Variability of Fiber Size, Capillary Density and Capillary Length Related to Horse Muscle Fixation Procedures

1988 ◽  
Vol 133 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Laurence Mermod ◽  
Hans Hoppeler ◽  
Susan R. Kayar ◽  
Reto Straub ◽  
Ewald R. Weibel
Keyword(s):  
Capillary Density ◽  
Capillary Length ◽  
Fiber Size

Ultrastructure of Aerobic Muscle in Antarctic Fishes may Contribute to Maintenance Of Diffusive Fluxes

1990 ◽  
Vol 150 (1) ◽  
pp. 205-220 ◽  
Author(s):  
RICHARD L. LONDRAVILLE ◽  
BRUCE D. SIDELL
Keyword(s):  
Muscle Metabolism ◽  
Antarctic Fish ◽  
Oxygen Demand ◽  
Capillary Density ◽  
Volume Density ◽  
Active Species ◽  
Published Data ◽  
Diffusion Distance ◽  
Capillary Length ◽  
Diffusive Fluxes

Quantitative ultrastructural analyses were performed on red (oxidative) and white (glycolytic) skeletal muscles from two species of antarctic fish to identify features of subcellular structure that may be related to muscle metabolism at cold body temperature. Trematomus newnesi (Boulenger) is an active pelagic species and Notothenia gibberifrons (Lönnberg) is a sluggish bottom-dweller. White fibres of both species are poorly vascularized [capillary density, NA(c,f), for T. newnesi 73.9±11.3mm−2; for N. gibberifrons is 76.0±14.1mm−2], and have low percentages of cell volume occupied by mitochondria [volume density, Vv(mit,f), for T. newnesi is 0.014±0.005; for N. gibberifrons is 0.006±0.003]. Ultrastructure of oxidative fibres in both species resembles that of cold-acclimated temperate-zone fishes. Mitochondrial volume densities of red fibres reflect differences in ecotype between species [Vv(mit,f) for T. newnesi is 0.348±0.012; for N. gibberifrons is 0.249±0.007]. The less clustered array of mitochondria in oxidative fibres of T. newnesi compared with N. gibberifrons may support an equivalent flux of aqueous metabolites between mitochondrial and cytoplasmic compartments, despite a greater mean intracellular diffusion distance (τh) between these compartments in T. newnesi than in N. gibberifrons (τh=1.05±0.07μm and 0.77±0.06μm, respectively). Although Vv(mit.)) is higher in red fibres of the active species, capillary supply is less extensive [capillary length density, Jv(c,f), for T. newnesi is 481.3±49.0mm mm−3; N. gibberifrons is 696.3±33.7mm mm−3] and the maximal diffusion-distance for oxygen is greater in T. newnesi than in N. gibberifrons (Krogh's radius, R=26.3±1.64μm and 21.5±0.51μm, respectively). A mismatch appears to exist between oxygen supply [Jv(c,f)] and oxygen demand [Vv(mit,f)] in T. newnesi red fibres in view of published data for other fishes. The twofold higher volume density of lipid [Vv(lip,f)] in T. newnesi compared with N. gibberifrons may resolve this paradox [Vv(lip,f) is 0.026±0.002 and 0.012±0.004, respectively]. Because oxygen is at least four times more soluble in lipid than in aqueous cytoplasm, lipid may enhance oxygen flux through oxidative muscle and play a role similar to myoglobin in these myoglobin-poor fishes.

scholarly journals Cold-induced angiogenesis in seasonally acclimatized rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 200 (16) ◽  
pp. 2263-2268 ◽  
Author(s):  
S Egginton ◽  
S Cordiner
Keyword(s):  
Rainbow Trout ◽  
Muscle Blood Flow ◽  
Capillary Density ◽  
Aerobic Performance ◽  
Muscle Fibres ◽  
Capillary Length ◽  
Humoral Factors ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Fibre Growth ◽  
Integrated Response

Seasonal acclimatization of rainbow trout induced an inverse relationship between environmental temperature and the capillary:fibre ratio of slow locomotory muscle, which increased from 1.73±0.09 in the summer (18 °C) to 2.50±0.15 in the winter (4 °C). However, the rate of capillary growth (angiogenesis) was exceeded by that of fibre growth at low temperatures such that the extensive fibre hypertrophy found at 4 °C led to a decrease in capillary density, NA(c,f), to 57 % of that found at 11 °C and 85 % of that at 18 °C. Cold-induced angiogenesis resulted in an expanded capillary bed of similar topology to the existing network, with capillary orientation deviating from that of muscle fibres by only 4­7 %. Capillary length density was maximal at 11 °C, JV(c,f)=2421±239 mm-2, which as previously described corresponds to the point when muscle blood flow is highest and the scope for aerobic swimming is greatest, reflecting an integrated response to optimize aerobic performance at intermediate temperatures. In contrast, ventricular NA(c,f) parallels heart rate and hence was highest at 18 °C, while there was no seasonal variation in myocyte diameter. Although a systemic response to seasonal adjustments in humoral factors may occur, the data reported here suggest that angiogenesis is probably stimulated by different mechanical factors in these two muscles.

scholarly journals Thermal compensation of peripheral oxygen transport in skeletal muscle of seasonally acclimatized trout

2000 ◽  
Vol 279 (2) ◽  
pp. R375-R388 ◽  
Author(s):  
S. Egginton ◽  
S. Cordiner ◽  
C. Skilbeck
Keyword(s):  
Marked Change ◽  
Capillary Density ◽  
Volume Density ◽  
Seasonal Effects ◽  
Intracellular Lipid ◽  
Fiber Size ◽  
Mitochondrial Volume ◽  
Natural Temperature ◽  
Extracellular Transport ◽  
Lipid Stores

Seasonal changes in ultrastructure of locomotory muscle were quantified after acclimatization to natural temperature and photoperiod. Only modest changes were seen in the volume density (Vv) of mitochondria in slow fibers ranging from 0.21 ± 0.01 (summer) to 0.24 ± 0.01 (winter), despite an increase in fiber size from 945 ± 19 to 1,594 ± 46 μm2, respectively, resulting in a significantly greater total mitochondrial volume at low temperatures. In contrast, intracellular lipid stores showed a marked change with season, from a maximum Vv of lipid droplets of 0.16 ± 0.01 in winter, progressively declining through spring and summer to a minimum of 0.07 ± 0.01 in autumn. For both organelles, the surface density reflected changes in Vv, indicating little modification of structure. Seasonal effects may dominate those of environmental temperature on mitochondrial separation, which in winter and spring fish at 4oC averaged 0.64 ± 0.06 and 1.20 ± 0.07 μm, respectively. The extracellular transport of oxygen also varies with season, the peak capillary density in autumn (2,851 ± 88 mm−2) resulting in a minimum tissue supply (domain) area of 529 ± 9μm2 per capillary. As a consequence, the predicted intracellular Po 2 (∼2.5 kPa) is similar throughout the year.

Delayed angiogenesis and VEGF production in CCR2−/− mice during impaired skeletal muscle regeneration

2007 ◽  
Vol 293 (2) ◽  
pp. R651-R661 ◽  
Author(s):  
Oscar Ochoa ◽  
Dongxu Sun ◽  
Sara M. Reyes-Reyna ◽  
Lindsay L. Waite ◽  
Joel E. Michalek ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Regeneration ◽  
Capillary Density ◽  
Skeletal Muscle Regeneration ◽  
Mouse Strains ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Fiber Size ◽  
Cc Chemokine Receptor 2 ◽  
Endothelial Growth Factor

The regulation of vascular endothelial growth factor (VEGF) levels and angiogenic events during skeletal muscle regeneration remains largely unknown. This study examined angiogenesis, VEGF levels, and muscle regeneration after cardiotoxin (CT)-induced injury in mice lacking the CC chemokine receptor 2 (CCR2). Muscle regeneration was significantly decreased in CCR2−/− mice as was the early accumulation of macrophages after injury. In both mouse strains, tissue VEGF was similar at baseline (no injections) and significantly decreased at day 3 post-CT. Tissue VEGF in wild-type (WT) mice was restored within 7 days postinjury but remained significantly reduced in CCR2−/− mice until day 21. Capillary density (capillaries/mm2) within regenerating muscle was maximal in WT mice at day 7 and double that of baseline muscle. In comparison, maximal capillary density in CCR2−/− mice occurred at 21 days postinjury. Maximal capillary density developed concurrent with the restoration of tissue VEGF in both strains. A highly significant, inverse relationship existed between the size of regenerated muscle fibers and capillaries per square millimeter. Although this relationship was comparable in WT and CCR2−/− animals, there was a significant decrease in the magnitude of this response in the absence of CCR2, reflecting the observation that regenerated muscle fiber size in CCR2−/− mice was only 50% of baseline at 42 days postinjury, whereas WT mice had attained baseline fiber size by day 21. Thus CCR2-dependent events in injured skeletal muscle, including impaired macrophage recruitment, contribute to restoration of tissue VEGF levels and the dynamic processes of capillary formation and muscle regeneration.

scholarly journals Muscle Fiber Composition and Capillary Density in Turner Syndrome: Evidence of increased muscle fiber size related to insulin resistance

Diabetes Care ◽  
2001 ◽  
Vol 24 (9) ◽  
pp. 1668-1673 ◽  
Author(s):  
C. H. Gravholt ◽  
B. Nyholm ◽  
B. Saltin ◽  
O. Schmitz ◽  
J. S. Christiansen
Keyword(s):  
Insulin Resistance ◽  
Turner Syndrome ◽  
Muscle Fiber ◽  
Capillary Density ◽  
Fiber Composition ◽  
Fiber Size

Geometry of blood-tissue exchange in bat flight muscle compared with bat hindlimb and rat soleus muscle

1992 ◽  
Vol 262 (6) ◽  
pp. R955-R965 ◽  
Author(s):  
O. Mathieu-Costello ◽  
J. M. Szewczak ◽  
R. B. Logemann ◽  
P. J. Agey
Keyword(s):  
Soleus Muscle ◽  
Sarcomere Length ◽  
Flight Muscle ◽  
Fiber Surface ◽  
Capillary Length ◽  
Fiber Volume ◽  
Cross Sectional ◽  
Fiber Size ◽  
Rat Soleus Muscle ◽  
Mitochondrial Volume

We investigated the relationship between capillary-to-fiber geometry and muscle aerobic capacity by comparing the bat flight muscle (pectoralis muscle), i.e., an ultimate case of extreme O2 demand in a mammalian skeletal muscle, with bat hindlimb and rat soleus muscles. At a given sarcomere length (2.1 microns), fiber cross-sectional area was considerably smaller in bat muscles (pectoralis 318 +/- 10 microns 2, hindlimb 447 +/- 35 microns 2) than in rat soleus muscle (2,027 +/- 125 microns 2). Capillary number per fiber cross-sectional area was much greater in bat pectoralis (6,394 +/- 380/mm2) than in bat hindlimb and rat soleus muscle (2,865 +/- 238 and 1,301 +/- 129/mm2, respectively; all values normalized to 2.1-microns sarcomere length). At the same sarcomere length (2.1 microns), the degree of tortuosity and branching of capillaries were significantly greater in bat pectoralis than in bat hindlimb and rat soleus muscle. In bat flight muscle, capillary length per fiber volume was very high (9,025 +/- 342/mm2). It was 2.2- and 5.4-fold larger than in bat hindlimb and rat soleus, respectively. Mitochondria occupied 35.3 +/- 1.2, 16.5 +/- 1.3, and 6.1 +/- 0.9% of the muscle fiber volume in bat pectoralis, hindlimb, and rat soleus muscles, respectively. There was a strong correlation between capillary length (as well as capillary surface) per fiber volume and mitochondrial volume density in all muscles. Considering capillary supply and mitochondrial volume on an individual fiber basis, we found that 1) the number of capillaries around a fiber was linearly related to mitochondrial volume per micron length of fiber in the muscles but that 2) capillary surface per fiber surface, at given mitochondrial volume per micron length of fiber, was about twice as large in bat pectoralis as in rat soleus muscle, whereas in bat hindlimb it was intermediate between that in bat pectoralis and that in rat soleus muscle. This was due to the differences in fiber size (rat soleus greater than bat muscles) and capillary-to-fiber ratio (bat pectoralis greater than hindlimb) between the muscles. It is notable that in the bat, the substantially greater O2 transfer capacity of the flight muscle compared with hindlimb was achieved by increasing the size of the capillary-to-fiber interface, i.e., capillary-to-fiber surface, via an increase in capillary number rather than by substantially reducing fiber size.

Greater capillary-fiber interface per fiber mitochondrial volume in skeletal muscles of old rats

2005 ◽  
Vol 99 (1) ◽  
pp. 281-289 ◽  
Author(s):  
O. Mathieu-Costello ◽  
Y. Ju ◽  
M. Trejo-Morales ◽  
L. Cui
Keyword(s):  
Fiber Type ◽  
Fiber Surface ◽  
Volume Ratio ◽  
Capillary Density ◽  
Volume Density ◽  
Capillary Length ◽  
Fiber Volume ◽  
Fiber Number ◽  
Mitochondrial Volume ◽  
Fiber Atrophy

The objective was to examine whether muscle structural capacity for O2 flux (i.e., capillary-to-fiber surface ratio) relative to fiber mitochondrial volume deteriorates with the muscle atrophy of aging in predominantly slow- (soleus, S) and fast-twitch (extensor digitorum longus, EDL) muscles of old (24 mo) and very old (35 mo) F344BN rats compared with adult (12 mo old). Wet muscle mass decreased 29% (196 ± 4 to 139 ± 5 mg) in S and 22% (192 ± 3 to 150 ± 3 mg) in EDL between 12 and 35 mo of age, without decline in body mass. Capillary density increased 65% (1,387 ± 54 to 2,291 ± 238 mm−2) in S and 130% (964 ± 95 to 2,216 ± 311 mm−2) in EDL, because of the muscle fiber atrophy, whereas capillary per fiber number remained unchanged. Altered capillary geometry, i.e., lesser contribution of tortuosity and branching to capillary length, was found in S at 35 compared with 12 and 24 mo, and not in EDL. Accounting for capillary geometry revealed 55% (1,776 ± 78 to 2,750 ± 271 mm−2) and 113% (1,194 ± 112 to 2,540 ± 343 mm−2) increases in capillary length-to-fiber volume ratio between 12 and 35 mo of age in S and EDL, respectively. Fiber mitochondrial volume density was unchanged over the same period, causing mitochondrial volume per micrometer fiber length to decrease in proportion to the fiber atrophy in both muscles. As a result of the smaller fiber mitochondrial volume in the face of the unchanged capillary-to-fiber number ratio, capillary-to-fiber surface ratio relative to fiber mitochondrial volume not only did not deteriorate, but in fact increased twofold in both muscles between 12 and 35 mo of age, independent of their different fiber type.

scholarly journals Development and Remodeling of Cerebral Blood Vessels and Their Flow in Postnatal Mice Observed with in vivo Videomicroscopy

1992 ◽  
Vol 12 (6) ◽  
pp. 935-946 ◽  
Author(s):  
Dan-Bing Wang ◽  
Nissa C. Blocher ◽  
Mary Ellen Spence ◽  
Carl M. Rovainen ◽  
Thomas A. Woolsey
Keyword(s):  
Blood Vessels ◽  
Barrel Cortex ◽  
Morphological Changes ◽  
Functional Differentiation ◽  
Capillary Density ◽  
Branch Points ◽  
Capillary Length ◽  
Shear Rates ◽  
Wall Shear

Changes of blood vessels in the mouse somatosensory (barrel) cortex were assessed from birth (P0) to adulthood. Surface vessel anatomy and flow were observed directly with videomicroscopy through closed cranial windows and with intravascular fluorescent tracers. Histology was used to determine the internal capillary density. At birth, arterioles had numerous anastomoses with each other, pial capillaries formed a dense surface plexus, and pial venules and veins were relatively small and irregular. Morphological changes over the next 2 weeks included (a) fewer arteriolar anastomoses, (b) formation and growth of venules, (c) more uniform diameters of all types of vascular segments, (d) increase in intraparenchymal capillary length density ( Lv), and (e) decreases in superficial capillary density and diameters. A simple morphological test showed that wall shear rates at arteriolar branch points were matched on average in neonates and adults. Flow characteristics in single vessels were evaluated. In arterioles of like diameters, (a) Vmax, (b) peak wall shear rates, and (c) peak flows were similar at all ages; (d) velocity was very high in occasional arteriovenous (AV) shunts in newborns; and (e) flow in arteriolar anastomoses was slow and variable. Although flow was heterogeneous in all types of vessel, the marked similarities in newborn and adult mice of average peak velocities and calculated wall shear rates in arterioles of the same size suggest that blood flow regulates in part the remodeling of blood vessels during development (Rovainen et al., 1992). The rodent barrel cortex undergoes major neuronal and vascular development, functional differentiation, and remodeling during the first weeks after birth. It provides special opportunities for testing how blood vessels grow and adapt to supply the local metabolic requirements of neural modules in the brain.

scholarly journals Capillarity and mitochondrial distribution in rat myocardium following exercise training

1986 ◽  
Vol 120 (1) ◽  
pp. 189-199 ◽  
Author(s):  
S. R. Kayar ◽  
K. E. Conley ◽  
H. Claassen ◽  
H. Hoppeler
Keyword(s):  
Oxygen Consumption ◽  
Exercise Training ◽  
Consumption Rate ◽  
Maximal Oxygen Consumption ◽  
Capillary Density ◽  
Volume Density ◽  
Rat Myocardium ◽  
Capillary Length ◽  
Heart Mass ◽  
Mitochondrial Distribution

Rats were subjected to a laddermill running programme either once per week for 6 weeks, or daily for 6 weeks. Heart mass and maximal oxygen consumption rate increased relative to controls and with the frequency of the running programme. Mitochondrial distribution, measured in seven regions within fibres, was similar in all hearts, with a peak volume density of 0.42 +/− 0.01 occurring 4–5 microns from the centre of a capillary. Capillary density decreased with increasing heart mass, but total capillary length and capillary-to-fibre ratio were constant. Thus the higher metabolic demands of the running programmes did not alter the volume density or distribution of mitochondria, despite significant increases in heart mass and decreases in capillarity.

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