Histological Changes in the Blood Vessels of Ruptured Human Anterior Cruciate Ligaments.

BACKGROUND: Anterior cruciate ligament (ACL) rupture is a commonly encountered sports injury worldwide. ACL rupture is known to have poor healing capacity, hypothesized to be due to low vascularity. ACL reconstruction surgery with ligament removal and tendon graft became essential for the higher grades of ACL tears. However, ACL-reconstructed patients faced post-traumatic osteoarthritis 10-15 years after surgery. In the recent past, the tibial remnant of ACL was shown to have intrinsic healing potential. Blood vessel density and the location of blood vessels of ACL remnants have critical implications in the newly upcoming remnant-preservation ACL reconstruction surgeries that showed better healing response. This study was performed to characterize the histological features of ruptured ACL remnants in terms of blood vessels to assess the healing potential and their utility in novel surgical techniques. METHODS: This was a descriptive cross-sectional study in which the tibial remnant of 24 ruptured ACL samples was evaluated for blood vessel density (per sq. mm), luminal area (sq. µm), and location of blood vessels using hematoxylin and eosin (H&E) staining with ImageJ software (U. S. National Institutes of Health, Bethesda, Maryland, USA). The blood vessel density and location of blood vessels were compared among various groups based on the duration of injury and number of injuries. RESULTS: Twenty-three male and one female adult patients with a mean duration of injury of 7.54 ± 5.63 months (range: 2-24 months) were included in the study. They were divided into three groups based on duration of injury: group I (2-5 months; n = 10), group II (6-8 months; n = 8), and group III (9-24 months; n = 6). The median blood vessel density (blood vessels per sq. mm) was 5.50 (3.30, 10.23) per sq. mm. There was no correlation of blood vessel density observed with duration of injury. All groups showed similar results statistically. More patients in earlier duration of injury showed very high range (10.1-40 per sq. mm) of blood vessels compared to the patients of later duration. Immature and intermediary blood vessels were identified denoting angiogenesis. Location of blood vessels varied in the groups based on duration of injury. There was no significant difference in blood vessel density and location of blood vessels between patients with single injury and those with multiple injuries. CONCLUSION: The present study demonstrates the presence of healing potential of ruptured anterior cruciate ligaments in terms of blood vessel density, luminal area, and location of blood vessels. Future studies looking into the functional outcome would enhance the understanding of utility of novel remnant-preservation surgeries in place of standard graft reconstruction surgeries.

Characterization of human placental fetal vessels in gestational diabetes mellitus.

Gestational diabetes mellitus is one of the most common complications during pregnancy. Its prevalence is rapidly increasing worldwide. Gestational diabetes mellitus is leading to an elevated risk for the development of endothelial dysfunction and cardiovascular diseases both in the mother and the child in later life. The underlying pathophysiological mechanisms are not well-understood. Therefore, we aimed to characterize the endothelial function in fetal placental vessels from mothers with gestational diabetes mellitus. In this study, we distinguished between insulin-treated and diet-controlled gestational diabetes mothers and compared them to a normoglycemic control group. The clinical data confirmed pre-conceptional overweight as a risk factor in women with insulin-treated gestational diabetes mellitus. The insulin-treated gestational diabetes group was also characterized by a recent family history of diabetes compared to mothers of the control or diet-controlled gestational diabetes group. Analyses of blood serum from umbilical cords suggested a reduced fetal insulin metabolism in the insulin-treated gestational diabetes group. Vascular function analysis in fetal placental vessels revealed an altered substance P-induced vasorelaxation in vessels from patients with insulin-dependent gestational diabetes. Inhibition of nitric oxide synthase affected only fetal vessel segments from the control group or diet-controlled gestational diabetes group, but not from insulin-dependent gestational diabetes. Finally, we found a significantly decreased substance P receptor (TACR1) mRNA expression in fetal vessel segments from patients with insulin-treated gestational diabetes. In conclusion, we provide evidence that different pathophysiological mechanisms might be responsible for the development of insulin-treated versus diet-controlled gestational diabetes. Only in fetal vessels from patients with insulin-treated gestational diabetes were we able to detect an endothelial dysfunction and a reduced fetal insulin conversion. This provides novel insights into the pathophysiology of the subtypes of gestational diabetes.

COVID-19 shed light on Virchow's law of thrombosis.

Virchow's law of thrombosis states that thrombosis in a vessel occurs as a combination of the following: (i) injury to the vessel wall, (ii) stasis of blood flow, and (iii) blood hypercoagulability. Injury to the wall includes infection/inflammation and/or injury to the resident cells of the wall. We postulate that in COVID-19, the SARS-CoV-2 virus directly infects the alveolar type II cell or directly or indirectly infects/injures the pericyte, promoting inflammation and interaction with endothelial cells, thereby causing a cascade of events leading to our observation that thrombosis occurred within the walls of the pulmonary vessels and not in the lumen of the vascular circulation.

MIS-C Like Features in a Patient of Atypical Kawasaki Disease: A Case Report.

ABSTRACT: Kawasaki Disease is multisystem vasculitis affecting young children and infants. While the diagnosis of a typical form of Kawasaki Disease is obvious, there are some patients who do not fulfill the classic diagnostic criteria for the disease which is termed as 'incomplete Kawasaki Disease' or 'Atypical Kawasaki Disease'. We present a case of a 6 months old child with fever who after failing to respond to IV antibiotics showed considerable improvement after administering aspirin and Intravenous Immunoglobulin thus diagnosed as Atypical Kawasaki Disease. Moreover, due to sharing of similar features by both Kawasaki Disease and Multiple Inflammatory Syndrome in Children, the case posed a diagnostic dilemma.

Cerebral small vessel injury in mice with damage to ACE2-expressing cerebral vascular endothelial cells and post COVID-19 patients.

INTRODUCTION: The angiotensin-converting enzyme 2 (ACE2), which is expressed in cerebral vascular endothelial cells (CVECs), has been currently identified as a functional receptor for SARS-CoV-2. METHODS: We specifically induced injury to ACE2-expressing CVECs in mice and evaluated the effects of such targeted damage through magnetic resonance imaging (MRI) and cognitive behavioral tests. In parallel, we recruited a single-center cohort of COVID-19 survivors and further assessed their brain microvascular injury based on cognition and emotional scales, cranial MRI scans, and blood proteomic measurements. RESULTS: Here, we show an array of pathological and behavioral alterations characteristic of cerebral small vessel disease (CSVD) in mice that targeted damage to ACE2-expressing CVECs, and COVID-19 survivors. These CSVD-like manifestations persist for at least 7 months post-recovery from COVID-19. DISCUSSION: Our findings suggest that SARS-CoV-2 may induce cerebral small vessel damage with persistent sequelae, underscoring the imperative for heightened clinical vigilance in mitigating or treating SARS-CoV-2-mediated cerebral endothelial injury throughout infection and convalescence. HIGHLIGHTS: Cerebral small vessel disease-associated changes were observed after targeted damage to angiotensin-converting enzyme 2-expressing cerebral vascular endothelial cells. SARS-CoV-2 may induce cerebral small vessel damage with persistent sequelae. Clinical vigilance is needed in preventing SARS-CoV-2-induced cerebral endothelial damage during infection and recovery.

Intracoronary thrombolysis combined with drug balloon angioplasty in a young ST-segment elevation myocardial infarction patient: A case report.

BACKGROUND: The combination of acute ST-segment elevation myocardial infarction (STEMI) and gastric ulcers poses a challenge to primary percutaneous coronary intervention (PPCI), particularly for young patients. The role of drug-coated balloons (DCBs) in the treatment of de novo coronary artery lesions in large vessels remains unclear, especially for patients with STEMI. Our strategy is to implement drug balloon angioplasty following the intracoronary administration of low-dose prourokinase and adequate pre-expansion. CASE SUMMARY: A 54-year-old male patient presented to the emergency department due to chest pain on June 24, 2019. Within the first 3 minutes of the initial assessment in the emergency room, the electrocardiogram (ECG) showed significant changes. There was atrial fibrillation with ST-segment elevation. Subsequently, atrial fibrillation terminated spontaneously and reverted to sinus rhythm. Soon after, the patient experienced syncope. The ECG revealed torsades de pointes ventricular tachycardia. A few seconds later, it returned to sinus rhythm. High-sensitivity tropon in I was normal. The diagnosis was acute STEMI. Emergency coronary angiography revealed subtotal occlusion with thrombus formation in the proximal segment of the left anterior descending artery. Considering the patient's age and history of peptic ulcer disease, after the intracoronary injection of prourokinase, percutaneous transluminal coronary angioplasty and cutting balloon angioplasty were conducted for thorough preconditioning, and paclitaxel drug-eluting balloon angioplasty was performed without any stents, achieving favorable outcomes. CONCLUSION: A PPCI without stents may be a viable treatment strategy for select patients with STEMI, and further research is warranted.

Higher small pulmonary artery and vein volume on computed tomography is associated with mortality in current and former smokers.

BACKGROUND: In chronic obstructive pulmonary disease (COPD), vascular alterations have been shown to contribute to hypoxia and pulmonary hypertension, but the independent contribution of small vessel abnormalities to mortality remains unclear. METHODS: We quantified artery and vein dimensions on computed tomography (CT) down to 0.2 mm. Small vessel volumes (<1 mmᴓ) were normalized by body surface area. In 7903 current and former smokers of the COPDGene study (53.2% male) the independent contribution of small artery and small vein volume to all-cause mortality was tested in multivariable Cox models. Additionally, we calculated the 95th percentile of small arteries and veins in 374 never smokers to create two groups: normal and high small artery or vein volume. We describe clinical, physiological and imaging characteristics of subjects with a high small artery and high small vein volume. FINDINGS: Both high small artery and high small vein volumes were independently associated with mortality with an adjusted hazard ratio of 1.07 [1.01, 1.14] and 1.34 [1.21, 1.49] per mL/m2 increase, respectively. In COPDGene, 447 (5.7%) had high small artery volume and 519 (9.1%) subjects had high small vein volume and both had more emphysema, more air trapping and more severe coronary calcium. INTERPRETATION: In smokers, abnormally high volumes in small arteries and veins are both relevant for mortality, which urges investigations into the aetiology of small pulmonary vessels and cardiac function in smokers. FUNDING: Award Number U01-HL089897 and U01-HL089856 from the NHLBI. COPD Foundation with contributions from AstraZeneca, Boehringer Ingelheim, Genentech, GlaxoSmithKline, Novartis, Pfizer, Siemens, and Sunovion.

Sampling strategy, quantification, characterization and hazard potential assessment of greywater from ships in the Baltic Sea.

Ship-generated greywater contains a variety of pollutants which, through various pathways, usually are discharged into the sea. To understand the seasonal variation in greywater volumes, the contaminant concentrations in, and the potential hazard of, ship-generated greywater streams, a four-phase strategy for sampling, characterization and hazard assessment of greywater was developed and implemented. Eight greywater streams, sampled from five ships, were characterized for selected pollutants. The metals Zn, Cu, Mn and the metalloid, As, collectively contributed 98 % to the Hazard Index. Laundry greywater had the highest average concentration of phosphorus (42 mg/l) while galley greywater had the highest average concentration of nitrogen (30 mg/l). The geometric means of COD-Cr, BOD5, TSS and P exceeded the IMO resolution MEPC 227(64) guideline values for sewage effluent from Advanced Wastewater Treatment Plants. The results establish the basis for and contribute to discussions on, the optimization of ship-generated greywater management and the establishment of potential regulatory strategies in the Baltic Region.

Accessing the vasculature in cancer: revising an old hallmark.

The classic cancer hallmark, inducing angiogenesis, was born out of the long-held notion that tumours could grow only if new vessels were formed. The attempts, based on this premise, to therapeutically restrain angiogenesis in hopes of controlling tumour growth have been less effective than expected. This is partly because primary and metastatic tumours can grow without angiogenesis. The discovery of nonangiogenic cancers and the mechanisms they use to exploit normal vessels, called 'vessel co-option,' has opened a new field in cancer biology. Consequently, the cancer hallmark, 'inducing angiogenesis,' has been modified to 'inducing or accessing vasculature.'

Soybean Isoflavones Alleviate Osteoarthritis Through Modulation of the TSC1/mTORC1 Signaling Pathway to Reduce Intrachondral Angiogenesis.

BACKGROUND: The incidence of osteoarthritis (OA) is increasing, yet its pathogenesis remains largely unknown. Recent studies suggest that abnormal subchondral bone remodeling plays a crucial role in OA development, highlighting a gap in clinical treatments targeting this aspect. Soybean Isoflavone (SI) has shown potential in treating OA, although its mechanisms are not fully understood. METHODS: This research investigated the effects of SI on subchondral bone remodeling in an OA rat model, assessing joint damage, OARSI scores, and type H vessel formation (CD31hiEmcnhi expression). Additionally, the expression of ALP, OCN, BMP, and TSC1 was evaluated to determine involvement of the mTORC1 pathway. In vitro studies on IL-1ß-induced osteoblasts further examined the impact of SI on TSC1/mTORC1 signaling and related markers. RESULTS: SI treatment reduced joint damage and OARSI scores in the rat OA model, significantly decreasing CD31hiEmcnhi expression, indicating a reduction in type H vessel formation. SI also downregulated ALP, OCN, and BMP expression while upregulating TSC1, suggesting inhibition of the mTORC1 signaling pathway and VEGF release. In vitro, SI increased TSC1 expression and decreased mTORC1 signaling, VEGF, ALP, OCN, and BMP levels in IL-1ß-induced osteoblasts. CONCLUSION: SI targets the TSC1/mTORC1 signaling pathway to suppress osteoblast activation and VEGF release, inhibiting type H vessel formation and slowing abnormal subchondral bone remodeling. These findings provide a novel therapeutic approach for OA by focusing on subchondral bone remodeling mechanisms.

Vitreous Tissue Cryopreservation Using a Blood Vessel Model and Cryomacroscopy for Scale-Up Studies: Observations and Mathematical Modeling.

Successful long term cryobanking of multicellular tissues and organs at deep subzero temperatures calls for the avoidance of ice cryoinjury by reliance upon ice-free cryopreservation techniques. However, the quality of the cryopreserved material is the direct result of its ability to survive a host of harmful mechanisms, chief among which is overcoming the trifecta effects of ice crystallization, toxicity, and mechanical stress. This study aims at exploring improved conditions to scale-up ice-free cryopreservation by combining DP6 as a base cryoprotective agent (CPA) solution with an array of synthetic ice modulators (SIMs). This study is conducted by integrating cryomacroscopy techniques, thermal modeling, solid mechanics analysis, and viability and contractility investigation to correlate physical effects, thermal outcomes, and cryobiology results. As an extension of previous work, this study aims at scale-up of established baseline blood vessel models, while comparing the relative toxicity and vitreous stability of 4ml and 10ml samples of DP6 containing either sucrose as a SIM, or the commercial synthetic ice blockers (X1000 and Z1000). Using that established protocol, the addition and removal of DP6+0.6M sucrose and DP6+1%X1000+1%Z1000 were both well tolerated in rabbit carotid and pig femoral artery models, when assessed for metabolic recovery and contractility. Using cryomacroscopy, it was demonstrated that DP6+0.6M sucrose provided a stable vitrification medium under marginal cooling and warming conditions that resulted in >50% survival rate. By contrast, DP6+1%X1000+1%Z1000 was subject to visible ice formation during cooling under the same thermal conditions, resulting in a significantly lower recovery of ∼20%. Thermal modeling is used in this study to verify the actual cooling and rewarming rates in the specimens, while thermo-mechanics analysis is used to explain why fractures were observed using cryomacroscopy when the specimens were contained in glass vials but not in plastic vials.

Deferoxamine Accelerates Mandibular Condylar Neck Fracture Early Bone Healing by Promoting Type H Vessel Proliferation.

BACKGROUND: Condylar fractures (CFs) are a common type of maxillofacial trauma, especially in adolescents. Conservative treatment of CF avoids the possible complications of surgical intervention, but prolongs the patient's suffering because of the requirement for extended intermaxillary fixation. Therefore, the development of a new strategy to accelerate the rate of fracture healing to shorten the period of conservative treatment is of great clinical importance. OBJECTIVE: To investigate the potential of deferoxamine (DFO) in promoting the healing process of CF in adolescent mice. METHODS: Thirty-two 4-week-old male C57BL/6J mice were randomly assigned to four groups: vehicle + sham group, vehicle + CF group, DFO + sham group and DFO + CF group. After constructing the mandibular CF model, mandibular tissue samples were collected respectively at 1, 2 and 4 weeks postoperatively. Radiographic and histomorphometric analyses were employed to assess bone tissue healing and vascular formation. RESULTS: Deferoxamine was observed to promote the early bone healing of fracture, both radiologically and histomorphometrically. Furthermore, this enhancement of condylar neck fracture healing was attributed to the upregulation of the hypoxia-inducible factor-1α (HIF-1α) signalling pathway while facilitating the formation of type H vessels. In addition, DFO did not produce significant effects on the condylar neck between vehicle + sham and DFO + sham group. CONCLUSION: The application of the HIF-1α inducer DFO can enhance type H vessels expansion thereby accelerating condylar neck fracture healing.

Upper eyelid lymphatic anatomy is associated with blepharoplasty recovery.

BACKGROUND: Lymphatic vessels support wound recovery and absorb excess fluid. Blepharoplasty involves excess tissue excision, and this study investigated the relationship between lymph vessel density in excised tissue and the postoperative course. METHODS: Forty eyelids from 21 patients with blepharoptosis who underwent blepharoplasty were included. Each resected excess tissue sample was divided into 4 parts by 3 parasagittal cuts-medial, central, and lateral. The area percentages occupied by lymphatic vessels and elastic fibers in the inner tissue between skin and muscle, exposed by these cuts, were determined histologically. The wound-healing process was assessed at 2 weeks and 1, 3, and 6 months postoperatively, using a visual analog scale (VAS) to estimate edema and the Vancouver Scar Scale (VSS) for scar assessment. RESULTS: With increasing age, the area percentage of lymphatic vessels declined significantly (r = -0.581, p < 0.001), while an increase in solar elastosis was observed. The percentage of lymphatic vessels was highest on the medial side of the eyelid (p < 0.05), where their relative distribution to the "shallow layer" close to the skin was also the highest (p < 0.01). Independent of age, the VSS values at 2 weeks and 1 month postoperatively were significantly lower in patients with a higher area percentage of lymphatic vessels (2 weeks: p < 0.05; 1 month: p < 0.01). CONCLUSIONS: In patients undergoing blepharoplasty, the percentage of lymphatic vessels in the upper eyelid tissue decreased with advancing age. Higher proportions of lymphatic vessels were associated with improved wound-healing outcomes.

The Effect of Cryotherapy on Buccal Blood Vessels Evaluated by Optical Coherence Tomography Angiography: A Pilot Study.

While cryotherapy is one of the traditional ways to reduce postoperative complications in maxillofacial surgery, the cooling degree is not regulated in most cases and the achieved effect is not properly controlled. Therefore, to develop optimal cooling modes, we propose to study the buccal vascular response to cooling, which has not been previously shown. To evaluate the effect of cooling, we analyzed vessel networks using optical coherence tomography angiography (OCT-A). The cheek vessels were OCT-A monitored using cooling by an ice bag/cooling mask. We found the advantages of using a cooling mask over an ice bag consist of a statistically significant decrease in the perfused vessel density (PVD) of the papillary layer at the oral mucosa. The absence of the reticular layer vessel reaction to any type of cooling was noted. We argue for the necessity to develop optimal modes of cryotherapy, which will contribute to blood perfusion reduction and reduction of PVD recovery.

In vivo spatiotemporal characterizing diverse body transportation of optical labeled high immunity aluminium adjuvants with photoacoustic tomography.

Vaccine development requires high-resolution, in situ, and visual adjuvant technology. To address this need, this work proposed a novel adjuvant labeling that involved indocyanine green (ICG) and bovine serum albumin (BSA) with self-assembled aluminium adjuvant (Alum), which was called BSA@ICG@Alum. This compound exhibited excellent photoacoustic properties and has been confirmed its safety, biocompatibility, high antigen binding efficiency, and superior induction of immune response. Photoacoustic tomography (PAT) tracked the distribution of Alum in lymph nodes (LNs) and lymphatic vessels in real time after diverse injection modalities. The non-invasive imaging approach revealed that BSA@ICG@Alum was transported to the draining LNs 60 min after intramuscular injection and to distal LNs within 30 min after lymph node injection. In conclusion, PAT enabled real-time three-dimensional and quantitative visualization, thus offering a powerful tool for advancing vaccine design by providing critical insights into adjuvant transport and immune system activation.

Application of superb microvascular imaging technology in clinical disease activity of rheumatoid arthritis.

OBJECTIVES: Detection of synovitis is essential for assessing the activity and predicting the prognosis of rheumatoid arthritis (RA). The aim of this study was to investigate the diagnostic performance of superb microvascular imaging (SMI) in RA patients with high, moderate, and low activity. METHODS: One hundred four patients with active RA were selected from the hospital between May 2022 and August 2023. The study observed the correlation between bone erosion of the carpal joint, joint cavity effusion, thickness of synovial hyperplasia of the carpal joint, positivity rate of synovial blood vessels, and their semiquantitative scores with the clinical disease activity of RA using SMI examination. RESULTS: The detection of synovial hyperplasia thickness and joint effusion in the high-activity group was higher than that in the low-activity group, and the difference was statistically significant (P < 0.05). The quantitative SMI test demonstrated that the synovial blood flow grading and semiquantitative grade increased gradually with activity level (P<0.05). During the high, moderate, and low-activity groups, the vascular index (VI) value of the hyperplastic synovial membrane decreased gradually, showing statistical significance both between and within the groups (P<0.05). CONCLUSION: SMI technology exhibited high sensitivity and accuracy in assessing disease activity in RA. It holds significant clinical application value as a reliable auxiliary tool for assessing disease activity in RA and treatment. Key Points • Super micro-vascular imaging (SMI) demonstrated higher detection rates of microvessels in RA patients with high disease activity compared to those with low activity, showing statistical significance. • The quantitative SMI test revealed a clear correlation between synovial blood flow grading and disease activity levels in RA patients, highlighting the potential of SMI as a valuable tool for disease activity and treatment of rheumatoid arthritis.

Artificial Meshed Vessel-Induced Dimensional Breaking Growth of Human Brain Organoids and Multiregional Assembloids.

Brain organoids are widely used to model brain development and diseases. However, a major challenge in their application is the insufficient supply of oxygen and nutrients to the core region, restricting the size and maturation of the organoids. In order to vascularize brain organoids and enhance the nutritional supply to their core areas, two-photon polymerization (TPP) 3D printing is employed to fabricate high-resolution meshed vessels in this study. These vessels made of photoresist with densely distributed micropores with a diameter of 20 µm on the sidewall, are cocultured with brain organoids to facilitate the diffusion of culture medium into the organoids. The vascularized organoids exhibit dimensional breaking growth and enhanced proliferation, reduced hypoxia and apoptosis, suggesting that the 3D-printed meshed vessels partially mimic vascular function to promote the culture of organoids. Furthermore, cortical, striatal and medial ganglionic eminence (MGE) organoids are respectively differentiated to generate Cortico-Striatal-MGE assembloids by 3D-printed vessels. The enhanced migration, projection and excitatory signaling transduction are observed between different brain regional organoids in the assembloids. This study presents an approach using TPP 3D printing to construct vascularized brain organoids and assembloids for enhancing the development and assembly, offering a research model and platform for neurological diseases.

Meningeal lymphatic function promotes oligodendrocyte survival and brain myelination.

The precise neurophysiological changes prompted by meningeal lymphatic dysfunction remain unclear. Here, we showed that inducing meningeal lymphatic vessel ablation in adult mice led to gene expression changes in glial cells, followed by reductions in mature oligodendrocyte numbers and specific lipid species in the brain. These phenomena were accompanied by altered meningeal adaptive immunity and brain myeloid cell activation. During brain remyelination, meningeal lymphatic dysfunction provoked a state of immunosuppression that contributed to delayed spontaneous oligodendrocyte replenishment and axonal loss. The deficiencies in mature oligodendrocytes and neuroinflammation due to impaired meningeal lymphatic function were solely recapitulated in immunocompetent mice. Patients diagnosed with multiple sclerosis presented reduced vascular endothelial growth factor C in the cerebrospinal fluid, particularly shortly after clinical relapses, possibly indicative of poor meningeal lymphatic function. These data demonstrate that meningeal lymphatics regulate oligodendrocyte function and brain myelination, which might have implications for human demyelinating diseases.

Expression of mRNA for molecules that regulate angiogenesis, endothelial cell survival, and vascular permeability is altered in endothelial cells isolated from db/db mouse hearts.

Metabolic syndrome (MetS) is a condition that includes symptoms, such as obesity, hyperglycemia, and hypertension, which elevate cardiovascular risk. An impaired angiogenic response of endothelial cells (ECs) in heart and peripheral organs has been proposed in MetS, but the mechanisms of this phenomenon have not been thoroughly explored. Results obtained from evaluating the whole myocardium are inconsistent, since different types of cells react differently to MetS environment and a variety of molecular pathways are involved in the angiogenic response. Therefore, the aim of this paper was to study one selected pathway-the VEGF/VEGFR pathway, which regulates the angiogenic response and microvascular permeability in ECs isolated from db/db mouse hearts. The expression of mRNAs for VEGF/VEGFR axis proteins was assessed with RT-PCR in ECs isolated from control and db/db mouse myocardium. The density of CD31-, VEGFR2-, and VE-cadherin-positive cells was examined with confocal microscopy, and the ultrastructure of ECs was analyzed with transmission electron microscopy. The aortic ring assay was used to assess the capacity of ECs to respond to angiogenic stimuli. Our results showed a decreased number of microvessels, diminished expression of VE-cadherin and VEGFR2 and widened gaps between the ECs of microcapillaries. The aortic ring assay showed a diminished number of sprouts in db/db mice. These results may indicate that ECs in MetS enhance the production of mRNA for VEGF/VRGFR axis proteins, yet sprout formation and vascular barrier maintenance are limited. These novel data may provide a foundation for further studies on ECs dysfunction in MetS.

Myonuclear position and blood vessel organization during skeletal muscle postnatal development.

Skeletal muscle development is a complex process involving myoblast fusion to generate multinucleated fibers. Myonuclei first align in the center of the myotubes before migrating to the periphery of the myofiber. Blood vessels (BVs) are important contributors to the correct development of skeletal muscle, and myonuclei are found next to BVs in adult muscle. Here, we show that most myonuclear migration to the periphery occurs between embryonic day 17.5 and postnatal day 1 in mouse. Furthermore, myonuclear accretion after postnatal day 7 does not result in centrally nucleated myofibers as observed in the embryo. Instead, myonuclei remain at the periphery of the myofiber without moving to the center. Finally, we show that hypovascularization of skeletal muscle alters the interaction between myonuclei and BVs, suggesting that BVs may contribute to myonuclear positioning during skeletal muscle postnatal development. Overall, this work provides a comprehensive analysis of skeletal muscle development during the highly dynamic postnatal period, bringing new insights about myonuclear positioning and its interaction with BVs.