A comparison of static and dynamic cerebral autoregulation during mild whole-body cold stress in individuals with and without cervical spinal cord injury: a pilot study

Study design: Experimental study. Objectives: To characterize static and dynamic cerebral autoregulation (CA) of individuals with cervical spinal cord injury (SCI) compared to able-bodied controls in response to moderate increases in mean arterial pressure (MAP) caused by mild whole-body cold stress. Setting: Japan Methods: Five men with complete autonomic cervical SCI (sustained>5y) and six age-matched able-bodied men participated in hemodynamic, temperature, catecholamine and respiratory measurements for 60 min during three consecutive stages: baseline (10 min; 330C water through a thin-tubed whole-body suit), mild cold stress (20 min; 250C water) and post-cold recovery (30 min; 330C water). Static CA was determined as the ratio between mean changes in middle cerebral artery blood velocity and MAP, dynamic CA as transfer function coherence, gain and phase between spontaneous changes in MAP to middle cerebral artery blood velocity. Results: MAP increased in both groups during cold and post-cold recovery (mean differences: 5 to 10 mm Hg; main effect of time: p=0.001). Static CA was not different between the able-bodied vs the cervical SCI group (mean [95% CI] of between-group difference: -4 [-11 to 3] and -2 [-5 to 1] cm/s/mmHg for cold (p=0.22) and post-cold (p=0.24), respectively). At baseline, transfer function phase was shorter in the cervical SCI group (mean [95% CI] of between-group difference: 0.6 [0.2 to 1.0] rad; p=0.006), while between-group differences in changes in phase were not different in response to the cold stress (interaction term: p=0.06). Conclusions: This pilot study suggests that static CA is similar between individuals with cervical SCI and able-bodied controls in response to moderate increases in MAP, while dynamic CA may be impaired in cervical SCI due to disturbed sympathetic control

Blood biochemistry and plasma levels of osteopontin and pitavastatin.

<p>Mouse plasma was prepared from 32-weeks old apoE^-/- mice fed with high-fat diet. Levels of phosphate (A), calcium (B), creatinine (C), cystatin C (D), urea (E), total cholesterol (F) and osteopontin (G) were measured in plasma from apoE^-/- mice (n = 10), CRD apoE^-/- mice (n = 14) and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 18). Data are shown as mean ± SEM. H: Plasma concentration of pitavastatin given as food admixture in mice. ApoE^-/- mice were fed a chow supplemented with pitavastatin at doses of 30, 100 and 300 mg/kg diet (0.003, 0.01 and 0.03% wt/wt) for 2 weeks. These doses were equivalent to 3, 10 and 30 mg pitavastatin/kg body weight, respectively. Mice treated with pitavastatin at a dose of 100 mg/kg diet had plasma concentration of 5.3 ± 1.0 ng/mL. Data are shown as mean ± SEM (n = 5).</p

A: Pitavastatin has no significant effect on calcification in vascular smooth muscle cells. Mouse vascular smooth muscle cells were treated with or without 50 nM pitavastatin (PTV) in the presence of calcium/phosphate (Ca/P, 3 mM calcium and 2 mM phosphate) for 7 days. Calcium deposition was determined by o-cresolphthalein complexone method and normalized by cellular protein content. Data are shown as mean ± SEM (n = 3 each group). B and C: Pitavastatin reduces osteopontin mRNA expression in peritoneal macrophages. Macrophages were preincubated with either DMSO control or pitavastatin (100 nM or 300 nM) and followed by stimulation with calcium/phosphate (Ca/P, 3 mM calcium and 2 mM phosphate or 5 mM phosphate). mRNA levels of osteopontin (B,C) were determined by real-time PCR and normalized by mRNA levels of GAPDH. Data are shown as mean ± SEM (n = 6 each group).

<p>A: Pitavastatin has no significant effect on calcification in vascular smooth muscle cells. Mouse vascular smooth muscle cells were treated with or without 50 nM pitavastatin (PTV) in the presence of calcium/phosphate (Ca/P, 3 mM calcium and 2 mM phosphate) for 7 days. Calcium deposition was determined by o-cresolphthalein complexone method and normalized by cellular protein content. Data are shown as mean ± SEM (n = 3 each group). B and C: Pitavastatin reduces osteopontin mRNA expression in peritoneal macrophages. Macrophages were preincubated with either DMSO control or pitavastatin (100 nM or 300 nM) and followed by stimulation with calcium/phosphate (Ca/P, 3 mM calcium and 2 mM phosphate or 5 mM phosphate). mRNA levels of osteopontin (B,C) were determined by real-time PCR and normalized by mRNA levels of GAPDH. Data are shown as mean ± SEM (n = 6 each group).</p

A: Pitavastatin reduces osteopontin expression in brachiocephalic arteries of CRD mice. Representative images of osteopontin immunostaining within atherosclerotic plaques in brachiocephalic arteries of control apoE^-/- mice (n = 8), CRD apoE^-/- mice (n = 12), and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 14). L indicates lumen. Quantitative assessment of OPN-positive area was shown as mean ± SEM. B: Pitavastatin has no significant effect on calcification in brachiocephalic arteries of CRD mice. Representative images of advanced calcification within atherosclerotic lesions in brachiocephalic arteries of control apoE^-/- mice (n = 6), CRD apoE^-/- mice (n = 11), and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 15). Quantitative assessment of von Kossa-positive area was shown as mean ± SEM. L indicates lumen.

<p>A: Pitavastatin reduces osteopontin expression in brachiocephalic arteries of CRD mice. Representative images of osteopontin immunostaining within atherosclerotic plaques in brachiocephalic arteries of control apoE^-/- mice (n = 8), CRD apoE^-/- mice (n = 12), and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 14). L indicates lumen. Quantitative assessment of OPN-positive area was shown as mean ± SEM. B: Pitavastatin has no significant effect on calcification in brachiocephalic arteries of CRD mice. Representative images of advanced calcification within atherosclerotic lesions in brachiocephalic arteries of control apoE^-/- mice (n = 6), CRD apoE^-/- mice (n = 11), and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 15). Quantitative assessment of von Kossa-positive area was shown as mean ± SEM. L indicates lumen.</p

A: Study design. High-cholesterol-fed apoE^-/- mice at 19 weeks of age were randomized into control mice (n = 10) and CRD mice treated or untreated with pitavastatin (n = 20 per group). Pitavastatin was administered as a food admixture for 10 weeks starting at 22 weeks. Development of luminal stenosis in brachiocephalic arteries was monitored by ultrasonography at 19 weeks (before nephrectomy) and at 31 weeks. Ex vivo near infrared fluorescence molecular imaging and tissue harvesting for histology were performed at 32 weeks. B: Histological evidence of kidney insufficiency in CRD mice. Hematoxylin and eosin staining demonstrates normal kidney morphology in control apoE^-/- mice and enlarged glomeruli in CRD apoE^-/- mice treated with or without pitavastatin (Black bar = 50 μm).

<p>A: Study design. High-cholesterol-fed apoE^-/- mice at 19 weeks of age were randomized into control mice (n = 10) and CRD mice treated or untreated with pitavastatin (n = 20 per group). Pitavastatin was administered as a food admixture for 10 weeks starting at 22 weeks. Development of luminal stenosis in brachiocephalic arteries was monitored by ultrasonography at 19 weeks (before nephrectomy) and at 31 weeks. Ex vivo near infrared fluorescence molecular imaging and tissue harvesting for histology were performed at 32 weeks. B: Histological evidence of kidney insufficiency in CRD mice. Hematoxylin and eosin staining demonstrates normal kidney morphology in control apoE^-/- mice and enlarged glomeruli in CRD apoE^-/- mice treated with or without pitavastatin (Black bar = 50 μm).</p

Pitavastatin reduces macrophage accumulation in brachiocephalic arteries of CRD mice.

<p>A: Ex vivo fluorescence reflectance imaging (FRI) analysis. Representative images of the fluorescence intensity in the entire aorta were shown as red-green-blue (RGB) readout. Quantitative assessment of the signal intensity in the brachiocephalic artery (ROI) was shown as mean ± SEM. B: Mac3 immunostaining of brachiocephalic arteries. Representative images of macrophage accumulation within atherosclerotic lesions in brachiocephalic arteries of control apoE^-/- mice (n = 9), CRD apoE^-/- mice (n = 9), and CRD apoE^-/- mice treated with pitavastatin (CRD apoE^-/- PTV, n = 15). L indicates lumen. Quantitative assessment of Mac3-postive area was shown as mean ± SEM.</p