Pregnancy in uremic patients: an eventful journey

Renal damage, which can be caused by gestational anomalies such as pre-eclampsia, carries a risk of gestational complications; the greatest risk being in women who become pregnant while on hemodialysis or peritoneal dialysis. If this rare event occurs, there is a marked increase in the risk of pre-eclampsia, early uterine contractions and hydramnios, hypertensive crisis, preterm delivery and intrauterine growth retard. Furthermore, newborns are almost always of low birthweight. Patients who undergo renal transplantation are another high-risk category. In such cases, the pregnancy itself can compromise the success of the transplant and the immunosuppressive therapy correlated to it can become a threat to the course of the pregnancy and normal fetal growth. Therefore, in view of the lack of appropriate guidelines for the best possible approach to the treatment of women on dialysis or of those with a renal transplantation, it is best to advise these patients against becoming pregnant and/or to provide a valid counselling service illustrating the extreme difficulties and dangers involved in becoming pregnant.     

Behavior of vascular endothelial growth factor and erythropoietin throughout the menstrual cycle in healthy women

OBJECTIVE: To evaluate any correlations between erythropoietin (EPO) and vascular endothelial growth factor (VEGF) levels in the serum and the menstrual fluid of healthy women during the different phases of the menstrual cycle. STUDY DESIGN: Blood samples from 25 healthy female volunteers were obtained for serum VEGF and EPO detection on the 1st, 7th, 14th, 21st and 25th days of the menstrual cycle. Menstrual fluid samples for VEGF and EPO detection were obtained on the 1st and 4th days of menstruation. RESULTS: Circulating VEGF levels were found to increase in a stage-dependent cyclic manner. The mean VEGF concentration in menstrual blood on the 1st day of the cycle was significantly higher than the mean plasma value and was reduced to a significant extent on the 4th day of the cycle. We found no significant changes in serum EPO levels. Mean EPO concentration detected in menstrual blood was comparable to those in serum blood either on the 1st or 4th day of the menstrual cycle. CONCLUSION: During menstruation, a local production of VEGF occurs independent of systemic production, thus sustaining angiogenic activity in autonomous, independent ways. Our findings demonstrate the presence of an "open compartment" that reflects the systemic pattern of EPO at the uterine level that allows us to speculate on different effects beyond the angiogenic action of EPO.     

A small molecule Smac mimic potentiates TRAIL-mediated cell death of ovarian cancer cells

OBJECTIVES: Ovarian cancer remains a leading cause of death in women and development of new therapies is essential. Second mitochondria derived activator of caspase (Smac) has been described to sensitize for apoptosis. We have explored the proapoptotic activity of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines (A2780 cells and its chemoresistant derivatives A2780/ADR and A2780/DDP), cancer cell lines and in primary ovarian cancer cells. METHODS: The effects of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines and primary ovarian cancer cells were determined by cell proliferation, apoptosis and biochemical assays. RESULTS: This compound added alone elicited only a weak proapoptotic effect; however, it strongly synergizes with tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or agonistic TRAILR2 antibody (Lexatumumab) in inducing apoptosis of ovarian cancer cells. CONCLUSIONS: These observations suggest that small molecule mimic of Smac/DIABLO could be useful for the development of experimental strategies aiming to treat ovarian cancer. Interestingly, in addition to its well known proapoptotic effects, Smac/DIABLO elicited a significant increase of pro-caspase-3 levels.     

HOXD8 hypermethylation as a fully sensitive and specific biomarker for biliary tract cancer detectable in tissue and bile samples

Background Biliary tract cancers (BTC) are rare but highly aggressive tumours with poor prognosis, usually detected at advanced stages. Herein, we aimed at identifying BTC-specific DNA methylation alterations.Methods Study design included statistical power and sample size estimation. A genome-wide methylation study of an explorative cohort (50 BTC and ten matched non-tumoral tissue samples) has been performed. BTC-specific altered CpG islands were validated in over 180 samples (174 BTCs and 13 non-tumoral controls). The final biomarkers, selected by a machine-learning approach, were validated in independent tissue (18 BTCs, 14 matched non-tumoral samples) and bile (24 BTCs, five non-tumoral samples) replication series, using droplet digital PCR.Results We identified and successfully validated BTC-specific DNA methylation alterations in over 200 BTC samples. The two-biomarker panel, selected by an in-house algorithm, showed an AUC > 0.97. The best-performing biomarker (chr2:176993479-176995557), associated with HOXD8, a pivotal gene in cancer-related pathways, achieved 100% sensitivity and specificity in a new series of tissue and bile samples.Conclusions We identified a novel fully efficient BTC biomarker, associated with HOXD8 gene, detectable both in tissue and bile by a standardised assay ready-to-use in clinical trials also including samples from non-invasive matrices.Subject terms: Diagnostic markers, Biliary tract cancer     

Supporting hemodynamics: what should we target? What treatments should we use?

Assessment and monitoring of hemodynamics is a cornerstone in critically ill patients as hemodynamic alteration may become life-threatening in a few minutes. Defining normal values in critically ill patients is not easy, because 'normality' is usually referred to healthy subjects at rest. Defining 'adequate' hemodynamics is easier, which embeds whatever pressure and flow set is sufficient to maintain the aerobic metabolism. We will refer to the unifying hypothesis proposed by Schrier several years ago. Accordingly, the alteration of three independent variables - heart (contractility and rate), vascular tone and intravascular volume - may lead to underfilling of the arterial tree, associated with reduced (as during myocardial infarction or hemorrhage) or expanded (sepsis or cirrhosis) plasma volume. The underfilling is sensed by the arterial baroreceptors, which activate primarily the sympathetic nervous system and renin-angiotensin-aldosterone system, as well as vasopressin, to restore the arterial filling by increasing the vascular tone and retaining sodium and water. Under 'normal' conditions, therefore, the homeostatic system is not activated and water/sodium excretion, heart rate and oxygen extraction are in the range found in normal subjects. When arterial underfilling occurs, the mechanisms are activated (sodium and water retention) - associated with low central venous oxygen saturation (ScvO₂) if underfilling is caused by low flow/hypovolemia, or with normal/high ScvO₂ if associated with high flow/hypervolemia. Although the correction of hemodynamics should be towards the correction of the independent determinants, the usual therapy performed is volume infusion. An accepted target is ScvO₂ >70%, although this ignores the arterial underfilling associated with volume expansion/high flow. For large-volume resuscitation the worst solution is normal saline solution (chloride load, strong ion difference = 0, acidosis). To avoid changes in acid-base equilibrium the strong ion difference of the infused solution should be equal to the baseline bicarbonate concentration.     

The single-channel properties of human acetylcholine alpha 7 receptors are altered by fusing alpha 7 to the green fluorescent protein

Neuronal nicotinic acetylcholine (AcCho) receptors composed of alpha7-subunits (alpha7-AcChoRs) are involved in many physiological activities. Nevertheless, very little is known about their single-channel characteristics. By using outside-out patch-clamp recordings from Xenopus oocytes expressing wild-type (wt) alpha7-AcChoRs, we identified two classes of channel conductance: a low conductance (gamma(L)) of 72 pS and a high one (gamma(H)) of 87 pS, with mean open-times (tau(op)) of 0.6 ms. The same classes of conductances, but longer tau(op) (3 ms), were seen in experiments with chimeric alpha7 receptors in which the wtalpha7 extracellular C terminus was fused to the green fluorescent protein (wtalpha7-GFP AcChoRs). In contrast, channels with three different conductances were gated by AcCho in oocytes expressing alpha7 receptors carrying a Leu-to-Thr 248 mutation (mutalpha7) or oocytes expressing chimeric mutalpha7-GFP receptors. These conductance levels were significantly smaller, and their mean open-times were larger, than those of wtalpha7-AcChoRs. Interestingly, in the absence of AcCho, these oocytes showed single-channel openings of the same conductances, but shorter tau(op), than those activated by AcCho. Accordingly, human homomeric wtalpha7 receptors open channels of high conductance and brief lifetime, and fusion to GFP lengthens their lifetime. In contrast, mutalpha7 receptors open channels of lower conductance and longer lifetime than those gated by wtalpha7-AcChoRs, and these parameters are not greatly altered by fusing the mutalpha7 to GFP. All this evidence shows that GFP-tagging can alter importantly receptor kinetics, a fact that has to be taken into account whenever tagged proteins are used to study their function.     

Association of RANTES G-403A gene polymorphism with increased risk of coronary arteriosclerosis

Aims Polymorphisms in the RANTES (G-403A), monocyte chemoattractantprotein-1 (MCP-1; A-2518G), stromal cell-derived factor-1ß(SDF-1ß; G801A), and C–C chemokine receptor-5(CCR5; 32) genes have been associated with functional effects.These chemokines have been implicated in leucocyte recruitmentto arterial lesions. In a case-control study, we explored relationsbetween these polymorphisms and coronary artery disease (CAD),with respect to angiographic abnormalities and acute coronarysyndromes (ACS). Methods and Results The LUdwigshafen Risk and Cardiovascularhealth (LURIC) cohort was genotyped by RFLP-PCR. Based on coronaryangiography, individuals were sub-divided into CAD cases and controls . RANTES-403 genotype frequencies were significantly different in cases and controls, as were A allele carrier frequencies (36.01% vs. 30.19%, OR=1.30 [95%-CI=1.06–1.60], ). By multivariate analysis, RANTES A-403 retained significantassociation with CAD . RANTES A-403 was associated with increased ACS prevalence (OR=1.36 [95%-CI=1.08–1.71],). MCP-1 G-2518, SDF-1ß A801, and CCR5 32 were not associated with CAD. Conclusions RANTES A-403 was associated with CAD independentlyfrom conventional risk factors and CRP or fibrinogen as inflammatorybiomarkers. The association was enhanced in smokers and ACS,conditions where platelet activation and inflammation predominate.RANTES A-403 may increase genetic susceptibility to CAD.     

Expression of functional neurotransmitter receptors in Xenopus oocytes after injection of human brain membranes

The Xenopus oocyte is a very powerful tool for studies of the structure and function of membrane proteins, e.g., messenger RNA extracted from the brain and injected into oocytes leads to the synthesis and membrane incorporation of many types of functional receptors and ion channels, and membrane vesicles from Torpedo electroplaques injected into oocytes fuse with the oocyte membrane and cause the appearance of functional Torpedo acetylcholine receptors and Cl(-) channels. This approach was developed further to transplant already assembled neurotransmitter receptors from human brain cells to the plasma membrane of Xenopus oocytes. Membranes isolated from the temporal neocortex of a patient, operated for intractable epilepsy, were injected into oocytes and, within a few hours, the oocyte membrane acquired functional neurotransmitter receptors to gamma-aminobutyric acid, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, and glycine. These receptors were also expressed in the plasma membrane of oocytes injected with mRNA extracted from the temporal neocortex of the same patient. All of this makes the Xenopus oocyte a more useful model than it already is for studies of the structure and function of many human membrane proteins and opens the way to novel pathophysiological investigations of some human brain disorders.