Right ventricular failure (RVF) increases morbidity and mortality. The RECOVER RIGHT study evaluated the safety and efficacy of a novel percutaneous right ventricular assist device, the Impella RP ...(Abiomed, Danvers, MA), in a prospective, multicenter trial.
Thirty patients with RVF refractory to medical treatment received the Impella RP device at 15 United States institutions. The study population included 2 cohorts: 18 patients with RVF after left ventricular assist device (LVAD) implantation (Cohort A) and 12 patients with RVF after cardiotomy or myocardial infarction (Cohort B). The primary end point was survival to 30 days or hospital discharge (whichever was longer). Major secondary end points included indices of safety and efficacy.
The patients (77% male) were a mean age of 59 ± 15 years, 53% had diabetes, 88.5% had a history of congestive heart failure, and 37.5% had renal dysfunction. Patients were on an average of 3.2 inotropes/pressors. Device delivery was achieved in all but 1 patient. Hemodynamics improved immediately after initiation of Impella RP support, with an increase in cardiac index from 1.8 ± 0.2 to 3.3 ± 0.23 liters/min/m(2) (p < 0.001) and a decrease in central venous pressure from 19.2 ± 4 to 12.6 ± 1 mm Hg (p < 0.001). Patients were supported for an average of 3.0 ± 1.5 days (range, 0.5-7.8 days). The overall survival at 30 days was 73.3%. All patients discharged were alive at 180 days.
In patients with life-threatening RVF, the novel percutaneous Impella RP device was safe, easy to deploy, and reliably resulted in immediate hemodynamic benefit. These data support its probable benefit in this gravely ill patient population.
Transected axons fail to regrow across anatomically complete spinal cord injuries (SCI) in adults. Diverse molecules can partially facilitate or attenuate axon growth during development or after ...injury
, but efficient reversal of this regrowth failure remains elusive
. Here we show that three factors that are essential for axon growth during development but are attenuated or lacking in adults-(i) neuron intrinsic growth capacity
, (ii) growth-supportive substrate
and (iii) chemoattraction
-are all individually required and, in combination, are sufficient to stimulate robust axon regrowth across anatomically complete SCI lesions in adult rodents. We reactivated the growth capacity of mature descending propriospinal neurons with osteopontin, insulin-like growth factor 1 and ciliary-derived neurotrophic factor before SCI
; induced growth-supportive substrates with fibroblast growth factor 2 and epidermal growth factor; and chemoattracted propriospinal axons with glial-derived neurotrophic factor
delivered via spatially and temporally controlled release from biomaterial depots
, placed sequentially after SCI. We show in both mice and rats that providing these three mechanisms in combination, but not individually, stimulated robust propriospinal axon regrowth through astrocyte scar borders and across lesion cores of non-neural tissue that was over 100-fold greater than controls. Stimulated, supported and chemoattracted propriospinal axons regrew a full spinal segment beyond lesion centres, passed well into spared neural tissue, formed terminal-like contacts exhibiting synaptic markers and conveyed a significant return of electrophysiological conduction capacity across lesions. Thus, overcoming the failure of axon regrowth across anatomically complete SCI lesions after maturity required the combined sequential reinstatement of several developmentally essential mechanisms that facilitate axon growth. These findings identify a mechanism-based biological repair strategy for complete SCI lesions that could be suitable to use with rehabilitation models designed to augment the functional recovery of remodelling circuits.
There have been tremendous advances in identifying cellular and molecular mechanisms constraining axon growth and strategies have been developed to overcome regenerative failure. However, ...reproducible and meaningful functional recovery remains elusive. An emerging reason is that neurons possess subtype-specific activation requirements. Much of this evidence comes from studying retinal ganglion cells following optic nerve injury. This review summarizes key neuropathologic events following spinal cord injury, and draws on findings from the optic nerve to suggest how a similar framework may be used to dissect and manipulate the heterogeneous and subtype-specific responses of neurons useful to target for spinal cord injury.
In the small intestine, type 2 responses are regulated by a signaling circuit that involves tuft cells and group 2 innate lymphoid cells (ILC2s). Here, we identified the microbial metabolite ...succinate as an activating ligand for small intestinal (SI) tuft cells. Sequencing analyses of tuft cells isolated from the small intestine, gall bladder, colon, thymus, and trachea revealed that expression of tuft cell chemosensory receptors is tissue specific. SI tuft cells expressed the succinate receptor (SUCNR1), and providing succinate in drinking water was sufficient to induce a multifaceted type 2 immune response via the tuft-ILC2 circuit. The helminth Nippostrongylus brasiliensis and a tritrichomonad protist both secreted succinate as a metabolite. In vivo sensing of the tritrichomonad required SUCNR1, whereas N. brasiliensis was SUCNR1 independent. These findings define a paradigm wherein tuft cells monitor microbial metabolites to initiate type 2 immunity and suggest the existence of other sensing pathways triggering the response to helminths.
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•Expression of receptors enabling chemosensing on tuft cells is tissue specific•Tuft cells in the small intestine express the succinate receptor SUCNR1•Succinate is sufficient to induce a multifaceted type 2 immune response•Immune sensing of Tritrichomonas colonization by tuft cells requires SUCNR1
Tuft cells have been proposed to act as immune sentinels in multiple tissues. Nadjsombati and McGinty et al. now show that detection of the microbial metabolite succinate by tuft cells in the small intestine is sufficient to induce a type 2 immune response, suggesting that tuft cells monitor microbial metabolites to initiate type 2 immunity.
Calcium uptake through the mitochondrial Ca2+ uniporter (MCU) is thought to be essential in regulating cellular signaling events, energy status, and survival. Functional dissection of the uniporter ...is now possible through the recent identification of the genes encoding for MCU protein complex subunits. Cancer cells exhibit many aspects of mitochondrial dysfunction associated with altered mitochondrial Ca2+ levels including resistance to apoptosis, increased reactive oxygen species production and decreased oxidative metabolism. We used a publically available database to determine that breast cancer patient outcomes negatively correlated with increased MCU Ca2+ conducting pore subunit expression and decreased MICU1 regulatory subunit expression. We hypothesized breast cancer cells may therefore be sensitive to MCU channel manipulation. We used the widely studied MDA-MB-231 breast cancer cell line to investigate whether disruption or increased activation of mitochondrial Ca2+ uptake with specific siRNAs and adenoviral overexpression constructs would sensitize these cells to therapy-related stress. MDA-MB-231 cells were found to contain functional MCU channels that readily respond to cellular stimulation and elicit robust AMPK phosphorylation responses to nutrient withdrawal. Surprisingly, knockdown of MCU or MICU1 did not affect reactive oxygen species production or cause significant effects on clonogenic cell survival of MDA-MB-231 cells exposed to irradiation, chemotherapeutic agents, or nutrient deprivation. Overexpression of wild type or a dominant negative mutant MCU did not affect basal cloning efficiency or ceramide-induced cell killing. In contrast, non-cancerous breast epithelial HMEC cells showed reduced survival after MCU or MICU1 knockdown. These results support the conclusion that MDA-MB-231 breast cancer cells do not rely on MCU or MICU1 activity for survival in contrast to previous findings in cells derived from cervical, colon, and prostate cancers and suggest that not all carcinomas will be sensitive to therapies targeting mitochondrial Ca2+ uptake mechanisms.
Huntington's disease (HD) is characterized by striatal medium spiny neuron (MSN) dysfunction, but the underlying mechanisms remain unclear. We explored roles for astrocytes, in which mutant ...huntingtin is expressed in HD patients and mouse models. We found that symptom onset in R6/2 and Q175 HD mouse models was not associated with classical astrogliosis, but was associated with decreased Kir4.1 K(+) channel functional expression, leading to elevated in vivo striatal extracellular K(+), which increased MSN excitability in vitro. Viral delivery of Kir4.1 channels to striatal astrocytes restored Kir4.1 function, normalized extracellular K(+), ameliorated aspects of MSN dysfunction, prolonged survival and attenuated some motor phenotypes in R6/2 mice. These findings indicate that components of altered MSN excitability in HD may be caused by heretofore unknown disturbances of astrocyte-mediated K(+) homeostasis, revealing astrocytes and Kir4.1 channels as therapeutic targets.
The lateral force separation of long chain biomolecules is demonstrated using an atomic force microscope (AFM). This is achieved by using an AFM tip to pull molecules away from the edge of a ...nanofluidic solution. By monitoring the torsion on the AFM cantilever, a characteristic force–distance signal is produced when long chain molecules separate and detach from the solvent edge. This lateral force separation using AFM (LFS-AFM) is demonstrated on egg albumin proteins and synthetic DNA strands. The detected length of the protein and nucleotide biopolymers was consistent with their calculated molecular contour length. LFS AFM provides separation and detection of single polymer strands that has potential applications in biochemical analysis, paleontology, and life detection.
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