ICAM-1 expression and leukocyte behavior in the microcirculation of chronically ischemic rat skeletal muscles

Endometrial regenerative cells for treatment of heart failure: a new stem cell enters the clinic

Heart failure is one of the key causes of morbidity and mortality world-wide. The recent findings that regeneration is possible in the heart have made stem cell therapeutics the Holy Grail of modern cardiovascular medicine. The success of cardiac regenerative therapies hinges on the combination of an effective allogeneic “off the shelf” cell product with a practical delivery system. In 2007 Medistem discovered the Endometrial Regenerative Cell (ERC), a new mesenchymal-like stem cell. Medistem and subsequently independent groups have demonstrated that ERC are superior to bone marrow mesenchymal stem cells (MSC), the most widely used stem cell source in development. ERC possess robust expansion capability (one donor can generate 20,000 patients doses), key growth factor production and high levels of angiogenic activity. ERC have been published in the peer reviewed literature to be significantly more effect at treating animal models of heart failure (Hida et al. Stem Cells 2008).

Current methods of delivering stem cells into the heart suffer several limitations in addition to poor delivery efficiency. Surgical methods are highly invasive, and the classical catheter based techniques are limited by need for sophisticated cardiac mapping systems and risk of myocardial perforation. Medistem together with Dr. Amit Patel Director of Clinical Regenerative Medicine at University of Utah have developed a novel minimally invasive delivery method that has been demonstrated safe and effective for delivery of stem cells (Tuma et al. J Transl Med 2012). Medistem is evaluating the combination of ERC, together with our retrograde delivery procedure in a 60 heart failure patient, double blind, placebo controlled phase II trial. To date 17 patients have been dosed and preliminary analysis by the Data Safety Monitoring Board has allowed for trial continuation.

The combined use of a novel “off the shelf” cell together with a minimally invasive 30 minute delivery method provides a potentially paradigm-shifting approach to cardiac regenerative therapy.

Effect of ischaemic exercise training of a normal limb on angiogenesis of a pathological ischaemic limb in rabbits

The present study was designed to test the hypothesis that local exercise of a normal limb can promote angiogenesis in a pathological ischaemic limb. New Zealand White rabbits underwent left femoral artery ligation (Lig) and electrode implantation on the right sciatic nerve. The rabbits were randomly assigned to four groups: (i) Lig-N group, which did not receive ES (electrical stimulation); (ii) Lig-High group, which received high-intensity ES (2.5 mA, 40Hz for 1 ms) on the right hindlimb; (iii) Lig-Low group, which received low-intensity ES (0.3 mA, 40Hz for 1 ms) on the right hindlimb; (iv) Double-Lig-High group, which underwent femoral artery ligation on both hindlimbs and received high-intensity ES (2.5 mA, 40Hz for 1 ms) on the right hindlimb. The ES procedure included 5 min of stimulation, followed by 5 min of rest, and was repeated eight times a day for 4 weeks. Collateral circulation was examined grossly by angiography, resting blood flow was measured using the microspheres technique, and capillary supply was evaluated by immunohistochemistry. VEGF (vascular endothelial growth factor) mRNA and protein were analysed by real-time RT (reverse transcription)–PCR and Western blotting respectively. Collateral blood flow in all of the major muscles of the left hindlimb in the Lig-High group was highest among the four groups (P<0.01). Capillary supply (P<0.001), VEGF mRNA (P<0.01) and VEGF protein (P<0.01) in the gastrocnemius muscle increased remarkably in the Lig-High group; no statistically significant difference was observed among the other three groups. In conclusion, angiogenesis associated with an up-regulation of VEGF expression in pathological ischaemic limb may be facilitated by 4 weeks of physiological ischaemic exercise training in a normal limb.

Attenuation of changes in capillary fine structure and leukocyte adhesion improves muscle performance following chronic ischaemia in rats

Acute ischaemia-reperfusion disrupts capillary fine structure and increases leukocyte adhesion in postcapillary venules. We determined whether chronic muscle ischaemia has similar consequences, and whether it is possible to ameliorate its effect on muscle performance. Following ischaemia (unilateral ligation, common iliac artery) rat hindlimb muscles were examined without other intervention or following treatment with an xanthine oxidase inhibitor (allopurinol), a Na(+)/H(+) exchange blocker (amiloride), or an oxygen free radical scavenger (vitamin E). No significant leukocyte adhesion or rolling, nor changes in capillary fine structure were observed 3 days postsurgery, when limb use was limited. However, leukocyte rolling and adhesion almost trebled by 7 days (P < 0.001), when normal gait was largely restored. Capillary fine structure was disturbed over a similar time course, e.g. relative endothelial volume (control 46%, 7 days 61%; P < 0.05), that resolved by 5 weeks. Where activity was increased by mild electrical stimulation 3 days after ligation muscles showed enhanced capillary swelling (endothelial volume 66% versus 50%, P < 0.005), but improved fatigue index (52% versus 16%, P < 0.001) as a result of greater blood flow. Muscle fatigue after ligation was related to the extent of contraction-induced hyperaemia (R(2) = 0.725), but not capillary swelling. Amiloride, and to a lesser extent allopurinol but not vitamin E, significantly decreased leukocyte rolling and adhesion, as well as capillary endothelial swelling. We conclude that increased activity of ischaemic muscles on recovery is likely to accentuate acidosis accompanying changes in microcirculation and contribute to enhanced muscle fatigue, whereas formation of oxygen free radicals may be attenuated by endogenous protective mechanisms.

Automatic in vivo microscopy video mining for leukocytes

Biological videos are very different from conventional videos. Automatic spatiotemporal mining of moving cells from in vivo microscopy videos is extremely difficult because of the severe noises, camera/subject movements, deformations, and strong dependencies on microscopy operators. In this paper, we present an automatic spatiotemporal mining system of rolling and adherent leukocytes for intravital videos. The magnitude of leukocyte adhesion and decrease in rolling velocity are common interests in inflammation response studies. Currently, there is no existing system which is perfect for such purposes. Several approaches have been proposed for tracking leukocytes. However, these approaches can either only track leukocytes that roll along the centerline of the blood vessel, or can only handle leukocytes with fixed morphologies. In addition, the camera/subject movement is a severe problem which occurs frequently while analyzing in vivo microscopy videos. In this paper, we proposed a new method for automatic recognition of non-adherent and adherent leukocytes. The proposed method includes three steps: (1) camera/subject movement alignment; (2) moving leukocytes detection; (3) adherent leukocytes detection. The experimental results demonstrate the effectiveness of the proposed method.