Total Number Of Capillaries Research Articles

The dynamics of bubble breakup in heart-shaped microchannels: Effect of structure

Heart-shaped microreactor (Advanced Flow Reactor, AFR) has been widely applied in industry, in which heart-shaped structure is important to break droplet or bubble up for mass transfer enhancement. The dynamics of bubble breakup in AFR (Channel A) and an improved AFR (Channel B) was visually investigated. Breakup regime with permanent obstruction was observed to undergo three stages: squeezing, transition and pinch-off. Results indicated that bubble breakup in Channel B has wider operating range, shorter time than those in Channel A. Moreover, the influences of various factors on bubble breakup in Channel B were studied systematically. It was found that the mother length (l0/wc) has only slight impact on breakup process, total capillary number (Ca) has always positive promoting effect on breakup during each stage, increasing liquid phase viscosity (μL) could facilitate the breakup in the squeezing and transition stages, while delay the thinning rate of bubble neck in the pinch-off stage.

Effects of Maternal Nutrient Restriction and Melatonin Supplementation on Cardiomyocyte Cell Development Parameters Using Machine Learning Techniques.

Simple SummaryThe major objectives of this study were to examine the effects of maternal feed restriction and melatonin supplementation on fetal cardiomyocyte cell development parameters and predict binucleation and hypertrophy using machine learning techniques using pregnant beef heifers. Interestingly, major findings include evidence that compromised pregnancy in cattle leads to a reduction in the number of cardiomyocytes while melatonin treatment can mitigate some of these disturbances.The objective of the current study was to examine the effects of maternal feed restriction and melatonin supplementation on fetal cardiomyocyte cell development parameters and predict binucleation and hypertrophy using machine learning techniques using pregnant beef heifers. Brangus heifers (n = 29) were assigned to one of four treatment groups in a 2 × 2 factorial design at day 160 of gestation: (1) 100% of nutrient requirements (adequately fed; ADQ) with no dietary melatonin (CON); (2) 100% of nutrient requirements (ADQ) with 20 mg/d of dietary melatonin (MEL); (3) 60% of nutrient requirements (nutrient-restricted; RES) with no dietary melatonin (CON); (4) 60% of nutrient requirements (RES) with 20 mg/d of dietary melatonin (MEL). On day 240 of gestation, fetuses were removed, and fetal heart weight and thickness were determined. The large blood vessel perimeter was increased in fetuses from RES compared with ADQ (p = 0.05). The total number of capillaries per tissue area exhibited a nutrition by treatment interaction (p = 0.01) where RES-MEL increased capillary number compared (p = 0.03) with ADQ-MEL. The binucleated cell number per tissue area showed a nutrition by treatment interaction (p = 0.010), where it was decreased in RES-CON vs. ADQ-CON fetuses. Hypertrophy was estimated by dividing ventricle thickness by heart weight. Based on machine learning results, for the binucleation and hypertrophy target variables, the Bagging model with 5 Decision Tree estimators and 3 Decision Tree estimators produced the best results without overfitting. In the prediction of binucleation, left heart ventricular thickness feature had the highest Gin importance weight followed by fetal body weight. In the case of hypertrophy, heart weight was the most important feature. This study provides evidence that restricted maternal nutrition leads to a reduction in the number of cardiomyocytes while melatonin treatment can mitigate some of these disturbances.

Effect of the Molecular Structure Change of a Matrix Polymer (Nylon 6) on the Deformation of Dispersed Phase (a Thermotropic Liquid Crystalline Polymer) Droplets in Shear Flow.

In this work, we investigated the effect of a change in the molecular structure and ensuing molar mass change of a matrix polymer (polyamide 6, Ny 6) on droplet deformation of a dispersed thermotropic liquid crystalline polymer (TLCP, a poly(ester amide)) in shear flow. This study focuses on a total capillary number (the sum of the shear capillary number and the elasticity capillary number) and the viscosity ratio between the TLCP and Ny 6, for the morphological development and mechanical performance of TLCP/Ny 6 blends. In contrast to Ny 6, which has a lower melt viscosity than the TLCP melt, a modified Ny 6 (m-Ny 6) with ca. 2 orders higher melt viscosity than that of Ny 6 at a shear rate of 1 s–1 was found to facilitate the deformation of the TLCP phase. A total capillary number was defined to characterize the viscoelasticity effect on droplet deformation in the blend system. The first normal stress difference obtained from the viscosity curve using Steller’s method was used for the evaluation of the elasticity capillary number. The total capillary number for the Ny 6 blend was far less than the critical capillary number and was insufficient for the dispersed TLCP droplets to be deformed. The shear capillary number of the m-Ny 6 blend was greater than the critical capillary number but was still insufficient for droplet deformation into fibril shapes. The total capillary number, including the elastic capillary number, was sufficiently greater than the critical capillary number for deformation of the dispersed TLCP droplets. Morphological observations and a comparison with the theoretical work confirmed the importance of the viscoelasticity of the melt in the immiscible Ny 6/TLCP blends for in situ composite fabrication in shear flow. Both the high viscosity and the first normal stress difference of m-Ny 6 promote the deformation and fibrillation of the dispersed TLCP droplets.

Pathological Analysis of Early Transplant Glomerulopathy in Renal Allografts Using Low-Vacuum Scanning Electron Microscopy

Aim: Low-vacuum scanning electron microscopy (LVSEM) has been reported to aid in diagnosis of renal biopsy. This study evaluated early transplant glomerulopathy in kidney transplant recipients using LVSEM. Methods: We selected 4 biopsies of cg0, 5 biopsies of cg1a, 5 biopsies of cg1b, and 4 biopsies of cg2 lesions that had been evaluated by light microscopy (LM) and transmission electron microscopy from recipients with acute/active or chronic, active antibody-mediated rejection (AABMR or CAABMR). Renal allograft paraffin sections (1 µm thickness) were stained with periodic acid-methenamine silver and observed using LVSEM. The cg score was based on the Banff classification. The parameter “percentage of duplicated capillary number” was calculated as follows: in 1 glomerulus with glomerular basement membrane (GBM) duplication, the total duplicated capillary number/the total number of capillaries ×100. Results: In all 4 biopsy specimens with AABMR showing cg0, LVSEM revealed GBM duplication not identified by LM. The average percentage of duplicated capillary number per glomerulus with GBM duplication was higher when observed by LVSEM than when observed by LM in all cg1b and cg2 biopsy specimens. Conclusion: LVSEM revealed early GBM duplication in AABMR. Early GBM duplication might progress in the very early phase of AABMR. GBM duplication was more frequently detected by LVSEM than by LM in biopsy specimens with early chronic, active antibody mediated rejection. Thus, LVSEM may be useful in diagnosis of early transplant glomerulopathy.

Smooth muscle SIRT1 reprograms endothelial cells to suppress angiogenesis after ischemia

Objective: Vascular smooth muscle cells (VSMCs) undergo the phenotypic changes from contractile to synthetic state during vascular remodeling after ischemia. SIRT1 protects against stress-induced vascular remodeling via maintaining VSMC differentiated phenotype. However, the effect of smooth muscle SIRT1 on the functions of endothelial cells (ECs) has not been well clarified. Here, we explored the role of smooth muscle SIRT1 in endothelial angiogenesis after ischemia and the underlying mechanisms.Methods: We performed a femoral artery ligation model using VSMC specific human SIRT1 transgenic (SIRT1-Tg) and knockout (KO) mice. Angiogenesis was assessed in in vivo by quantification of the total number of capillaries, wound healing and matrigel plug assays, and in vitro ECs by tube formation, proliferation and migration assays. The interaction of HIF1α with circRNA was examined by using RNA immunoprecipitation, RNA pull-down and in situ hybridization assays.Results: The blood flow recovery was significantly attenuated in SIRT1-Tg mice, and markedly improved in SIRT1-Tg mice treated with SIRT1 inhibitor EX527 and in SIRT1-KO mice. The density of capillaries significantly decreased in the ischemic gastrocnemius of SIRT1-Tg mice compared with SIRT1-KO and WT mice, with reduced expression of VEGFA, which resulted in decreased number of arterioles. We identified that the phenotypic switching of SIRT1-Tg VSMCs was attenuated in response to hypoxia, with high levels of contractile proteins and reduced expression of the synthetic markers and NG2, compared with SIRT1-KO and WT VSMCs. Mechanistically, SIRT1-Tg VSMCs inhibited endothelial angiogenic activity induced by hypoxia via the exosome cZFP609. The cZFP609 was delivered into ECs, and detained HIF1α in the cytoplasm via its interaction with HIF1α, thereby inhibiting VEGFA expression and endothelial angiogenic functions. Meantime, the high cZFP609 expression was observed in the plasma of the patients with atherosclerotic or diabetic lower extremity peripheral artery disease, associated with reduced ankle-brachial index. Knockdown of cZFP609 improved blood flow recovery after hindlimb ischemia in SIRT1-Tg mice.Conclusions: Our findings demonstrate that SIRT1 may impair the plasticity of VSMCs. cZFP609 mediates VSMCs to reprogram endothelial functions, and serves as a valuable indicator to assess the prognosis and clinical outcomes of ischemic diseases.

Muscle-Specific Sensitivity to Voluntary Physical Activity and Detraining.

Aerobic physical activity triggers adaptations in skeletal muscle including a fast-to-slow shift in myosin heavy chain (MHC) isoforms, an enhanced capillary network, and mitochondrial biogenesis to meet increased demands placed upon this tissue. Although the magnitude of these responses appears to be dependent on muscle phenotype as well as training volume and/or intensity, the whole-muscle response to detraining remains mostly unexplored. Here, we hypothesized that the shifts toward slower MHC phentotype and the increased capillarity and mitochondrial oxidative markers induced with training would return toward sedentary (SED) control levels sooner in the fast plantaris than in the slow soleus muscle as a result of detraining. Soleus and plantaris muscles from 8-week (TR 8wk) voluntarily running adult female Sprague–Dawley rats were compared to muscles from SED and detrained rats (DETR) (4 weeks voluntary running followed by 4 weeks of reduced activity), which were subdivided into low- (DETR Lo) and high-running-distance (DETR Hi) groups. We show that maintaining the fast-to-slow MHC isoform shift required consistent aerobic training in the soleus and plantaris muscles: detraining clearly abolished any fast-to-slow gains in the plantaris, whereas the training volume in DETR Hi rats appeared to influence the MHC return to basal levels in the soleus. Total capillary number (per mm2) in the plantaris increased in all groups compared to SED levels, but, in the soleus, this enhancement was observed only in the TR 8wk rats. Generally, increased mitochondrial markers for aerobicitiy were observed in TR 8wk plantaris, but not soleus, muscles. In a second experiment, we show that the muscle-specific adaptations were similar after 4 weeks of voluntary exercise (TR 4wk) as in 4 weeks (TR 8wk). Taken together, our findings suggest that the plantaris muscle is more sensitive to voluntary physical activity and detraining than the soleus muscle; these results also demonstrate that the soleus muscle requires a greater aerobic challenge (i.e., intensity, duration) to trigger phenotypic, angiogenic, or aerobic enzyme adaptations. Our findings generally suggest that muscular aerobic fitness to voluntary running, or its loss during detraining, manifests as changes occurring primarily within fast, rather than slow, muscle phenotypes.

Cam-based vibration-counter-balanced laser-induced fluorescence scanner for multiplexed capillary detection

Laser-induced fluorescence (LIF) rotary scanners have been successfully used for multiplexed capillary detection. However, these scanners have a limitation that the capillaries have to be assembled in a circular format, which can be inconvenient for certain applications. A linear LIF scanner works well for flat parallel capillary arrays, but motor accelerations/decelerations (for direction changes) and scanning head vibrations introduce high instrumental noises. The number of capillaries that can be scanned by a linear scanner is limited because of the above constraints. We have constructed a cam-based scanner in an attempt to address these issues. A cam-based scanner eliminates the motor accelerations/decelerations but not the scanning head vibrations. In this work, we attach a second scanning head to the cam on the opposite side of the first scanning head to counter-balance the mechanical vibrations. With this modification, we improve the limit of detection by more than 3 times (from 69 pM to 20 pM fluorescein). We also increase the capillary number capacity by more than 6 times; the total number of capillaries that can be scanned is 426 if 150-μm-o.d. capillaries are used or 320 if 200-μm-o.d. capillaries are used. To demonstrate the utility of this instrument, we assemble a 99-capillary array on one capillary holder and perform capillary electrophoresis of two fluorescent dyes; separations in all capillaries are successfully monitored simultaneously. We also apply it for detecting fluorescently labeled proteins resolved by 24 s-dimension capillaries in a chip-capillary hybrid device; two-dimensional separation results are nicely produced.

Effect of treatment with iloprost with or without bosentan on nailfold videocapillaroscopic alterations in patients with systemic sclerosis

Introduction: Vascular involvement plays a decisive role in systemic sclerosis (SSc) pathogenesis; it is responsible for some important clinical manifestations of the disease such as Raynaud’s phenomenon and digital ulcers (DU). Bosentan, a dual receptor endothelin antagonist, and iloprost, often in combination therapy, seems to be able to interfere with the scleroderma microangiopathy.Objectives: Aim of the study was to evaluate the effect of bosentan and iloprost on scleroderma microangiopathy, analyzed by means of capillaroscopic skin ulcer risk index (CSURI), in SSc patients treated for the prevention of DU.Methods: Nailfold videocapillaroscopy (NVC) was performed in 95 SSc patients, treated with iloprost alone (group 1) or combination therapy with iloprost and bosentan (group 2), at baseline and after one year. In all patients CSURI was calculated according to the formula “diameter × number of megacapillaries/(total number of capillaries)2”: in addition, total number of capillaries, giant capillaries, micro-hemorrhages, disorganization of the vascular array, and ramified capillaries were evaluated by means of a semiquantitative score.Results: After 12 months, we observed a reduction of the number of giant capillaries in both groups, while an increase of ramified capillaries was recorded only in group 2. CSURI improved slightly in group 2 without statistical significance; on the contrary, in group 1 a significant worsening was recorded (p ≤ 0.001).Conclusions: Our study confirms the effectiveness of bosentan, in combination with iloprost, in SSc microangiopathy observed to NVC. Moreover, the observed findings further support the role of CSURI in the evaluation and monitoring of SSc microangiopathy.

Preeclampsia does not alter vascular growth and expression of CD31 and vascular endothelial cadherin in human placentas.

Preeclampsia is characterized by maternal endothelial dysfunction (e.g., increased maternal vascular permeability caused by the disassembly of endothelial junction proteins). However, it is unclear if preeclampsia is associated with impaired vascular growth and expression of endothelial junction proteins in human placentas. Herein, we examined vascular growth in placentas from women with normal term (NT) and preeclamptic (PE) pregnancies using two endothelial junction proteins as endothelial markers: CD31 and vascular endothelial-cadherin (VE-Cad). We also compared protein and mRNA expression of CD31 and VE-Cad between NT and PE placentas, and determined the alternatively spliced expression of CD31 using PCR. We found that CD31 and VE-Cad were immunolocalized predominantly in villous endothelial cells. However, capillary number density (total capillary number per unit villous area) and capillary area density (total capillary lumen area per unit villous area) as well as CD31 and VE-Cad protein and mRNA levels were similar between NT and PE placentas. PCR in combination with sequence analysis revealed a single, full-length CD31, suggesting that there are no alternatively spliced isoform of CD31 expressed in placentas. These data indicate that preeclampsia does not significantly affect vascular growth or the expression of endothelial junction proteins in human placentas.

Effects of phytoestrogen supplementation in the feed on the shell gland of laying hens at the end of the laying period

Shell quality decreases as laying hens age and the aim of present study was to investigate how a supplement of daidzein, a natural phytoestrogen in soya, affects key factors in the shell gland and eggshell quality in late-stage laying hens. Hybrids of Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), received either a daidzein diet (50mg/kg feed) or a control diet from 60 to 72 weeks of age. Both the total number of capillaries and capillaries with carbonic anhydrase (CA) activity were higher in the LSL hybrid than in the LB. After daidzein supplementation the number of CA positive capillaries was unaffected in the LSL but increased in the LB hybrid indicating a higher sensitivity to daidzein in this hybrid. Estrogen receptor alpha and beta (ERα, ERβ) were localized and the complete picture of the two ERs can now be described in shell gland of domestic hens. Nuclear and cytoplasmic staining was generally stronger for ERβ, while membrane associated staining was present only for ERα. Interestingly, capillary endothelium contained only ERβ and since estrogen regulation of CA is well documented, the presence of an endothelial ER provides one possible route for the increase in CA positive capillaries found in LB hybrids. Eggshell quality or egg production was not affected by daidzein supplementation. The hybrids used in this study showed anatomical differences and reacted differently to daidzein supplementation, but if this can be explained by the divergences in ERβ localization noted between the hybrids remains to be clarified.

Endothelial Cells Derived From Human iPSCS Increase Capillary Density and Improve Perfusion in a Mouse Model of Peripheral Arterial Disease

Stem cell therapy for angiogenesis and vascular regeneration has been investigated using adult or embryonic stem cells. In the present study, we investigated the potential of endothelial cells (ECs) derived from human induced pluripotent stem cells (hiPSCs) to promote the perfusion of ischemic tissue in a murine model of peripheral arterial disease. Endothelial differentiation was initiated by culturing hiPSCs for 14 days in differentiation media supplemented with BMP-4 and vascular endothelial growth factor. The hiPSC-ECs exhibited endothelial characteristics by forming capillary-like structures in matrigel and incorporating acetylated-LDL. They stained positively for EC markers such as KDR, CD31, CD144, and eNOS. In vitro exposure of hiPSC-ECs to hypoxia resulted in increased expression of various angiogenic related cytokines and growth factors. hiPSC-ECs were stably transduced with a double fusion construct encoded by the ubiquitin promoter, firefly luciferase for bioluminescence imaging and green fluorescence protein for fluorescent detection. The hiPSC-ECs (5×10(5)) were delivered by intramuscular injection into the ischemic hindlimb of SCID mice at day 0 and again on day 7 after femoral artery ligation (n=8). Bioluminescence imaging showed that hiPSC-ECs survived in the ischemic limb for at least 2 weeks. In addition, laser Doppler imaging showed that the ratio of blood perfusion was increased by hiPSC-EC treatment by comparison to the saline-treated group (0.58±0.12 versus 0.44±0.04; P=0.005). The total number of capillaries in the ischemic limb of mice receiving hiPSC-EC injections was greater than those in the saline-treated group (1284±155 versus 797±206 capillaries/mm(2)) (P<0.002). This study is a first step toward development of a regenerative strategy for peripheral arterial disease based on the use of ECs derived from hiPSCs.

Correlation of a quantitative videocapillaroscopic score with the development of digital skin ulcers in scleroderma patients

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and visceral organs. The microangiopathy is early detectable in the course of the disease by nailfold videocapillaroscopy (NVC), a non-invasive technique with a high diagnostic value. Aim of our study was to evaluate the feasibility of a quantitative score and its correlation with the digital skin ulcers, which frequently complicate SSc microangiopathy. We retrospectively analysed the NVC of 65 SSc patients, performed by 200x videocapillaroscopy connected to image analyse software (Videocap; DS MediGroup, Milan, Italy). The analysis of NVC images included: total number of capillaries in the distal row (N), maximum diameter (D) and number of giant capillaries (M), M/N ratio and percentage of M, presence/absence of micro-haemorrhages and tortuosity. 21/65 SSc patients experienced digital ulcers within three months after the NVC examination. The N, D, M/N, and percentage of M significantly correlated with the appearance of ischemic ulcers. A multiple regression analysis showed a statistically significant correlation for N, M/N and D, while sensitivity and specificity of these parameters were unsatisfactory. A capillaroscopic score, according to the formula D x M/N2, showed a high specificity and sensibility (93.2% and 85.7% respectively; area under ROC curve: 0.918) to predict the appearance of digital ulcers. This capillaroscopic score may represent a feasible and simple tool in SSc patients' assessment. The routinely use of this parameter might permit to recognize and to preventively treat SSc patients at high risk to develop digital ulcers.

The Application of Stereological Methods for Estimating Structural Parameters in the Human Heart

This study describes and exemplifies generally applicable design-based stereological methods for obtaining quantitative estimates of the numbers and sizes of capillaries, cardiomyocytes, and cardiomyocyte nuclei in immersion-fixed human left ventricles (N = 6). The design-based stereological methods are valid in all cardiac investigations onto quantifying changes in structure and function as seen under various conditions such as during development, aging, hypertrophy, and following ischemia/reperfusion. The applied principles of unbiased stereology were as follows: 1) uniform random sampling was taken at all levels, also in respect to orientations, for estimates of length and mean sizes. 2) All global structural quantities were estimated as total quantity = density x volume of the left ventricle. As an example, the left ventricle contains 1.5 x 10(9) capillaries with a total length of just below 200 km. 3) Stereological methods were used for estimating the volume density, surface area density, and length density of capillaries and cardiomyocytes. The numerical density of cardiomyocyte nuclei and capillaries was estimated, using the optical and physical disector, respectively. 4) In all local quantities, "size" was estimated either directly, using unbiased estimators to obtain the average individual size and size distribution parameters, or indirectly, using the relationship that: average size = total quantity/total number. In the six hearts constituting this study, we observed the anticipated correlation between left ventricular volume and global estimates such as total number of capillaries. There were no correlation between local quantities and total left ventricular volume (e.g., average star volume of individual cardiomyocytes).

Capillaroscopic skin ulcer risk index: A new prognostic tool for digital skin ulcer development in systemic sclerosis patients

Digital ulcerations are one of the most frequent manifestations of microangiopathy in patients with systemic sclerosis (SSc; scleroderma). The early detection of SSc patients who are at high risk to develop digital ulcers could allow a preventive treatment of these complications with reduction of morbidity and social costs. The aim of our study was to develop a capillaroscopic skin ulcer risk index (CSURI) that can predict the onset of new digital ulcers by using nailfold videocapillaroscopy (NVC) in patients with SSc. We performed NVC in 120 consecutive unselected patients with SSc (13 men, 107 women, mean +/- SD age 56.1 +/- 13.4 years, mean +/- SD SSc duration 44.7 +/- 60.7 months) to assess the total number of capillaries in the distal row (N), maximum loop diameter (D), number of megacapillaries (M), and the M:N ratio. Within 3 months since NVC examination, 35 of 120 patients experienced digital ulcers. A significant association between ischemic lesions and the M:N ratio, N, and D was observed; the combination of these parameters allowed us to develop the CSURI, which is characterized by the formula D x M:N(2). A receiver operating characteristic curve analysis showed an area under the curve of 0.926 for ulcer appearance, with specificity and sensitivity of 85.9% and 94.3%, respectively, at the cutoff value of 2.94. Interestingly, 33 of 35 patients with new skin ulcers had a CSURI >2.94, but only 2 of 35 had a CSURI < or =2.94. The proposed CSURI may represent a novel tool with the ability to predict the development of digital ulcers in patients with scleroderma.

Le cerveau aux limites du vieillissement: à propos des nonagénaires et centenaires

The elderly population represents the fastest growing age group worldwide and there is a growing awareness of age-related diseases such as dementia. By 2020 it is estimated that at least 1 billion people will be older than 60 years representing more than 20% of the total population. However, recent epidemiological studies of very old individuals have shown that prevalence rates of dementia vary from 27 to 62% pointing to the fact that dementia is not inevitable in very old individuals and that the risk of Alzheimer's disease (AD) decreases significantly after age 90, suggesting a relative resistance of centenarians to the degenerative process. Normal brain aging is characterised by the formation of neurofibrillary tangles (NFT) and senile plaques (SP), as well as neuronal and synaptic loss in both cognitively intact individuals and patients with AD. In non-demented cases neurofibrillary tangles are usually restricted to the hippocampal formation, whereas the progressive involvement of the association areas in the temporal neocortex parallels the development of overt clinical signs of dementia. In contrast, there is no correlation between the quantitative distribution of senile plaques and severity of AD. The pattern of lesion distribution and neuronal loss changes in extreme aging. Several neuropathologic analyses postulated that in contrast to younger cases where dementia is mainly related to severe NFT formation within adjacent components of the medial and inferior aspects of the temporal cortex, oldest-old individuals display a preferential involvement of the anterior part of the CA1 field of the hippocampus whereas the inferior temporal and frontal association areas are relatively spared, supposing that the extent of NFT development in the hippocampus is the key determinant of dementia in the very old. In our first series of 12 patients older than 90 years with sterological analysis we found a significant difference in NFT densities, in the anterior CA1 field, but not in the posterior CA1 field and entorhinal cortex (EC), between demented and non-demented very old patients and suggested that nonagenarians and centenarians may show a displacement of subregional distribution of NFT within the CA field. Cortical association areas were relatively preserved. The progression of NFT formation across the different CDR groups was significantly slower in nonagenarians and centenarians compared to younger cases in the CA1 field and EC; even cases with moderate dementia display only mild NFT formation in this area with more than 80% of preserved neurons. The total amyloid and the neuronal loss in the entorhinal cortex and CA1 field in these cases were also significantly lower than that reported in younger AD cases. In a second stereologic study of 19 very old individuals with various degrees of cognitive impairment we also assessed total capillary length, number and length-weighted mean diameters in the CA1 and entorhinal cortex. Both mean diameters and total capillary numbers, but no capillary length, were strongly related to total neuron numbers in the CA1 field and entorhinal cortex. In conclusion, the most intriguing results of these studies were the relative paucity of correlations between AD pathological hallmarks in the hippocampal formation and clinical status after 90 years and the clear dissociation between total neuron numbers and AD-related lesions in the hippocampal formation. Microvascular parameters such as mean capillary diameters may be a key factor to consider for the prediction of cognitive decline in the oldest-old.

Vascular endothelial growth factor is highly expressed in muscle tissue of patients with polymyositis and patients with dermatomyositis

To investigate the expression of vascular endothelial growth factor (VEGF) in muscle biopsy specimens and serum from patients with polymyositis and patients with dermatomyositis compared with that in healthy control subjects. Muscle biopsy specimens from 33 patients with polymyositis or dermatomyositis and 15 healthy control subjects and serum samples from 56 patients and 56 healthy control subjects were analyzed. Patients were categorized into 3 groups, depending on disease duration and the presence or absence of inflammatory infiltrates. The expression of VEGF and the vessel marker CD31 in muscle was analyzed by immunohistochemistry, the expression of VEGF messenger RNA (mRNA) was analyzed by in situ hybridization, and serum levels of VEGF were determined by enzyme-linked immunosorbent assay. Patients with polymyositis or dermatomyositis in the early or chronic phase without inflammatory infiltrates had a decreased total number of capillaries compared with healthy individuals. In patients with early disease without inflammatory infiltrates, the number of VEGF-expressing muscle fibers was increased compared with that in control subjects, whereas VEGF expression was unchanged in the chronic phase of disease. In patients with established disease with inflammatory infiltrates, total VEGF expression was high compared with that in healthy control subjects. In healthy control subjects, VEGF was expressed in endothelial cells and in occasional muscle fibers. VEGF mRNA was expressed in muscle fibers in both healthy individuals and patients. The level of serum VEGF was significantly increased in patients compared with control subjects. Our observations support a role of VEGF in the early phases of polymyositis and dermatomyositis. A reduced number of capillaries could lead to induction of VEGF expression in muscle fibers. Furthermore, differences in molecular expression during certain phases of disease may help in the development of specific therapeutic algorithms in the treatment of myositis.

Vascular Effects of FGF-2 and VEGF-B in Rabbits with Bilateral Hind Limb Ischemia

Aims: To assess fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor-B (VEGF-B) effects on flow reserve and morphological adaptation in the rabbit ischemic hind limb. Methods: Following bilateral femoral artery ligation, calf blood pressure (C_BP), flow reserve, collateral artery numbers and capillary numbers were assessed. Treatment consisted of rabbit serum albumin (RSA), FGF-2, VEGF-B or FGF-2 + VEGF-B. Results: Ligation decreased C_BP; on day 14, a 48% deficit remained in the RSA group compared with a deficit of only 22% in FGF-2 and VEGF-B groups. On day 3, flow reserve was attenuated 60%, but recovered by day 14 (with no treatment effects). Collateral artery numbers increased with RSA (+28%), FGF-2 (+53%), VEGF-B (+47%) and FGF-2 + VEGF-B (+59%). Rectus femoris muscle total capillary profiles and fibers per cross-section were alike across groups. Tibialis anterior muscle cross-sectional area was lower with ligation and total capillary number was less in RSA and FGF-2 groups, providing evidence for angiogenesis with VEGF-B. Capillary/muscle fiber ratio was similar in each group. Conclusions: FGF-2 and VEGF-B enhanced lower limb perfusion as indicated by improved C_BP and combined treatment increased collateral artery number. Flow reserve recovery was not enhanced by cytokine treatment. VEGF-B, but not FGF-2, caused angiogenesis in the tibialis anterior muscle. Overall, VEGF-B may have advantages over FGF-2 in this setting; however, their combination may further improve arteriogenesis.

Oxidative Phenotype Protects Myofibers from Pathological Insults Induced by Chronic Heart Failure in Mice

The fiber specificity of skeletal muscle abnormalities in chronic heart failure (CHF) has not been defined. We show here that transgenic mice (8 weeks old) with cardiac-specific overexpression of calsequestrin developed CHF (50.9% decrease in fractional shortening and 56.4% increase in lung weight, P<0.001), cachexia (37.8% decrease in body weight, P<0.001), and exercise intolerance (69.3% decrease in running distance to exhaustion, P<0.001) without a significant change in muscle fiber-type composition. Slow oxidative soleus muscle maintained muscle mass, whereas fast glycolytic tibialis anterior and plantaris muscles underwent atrophy (11.6 and 13.3%, respectively; P<0.05). In plantaris muscle, glycolytic type IId/x and IIb, but not oxidative type I and IIa, fibers displayed significant decreases in cross-sectional area (20.3%, P<0.05). Fast glycolytic white vastus lateralis muscle showed sarcomere degeneration and decreased cytochrome c oxidase IV (39.5%, P<0.01) and peroxisome proliferator-activated receptor gamma co-activator 1alpha protein expression (30.3%, P<0.01) along with a dramatic induction of the MAFbx/Atrogin-1 mRNA. These findings suggest that exercise intolerance can occur in CHF without fiber type switching in skeletal muscle and that oxidative phenotype renders myofibers resistant to pathological insults induced by CHF.

Pathophysiologic Changes in the Optic Nerves of Eyes with Primary Open Angle and Pseudoexfoliation Glaucoma

To determine whether differences in the optic nerve occur in eyes with primary versus secondary open-angle glaucoma. Optic nerves obtained at autopsy from 36 eyes with primary open-angle glaucoma (POAG) and 15 with pseudoexfoliation glaucoma (PEXG) were studied quantitatively and qualitatively. Axon counts, fibrosis, capillary number and density, and arteriosclerotic changes were assessed in the postlaminar optic nerve and compared to normal age-matched autopsy eyes. Changes in composition of extracellular matrix components were evaluated by immunohistochemistry and electron microscopy. Marked differences were found between POAG and PEXG. Axon loss in eyes with POAG but not in PEXG was associated with increasing connective tissue in the septa and surrounding the central retinal vessels, including increased amounts of type IV and VI collagen. The total number of capillaries decreased with the loss of axons in both POAG and PEXG. POAG nerves, however, had a decrease in the density of capillaries, whereas in PEXG the capillary density did not change with axon loss. Arteriosclerotic changes were more common in glaucomatous eyes than in age-matched control eyes. The difference in morphology of the optic nerves between POAG and PEXG indicates that in eyes with POAG, elevated IOP cannot be the only pathogenetic factor in glaucomatous optic neuropathy. Additional factors, inducing fibrosis and loss of capillaries, seem to be involved. Such additional factors may also contribute to the clinical finding in POAG that nerves can become damaged without elevation of intraocular pressure.

West, Brown and Enquist's model of allometric scaling again: the same questions remain

West, Brown and Enquist's model of allometric scaling again: the same questions remain