Transradial experience with bioresorbable vascular scaffolds: A case-matched study with metallic drug-eluting stents.

BACKGROUND: Whether polymeric bioresorbable vascular scaffolds (BVS) implantation with transradial approach is feasible and safe is unknown. We compared the feasibility and safety of the transradial approach for BVS delivery with metallic drug-eluting stents (DES). METHODS: We identified 118 consecutive patients who underwent BVS implantation and we compared 30-days and 1-year results with 118 matched patients with DES. Patients were matched for age, sex, risk factors and clinical indication. RESULTS: Rates of transradial approach were 98% in the BVS group vs 95% in the DES group (P = 0.16) with 5Fr used in 38% and 32% (P = 0.34), respectively. The number of stents was similar in both groups, 2.6 ±â€¯1.5 vs 2.4 ±â€¯1.3 (P = 0.23). Although maximal pressure for stent deployment was identical in both groups (16 ±â€¯3 atm), more lesions were pre-dilated (83% vs 52%, P < 0.001) and post-dilated (71% vs 33%, P < 0.001) in the BVS group. Contrast volume (217 ±â€¯97 vs 175 ±â€¯108 ml, P < 0.001), fluoroscopy time (16 [10-23] vs 13 [8-21] min, P = 0.04) and procedure duration (65 ±â€¯31 vs 56 ±â€¯47 min, P = 0.045) were significantly higher in the BVS group. Major adverse cardiac events, including death, myocardial infarction and target vessel revascularization remained similar in both groups, 1.7% vs 0.8% (P = 0.56) at 30 days and 10% vs 8.5% (P = 0.66) at 1 year. At 1 year, stent thrombosis occurred in 2 (1.7%) patients in the BVS group and 1 (0.8%) patient in the DES group (P = 0.56). CONCLUSION: The use of transradial approach for BVS compared to DES implantation was feasible and safe in all-comers, although BVS implantation included more technical challenges. Outcomes up to 1-year remained comparable in both groups.

Extracellular Na(+) levels regulate formation and activity of the NaX/alpha1-Na(+)/K(+)-ATPase complex in neuronal cells.

MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as sensors of extracellular sodium concentration ([Na(+)]out). The mechanism underlying Na(+)-sensing involves Na(+)-flow through the NaX channel, directly regulated by the Na(+)/K(+)-ATPase α1-isoform which controls Na(+)-influx by modulating channel permeability. Together, these two partners form a complex involved in the regulation of intracellular sodium ([Na(+)]in). Here we aim to determine whether environmental changes in Na(+) could actively modulate the NaX/Na(+)/K(+)-ATPase complex activity. We investigated the complex activity using patch-clamp recordings from rat MnPO neurons and Neuro2a cells. When the rats were fed with a high-salt-diet, or the [Na(+)] in the culture medium was increased, the activity of the complex was up-regulated. In contrast, drop in environmental [Na(+)] decreased the activity of the complex. Interestingly under hypernatremic condition, the colocalization rate and protein level of both partners were up-regulated. Under hyponatremic condition, only NaX protein expression was increased and the level of NaX/Na(+)/K(+)-ATPase remained unaltered. This unbalance between NaX and Na(+)/K(+)-ATPase pump proportion would induce a bigger portion of Na(+)/K(+)-ATPase-control-free NaX channel. Thus, we suggest that hypernatremic environment increases NaX/Na(+)/K(+)-ATPase α1-isoform activity by increasing the number of both partners and their colocalization rate, whereas hyponatremic environment down-regulates complex activity via a decrease in the relative number of NaX channels controlled by the pump.

Regulation of central Na+ detection requires the cooperative action of the NaX channel and α1 Isoform of Na+/K+-ATPase in the Na+-sensor neuronal population.

The median preoptic nucleus (MnPO) holds a strategic position in the hypothalamus. It is adjacent to the third ventricle; hence, it can directly access the ionic composition of the CSF. MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as central sensors of extracellular Na(+) concentration ([Na(+)](ext)). The mechanism underlying Na(+) sensing involves the atypical Na(+) channel, Na(X). Here we sought to determine whether Na(+) influx in Na(+) sensors is actively regulated via interaction with other membrane proteins involved in cellular Na(+) homeostasis, such as Na(+)/K(+)-ATPase. The Na(+)/K(+)-ATPase role was investigated using patch-clamp recordings in rat MnPO dissociated neurons. Na(+) current evoked with hypernatriuric solution was diminished in the absence of ATP/GTP, indicating that Na(+)/K(+)-ATPase play a central role in [Na(+)](ext) detection. Specific blockers of α1 and α3 isoforms of Na(+)/K(+)-ATPase, ouabain or strophanthidin, inhibited this Na(+) current. However, strophanthidin, which selectively blocks the α1 isoform, was more effective in blocking Na(+) current, suggesting that the Na(+)/K(+)-ATPase-α1 isoform is specifically involved in [Na(+)](ext) detection. Although strophanthidin did not alter either the membrane resistance or the Na(+) reversal potential, the conductance and the permeability of the Na(X) channel decreased significantly. Our results suggest that Na(+)/K(+)-ATPase interacts with the Na(X) channel and regulates the high [Na(+)](ext)-evoked Na(+) current via influencing the Na(+) influx rate. This study describes a novel intracellular regulatory pathway of [Na(+)](ext) detection in MnPO neurons. The α1 isoform of Na(+)/K(+)-ATPase acts as a direct regulatory partner of the Na(X) channel and influences Na(+) influx via controlling the Na(+) permeability of the channel.

The Expression Pattern of the Na(+) Sensor, Na(X) in the Hydromineral Homeostatic Network: A Comparative Study between the Rat and Mouse.

The Scn7a gene encodes for the specific sodium channel Na(X), which is considered a primary determinant of sodium sensing in the brain. Only partial data exist describing the Na(X) distribution pattern and the cell types that express Na(X) in both the rat and mouse brain. To generate a global view of the sodium detection mechanisms in the two rodent brains, we combined Na(X) immunofluorescence with fluorescent cell markers to map and identify the Na(X)-expressing cell populations throughout the network involved in hydromineral homeostasis. Here, we designed an anti-Na(X) antibody targeting the interdomain 2-3 region of the Na(X) channel's α-subunit. In both the rat and mouse, Na(X) immunostaining was colocalized with vimentin positive cells in the median eminence and with magnocellular neurons immunopositive for neurophysin associated with oxytocin or vasopressin in both the supraoptic and paraventricular nuclei. Na(X) immunostaining was also detected in neurons of the area postrema. In addition to this common Na(X) expression pattern, several differences in Na(X) immunostaining for certain structures and cell types were found between the rat and mouse. Na(X) was present in both NeuN and vimentin positive cells in the subfornical organ and the vascular organ of the lamina terminalis of the rat whereas Na(X) was only colocalized with vimentin positive cells in the mouse circumventricular organs. In addition, Na(X) immunostaining was specifically observed in NeuN immunopositive cells in the median preoptic nucleus of the rat. Overall, this study characterized the Na(X)-expressing cell types in the network controlling hydromineral homeostasis of the rat and mouse. Na(X) expression pattern was clearly different in the nuclei of the lamina terminalis of the rat and mouse, indicating that the mechanisms involved in systemic and central Na(+) sensing are specific to each rodent species.

Combined fluorescent in situ hybridization and immunofluorescence: limiting factors and a substitution strategy for slide-mounted tissue sections.

The simultaneous localization of several anatomical markers is often required to understand and analyze the organization of complex brain nuclei or identify neuronal networks recruited during a specific biological stimulus. Gathering such information is usually achieved by the combined detection of both mRNA and proteins. Staining techniques using fluorescence have progressively overtaken the use of radioactive tissue labeling and immunostaining based on the avidin-biotin-peroxidase complex. Despite the promise offered by the combination of fluorescent in situ hybridization (FISH) and immunofluorescence (IF), in terms of reduced bench time and easy visualization of multiple labels at once, some technical hurdles have to be overcome to produce reliable data from these state-of-the-art neuroanatomy techniques. Here, we have adapted a combination of FISH and IF for slices mounted on a microscope slide, using mRNA (GAD65 mRNA) and proteins (NeuN, FosB or TH) widely studied in neuroanatomy, to validate this method. Proteinase K (PK), which is often used to optimize riboprobe penetration, is a major limiting factor in obtaining successful IF labeling. This study demonstrates the inaccuracy of PK and provides appropriate tools to improve the efficiency of the combined FISH-IF procedure to obtain high quality fluorescent multi-labeling.

Neuronal sodium leak channel is responsible for the detection of sodium in the rat median preoptic nucleus.

Sodium (Na(+)) ions are of primary importance for hydromineral and cardiovascular homeostasis, and the level of Na(+) in the body fluid compartments [plasma and cerebrospinal fluid (CSF)] is precisely monitored in the hypothalamus. Glial cells seem to play a critical role in the mechanism of Na(+) detection. However, the precise role of neurons in the detection of extracellular Na(+) concentration ([Na(+)](out)) remains unclear. Here we demonstrate that neurons of the median preoptic nucleus (MnPO), a structure in close contact with the CSF, are specific Na(+) sensors. Electrophysiological recordings were performed on dissociated rat MnPO neurons under isotonic [Na(+)] (100 mM NaCl) with local application of hypernatriuric (150, 180 mM NaCl) or hyponatriuric (50 mM NaCl) external solution. The hyper- and hyponatriuric conditions triggered an in- and an outward current, respectively. The reversal potential of the current matched the equilibrium potential of Na(+), indicating that a change in [Na(+)](out) modified the influx of Na(+) in the MnPO neurons. The conductance of the Na(+) current was not affected by either the membrane potential or the [Na(+)](out). Moreover, the channel was highly selective for lithium over guanidinium. Together, these data identified the channel as a Na(+) leak channel. A high correlation between the electrophysiological recordings and immunofluorescent labeling for the Na(X) channel in dissociated MnPO neurons strongly supports this channel as a candidate for the Na(+) leak channel responsible for the Na(+)-sensing ability of rat MnPO neurons. The absence of Na(X) labeling and of a specific current evoked by a change in [Na(+)](out) in mouse MnPO neurons suggests species specificity in the hypothalamus structures participating in central Na(+) detection.

Endogenous angiotensin II facilitates GABAergic neurotransmission afferent to the Na+-responsive neurons of the rat median preoptic nucleus.

The median preoptic nucleus (MnPO) is densely innervated by efferent projections from the subfornical organ (SFO) and, therefore, is an important relay for the peripheral chemosensory and humoral information (osmolality and serum levels ANG II). In this context, controlling the excitability of MnPO neuronal populations is a major determinant of body fluid homeostasis and cardiovascular regulation. Using a brain slice preparation and patch-clamp recordings, our study sought to determine whether endogenous ANG II modulates the strength of the SFO-derived GABAergic inputs to the MnPO. Our results showed that the amplitude of the inhibitory postsynaptic currents (IPSCs) were progressively reduced by 44 +/- 2.3% by (Sar(1), Ile(8))-ANG II, a competitive ANG type 1 receptor (AT(1)R) antagonist. Similarly, losartan, a nonpeptidergic AT(1)R antagonist decreased the IPSC amplitude by 40.4 +/- 5.6%. The facilitating effect of endogenous ANG II on the GABAergic input to the MnPO was not attributed to a change in GABA release probability and was mimicked by exogenous ANG II, which potentiated the amplitude of the muscimol-activated GABA(A)/Cl(-) current by 53.1 +/- 11.4%. These results demonstrate a postsynaptic locus of action of ANG II. Further analysis reveals that ANG II did not affect the reversal potential of the synaptic inhibitory response, thus privileging a cross talk between postsynaptic AT(1) and GABA(A) receptors. Interestingly, facilitation of GABAergic neurotransmission by endogenous ANG II was specific to neurons responding to changes in the ambient Na(+) level. This finding, combined with the ANG II-mediated depolarization of non-Na(+)-responsive neurons reveals the dual actions of ANG II to modulate the excitability of MnPO neurons.

Postsynaptic mu-opioid receptor response in the median preoptic nucleus is altered by a systemic sodium challenge in rats.

The median preoptic nucleus (MnPO) is an integrator site for the chemosensory and neural signals induced by a perturbation in the hydromineral balance, and it is highly involved in controlling fluid and electrolyte ingestion. Here, we hypothesize that opioid peptides, previously recognized to control ingestive behaviors, may regulate the excitability of MnPO neurons and that this regulatory action may depend on the natriuric (Na(+)) status of body fluid compartments. Our results show that activation of mu-, but not delta-, opioid receptors (OR) triggered a membrane hyperpolarization by recruiting a G-protein-regulated inward-rectifier K(+) (GIRK) conductance in 41% of the neurons tested. Interestingly, 24 h Na(+) depletion strengthened this opioid-mediated control of neuronal excitability. In Na(+)-depleted animals, the neuronal population displaying the mu-OR-induced hyperpolarization expanded to 60% (Z-test, P = 0.012), whereas Na(+) repletion restored this population to the control level (39%; Z-test, P = 0.037). Among the neurons displaying mu-OR-induced hyperpolarization, Na(+) depletion specifically increased the neuronal population responsive to variation in ambient Na(+) (from 27% to 43%; Z-test, P = 0.029). In contrast, Na(+) repletion dramatically reduced the population that was unresponsive to Na(+) (from 17% to 3%; Z-test, P = 0.031). Neither the basic properties of the neurons nor the characteristics of the mu-OR-induced response were altered by the body Na(+) challenge. Our results indicate that an episode of Na(+) depletion/Na(+) repletion modifies the organization of the opioid-sensitive network of the MnPO. Such network plasticity might be related to the avid salt ingestion triggered by repeated Na(+) depletion.

Contribution of neurokinin 1 receptors in the cutaneous orofacial inflammatory pain.

This study investigated the role of neurokinin 1 receptors (NK1R) in inflammatory cutaneous orofacial pain. The effects of subcutaneous and intracisternal administration of the NK1R antagonist SR140333 on the face rubbing response provoked by injection of 50 micro l of 1.5% formalin into the vibrissa pad were examined. Subcutaneous administration of SR140333 (5, 15, 30 mg/kg) induced a dose-related depressant effect on both the first and second phases of the formalin test. In contrast, intracisternal administration of SR140333 (10, 30, 60, 90 microg) produced a decrease only on the second phase with an apparent ceiling effect at approximately 50%. These data suggest that persistent nociceptive effects associated with orofacial cutaneous inflammation depend at least in part on the activation of NK1R.