Discovery of RXFP2 genetic association in resistant hypertensive men and RXFP2 antagonists for the treatment of resistant hypertension.

Hypertension remains a leading cause of cardiovascular and kidney diseases. Failure to control blood pressure with ≥ 3 medications or control requiring ≥ 4 medications is classified as resistant hypertension (rHTN) and new therapies are needed to reduce the resulting increased risk of morbidity and mortality. Here, we report genetic evidence that relaxin family peptide receptor 2 (RXFP2) is associated with rHTN in men, but not in women. This study shows that adrenal gland gene expression of RXFP2 is increased in men with hypertension and the RXFP2 natural ligand, INSL3, increases adrenal steroidogenesis and corticosteroid secretion in human adrenal cells. To address the hypothesis that RXFP2 activation is an important mechanism in rHTN, we discovered and characterized small molecule and monoclonal antibody (mAb) blockers of RXFP2. The novel chemical entities and mAbs show potent, selective inhibition of RXFP2 and reduce aldosterone and cortisol synthesis and release. The RXFP2 mAbs have suitable rat pharmacokinetic profiles to evaluate the role of RXFP2 in the development and maintenance of rHTN. Overall, we identified RXFP2 activity as a potential new mechanism in rHTN and discovered RXFP2 antagonists for the future interrogation of RXFP2 in cardiovascular and renal diseases.

Complement factor C1q mediates sleep spindle loss and epileptic spikes after mild brain injury.

Although traumatic brain injury (TBI) acutely disrupts the cortex, most TBI-related disabilities reflect secondary injuries that accrue over time. The thalamus is a likely site of secondary damage because of its reciprocal connections with the cortex. Using a mouse model of mild TBI (mTBI), we found a chronic increase in C1q expression specifically in the corticothalamic system. Increased C1q expression colocalized with neuron loss and chronic inflammation and correlated with disruption in sleep spindles and emergence of epileptic activities. Blocking C1q counteracted these outcomes, suggesting that C1q is a disease modifier in mTBI. Single-nucleus RNA sequencing demonstrated that microglia are a source of thalamic C1q. The corticothalamic circuit could thus be a new target for treating TBI-related disabilities.

Dach1 Extends Artery Networks and Protects Against Cardiac Injury.

[Figure: see text].

Gamma rhythms and visual information in mouse V1 specifically modulated by somatostatin+ neurons in reticular thalamus.

Visual perception in natural environments depends on the ability to focus on salient stimuli while ignoring distractions. This kind of selective visual attention is associated with gamma activity in the visual cortex. While the nucleus reticularis thalami (nRT) has been implicated in selective attention, its role in modulating gamma activity in the visual cortex remains unknown. Here, we show that somatostatin- (SST) but not parvalbumin-expressing (PV) neurons in the visual sector of the nRT preferentially project to the dorsal lateral geniculate nucleus (dLGN), and modulate visual information transmission and gamma activity in primary visual cortex (V1). These findings pinpoint the SST neurons in nRT as powerful modulators of the visual information encoding accuracy in V1 and represent a novel circuit through which the nRT can influence representation of visual information.

Nanofibrous hyaluronic acid scaffolds delivering TGF-ß3 and SDF-1α for articular cartilage repair in a large animal model.

Focal cartilage injuries have poor intrinsic healing potential and often progress to osteoarthritis, a costly disease affecting almost a third of adults in the United States. To treat these patients, cartilage repair therapies often use cell-seeded scaffolds, which are limited by donor site morbidity, high costs, and poor efficacy. To address these limitations, we developed an electrospun cell-free fibrous hyaluronic acid (HA) scaffold that delivers factors specifically designed to enhance cartilage repair: Stromal Cell-Derived Factor-1α (SDF-1α; SDF) to increase the recruitment and infiltration of mesenchymal stem cells (MSCs) and Transforming Growth Factor-ß3 (TGF-ß3; TGF) to enhance cartilage tissue formation. Scaffolds were characterized in vitro and then deployed in a large animal model of full-thickness cartilage defect repair. The bioactivity of both factors was verified in vitro, with both SDF and TGF increasing cell migration, and TGF increasing matrix formation by MSCs. In vivo, however, scaffolds releasing SDF resulted in an inferior cartilage healing response (lower mechanics, lower ICRS II histology score) compared to scaffolds releasing TGF alone. These results highlight the importance of translation into large animal models to appropriately screen scaffolds and therapies, and will guide investigators towards alternative growth factor combinations. STATEMENT OF SIGNIFICANCE: This study addresses an area of orthopaedic medicine in which treatment options are limited and new biomaterials stand to improve patient outcomes. Those suffering from articular cartilage injuries are often destined to have early onset osteoarthritis. We have created a cell-free nanofibrous hyaluronic acid (HA) scaffold that delivers factors specifically designed to enhance cartilage repair: Stromal Cell-Derived Factor-1α (SDF-1α; SDF) to increase the recruitment and infiltration of mesenchymal stem cells (MSCs) and Transforming Growth Factor-ß3 (TGF-ß3; TGF) to enhance cartilage tissue formation. To our knowledge, this study is the first to evaluate such a bioactive scaffold in a large animal model and demonstrates the capacity for dual growth factor release.

Single-cell analysis of early progenitor cells that build coronary arteries.

Arteries and veins are specified by antagonistic transcriptional programs. However, during development and regeneration, new arteries can arise from pre-existing veins through a poorly understood process of cell fate conversion. Here, using single-cell RNA sequencing and mouse genetics, we show that vein cells of the developing heart undergo an early cell fate switch to create a pre-artery population that subsequently builds coronary arteries. Vein cells underwent a gradual and simultaneous switch from venous to arterial fate before a subset of cells crossed a transcriptional threshold into the pre-artery state. Before the onset of coronary blood flow, pre-artery cells appeared in the immature vessel plexus, expressed mature artery markers, and decreased cell cycling. The vein-specifying transcription factor COUP-TF2 (also known as NR2F2) prevented plexus cells from overcoming the pre-artery threshold by inducing cell cycle genes. Thus, vein-derived coronary arteries are built by pre-artery cells that can differentiate independently of blood flow upon the release of inhibition mediated by COUP-TF2 and cell cycle factors.

DACH1 stimulates shear stress-guided endothelial cell migration and coronary artery growth through the CXCL12-CXCR4 signaling axis.

Sufficient blood flow to tissues relies on arterial blood vessels, but the mechanisms regulating their development are poorly understood. Many arteries, including coronary arteries of the heart, form through remodeling of an immature vascular plexus in a process triggered and shaped by blood flow. However, little is known about how cues from fluid shear stress are translated into responses that pattern artery development. Here, we show that mice lacking endothelial Dach1 had small coronary arteries, decreased endothelial cell polarization, and reduced expression of the chemokine Cxcl12 Under shear stress in culture, Dach1 overexpression stimulated endothelial cell polarization and migration against flow, which was reversed upon CXCL12/CXCR4 inhibition. In vivo, DACH1 was expressed during early arteriogenesis but was down in mature arteries. Mature artery-type shear stress (high, uniform laminar) specifically down-regulated DACH1, while the remodeling artery-type flow (low, variable) maintained DACH1 expression. Together, our data support a model in which DACH1 stimulates coronary artery growth by activating Cxcl12 expression and endothelial cell migration against blood flow into developing arteries. This activity is suppressed once arteries reach a mature morphology and acquire high, laminar flow that down-regulates DACH1. Thus, we identified a mechanism by which blood flow quality balances artery growth and maturation.

Endothelial cells respond to the direction of mechanical stimuli through SMAD signaling to regulate coronary artery size.

How mechanotransduction intersects with chemical and transcriptional factors to shape organogenesis is an important question in developmental biology. This is particularly relevant to the cardiovascular system, which uses mechanical signals from flowing blood to stimulate cytoskeletal and transcriptional responses that form a highly efficient vascular network. Using this system, artery size and structure are tightly regulated, but the underlying mechanisms are poorly understood. Here, we demonstrate that deletion of Smad4 increased the diameter of coronary arteries during mouse embryonic development, a phenotype that followed the initiation of blood flow. At the same time, the BMP signal transducers SMAD1/5/8 were activated in developing coronary arteries. In a culture model of blood flow-induced shear stress, human coronary artery endothelial cells failed to align when either BMPs were inhibited or SMAD4 was depleted. In contrast to control cells, SMAD4-deficient cells did not migrate against the direction of shear stress and increased proliferation rates specifically under flow. Similar alterations were seen in coronary arteries in vivo Thus, endothelial cells perceive the direction of blood flow and respond through SMAD signaling to regulate artery size.

Multidisciplinary protocol for rapid head computed tomography turnaround time in acute stroke patients.

BACKGROUND: The door-to-computed tomography (CT) head reporting time is an essential step to determining eligibility for thrombolysis in acute stroke patients, but the specific components of the process have not been reported in detail. METHODS: We performed a retrospective cross-sectional analysis of the prospectively collected Get-With-The-Guidelines database in our comprehensive stroke center to evaluate the effect of a structured multidisciplinary protocol on head CT times in acute stroke patients under consideration for thrombolysis. RESULTS: The median CT turnaround time in the first 6-month period was 27 (interquartile range [IQR], 27) and decreased in all subsequent periods after implementation of a formal protocol to 18 (IQR, 12; range, 17-20 minutes; P < .0001 for all pairwise comparisons). The median CT turnaround time was 18 (IQR, 12) versus 20 (IQR, 14) minutes for patients with admission diagnosis of stroke (n = 1123) versus nonstroke (n = 685; P < .0001), respectively. CONCLUSIONS: A structured multidisciplinary protocol for obtaining acute stroke protocol head CT scan was associated with reduced CT turnaround time over the study period. Prospective studies should be done to determine if implementation in other stroke centers confirms the effectiveness of our protocol.

The sinus venosus contributes to coronary vasculature through VEGFC-stimulated angiogenesis.

Identifying coronary artery progenitors and their developmental pathways could inspire novel regenerative treatments for heart disease. Multiple sources of coronary vessels have been proposed, including the sinus venosus (SV), endocardium and proepicardium, but their relative contributions to the coronary circulation and the molecular mechanisms regulating their development are poorly understood. We created an ApjCreER mouse line as a lineage-tracing tool to map SV-derived vessels onto the heart and compared the resulting lineage pattern with endocardial and proepicardial contributions to the coronary circulation. The data showed a striking compartmentalization to coronary development. ApjCreER-traced vessels contributed to a large number of arteries, capillaries and veins on the dorsal and lateral sides of the heart. By contrast, untraced vessels predominated in the midline of the ventral aspect and ventricular septum, which are vessel populations primarily derived from the endocardium. The proepicardium gave rise to a smaller fraction of vessels spaced relatively uniformly throughout the ventricular walls. Dorsal (SV-derived) and ventral (endocardial-derived) coronary vessels developed in response to different growth signals. The absence of VEGFC, which is expressed in the epicardium, dramatically inhibited dorsal and lateral coronary growth but left vessels on the ventral side unaffected. We propose that complementary SV-derived and endocardial-derived migratory routes unite to form the coronary vasculature and that the former requires VEGFC, revealing its role as a tissue-specific mediator of blood endothelial development.

Streptococcus bovis septic shock due to contaminated transfused platelets.

Although most physicians and the public are primarily concerned about the risk of transmitting human immunodeficiency virus (HIV) or hepatitis virus during a platelet transfusion, bacterial contamination is actually the most common infectious complication. Unlike red blood cells, platelets are stored at room temperature (20-24 degrees C), which raises the risk of bacterial proliferation. The risk of bacterial sepsis is 2.5-fold higher for each unit of transfused platelets compared to each unit of red blood cells. We report an unusual case of Streptococcus bovis septic shock associated with a contaminated platelet transfusion.

Pelvic congestion syndrome (pelvic venous incompetence): impact of ovarian and internal iliac vein embolotherapy on menstrual cycle and chronic pelvic pain.

PURPOSE: The purpose of this study was to analyze the impact of transcatheter embolotherapy on pain perception and menstrual cycle in women with chronic pelvic pain caused by the presence of ovarian and pelvic varices (ie, women with pelvic congestion syndrome or pelvic venous incompetence). MATERIALS AND METHODS: From July 1998 to August 2000, 56 patients (mean age, 32.3 y) were treated for chronic pelvic pain. Diagnostic venography of the ovarian veins was followed by transcatheter embolotherapy with a sclerosing agent and coils. A second session was completed to embolize the internal iliac veins in 43 of 56 patients. Visual analog scales (VAS) used to measure pain were administered before embolization and at 3-, 6-, and 12-month follow-up. Questionnaires regarding menstrual history were used as part of the postprocedural analysis. RESULTS: Percutaneous transcatheter embolotherapy of ovarian and pelvic varices was technically successful in 56 of 56 patients (100%); three patients developed recurrent varices, two of whom were treated with repeat transcatheter embolotherapy. Two patients, early in the experience, had complications in which coils placed in the internal iliac veins embolized to the pulmonary circulation; the coils were snared without clinical sequelae. On the VAS, the mean baseline pain level was 7.8 (range, 3.2-9.8; n = 56); at 3-month follow-up, it was 4.2 (range, 0.0-7.2; n = 56); at 6 months, 3.8 (range, 0.0-6.7; n = 41); and at 12 months, 2.7 (range, 0.0-6.9; n = 32). Differences were significant (P <.001) between baseline pain levels and those at all follow-up intervals (ie, 3, 6, and 12 months). The mean decrease in VAS was 5.1 (65% decrease). The clinical follow-up in this series ranged between 6 and 38 months; the mean was 22.1 months. Regarding the impact of embolization on menstruation, all 24 patients responding to questionnaires indicated no change in menstrual cycle. CONCLUSION: For patients with ovarian/internal iliac varices, transcatheter embolotherapy provides a nonsurgical treatment option. There is a significant decrease in pain based on VAS without any notable impact on menstrual cycle.