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PubMed1981

[Myocardial capillarity of white rats during high-altitude hypoxia].

In 128 mature white rats (males) after adaptation for 1--45 days, to 4,000 m altitude (North-West Pamir, Glasier Fortambek), weight characteristics of the heart were estimated (capillary diameters, their network density per 1 mm2 of the section summing length and volume in 1 mm3 of the right and left ventricular myocardium. Since the 21st day of the animals' staying at the altitute mentioned, a stable increase in the ventricular index occurs demonstrating a predominant right ventricular hyperfunction; the blood capillary volume in the left ventricular myocardium, during the whole time of the experiment, remains at the control levels, at the expense of the concomitant changes in the diameter and density. The blood capillary volume in the right ventricular myocardium, beginning from the first day of the experiment, increase essentially; this increase was kept up to the 14th day of the experiment, but, nevertheless, it remains at the control levels, at the expense of the concomitant changes in the diameter and density. The blood capillary volume in the right ventricular myocardium, beginning from the first day of the experiment, increase essentially; this increase was kept up to the 14th day of the experiment, but, nevertheless, it remains at the control levels, at the expense of the concomitant changes in the diameter and density. The blood capillary volume in the right ventricular myocardium, beginning from the first day of the experiment, increase essentially; this increase was kept up to the 14th day of the experiment, but, nevertheless, it did not exceed the volume indices of the left ventricular capillaries.

Acclimatization↗
PubMed1976

[Histological studies on the capillarization of various muscles in industrially raised rabbits].

The longissimus dorsi, semitendinosus, psoas major and biceps femoris muscles of 40 industrially kept rabbits were studied in regard to their numbers of capillaries per square mm. The relation between the number of capillaries and muscle fibres is narrower in a red muscle than in a white one. The total body mass is of more influence on the number of capillaries per square mm than the age.

Age Factors↗
PubMed1994

Regional changes in capillary supply in skeletal muscle of interval-sprint and low-intensity, endurance-trained rats.

OBJECTIVE: Exercise training produces regional increases in blood flow capacity among muscle fibers that experience increased activity during exercise. We tested the hypothesis that this increase is partially due to capillary angiogenesis among muscle fibers with large increases in activity during exercise training bouts. METHODS: Two training programs were evaluated: a program consisting of 10-12 weeks of exposure to low-intensity (30 m/min, 0 incline, 60 min/day) (LET) exercise bouts, 5 days/week, and a second program consisting of 8-10 weeks of exposure to repetitive bouts (6/day) of sprint (60 m/min, 15% incline) exercise, alternating running (2.5 min) and recovery (4.5 min), 5 days/week (IST). Cage-confined rats were utilized (SED) as controls. After training was completed, rat hindquarters were perfusion-fixed with modified Karnovsky's fixative. Transverse sections from soleus (Sol), and red (GR), mixed (GM), and white (GW) portions of gastrocnemius muscle were prepared to evaluate capillarization. Sections were analyzed using the Olympus Cue 2 Image Analyzer to determine capillary/muscle fiber ratio (C/F), number of capillary profiles per square millimeter of muscle area (CND), capillary surface area per volume of tissue, and capillary volume density. RESULTS: Average area per muscle fiber and sarcomere length did not differ among groups. LET did not affect capillarization of the GW, whereas increasing C/F in GM (2.3 +/- 0.1 versus 2.1 +/- 0.1 for SED) and GR (3.0 +/- 0.1 versus 2.6 +/- 0.1 for SED). IST increased C/F and CND in GW (1.6 +/- 0.1 versus 1.3 +/- 0.0 for SED and 657 +/- 74 versus 418 +/- 53 for SED, respectively) and increased C/F ratio in GM (2.3 +/- 0.1 versus 2.1 +/- 0.1 for SED). IST did not increase capillarization of the GR. The capillarization of the soleus muscle was not affected by either exercise training program. CONCLUSION: IST increased capillarization in muscle tissue composed of a high percentage of fast glycolytic fibers (GW and GM) and LET increased capillarization of muscle tissue composed of a high percentage of fast oxidative-glycolytic fibers (GW and GR).

Animals↗
PubMed2005

Improved controllability of opal film growth using capillaries for the deposition process.

A capillary deposition method for the preparation of opal and inverse opal films has been developed. By this method, one can control the film thickness and the crack arrangement in opal as well as inverse opal structures. This method combines tube capillarity with cell capillarity or with gravity depending on the stability of the suspensions. The combination of tube capillarity with cell capillarity is used to prepare opal films from stable suspensions. The tube capillary transports the suspension, while the cell capillary helps to assemble the spheres. The setup defines the drying fronts, thickness, and crack arrangements of the opal films. The combination of capillarity with gravity is useful for making opal films from unstable suspensions. Opal films of spheres with size up to 1 mum can be easily prepared from this combination. Here, the gravity influences the arrangement of the spheres. The two-capillary setup has also been used to infiltrate the opal films with a titania precursor. After calcination, inverse titania opal films with skeleton structure have been obtained.

Journal Article↗
PubMed1997

Femoral artery ligation stimulates capillary growth and limits training-induced increases in oxidative capacity in rats.

OBJECTIVE: The purpose of this study was to assess the interaction of arterial insufficiency and exercise training on soleus and plantaris muscle capillarity and oxidative capacity in adult rats. METHODS: Arterial insufficiency was created by ligation (LIG) of the right femoral artery, and exercise training (TR) was performed on a rodent treadmill. The left hindlimb served as a normally (NORM) perfused control. Capillary:fiber ratio number of capillary contacts per fiber, and citrate synthase activity (CS) were evaluated in the plantaris (Plant) and soleus (Sol) muscles. RESULTS: In sedentary rats, CS was similar between LIG and NORM (Plant: 24.4 vs. 24.3 mumol.min-1.g-1; Sol: 16.6 vs. 16.9 mumol.min-1.g-1), but capillaries per fiber and capillary contacts per fiber were significantly elevated in the plantaris muscle of LIG (2.46 vs. 2.10 caps/fiber, 5.78 vs. 5.03 capillary contacts). CS was elevated in both limbs of TR but was lower in LIG than in NORM (Plant: 28.5 vs. 32.4 mumol.min-1.g-1; Sol: 21.1 vs. 24.9 mumol.min-1.g-1). Treadmill training did not significantly affect capillarity in NORM. However, muscles in the ligated limb of TR tended to have greater capillarity than comparable muscles in either NORM of TR of LIG in SED. CONCLUSIONS: These results demonstrate capillary proliferation in the plantaris but not soleus muscle of rat hindlimbs with femoral artery ligation. Capillarity and CS adaptations were not obligatorily related in LIG, and femoral artery ligation and exercise training appeared to have interactive effects on skeletal muscle capillarity.

Animals↗
PubMed2004

Morphometric evidence that villous development and fetoplacental angiogenesis are compromised by intrauterine growth restriction but not by pre-eclampsia.

The aim of this study was to compare morphometric measures of villous development, villous capillarization, fetoplacental angiogenesis and capillary lumen remodelling in normal pregnancies with those complicated by intrauterine growth restriction (IUGR) with and without preeclampsia (PE). To this end, term placentas from control pregnancies (n = 9) and cases of IUGR alone (n = 5), PE alone (n = 5) and IUGR with PE (n = 5) provided random samples of tissue. These were fixed in formalin and Masson trichrome-stained wax sections were analysed stereologically. Overall growth of peripheral villi and fetal capillaries was assessed by estimating total volumes, surface areas and lengths. Villous capillarization was monitored using volume, surface and length densities and capillary:villus surface and length ratios. Measures of villous maturation and capillary lumen remodelling comprised mean cross-sectional areas, perimeters and shapes (perimeter(2)/area). Between-group comparisons were drawn using two-way analysis of variance. IUGR was associated with abnormal growth of villi and fetal capillaries. Reduced villous growth was not accompanied by changes in measures of villous capillarization or maturation and reduced capillary growth was not accompanied by changes in lumen calibre or shape. In contrast, PE was not associated with any main or interaction effects on placental morphometry. It is concluded that IUGR, but not PE, is associated with impoverished villous development and fetoplacental angiogenesis. The latter is due to production of fewer and/or shorter capillary segments (rather than a decrease in capillary calibre), does not affect villous capillarization and is not accompanied by luminal remodelling.

Capillaries↗
PubMed2006

A pathological analysis of lymphatic vessels in early renal allograft.

Lymphatic vessels are an essential part of the immunological response. Nevertheless, little is known about the pathology of renal transplant rejection. In part the reason may be not distinguishing peritubular capillaries from lymphatic vessels by periodic acid-Schiff (PAS) staining. This study examined the morphology of lymphatic vessels in early renal allografts using double staining with PAS and podoplanin. The 41 cases were divided into four categories: (I) acute antibody-mediated rejection, (II) acute cellular rejection, (III) peritubular capillaritis only, and (IV) controls. I through III had the evidence of peritubular capillaritis exceeding grade 1 on a biopsy obtained an average of 17.3 +/- 5.5 days after kidney transplantation. In addition, each lymphatic vessel density (LVD) and nodular lesion of lymphocytes (NL) were quantified as the number of each podoplanin-positive vascular profiles and NL per unit area of cortex measured Lumina Vision (Mitani). The average of the LVD was 73.0, 35.1, 37.1, and 8.1 per 10 mm2 for groups I to IV and the average of NL was 2.8, 5.5, 1.3, 0.9, respectively. There was a significant correlation between LVD and NL. NL showed a strong relation to the accumulation of lymphocytes in lymphatic vessels (AL); 22% of the AL scores were greater than the peritubular capillaritis grade. We found lymphatic vessels to be strongly associated with any kind of inflammatory process that occurred unexpectedly soon after kidney transplantation. In addition, to avoid misdiagnosis of peritubular capillaritis, NL in early renal allograft must especially be excluded.

Adult↗
PubMed2001

Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat.

The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals' drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.

Analysis of Variance↗
PubMed1999

Exercise stimulates neovascularization in occluded muscle without affecting bFGF content.

PURPOSE: This study was conducted to determine whether exercise-induced improvements in capillarity in muscle with peripheral arterial insufficiency (PAI) was accompanied by endothelial cell mitosis, and whether that response could be explained by changes in the expression of basic fibroblast growth factor (bFGF), a known mitogen. METHODS: After bilateral ligation of femoral arteries, Sprague-Dawley rats either remained sedentary or participated in a treadmill running protocol. Running time to exhaustion at each session was recorded. On days 1, 2, 3, 5, and 7 of the experimental period, trained-ligated and sedentary-ligated animals were euthanized, and segments of muscle from the gastrocnemius were obtained. Capillarity was determined with histochemistry, and endothelial cell mitotic activity (cell proliferation) was assayed via nuclear uptake of 5'-bromo-2'-deoxyuridine (BrdU), an analog of thymidine. Content of endogenous bFGF was assessed with immunoblotting techniques. RESULTS: Exercise training resulted in augmented function of PAI affected muscle as evidenced by a nearly threefold increase in running time until exhaustion. Trained-ligated muscle demonstrated significantly (P < 0.05) greater capillarity than sedentary-ligated muscle. Vascular remodeling elicited by exercise included the formation of new capillaries (angiogenesis) as indicated by enhanced endothelial cell proliferation at days 3, 5, and 7 of the study. However, exercise training did not alter the content of bFGF in occluded muscle. CONCLUSION: In muscle with PAI, exercise training improved functional capacity and capillarity. Angiogenesis was confirmed by the increased mitotic activity of endothelial cells. However, the content of bFGF, a potent angiogenic factor, was not altered. Thus, exercise-induced angiogenesis in PAI affected muscle is not dependent upon increased expression of endogenous bFGF.

Animals↗
PubMed1991

Ultrastructural localization of type IV collagen and laminin in the Disse space of rat liver with carbon tetrachloride induced fibrosis.

Monospecific antibodies, directed against type IV collagen and laminin, were used to clarify the process of sinusoidal capillarization in rats after carbon tetrachloride (CCl4) intoxication by the direct immunoperoxidase method. After acute intoxication, both type IV collagen and laminin were increased in the area of hepatic necrosis, adjacent to the central veins; however, sinusoidal capillarization was not found. During chronic intoxication, deposition of laminin was co-distributed with that of type IV collagen, but deposition proceeded more slowly than that of the type IV collagen. Deposition of laminin was increased in the Disse space. Sinusoidal capillarization was noted as thick deposition of both antigens by light microscopy. Immunoelectron microscopy showed that both components were continuously present in the Disse space. Intracellularly, both antigens were found in the rough endoplasmic reticulum (RER) of fat-storing cells (FSC) and endothelial cells, and these cells showed morphological changes, becoming slender and flattened. In contrast, few immunoreactive products of the two components were observed in the hepatocytes. These findings suggest that type IV collagen and laminin are indispensable for the establishment of sinusoidal capillarization, and that FSC play an important role in the production of both components.

Animals↗
PubMed2001

Muscle angiogenic growth factor gene responses to exercise in chronic renal failure.

Patients with chronic renal failure (CRF) have impaired exercise capacity even after erythropoietin treatment. We recently showed that although this is explained in part by reduced convective O(2) delivery to muscles, there is also an impairment of O(2) transport from muscle capillaries to the mitochondria. Given the importance of the capillary surface area for capillary mitochondrial O(2) transport and reports of reduced capillarity in CRF, we hypothesized that the angiogenic gene response to exercise is impaired in such patients. Six patients with CRF and six control subjects matched for age, size, and sedentary lifestyle exercised on a single occasion for 1 h at similar work intensities averaging 50% of maximal capacity. Exercise was confined to the knee extensors of a single leg by means of a specially designed leg-kick ergometer. A percutaneous biopsy of the quadriceps was taken within 30 min of cessation of exercise and compared with a similar biopsy done at different times without any prior exercise for 24 h. Conventional Northern blots were prepared and probed for vascular endothelial growth factor (VEGF; the major putative angiogenic growth factor for muscle), basic fibroblast growth factor (bFGF), and transforming growth factor (TGF)-beta(1). Data during both rest and exercise were successfully obtained in four subjects of each group. We also assessed muscle capillarity and mitochondrial oxidative capacity to relate to these changes. Mitochondrial oxidative capacity was normal, whereas capillary number per fiber was 12% lower than in normal subjects. VEGF mRNA abundance was increased after exercise by about one order of magnitude, with no reduction in response in CRF. For bFGF and TGF-beta(1), exercise elicited no response in either group. Reduced muscle capillarity in CRF does not, therefore, stem from reduced transcription of VEGF. To the extent that VEGF is important to exercise-induced angiogenesis in muscle, we suspect a posttranscriptional aberration in this response occurs in CRF to explain reduced capillarity.

Adolescent↗
PubMed1998

Cellular adaptations of skeletal muscles to cyclosporine.

The aim of this study was to evaluate the cellular response of the diaphragm, extensor digitorum longus (EDL), and soleus (Sol) muscles to clinically relevant doses of cyclosporine administered to male rats over 4 wk. Control rats were provided with vehicle only. Muscle fiber types, cross-sectional areas, indexes of capillarity, and succinate dehydrogenase (SDH) activity were determined by quantitative histochemistry. Myosin heavy chain isoforms were identified by SDS-PAGE, and their proportions were measured by scanning densitometry. Serum cyclosporine level, 20-24 h after the last dose of cyclosporine, was 145 +/- 81 ng/ml. Final body weight and muscle mass were similar between the cyclosporine and control groups. In the diaphragm, EDL, and Sol, no differences were observed between the groups with regard to fiber type proportions, fiber cross-sectional areas, and proportions of myosin heavy chain isoforms. In the EDL, reductions, both in SDH activity in type I, IIx, and IIb fibers (-26 to -37%) and in indexes of capillarity (-18 to -37%), were noted. In the Sol, SDH activity and capillarity were similar between the groups. In the diaphragm of cyclosporine-treated rats, there was significant reduction in the number of capillaries around individual fibers (-5%), whereas levels of SDH activity tended to be lower. This suggests that activation history may in part determine muscle-specific responses to cyclosporine. We speculate that reduced oxidative activity and capillarity of some limb muscles contribute to reduced exercise capacity and the "deconditioned state" observed in patients receiving cyclosporine after successful solid-organ transplantation.

Animals↗
PubMed1999

Differential microvascular response to disuse in rat hindlimb skeletal muscles.

The aim of the study was to address discrepant findings in the literature regarding coupling between decreased functional demand during disuse and reduced capillarity. We previously reported [K. Tyml, O. Mathieu-Costello, and E. Noble. Microvasc. Res. 49: 17-32, 1995] that severe disuse of rat extensor digitorum longus (EDL) muscle caused by a 2-wk application of tetrodotoxin (TTX) on the sciatic nerve is not accompanied by capillary loss. Using the same animal model, the present study examined whether this absence of coupling could be explained in terms of 1) too short a duration of disuse and 2) muscle-specific response to disuse. Fischer 344 rats were exposed to either no treatment (control) or to 2- or 8-wk TTX applications. Fiber size, capillary density per fiber cross-sectional area, and capillary-to-fiber (C/F) ratio were determined by morphometry in the EDL muscle (control, 2- and 8-wk groups) and in the superficial portion of medial gastrocnemius (Gas) muscle (control, 2 wk). In both muscles, microvascular blood flow was evaluated by intravital microscopy [red blood cell velocity in capillaries (V(RBC))] and by laser Doppler flowmetry (LDF). Regardless of duration of TTX application or muscle type, TTX-induced disuse resulted in a significant reduction of fiber area (44-71%). However, capillary density increased in EDL muscle (both at 2 and 8 wk) but not in Gas muscle. C/F ratio decreased in EDL muscle at 8 wk (18%) and in Gas muscle (39%). This indicates that the effect on capillarity depended on duration of disuse and on muscle type. V(RBC) and LDF signal were significantly larger in EDL than in Gas muscle. Analysis of change in capillarity vs. V(RBC) suggested that the outcome of disuse may be modulated by blood flow. We conclude that the duration of skeletal muscle disuse per se does not dictate capillary loss, and we hypothesize that discrepant findings of coupling between functional demand and capillarity could be due to the presence/absence of flow-related angiogenesis superimposed on the capillary removal process during disuse.

Animals↗