International journal of microcirculation, clinical and experimental最新文献

We treated 14 patients suffering from critical limb ischemia (CLI) as defined by the Consensus Document, and in whom possibilities of surgical or percutaneous arterial reconstruction were excluded, by PGE1 60 micrograms i.v. daily during 3 weeks. Effects were evaluated by clinical, macrocirculatory and microcirculatory parameters during a follow-up of 1 year. After treatment with PGE1, we noted a significant reduction in analgesic use and in pain score. The average tcpO2 values on the forefoot in the supine and sitting positions, with or without inhalation of O2 through a face mask, showed a significant improvement after 3 weeks, as well as capillary stage. Laser Doppler flux did not change, but was significantly higher in diabetic patients than in nondiabetics with CLI. In 4 patients (28%) no improvement could be found after 3 weeks' treatment. Although in 6 patients the improvement lasted for up to 4 months, the legs eventually deteriorated. In 4 patients (28%) the legs were preserved after 1 year without further active therapy. No patient with initial tcpO2 values above 40 mm Hg in the supine and 100 mm Hg in the sitting positions during O2 inhalation lost a leg. Although other effects like local care could have influenced the outcome favorably, we noticed a beneficial albeit transient effect of PGE1 for the majority of our patients with CLI. TcpO2 measurements with O2 inhalation might be a valuable predictor of a positive long-term result.

Ten samples of pyogenic granuloma and 10 of normal skin from age- and sex-matched controls were grafted onto the chick embryo chorioallantoic membrane (CAM) to investigate their possible angiogenic activity. The angiogenic response in pathological and control implants was assessed on histologic sections by a planimetric point-count method 4 days after grafting. The CAM mast cells were also quantified. The vascular counts in the area underlying the pyogenic granuloma were four times higher than those of normal skin. A higher number of mucosa-like mast cells was detected in the intermediate mesenchyme of the CAM in pathological samples in comparison to controls. Pyogenic granuloma may promote angiogenesis leading to release of several angiogenic factors. The role played in angiogenic response by the inflammatory cells, mainly mast cells, forming the perilesional infiltrate was supported by this study.

Myeloperoxidase (MPO) activity is assessed for the quantification of neutrophil accumulation in tissues. In particular, it may be used to support in vivo data on leukocyte kinetics obtained by intravital microscopy and to clarify whether phenomena observed on the organ surface reflect the situation of the whole organ microcirculation. Previous measurements of MPO activity were limited by interference with other peroxidases and by inhibition of MPO activity by specific enzymes. To circumvent these limitations, a modified assay was devised that combined a two-step tissue homogenization technique with heat incubation in a continuous photometric measurement. MPO activity was quantified in neutrophils isolated from rat and rabbit whole blood, rat brain and rabbit lung and compared with intravital microscopic data on leukocyte accumulation. The modified assay is characterized by high reproducibility, strong correlation of MPO activity with number of neutrophils and full recovery of neutrophils added to tissue homogenate. MPO activity per neutrophil was 342.9 +/- 11.7 mU/10(6) cells in rats and 40.3 +/- 0.8 mU/10(6) cells in rabbits. MPO activity in tissue was significantly lower in rat brains (18.9 +/- 29.7 mU/g) as compared to rabbit lungs (741 +/- 67 mU/g). Whereas global cerebral ischemia/reperfusion did not increase MPO activity in rat brain (18.1 +/- 26.1 mU/g), intravenous infusion of cobra venom factor (1,447 +/- 407 mU/g) or endotoxin (1,439 +/- 285 mU/g), enhanced MPO activity in rabbit lung. These results parallel microcirculatory data from the organ surface. Therefore they supplement the intravital microscopic observations by demonstrating that these are indeed representative of deeper parenchymal tissue areas.

The reliability of intravital capillaroscopy for determining capillary density (CD) of skin has been questioned because it depends upon the variability of the measuring process and subjective interpretation of data as well as the intrinsic heterogeneity of capillary spacing. The aim of this study was to assess the repeatability of a standardised method for measuring CD of the skin of the dorsum of foot. In each of 30 subjects (10 controls and 20 patients with peripheral vascular disease), the foot was systematically mapped by examining 20 sites on the dorsum of foot and 2 sites on each toe, using white light (native) videomicroscopy at 40 x magnification. Off-line analysis of videoprints was then undertaken to determine CD at each site, by counting capillaries within areas of acceptable photographic quality only, having first defined the criteria for counting capillaries. The mean values were then calculated and taken to represent the CD of the foot or toes. Repeatability of the measuring equipment was first assessed by noting the presence or absence of each corresponding capillary in 2 prints, taken at intervals of hours or days (in 10 subjects) or months (in 2 patients), of an identical area of skin which was marked by a microtattoo on the first occasion. On average, 95% of corresponding capillaries were identified in both prints (from controls and patients), thus implying little intrinsic temporal variation of capillary anatomy as well as excellent repeatability of the measuring equipment. Repeatability of data analysis was assessed by the same observer reading the same 20 prints in a blinded manner on three separate occasions (intraobserver repeatability), and 2 observers reading the same 24 prints (interobserver repeatability). The mean coefficient of intraobserver variation of CD estimate was 5.6% and the interobserver correlation coefficient was 0.94. Finally, overall repeatability of the method was assessed by repeating the procedure on a subsequent occasion (mean time interval of 5 days) in 10 subjects. The rate of agreement in mean CD between the two procedures [defined as 100- (difference between the two measurements/mean of the two measurements) x 100]% ranged from 86.4 to 97.1% (mean 93.5%). Thus using the above methodological technique, native capillaroscopy can be reliably used to determine CD of the dorsum of foot in comparing patient subgroups, as well as in longitudinal studies.

We recently reported that the subcutaneous (s.c.) administration of a low-molecular-weight heparin (LMWH) fraction significantly inhibited de novo angiogenesis in the mesentery induced by the intraperitoneal (i.p.) injection of saline to adult rats compared with unfractionated heparin and high-molecular-weight heparin (HMWH) fractions. The present study assesses the effect on basic fibroblast growth factor (bFGF)-mediated de novo angiogenesis in the mesentery of the systemic administration of a LMWH fraction (2.6 kD) and a series of four HMWH fractions (about 20 kD) with varying degrees of polydispersity, charge density and anticoagulant activity. bFGF, a prototypic heparin-binding angiogenic growth factor, was injected i.p. at 220 pM on days 0-4. The heparins were given s.c. on days 0-13 or 0-14 at doses which were approximately within the range used clinically. Angiogenesis was assessed by microscopic morphometry and image analysis in groups of animals killed on days 14 and 15. Compared with the saline control, the LMWH and three of the HMWHs significantly inhibited angiogenesis in terms of microvascular length (MVL), a measure of microvascular density. Interestingly, the vascularized area (VA), a measure of microvascular spatial extension, and the total microvascular length (VA x MVL) were significantly lower in the LMWH-treated animals than in the animals treated with one of the HMWHs. The total microvascular length was, moreover, significantly reduced in the LMWH-treated animals compared with the combined data of all the HMWH-treated animals. No significant effects were related to the degree of charge density and anticoagulant activity of the heparins. In view of the putative significant angiogenic role of bFGF in human angiogenesis diseases, the present findings may have implications for the choice of anticoagulant treatment modality for patients suffering from cancer and other angiogenesis diseases.