, FSH, 17beta-estradiol, and progesterone concentrations were also determined. The adrenomedullin profile during ovarian cycle was similar to that of LH; plasma adrenomedullin increased from 10.9 pg/ml at the 7th day to 15.1 pg/ml at the 14th, and decreased to 8.5 pg/ml in the subsequent menses. The changes in plasma adrenomedullin were related to changes in LH and 17beta-estradiol. The cause of the increase in adrenomedullin levels during the late follicular phase of the menstrual cycle is not clear. Since it has been demonstrated that adrenomedullin is involved in the regulation of hypothalamus-pituitary-adrenal gland and its secretion is regulated by sex hormones we speculate that adrenomedullin could also play a role in regulating the hypothalamus-pituitary-ovary feedback. Alternatively it may be involved in the regulation of fluid and electrolyte homeostasis during the menstrual cycle.

Amniotic fluid concentrations of adrenomedullin in preterm labor

OBJECTIVE

To determine whether adrenomedullin levels in amniotic fluid were associated with preterm labor.

METHODS

We measured immunoreactive adrenomedullin in amniotic fluid collected by amniocentesis from 36 women with clinical diagnosis of preterm labor or preterm premature rupture of membranes (PROM) and from 18 normal pregnant women.

RESULTS

Amniotic fluid from cases of PROM and failure to respond to tocolysis were associated significantly with higher amniotic fluid adrenomedullin concentrations (177.0 +/- 22.5 pg/mL and 182.7 +/- 22.0 pg/mL, respectively, P < .01) than that from uncomplicated pregnancies (101.2 +/- 28.1 pg/mL) or preterm labor responsive to tocolysis (102.3 +/- 26.8 pg/mL).

CONCLUSION

Amniotic fluid adrenomedullin is higher than normal in cases of PROM and preterm labor unresponsive to tocolysis, perhaps indicating enhanced synthesis from placenta or fetal membranes being stimulated by bacterial products.

Adrenomedullin production is increased in normal human pregnancy

OBJECTIVE

Adrenomedullin, a recently discovered vasoactive peptide originally identified in pheochromocytoma, has been found to be increased in the plasma of pregnant women at term. This study was designed to elucidate whether adrenomedullin secretion is dependent on gestational age and the possible source and function of this peptide in human pregnancy.

STUDY DESIGN

Adrenomedullin concentrations were determined by RIA in amniotic fluid and maternal plasma obtained from 110 pregnant women between 8 and 40 weeks of gestation. Subjects were stratified into five groups according to gestational age. In term patients (n = 15), adrenomedullin was also measured in the umbilical artery and vein separately.

RESULTS

High concentrations of adrenomedullin were present in plasma and amniotic fluid samples from patients in the first, second and third trimester. There was no significant difference in mean maternal plasma concentration of adrenomedullin between the five patient groupings. Amniotic fluid adrenomedullin concentrations decreased from 81.2 +/- 11.7 pg/ml at 8-12 weeks of gestation to 63.7 +/- 6.0 pg/ml at 13-20 weeks of gestation and then increased at 21-28 weeks of gestation to 99.1 +/- 10.4 pg/ml. A further increase was found in samples collected after 37 weeks of gestation (132.6 +/- 10.1 pg/ml). In the umbilical vein, adrenomedullin concentration was higher (P < 0.05) than in the artery (65.7 +/- 6.1 pg/ml and 48.5 +/- 5.2 pg/ml respectively), suggesting that adrenomedullin in the fetal circulation derives from the placenta.

CONCLUSIONS

Our results demonstrate the presence of adrenomedullin in maternal plasma and amniotic fluid throughout gestation, and show that its production starts very early in gestation, suggesting that this hormone may have an important role in human reproduction, from implantation to delivery.

Immunohistochemical localization of adrenomedullin in fetal and neonatal lung

Adrenomedullin is a potent hypotensive peptide that has been demonstrated to increase pulmonary blood flow in fetal sheep. To examine whether adrenomedullin plays a role in the transitional changes of human pulmonary blood flow at birth, we have evaluated, by immunohistochemistry, its presence and distribution in fetal lung during gestation using a polyclonal antibody directed toward human adrenomedullin 1-52. We collected lung specimen from abortive fetuses (n = 6), preterm neonates (n = 4). and term infants (n = 3). Two adult lung specimen were used as controls. Immunoreactive adrenomedullin was detected in fetal lung collected as early as at 18 wk of gestation and in all tissues throughout gestation. Adrenomedullin was localized predominantly in the epithelial cells of bronchi, with an apical distribution. Endothelial cells also stained for adrenomedullin. The intensity of staining and the percentage of positive bronchial epithelial cells increased as gestation progressed: but staining for adrenomedullin was absent in tissues collected after breathing and in the adult controls. These findings indicate that adrenomedullin may play an important role in respiratory homeostasis at birth. Moreover, the immunohistochemical expression of AM in the late organogenetic period and its increasing staining during fetal lung development may suggest a possible role in the mechanisms of fetal lung differentiation and/or maturation.

New peptides, hormones and parturition

This brief review emphasizes the importance of three novel discovered factors produced by fetal membranes, placenta and/or by the fetus itself in regulating uterine contractility. We have shown that, as reported for other hormones and substances, nitric oxide and endothelin may influence myometrial activity in an autocrine/paracrine manner interacting with other well-known agents such as prostaglandins, oxytocin and hormones. We also demonstrated that different isoforms of nitric oxide synthase (NOS) may play different roles throughout gestation and during labor. We have suggested that another peptide produced by trophoblast cells, adrenomedullin, may affect, directly or indirectly, myometrial contractility during pregnancy, although much remains to be learned about the mechanisms controlling adrenomedullin expression by the feto-placental tissues cells during pregnancy. Continued research is necessary to better define the complex interactions that result in parturition, both at term and preterm, and to allow a more rational approach to management of the premature labor, exploring new possible pharmacological solutions.

Adrenomedullin, a new vasoactive peptide, is increased in preeclampsia

Adrenomedullin is a novel peptide that elicits a long-lasting vasorelaxant activity. Recently, we found high concentrations of adrenomedullin in maternal and umbilical cord plasma and in amniotic fluid in full-term human pregnancy, indicating a role of this peptide during gestation. To investigate the possibility that adrenomedullin is involved in the pathophysiology of preeclampsia, we measured its concentration in maternal and fetoplacental compartments. We studied 12 normotensive nonpregnant women, 13 hypertensive nonpregnant subjects, 29 patients with preeclampsia, and 30 normotensive pregnant women. In all patients, plasma was collected from the cubital vein, and amniotic fluid samples were obtained by transabdominal amniocentesis or at elective cesarean section. Plasma samples from umbilical vein and placental tissues were collected at delivery. Adrenomedullin was assayed on plasma and amniotic fluid samples using a specific radioimmunoassay, and its localization and distribution on placental sections was determined by immunohistochemistry. Adrenomedullin concentrations were higher in hypertensive than in normotensive nonpregnant patients. Pregnant women had higher adrenomedullin levels than nonpregnant subjects, although maternal plasma adrenomedullin concentrations did not differ between normal pregnant and preeclamptic women. Preeclamptic patients showed higher concentrations (P<0.01) than normotensive pregnant women of adrenomedullin in amniotic fluid (252+/-29 versus 112+/-10 fmol/ micromol creatinine) and umbilical vein plasma (18.1+/-2.1 versus 8. 5+/-1.1 fmol/mL). Increased local production of adrenomedullin is associated with preeclampsia. The fetus seems to be responsible for the higher levels of this hormone. Increased adrenomedullin concentrations may be necessary to maintain placental vascular resistance and/or fetal circulation at a physiological level.

Immunoreactive adrenomedullin in human fetoplacental tissues

OBJECTIVE

Adrenomedullin is increased in maternal plasma in pregnancy and has been found in very high concentrations in amniotic fluid and umbilical plasma. To identify adrenomedullin-producing tissue in pregnancy we measured adrenomedullin concentration and distribution in fetoplacental tissues.

STUDY DESIGN

By use of a specific radioimmunoassay we determined the concentrations of adrenomedullin and, by immunohistochemical studies, its localization and distribution in fetal membranes and placentas collected at elective cesarean section from 11 healthy pregnant women at term.

RESULTS

The content of adrenomedullin in placentas (117.7 +/- 7.8 pg/mg wet tissue) and fetal membranes (168.7 +/- 2.3 pg/mg wet tissue) was similar to the adrenomedullin concentration in adrenal medulla (157.3 +/- 4.4 pg/mg wet tissue). Adrenomedullin staining appears to be greater in fetal membranes than in placentas and was localized in amnion and trophoblast cells. In term placentas positive staining was detected predominantly in extravillous trophoblast cells, although a few syncytiotrophoblast cells and endothelial cells of primary villi stained for adrenomedullin.

CONCLUSION

This study provides evidence that is consistent with fetoplacental tissues as a site of synthesis or action of adrenomedullin during pregnancy.

Effect of betamethasone in vivo on placental corticotropin-releasing hormone in human pregnancy

OBJECTIVE

The objective was to determine the effects of in vivo administration of prenatal betamethasone in patients at 26 to 35 weeks' gestation on corticotropin-releasing hormone concentrations in maternal and fetal plasma and amniotic fluid, and on corticotropin-releasing hormone localization in placenta and fetal membranes.

STUDY DESIGN

A total of 49 pregnant women at risk for preterm delivery between 26 and 35 weeks' gestation were studied. Twenty-six patients received betamethasone (12 mg intramuscularly) for stimulation of fetal lung maturity. Cord blood, amniotic fluid, placental tissue, and fetal membranes were obtained from 22 of these patients at delivery by elective cesarean section at 33.8+/-2.4 weeks' gestation. In control patients (n=23) at comparable gestational age, blood samples were taken for hormone analysis (n=8), and cord blood, amniotic fluid, and tissues were collected at elective cesarean section at 34.1+/-2.3 weeks' gestation. Concentrations of corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol were determined by radioimmunoassay. Localization of tissue immunoreactive corticotropin-releasing hormone was assessed by immunohistochemistry.

RESULTS

Betamethasone caused approximately 90% reduction in maternal cortisol and 50% reduction in maternal plasma adrenocorticotropic hormone. In patients at >30 weeks' gestation, there was a significant increase in maternal plasma corticotropin-releasing hormone concentrations after betamethasone; maternal corticotropin-releasing hormone was not altered significantly in untreated patients. Corticotropin-releasing hormone levels were raised in umbilical cord blood by 48 hours and in amniotic fluid 1 week after betamethasone administration. There was increased immunohistochemical staining for corticotropin-releasing hormone in placental syncytiotrophoblast and in fetal membranes of patients treated with betamethasone.

CONCLUSIONS

These studies provide the first evidence for in vivo stimulation of plasma corticotropin-releasing hormone, likely of placental origin, by glucocorticoids in third trimester human pregnancy. The results suggest that increases in endogenous cortisol during normal gestation may contribute to placental corticotropin-releasing hormone output and to the rise in maternal plasma corticotropin-releasing hormone concentrations during late pregnancy.

Nitric oxide in preeclampsia: lack of evidence for decreased production

The purpose of our study was to determine the involvement of the L-arginine-NO system in preeclampsia. We studied 26 patients with preeclampsia and 27 normotensive pregnancies. Maternal and cord plasma, urine and amniotic fluid were assayed for nitric oxide metabolites (nitrite and nitrate) using the Griess reaction. Sections of placenta and fetal membranes were immunostained with polyclonal anti-endothelial and anti-neuronal nitric oxide synthase antibodies. The concentration of nitrate in the amniotic fluid of preeclamptic patients (median 10.3 mumol/mg creatinine) was significantly higher (P < 0.001) than in the normotensive group (5.6 mumol/mg creatinine). Nitrate concentrations in maternal and cord plasma and in urine were similar in the two groups. Endothelial cells of the villi of preeclamptic placentas showed a higher positivity in endothelial nitric oxide synthase immunostaining with respect to normotensive controls. Our results indicate that feto-placental NO production is not reduced in preeclampsia. In contrast, the increased concentrations of NO metabolites in amniotic fluid and the positive immunostaining of endothelial nitric oxide synthase in the placental villi suggest that the placental L-arginine-NO system is up-regulated in preeclampsia.

Amniotic fluid nitric oxide and uteroplacental blood flow in pregnancy complicated by intrauterine growth retardation

OBJECTIVE

To examine the correlation between placental nitric oxide production and uteroplacental blood flow.

PARTICIPANTS

Thirty-one pregnant women with fetuses with intrauterine growth retardation and 27 normal pregnancies as controls.

DESIGN

Correlation between amniotic fluid measurements of nitrite metabolite in the third trimester and flow velocimetry waveforms recorded from uterine, umbilical and fetal middle cerebral arteries. Intrauterine growth retarded pregnancies were compared with controls.

MAIN OUTCOME MEASURES

Concentrations of nitric oxide metabolites (NO2- and NO3-) in amniotic fluid were correlated with flow velocimetry waveforms findings by the determination of correlation coefficient.

RESULTS

Overall median nitrite values in amniotic fluid were higher (P < 0.01) in intrauterine growth retarded patients (median 8.6 micromol/mg creatinine) than in controls (5.6 micromol/mg creatinine). Pathologic uterine flow velocimetry waveforms in uterine artery (-2SD) were observed in 12 women of the intrauterine growth retarded group, and the concentration of amniotic fluid nitrite was significantly lower (P < 0.01) in these patients (median 4.45 micromol/mg creatinine) than in those with normal flow velocity waveforms (median 11.43 micromol/mg creatinine). A significant negative correlation was observed between nitrite concentrations and uterine artery resistance index, umbilical artery pulsatility index and umbilical artery pulsatility index:middle cerebral artery pulsatility index ratio.

CONCLUSIONS

We conclude that placental nitric oxide is significantly associated with uteroplacental blood flow and may be important in maintaining adequate uteroplacental perfusion in intrauterine growth retarded pregnancies.