Capillary Density Research Articles

Aerobic Exercise Prevents High-Fat-Diet-Induced Adipose Tissue Dysfunction in Male Mice

Background/Objectives: This study aimed to assess the effect of aerobic exercise on capillary density and vascular smooth muscle cell (VSMC) phenotype in the visceral and subcutaneous adipose tissue of high-fat-diet (HFD) mice in order to understand the mechanisms underlying improvements in insulin resistance (IR) and chronic inflammation in adipose tissue (AT). Methods: Male C57BL/6J mice were divided into HFD and normal diet groups for 12 weeks and then further split into sedentary and aerobic exercise subgroups for an additional 8 weeks. Various parameters including body weight, fat weight, blood glucose, lipid profile, insulin levels, glucose tolerance, and inflammatory cytokines were evaluated. Results: Aerobic exercise reduced HFD-induced weight gain, IR, and improved lipid profiles. HFD had a minimal effect on inflammatory cytokines except in visceral adipose tissue (VAT). IR was associated with capillary density in subcutaneous adipose tissue (SAT) and VSMC phenotype in VAT. Aerobic exercise promoted anti-inflammatory responses in VAT, correlating with VSMC phenotype in this tissue. Conclusions: Aerobic exercise can alleviate HFD-induced IR and inflammation through the modulation of VSMC phenotype in AT.

6912 Nail Fold Capillary Findings In Patients With Somatic EPAS1 Pathogenic Variants

Abstract Disclosure: H. Alkaissi: None. B. Turturice: None. J.S. Rosenblum: None. A.S. Alzahrani: None. S. Talvacchio: None. A. Derkyi: None. M. Nazari: None. H. Wang: None. I. Pinal Fernandez: None. Z. Zhuang: None. K. Pacak: None. We recently discovered a new syndrome characterized by a triad of pheochromocytoma/paraganglioma, polycythemia, and somatostatinoma (so called Pacak-Zhuang syndrome) caused by somatic gain-of-function pathogenic variants in the EPAS1 gene, encoding hypoxia-inducible factor 2α (HIF-2α). Recently, we have described additional features of this syndrome, including systemic developmental vascular malformations in patients and the mouse model [1]. Here we evaluated vascular changes in the nailfold capillaries by using video capillaroscopy in four patients, three of whom were female and carried the same pathogenic somatic EPAS1 variant allele (EPAS1A530V). The first patient is an 18-year-old female with a history of ventricular septal defect since birth, acrocyanosis, abdominal paraganglioma, left adrenal pheochromocytoma, and polycythemia. The second patient is a 64-year-old female who presented with paraganglioma without polycythemia, in whom we found the EPAS1A530V variant from hair sample, and an additional variant (EPAS1P53[1]A) in a resected paraganglioma, confirming the diagnosis. The third patient is a 33-year-old female had polycythemia, right adrenal pheochromocytoma, abdominal paragangliomas and duodenal somatostatinoma. The fourth patient is a 25-year-old male with PZS bearing a somatic EPAS1M535V pathogenic variant and an additional D536_L542 deletion, with hypoplastic left ventricle and metastatic paraganglioma who never developed polycythemia due to concomitant sickle cell-thalassemia traits. Despite the notable differences in genotype between the first three patients compared to the fourth patient, whose genotype is more complex, nailfold video capillaroscopy of all these patients showed similar phenotype—abnormal capillary structure marked by widespread dilations, megacapillaries, sporadic capillary hemorrhages, and regions with diminished capillary density. While polycythemia has been implicated in megacapillaries phenotype, two of our patients did not have polycythemia at the time of evaluation, further supporting the role of HIF-2a in angiogenesis. In conclusion, we describe nailfold capillary changes on video capillaroscopy as a non-invasive clinical sign in patients with EPAS1 pathogenic variants. Whether this finding is due to circulating angiogenic factors secreted by the tissues harboring HIF-2α mutation, or a direct effect of HIF-2α on angiogenesis remains to be determined.

Repeated treatment with VEGF receptor inhibitors induces phenotypic changes in endothelial cells and pericytes in the rat retina

Abnormal ocular angiogenesis is a major cause of visual impairment and vision loss in neovascularization-related diseases. Currently, anti-vascular endothelial growth factor (VEGF) drugs are used to treat ocular neovascularization, but repeated injections are needed to maintain their therapeutic effects. However, repeated injection of anti-VEGF drugs may affect the retinal blood vessel phenotype and diminish therapeutic effects. In this study, we aimed to investigate the phenotypic changes in endothelial cells and pericytes caused by the repeated interruption of the VEGF receptor signaling pathway in neonatal rats. KRN633 (10 mg/kg), a VEGF receptor tyrosine kinase inhibitor, was subcutaneously administered on postnatal day (P)-7 and P8 (first round), P14 and P15 (second round), and P21 and P22 (third round). The rat eyes were collected on P7, P9, P14, P16, P21, P23, P28, and P35. Using retinal flat-mount specimens stained with specific markers for vascular endothelial cells, basement membranes, and pericytes, the arteriolar tortuosity, capillary area density, and distribution of pericytes were evaluated. Significant loss of capillaries was observed the day after the first round of KRN633 treatment, after which aggressive angiogenesis occurred, leading to the formation of tortuous arterioles. Rats that completed second and third rounds of KRN633 treatment showed more severe abnormalities in the retinal vasculature than those that only completed first round treatment. Repeated treatment with KRN633 decreased the anti-angiogenic effects but increased the immunoreactivity of α-smooth muscle actin in the pericytes on veins and capillaries. α-Smooth muscle actin expression was inversely correlated to anti-angiogenic effects. Overall, these results revealed that repeated interruption of VEGF receptor signaling pathway altered the phenotypes of endothelial cells and pericytes and induced anti-VEGF drug resistance. Therefore, careful follow-up is necessary when using anti-VEGF drugs to treat abnormal angiogenesis-associated ocular diseases.

Optical Coherence Tomography Angiography of Macular Microangiopathy in Children With Sickle Cell Disease.

In this study, we identified the presence of sickle cell maculopathy and determined correlations between hemolysis indicators and systemic and ocular manifestations in children with sickle cell disease (SCD). Thirty-three patients with SCD 5 to 18 years of age underwent optical coherence tomography angiography (OCTA) as part of a thorough eye examination. The hematological indices and clinical data (hemoglobin, fetal hemoglobin, mean corpuscular volume, and frequency of sickle cell-associated complications and therapy) were collected. The SCD group contained 33 patients (66 eyes), and the control group contained 36 healthy participants (72 eyes). The SCD group had significantly thinner parafoveal thickness ( P =0.041) and significantly smaller parafoveal volume ( P =0.041) than the controls. The SCD group had lower deep capillary plexus density than the controls ( P =0.029). The SCD group had significantly smaller flow areas than the controls ( P <0.001). The foveal avascular zone (FAZ) perimeter, foveal density, and FAZ area in the entire retina did not differ significantly between the groups ( P >0.05). The platelet level was negatively correlated with parafoveal and perifoveal thickness and density. OCTA detected early macular microvascular changes in children and adolescents with asymptomatic SCD.

Decreased Liver Kinase B1 Expression and Impaired Angiogenesis in a Murine Model of Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is characterized by impaired lung alveolar and vascular growth. We investigated the hypothesis that neonatal exposure to hyperoxia leads to persistent BPD phenotype caused by decreased expression of liver kinase B1 (LKB1), a key regulator of mitochondrial function. We exposed mouse pups from Postnatal Day (P)1 through P10 to 21% or 75% oxygen. Half of the pups in each group received metformin or saline intraperitoneally from P1 to P10. Pups were killed at P4 or P10 or recovered in 21% O2 until euthanasia at P21. Lung histology and morphometry, immunofluorescence, and immunoblots were performed to detect changes in lung structure and expression of LKB1; downstream targets AMPK, PGC-1α, and electron transport chain (ETC) complexes; and Notch ligands Jagged 1 and delta-like 4. LKB1 signaling and invitro angiogenesis were assessed in human pulmonary artery endothelial cells (exposed to 21% or 95% O2 for 36 hours. Levels of LKB1, phosphorylated AMPK, PGC-1α, and ETC complexes were decreased in lungs at P10 and P21 in hyperoxia. Metformin increased LKB1, phosphorylated AMPK, PGC-1α, and ETC complexes at P10 and P21 in pups exposed to hyperoxia. Radial alveolar count was decreased, and mean linear intercept increased in pups exposed to hyperoxia at P10 and P21; these were improved by metformin. Lung capillary density was decreased in hyperoxia at P10 and P21 and was increased by metformin. In vitro angiogenesis was decreased in human pulmonary artery endothelial cells by 95% O2 and was improved by metformin. Decreased LKB1 signaling may contribute to decreased alveolar and vascular growth in a mouse model of BPD.

Hypertension toxicity of VEGFR-TKIs in cancer treatment: incidence, mechanisms, and management strategies.

Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) are a class of targeted anticancer agents that include pazopanib, sunitinib, axitinib, and others. Currently, VEGFR-TKIs are widely used in the clinical treatment of various tumors, which can prolong patients' survival and even cure tumors. However, the use of VEGFR-TKIs is frequently associated with the occurrence of cardiovascular adverse events, with hypertension being the most prevalent. Hypertension and its complications can significantly impact the prognosis of patients, potentially jeopardizing their lives and resulting in the reduction or even cessation of treatment in severe cases. This review addresses the incidence of hypertension due to VEGFR-TKIs, mechanisms of toxicity, management strategies, and future research directions. In addition, hypertension due to VEGFR-TKIs may be associated with salt sensitivity, and possible mechanisms of hypertensive side effects are vasodilator imbalance, decreased capillary density, renal injury, impaired endothelial function due to oxidative stress, decreased lymphatic vascular density, and "off-target effect". A comprehensive understanding of hypertension toxicity due to cancer treatment with VEGFR-TKIs, can enhance clinical practice, thereby improving the prognostic outcomes of VEGFR-TKIs in oncology patients.

Association between the lactate-albumin ratio and microcirculation changes in Pediatric Septic patients

A lactate/albumin ratio (LAR) greater than 0.5 measured early in the course of pediatric critical illness is associated with greater mortality. Whether the elevated LAR can be explained by microcirculation disorders in children with sepsis is not known. In this longitudinal retrospective study (January 2021-January 2024), serum albumin and lactate were measured on admission to the pediatric intensive care unit (PICU), with sublingual video microscopy performed simultaneously to measure microcirculation. A total of 178 children were included, 37% of whom had septic shock measured with the Phoenix Sepsis Score. Patients with remote sepsis had greater odds of an elevated LAR (aOR 6.87: 95% CI 1.98–23.73; p < 0.01). Children with an elevated LAR had more microvascular blood flow abnormalities (aOR 1.31 95% CI 1.08–1.58; p < 0.01), lower 4-6-micron capillary density (aOR 1.03 95% CI 1.01–1.05; p < 0.01) and greater odds of dying (aOR 3.55 95% CI 1.21–10.38; p = 0.02) compared to those with a low LAR. We found no association between LAR and endothelial glycocalyx degradation. A normal LAR is associated with less risk of microcirculatory injury (aOR 0.77 95% CI 0.65–0.93; p < 0.01). In children with sepsis, an elevated LAR is associated with microcirculation abnormalities (microvascular density and flow). The lactate/albumin ratio is a potentially useful biomarker for microcirculatory injury in sepsis.

Increased cGMP improves microvascular exercise training adaptations independent of endothelial nitric oxide synthase.

Impaired microvascular function is a hallmark of pre-diabetes. With development of atherosclerosis this impaired microvascular function can result in diminished capacity for ambulation and is a risk factor for Type 2 Diabetes. Dynamic changes in vascular tone are determined, in large part, by the eNOS/NO/cGMP axis. We used gain of function of the eNOS/NO/cGMP axis in diet-induced obese (DIO) mice and reduced function in lean mice to test the hypothesis that functionality of this vascular control mechanism parallels the benefits of an exercise training regimen. DIO mice have lower exercise capacity than lean mice and were used for pharmacological gain of function. The PDE-5a inhibitor - sildenafil - increases cGMP and was administered to DIO mice daily. In sedentary mice, we find that sildenafil does not improve exercise capacity. In contrast, it amplifies the microcirculatory effects of exercise training. Sildenafil synergizes with exercise training to improve performance during an incremental exercise test. Improved exercise performance was accompanied by increased skeletal muscle capillary flow velocity and capillary density measured via intravital microscopy. Loss of function was tested in lean mice hemizygous for endothelial cell (EC) specific eNOS creating an EC-eNOS knockdown (KD). EC-eNOS KD decreases capillary density and exercise tolerance in sedentary mice; however, it did not prevent exercise-training induced improvements in endurance capacity. These data show that 1) increasing cGMP with sildenafil enhances microcirculatory function and exercise work tolerance that results from training; 2) eNOS KD does not prevent the microcirculatory or improvements in exercise tolerance with training. PDE-5a inhibitors combined with physical exercise are a potential mechanism for improving ambulation in patients with circulatory limitations.

Superficial vessel density and determinants of macular microvasculature in healthy Chinese subjects

BackgroundThe purpose of this study was to investigate the vessel density (VD) of the macular superficial capillary plexus (SCP) and its associated factors in healthy subjects. MethodsThis prospective, cross-sectional study enrolled healthy Chinese volunteers. The optical coherence tomography angiography (OCTA) was used to measure the superficial VD in macula. A generalized estimation equation (GEE) model was used to analyze the ocular and systemic associated factors. ResultsA total of 516 eyes of 262 healthy subjects were included (mean age 38.59 ± 21.03 years). The total VD of macular SCP was 16.85 ± 2.28 mm−1. The VD in the inner ring and outer ring were significantly higher than that in the central ring, with the density being highest in nasal quadrant and lowest in the superior quadrant. After adjusting the ocular and systemic factors, age (β=-0.0085, P = 0.0122) and SSI (β=1.3261, P < 0.001) were significantly associated with total VD of the macular SCP. ConclusionsAmong the healthy Chinese subjects included in the study, the mean total VD of macular SCP was 16.85 ± 2.28mm-1. The macular superficial capillary density was positively associated with age and SSI. Further studies are still required to better understand the change of macular VD in aging and other pathological conditions.

Retinal nerve fiber layer thickness and radial peripapillary capillaries density in myopic adults with optical coherence tomography angiography

PurposeTo evaluate retinal nerve fiber layer thickness (RNFLT) and radial peripapillary capillaries (RPC) density in adults with different degrees of myopia using optical coherence tomography angiography (OCTA) and explore their relationship with ocular factors, such as axial length (AL) and disc area.MethodsA total of 188 subjects were included in this cross-sectional study. The eyes were divided into four groups according to AL. OCTA was used for the assessment of RNFLT, RPC density, and other optic disc measurements, such as disc area. One-way analysis of variance was performed to compare differences between four groups, and P value < 0.01 was considered significant.ResultsThe RNFLT was significantly thinner in high myopia (HM) group at inferior nasal (IN) quadrant (P = 0.004) than low myopia (LM) group, but thicker at temporal inferior (TI) quadrant (P = 0.006). The RPC density of nasal superior (NS) quadrant, nasal inferior (NI) quadrant, and inferior nasal (IN) quadrant significantly decreased as AL increasing. By simple linear regression analysis, the inside disc RPC (iRPC) density tended to be correlated significantly with AL (0.3997%/mm, P < 0.0001). Peripapillary RPC (pRPC) density was in significant correlation with AL (-0.2791%/mm, P = 0.0045), and peripapillary RNFLT (pRNFLT) was in significant correlation with disc area (0.2774%/mm2, P = 0.0001).ConclusionRNFLT and RPC density were closely associated with AL and disc area. They might be new indexes in assessing and detecting myopia development via OCTA.

Retinal thickness and macular microvascular changes seen on optical coherence tomography angiography (OCTA) in patients with sickle cell retinopathy in a tertiary care eye hospital

PurposeTo report retinal thickness values and macular vascular flow characteristics identified by optical coherence tomography angiography (OCT-A) in patients with various sickle cell genotypes in a population from sub-Saharan Africa. DesignRetrospective, observational study. MethodsThis is a single-institution case series of adult patients with various sickle cell genotypes who presented to the Eye Foundation Hospital Lagos between January 2022 and December 2023. Case files of patients were reviewed, and macular OCT and OCT-A images analyzed quantitatively for macular thickness, areas of flow loss, size of foveal avascular area, parafoveal flow, as well as vascular density in both the superficial and deep vascular plexi. The findings were compared by sickle cell genotype and comparisons made with age matched normal patients. ResultsA total of 38 eyes of 19 patients’ records were reviewed, and 35 eyes met the inclusion criteria; 16 eyes of 9 age and gender matched controls were included. The mean central foveal thickness (CFT) was 242.4 μm ± 33.3 μm among patients’ eyes, while a mean CFT of 236.1 μm ± 10.1 μm was measured among controls (p = 0.312). A smaller mean FAZ area of 0.270 mm2 ± 0.116 mm2 was seen among the control eyes compared to a mean of 0.314 mm2 ± 0.206 mm2 among patients’ eyes (p = 0.439). The mean flow area was larger among control eyes with 0.849 mm2 ± 0.647 mm2 compared to a mean flow of 0.822 mm2 ± 0.471 mm2 among patients’ eyes (0.868). The mean superficial foveal vessel density was greater among control eyes (19.30 ± 4.58) compared to patient eyes (18.77 ± 7.78) (p = 0.765). The mean deep foveal vessel density was greater among controls (35.30 ± 8.36) than among patients (34.06 ± 9.30) (p = 0.650). The difference between eyes of SC (53.37 ± 5.13) patients and SS (47.94 ± 8.44) patients in the deep temporal perifoveal VD was statistically significant (p = 0.035). ConclusionThe retina in eyes with sickle retinopathy and that of controls tends to be thickest in the nasal quadrant, then the superior, then inferior, and then thinnest in the temporal quadrant. Macular vessel density in both the superficial and deep capillary plexi was thicker among controls compared to eyes with sickle cell retinopathy. Among patients’ eyes, the deep capillary vessel density in the temporal perifoveal quadrant was greater among SC patients compared to SS (p = 0.035).

Anti TNF-Alpha Treatment Improves Microvascular Endothelial Dysfunction in Rheumatoid Arthritis Patients.

Nailfold capillaroscopy is a non-invasive investigation, which allows for the study of the microvasculature (anatomical and functional). Rheumatoid arthritis (RA) is associated with a high risk of cardiovascular atherosclerotic diseases, with endothelial dysfunction (macrovascular and microvascular) representing the first step in atherosclerosis development. The aim of this study is represented by the assessment of microvascular endothelial dysfunction in RA patients by means of nailfold capillaroscopy and to assess its evolution after a period of 12 months of anti TNF-alpha treatment. The study included 70 consecutive patients with RA and 70 healthy subjects, matched for age and gender, as the control group. Rheumatoid factor, anti-cyclic citrullinated peptide antibodies, serum TNF-α, C reactive protein, and erythrocytes sedimentation rate were evaluated in all patients, but in controls, only rheumatoid factor, serum TNF-α, C reactive protein, and erythrocytes sedimentation rate were measured. The RA activity was measured by DAS28. Nailfold capillaroscopy was carried out in all patients and controls, determining the baseline nailfold capillary density (Db), nailfold capillary density during reactive hyperemia (Dh), and nailfold capillary density after venous congestion (Dc). Data were presented as mean ± standard deviation. Statistical analysis was performed using ANOVA and Pearson's correlation, with p < 0.05 being statistically significant. Db, Dh, and Dc were lower in RA patients than in controls (p < 0.0001), correlating with RA activity and TNF-α (p < 0.05). After 12 months of anti TNF-α treatment, microvascular endothelial dysfunction improved (p < 0.0001). Microvascular endothelial dysfunction can be assessed by nailfold capillaroscopy, with anti TNF-α medication contributing to its improvement.

Endothelial estrogen - myocardial cGMP axis critically determines angiogenesis and cardiac performance during pressure-overload.

Estrogen exerts beneficial cardiovascular effects by binding to specific receptors on various cells to activate nuclear and non-nuclear actions. Estrogen receptor α (ERα) non-nuclear signaling confers protection against heart failure remodeling, involving myocardial cyclic guanosine monophosphate (cGMP) - cGMP-dependent protein kinase G (PKG) activation; however, its tissue-specific role remains elusive. Herein, we examined the cell type-specific role of ERα non-nuclear signaling in estrogen-conferred protection against heart failure. We first assessed the tissue-specific impacts of ERα in estrogen's cardiac benefits, utilizing endothelial ERα deletion (ERαf/f/Tie2Cre+) and myocyte ERα deletion (ERαf/f/αMHCCre+) female mice. Female mice were ovariectomized and the effect of estradiol (E2) was assessed in hearts exposed to 3week pressure-overload (TAC). E2 failed to improve cardiac function in ERαf/f/Tie2Cre+ TAC hearts but provided benefits in ERαf/f/αMHCCre+ TAC hearts, indicating that endothelial ERα is essential. We next assessed the role of non-nuclear signaling in endothelial cells, employing animals with endothelial-specific inactivation of ERα non-nuclear signaling (ERαKI/KI/Tie2Cre+). Female OVX mice were supplemented with E2 and subjected to 3-week TAC. ERαKI/KI/Tie2Cre+ TAC hearts revealed exacerbated cardiac dysfunction and reduced myocardial PKG activity as compared to littermate TAC hearts, which was associated with attenuated myocardial induction of vascular endothelial growth factor (VEGF) and angiogenesis as assessed with CD31-stained capillary density. This phenotype of ERαKI/KI/Tie2Cre+ was rescued by myocardial PKG activation from chronic treatment with soluble guanylate cyclase (sGC) stimulator. We performed co-culture experiments to determine endothelial-cardiomyocyte interactions. VEGF induction by E2 in cardiac myocytes required co-existence of intact endothelial ERα signaling in a NOS-dependent manner. On the other hand, VEGF was induced in myocytes directly with an sGC stimulator in the absence of endothelial cells. An endothelial estrogen - myocardial cGMP axis stimulates angiogenic response and improves cardiac performance during pressure-overload.

Macrophage extracellular vesicle-packaged miR-23a-3p impairs maintenance and angiogenic capacity of human endothelial progenitor cells in neonatal hyperoxia-induced lung injury

BackgroundPremature infants requiring mechanical ventilation and supplemental oxygen for respiratory support are at increased risk for bronchopulmonary dysplasia (BPD), wherein inflammation have been proposed as a driver of hyperoxia-induced injuries, including persistent loss of endothelial progenitor cells (EPCs), impaired vascularization and eventual alveolar simplification in BPD lungs. However, the underlying mechanisms linking these phenomena remain poorly defined.MethodsWe used clodronate liposomes to deplete macrophages in a mouse model of neonatal hyperoxia-induced lung injury to evaluate if EPC loss in BPD lungs could be an effect of macrophage infiltration. We further generated in vitro culture systems initiated with cord blood (CB)-derived CD34+ EPCs and neonatal macrophages either polarized from CB-derived monocytes or isolated from tracheal aspirates of human preterm infants requiring mechanical ventilation and oxygen supplementation, to identify EV-transmitted molecular mechanism that is critical for inhibitory actions of hyperoxic macrophages on EPCs.ResultsInitial experiments using mouse model identified the crucial role of macrophage infiltration in eliciting significant reduction of c-Kit+ EPCs in BPD lungs. Further examination of this concept in human system, we found that hyperoxia-exposed neonatal macrophages hamper human CD34+ EPC maintenance and impair endothelial function in the differentiated progeny via the EV transmission of miR-23a-3p. Notably, treatment with antagomiR-23a-3p to silence miR-23a-3p in vivo enhances c-Kit+ EPC maintenance, and increases capillary density, and consequently mitigates simplified alveolarization in BPD lungs.ConclusionOur findings highlight the importance of pulmonary intercellular communication in the pathophysiology of BPD, by identifying a linkage through vesicle transfer of miR-23a-3p from hyperoxic macrophages to EPCs, and thus demonstrating potential for novel therapeutic target in BPD.

Years of endurance exercise training remodel abdominal subcutaneous adipose tissue in adults with overweight or obesity.

Abnormalities in the structure and metabolic function of abdominal subcutaneous adipose tissue (aSAT) underlie many obesity-related health complications. Endurance exercise improves cardiometabolic health in adults with overweight or obesity, but the effects of endurance training on aSAT are unclear. We included male and female participants who were regular exercisers with overweight or obesity who exercised for >2 years, and cross-sectionally compared them with well-matched non-exercisers with overweight or obesity. Here we show aSAT from exercisers has a higher capillary density, lower Col6a abundance and fewer macrophages compared with non-exercisers. This is accompanied by a greater abundance of angiogenic, ribosomal, mitochondrial and lipogenic proteins. The abundance of phosphoproteins involved in protein translation, lipogenesis and direct regulation of transcripts is also greater in aSAT collected from exercisers. Exploratory ex vivo experiments demonstrate greater angiogenic capacity and higher lipid-storage capacity in samples cultured from aSAT collected from exercisers versus non-exercisers. Regular exercise may play a role in remodelling aSAT structure and proteomic profile in ways that may contribute to preserved cardiometabolic health.

Increased Myocardial MAO-A, Atrogin-1, and IL-1β Expression in Transgenic Mice with Pancreatic Carcinoma-Benefit of MAO-A Inhibition for Cardiac Cachexia.

Cancer cachexia (CC) continues to challenge clinicians by massively impairing patients' prognosis, mobility, and quality of life through skeletal muscle wasting. CC also includes cardiac cachexia as characterized by atrophy, compromised metabolism, innervation and function of the myocardium through factors awaiting clarification for therapeutic targeting. Because monoamine oxidase-A (MAO-A) is a myocardial source of H2O2 and implicated in myofibrillar protein catabolism and heart failure, we presently studied myocardial MAO-A expression, inflammatory cells, and capillarization together with transcripts of pro-inflammatory, -angiogenic, -apoptotic, and -proteolytic signals (by qRT-PCR) in a 3x-transgenic (LSL-KrasG12D/+; LSL-TrP53R172H/+; Pdx1-Cre) mouse model of orthotopic pancreatic ductal adenoarcinoma (PDAC) compared to wild-type (WT) mice. Moreover, we evaluated the effect of MAO-A inhibition by application of harmine hydrochloride (HH, 8 weeks, i.p., no sham control) on PDAC-related myocardial alterations. Myocardial MAO-A protein content was significantly increased (1.69-fold) in PDAC compared to WT mice. PDAC was associated with an increased percentage of atrogin-1+ (p < 0.001), IL-1β+ (p < 0.01), COX2+ (p < 0.001), and CD68+ (p > 0.05) cells and enhanced transcripts of pro-inflammatory IL-1β (2.47-fold), COX2 (1.53-fold), TNF (1.87-fold), and SOCS3 (1.64-fold). Moreover, PDAC was associated with a reduction in capillary density (-17%, p < 0.05) and transcripts of KDR (0.46-fold) but not of VEGFA, Notch1, or Notch3. Importantly, HH treatment largely reversed the PDAC-related increases in atrogin-1+, IL-1β+, and TNF+ cell fraction as well as in COX2, IL-1β, TNF, and SOCS3 transcripts, whereas capillary density and KDR transcripts failed to improve. In mice with PDAC, increased myocardial pro-atrophic/-inflammatory signals are attributable to increased expression of MAO-A, because they are significantly improved with MAO-A inhibition as a potential novel therapeutic option. The PDAC-related loss in myocardial capillary density may be due to other mechanisms awaiting evaluation with consideration of cardiomyocyte size, cardiac function and physical activity.

Nitroglycerin challenge identifies microcirculatory target for improved resuscitation in patients with circulatory shock

BackgroundCirculatory shock and multi-organ failure remain major contributors to morbidity and mortality in critically ill patients and are associated with insufficient oxygen availability in the tissue. Intrinsic mechanisms to improve tissue perfusion, such as up-regulation of functional capillary density (FCD) and red blood cell velocity (RBCv), have been identified as maneuvers to improve oxygen extraction by the tissues; however, their role in circulatory shock and potential use as resuscitation targets remains unknown. To fill this gap, we examined the baseline and maximum recruitable FCD and RBCv in response to a topical nitroglycerin stimulus (FCDNG, RBCvNG) in patients with and without circulatory shock to test whether this may be a method to identify the presence and magnitude of a microcirculatory reserve capacity important for identifying a resuscitation target.MethodsSublingual handheld vital microscopy was performed after initial resuscitation in mechanically ventilated patients consecutively admitted to a tertiary medical ICU. FCD and RBCv were quantified using an automated computer vision algorithm (MicroTools). Patients with circulatory shock were retrospectively identified via standardized hemodynamic and clinical criteria and compared to patients without circulatory shock.Results54 patients (57 ± 14y, BMI 26.3 ± 4.9 kg/m2, SAPS 56 ± 19, 65% male) were included, 13 of whom presented with circulatory shock. Both groups had similar cardiac index, mean arterial pressure, RBCv, and RBCvNG. Heart rate (p < 0.001), central venous pressure (p = 0.02), lactate (p < 0.001), capillary refill time (p < 0.01), and Mottling score (p < 0.001) were higher in circulatory shock after initial resuscitation, while FCD and FCDNG were 10% lower (16.9 ± 4.2 and 18.9 ± 3.2, p < 0.01; 19.3 ± 3.1 and 21.3 ± 2.9, p = 0.03). Nitroglycerin response was similar in both groups, and circulatory shock patients reached FCDNG similar to baseline FCD found in patients without shock.ConclusionCritically ill patients suffering from circulatory shock were found to present with a lower sublingual FCD. The preserved nitroglycerin response suggests a dysfunction of intrinsic regulation mechanisms to increase the microcirculatory oxygen extraction capacity associated with circulatory shock and identifies a potential resuscitation target. These differences in microcirculatory hemodynamic function between patients with and without circulatory shock were not reflected in blood pressure or cardiac index.

Brain Microvascular Pericyte Pathology Linking Alzheimer's Disease to Diabetes.

The brain microvasculature, which delivers oxygen and nutrients and forms a critical barrier protecting the central nervous system via capillaries, is deleteriously affected by both Alzheimer's disease (AD) and type 2 diabetes (T2D). T2D patients have an increased risk of developing AD, suggesting potentially related microvascular pathological mechanisms. Pericytes are an ideal cell type to study for functional links between AD and T2D. These specialized capillary-enwrapping cells regulate capillary density, lumen diameter, and blood flow. Pericytes also maintain endothelial tight junctions to ensure blood-brain barrier integrity, modulation of immune cell extravasation, and clearance of toxins. Changes in these phenomena have been observed in both AD and T2D, implicating "pericyte pathology" as a common feature of AD and T2D. This review examines the mechanisms of AD and T2D from the perspective of the brain microvasculature, highlighting how pericyte pathology contributes to both diseases. Our review identifies voids in understanding how AD and T2D negatively impact the brain microvasculature and suggests future studies to examine the intersections of these diseases.

Allogenic Vertebral Body Adherent Mesenchymal Stromal Cells Promote Muscle Recovery in Diabetic Mouse Model of Limb Ischemia

Chronic limb threatening ischemia (CLTI) carries a significant risk for amputation especially in diabetic patients with poor options for revascularization. Phase I trials have demonstrated efficacy of allogeneic mesenchymal stromal cells (MSC) in treating diabetic CLTI. Vertebral bone adherent mesenchymal stromal cells (vBA-MSC) are derived from vertebral bodies of deceased organ donors which offer the distinct advantage of providing a 1,000x greater yield compared to that of living donor bone aspiration. This study describes the effects of intramuscular injection of allogenic vBA-MSC in promoting limb perfusion and muscle recovery in a diabetic CLTI mouse model. A CLTI mouse model was created through unilateral ligation of the femoral artery in male polygenic diabetic TALLYHO mice. Treated mice were injected with vBA-MSC into the gracilis muscle of the ischemic limb 7 days post ligation. Gastrocnemius or tibialis muscle was assessed post-mortem for fibrosis by collagen staining, capillary density via immunohistochemistry, and mRNA by quantitative real time PCR. Laser Doppler perfusion imaging and plantar flexion muscle testing were performed to quantify changes in limb perfusion and muscle function. Compared to vehicle control, treated mice demonstrated indicators of muscle recovery including decreased fibrosis, increased perfusion, muscle torque, and angiogenesis. PCR analysis of muscle obtained 7- and 30-days post vBA-MSC injection showed an upregulation in expression of MyoD1 (p = 0.03) and MyH3 (p = 0.008) mRNA representing muscle regeneration, VEGF-A (p = 0.002 ; p = 0.004) signifying angiogenesis as well as IL-10 (p < 0.001), T regulatory cell marker Foxp3 (p = 0.04), and M2-biased macrophage marker Mrc1 (CD206) (p = 0.02). These findings indicate human allogeneic vBA-MSC ameliorate ischemic muscle damage and rescue muscle function. These results in a murine model will enable further studies to develop potential therapies for diabetic CLTI patients.

Abstract 55: Mouse Offspring Exposed to Preeclampsia/Eclampsia-like Symptoms Exhibit Changes in Regional Cerebral Perfusion at 2 months of age

Children born to mothers with preeclampsia, a hypertensive pregnancy disorder, or eclampsia, new-onset seizures during pregnancy, are more likely to develop learning and memory deficits and are more susceptible to neurovascular diseases compared to those born from normal pregnancies. The contributing mechanisms are unknown. The objective of this study was to determine whether mice exposed to reduced uteroplacental perfusion (RUPP), to mimic preeclampsia with or without pentylenetetrazol (PTZ) injection (to induce seizures and model eclampsia), results in regional cerebral perfusion changes at 2 months of age. On gestational day (GD) 13.5, pregnant C57BL/6 mice underwent sham or RUPP surgery followed by injection or no treatment with PTZ (40 mg/kg) on GD 18.5. At 2 months of age, cerebral perfusion was measured using Laser Speckle Imaging, and averaged to obtain mean data per sex, per litter (n = 3-6 average datapoints per group). Perfusion data were normalized to the area of each region of interest. Data were analyzed using Two-Way ANOVA. Our findings indicate a reduction in cerebral perfusion in offspring exposed indirectly to RUPP specifically of the right parietal cortex (p = 0.013), superior sagittal sinus (p = 0.003), cerebellum (p = 0.003) and whole brain (p = 0.021). We also observed an overall significant reduction in perfusion, after indirect PTZ exposure, in the right parietal cortex (p = 0.002), transverse sinus (p = 0.003), and cerebellum (p &lt; 0.001); and increase in prefrontal cortex perfusion (p = 0.001). Further observation showed an overall difference in hematocrit (p = 0.001), SPO2 (p &lt; 0.001), and cerebellum water content (p = 0.007) after indirect PTZ exposure. There was no difference in perfusion of the left parietal cortex, body weight, organ weight (except brain, where RUPP exposure led to overall increased brain weight; p = 0.030). Together, our results are consistent with the hypothesis that exposure to preeclampsia/eclampsia conditions leads to changes in offspring cerebrovascular function, with a net reduction in perfusion. Reduced cerebral perfusion is generally associated with reduced cognitive function. Whether this occurs along with changes in capillary density, or is exacerbated with age are areas of active investigation.