Impaired Functional Recovery Research Articles

009 The relationship between myocardial hemorrhage and regional left ventricular functional recovery in patients with reperfused acute myocardial infarction

Microvascular obstruction (MO) is one of the strongest predictors of adverse outcome after reperfusion therapy in acute myocardial infarction (MI). Animal data suggest that myocardial hemorrhage is a complication of reperfusion therapy in regions that sustain more severe microvascular ischemic damage. Due to a lack of appropriate imaging techniques, the consequences of reperfusion hemorrhage have not been studied. In this study, we sought to investigate the relationship between myocardial hemorrhage and regional left ventricular (LV) functional recovery at 6 months using T2*-weighted cardiovascular magnetic resonance (CMR) imaging. Nineteen patients with reperfused acute MI were studied. Repeat CMR studies consisted of cine, T2*-weighted, early enhancement (2-5 minutes post contrast) and late gadolinium enhancement (LGE) images were performed 3-5 days and 6 months after onset. Using images acquired 3-5 days after onset, the presence of hemorrhage was assessed with T2*-weighted images and the presence of MO was visualized with early enhancement. Using a 16-segment model, each segment was classified into one of 4 groups; (a. no infarction, b. infarction without MO, c. MO without hemorrhage, d. MO with hemorrhage). Systolic wall thickening with cine CMR at 6 months was evaluated as a marker of regional contractile function. Two basal slices were excluded where the LV outflow tract interrupts continuous myocardial contours on cine images, and one apical slice was excluded due to poor image quality. In total, 288 segments were analyzed and 62 segments were positive for infarction. Out of 62 segments with infarction, 22 showed both MO and hemorrhage and 7 showed MO but without hemorrhage. Systolic wall thickening for each group at 6 months was a. 78+/−56%, b. 48+/−37%, c. 39+/−30%, d. 11+/−21%. Systolic wall thickening at 6 months in group d. (MO with hemorrhage) was significantly smaller than group b. (infarction without MO) (11+/−21% vs. 48+/−37%, P < 0.05) and group c. (MO without hemorrhage) (11+/−21% vs. 39+/−30%, P < 0.05), whereas those in group c. (MO without hemorrhage) was not significantly different from those in group b. (infarction without MO) (39+/−30% vs. 48+/−37%, P = N.S.). Myocardial hemorrhage detected with T2*-weighted CMR strongly relates to impaired regional functional recovery at 6 months. The presence of myocardial hemorrhage may have significant predictive value for adverse outcome over the presence of MO.

Autacoid 14 S,21 R-Dihydroxy-Docosahexaenoic Acid Counteracts Diabetic Impairment of Macrophage Prohealing Functions

Impaired macrophage functions imposed by diabetic complications and the suppressed formation of 14S,21R-dihydroxydocosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21R-diHDHA) in wounds contribute significantly to deficient wound healing in diabetics, but how are macrophage functions and 14S,21R-diHDHA formation associated? We studied 14S,21R-diHDHA generation from macrophages using liquid chromatography/mass spectrometry. The role in macrophage-mediated wound healing functions was determined using a murine splinted excisional wound healing model and in vitro assays. 14S,21R-diHDHA acts as a macrophage-generated autacoid, and its attenuated formation in macrophages of diabetic db/db mice was accompanied by impairment of macrophage prohealing functions. 14S,21R-diHDHA restored db/db macrophage-impaired prohealing functions by promoting wound re-epithelialization, formulation of granulation tissue, and vascularization. Additionally, 12/15-lipoxygenase-deficient macrophages, which are unable to produce 14S,21R-diHDHA, exhibited impaired prohealing functions, which also were restored by 14S,21R-diHDHA treatment. The molecular mechanism for 14S,21R-diHDHA-induced recovery of impaired prohealing functions of db/db macrophages involves enhancing their secretion of vascular endothelial growth factor and platelet-derived growth factor BB, decreasing hyperglycemia-induced generation of reactive oxygen species, and increasing IL-10 expression under inflammatory stimulation. Taken together, these results indicate that deficiency of 14S,21R-diHDHA formation by diabetic macrophages contributes to their impaired prohealing functions. Our findings provide mechanistic insights into wound healing in diabetics and suggest the possibility of using autologous macrophages/monocytes, treated with 14S,21R-diHDHA, or related compounds, to promote diabetes-impaired wound healing.

Postoperative anemia does not impede functional outcome and quality of life early after hip and knee arthroplasties

Clinicians have adopted a restrictive transfusion threshold (75-80 g/L) after major orthopedic surgery. Anemia may be associated with a decrease in postoperative vigor. We hypothesize that, in these patients, a threshold hemoglobin (Hb) concentration exists below which functional recovery and quality of life (QoL) become difficult. A prospective, observational cohort study in 305 patients 60 years or older undergoing a total hip or knee arthroplasty was conducted. Major outcome variables were distance walked in 6 minutes (6MWT), score on the Borg Scale for perception of effort, maximal dominant hand strength, and Short Form 36 (SF-36) QoL assessment in the preoperative and early postoperative periods. Patients were categorized according to their Hb level the day of the postoperative 6MWT (≤ 80, 81-90, 91-100, and >100 g/L). There was no difference between Hb groups in the decrease of the distance walked preoperatively versus postoperatively. For both moments of observation, the 6MWT was not significantly different between Hb groups (p = 0.190). Similar results were found with perception of effort, maximal dominant hand strength, and SF-36 QoL assessment scores. In a regression model, the decrease in Hb concentration could explain only 1.9% of the total variation observed in the 6MWT (p = 0.008). Moderate anemia is not associated with an impaired functional recovery or QoL in the immediate postoperative period after major arthroplasties. Further studies will be required to determine the long-term consequences of a restrictive transfusion strategy in these patients.

Overexpression of Catalase in Myeloid Cells Causes Impaired Postischemic Neovascularization

Myeloid lineage cells (MLCs) such as macrophages are known to play a key role in postischemic neovascularization. However, the role of MLC-derived reactive oxygen species in this process and their specific chemical identity remain unknown. Transgenic mice with MLC-specific overexpression of catalase (Tg(Cat-MLC) mice) were created on a C57BL/6 background. Macrophage catalase activity was increased 3.4-fold compared with wild-type mice. After femoral artery ligation, laser Doppler perfusion imaging revealed impaired perfusion recovery in Tg(Cat-MLC) mice. This was associated with fewer collateral vessels, as assessed by microcomputed tomography angiography, and decreased capillary density. Impaired functional recovery of the ischemic limb was also evidenced by a 50% reduction in spontaneous running activity. The deficient neovascularization was associated with a blunted inflammatory response, characterized by decreased macrophage infiltration of ischemic tissues, and lower mRNA levels of inflammatory markers, such as tumor necrosis factor-α, osteopontin, and matrix mettaloproteinase-9. In vitro macrophage migration was impaired in Tg(Cat-MLC) mice, suggesting a role for H(2)O(2) in regulating the ability of macrophages to infiltrate ischemic tissues. MLC-derived H(2)O(2) plays a key role in promoting neovascularization in response to ischemia and is a necessary factor for the development of ischemia-induced inflammation.

Mitochondrial Transporter ATP Binding Cassette Mitochondrial Erythroid Is a Novel Gene Required for Cardiac Recovery After Ischemia/Reperfusion

Oxidative stress and mitochondrial dysfunction are central mediators of cardiac dysfunction after ischemia/reperfusion. ATP binding cassette mitochondrial erythroid (ABC-me; ABCB10; mABC2) is a mitochondrial transporter highly induced during erythroid differentiation and predominantly expressed in bone marrow, liver, and heart. Until now, ABC-me function in heart was unknown. Several lines of evidence demonstrate that the yeast ortholog of ABC-me protects against increased oxidative stress. Therefore, ABC-me is a potential modulator of the outcome of ischemia/reperfusion in the heart. Mice harboring 1 functional allele of ABC-me (ABC-me(+/-)) were generated by replacing ABC-me exons 2 and 3 with a neomycin resistance cassette. Cardiac function was assessed with Langendorff perfusion and echocardiography. Under basal conditions, ABC-me(+/-) mice had normal heart structure, hemodynamic function, mitochondrial respiration, and oxidative status. However, after ischemia/reperfusion, the recovery of hemodynamic function was reduced by 50% in ABC-me(+/-) hearts as a result of impairments in both systolic and diastolic function. This reduction was associated with impaired mitochondrial bioenergetic function and with oxidative damage to both mitochondrial lipids and sarcoplasmic reticulum calcium ATPase after reperfusion. Treatment of ABC-me(+/-) hearts with the superoxide dismutase/catalase mimetic EUK-207 prevented oxidative damage to mitochondria and sarcoplasmic reticulum calcium ATPase and restored mitochondrial and cardiac function to wild-type levels after reperfusion. Inactivation of 1 allele of ABC-me increases the susceptibility to oxidative stress induced by ischemia/reperfusion, leading to increased oxidative damage to mitochondria and sarcoplasmic reticulum calcium ATPase and to impaired functional recovery. Thus, ABC-me is a novel gene that determines the ability to tolerate cardiac ischemia/reperfusion.

Zyklisches apparatives Bewegungstraining versus konventionelles Gangtraining in der Rehabilitation des hemiparetischen Ganges nach Schlaganfall: Eine Pilotstudie

Recovery of impaired motor functions following stroke is commonly incomplete in spite of intensive rehabilitation programmes. At 6 months following a stroke up to 60% of affected individuals still suffer from permanent motor deficits, in particular hemiparetic gait, that are relevant for daily life. Novel innovative therapeutic strategies are needed to enhance the recovery of impaired gait function following stroke. This pilot study has investigated the effectiveness of conventional physiotherapy in comparison to an apparative cyclic movement training over a period of 4 weeks to improve (i) power during a submaximal cyclic movement training of the lower limbs, (ii) cardiac fitness, (iii) balance and gait ability, and (iv) quality of life in stroke patients. In comparison to physiotherapy apparative cyclic movement training improved power, balance, cardiac fitness and quality of life to a greater extent. However, there was a statistically significant difference between both intervention groups only for balance but not for the other parameters assessed. The present pilot study should inspire future research with larger patient cohorts to allow appropriate judgement on the effectiveness of apparative cyclic movement training in stroke rehabilitation.

Commentary [Research Highlights : Neurotrophic Factor Treatment of Neurological Disorders: The Benefits of a Pleiotropic Treatment Approach

Neurotrophic factors are essential for the survival and differentiation of developing neurons and also for their protection and recovery under pathological conditions. Therefore neurotrophic factors are being considered as a crucial therapeutic strategy for neurological disorders such as dementia or stroke. Similar pharmacological effects have been shown for Cerebrolysin, a neuropeptide preparation used for the treatment of neurodegenerative and cerebrovascular disorders. Experimental studies have shown protective and restorative effects of Cerebrolysin after stroke by inhibition of calpain [1], stabilizing neuronal integrity [2] and reducing apoptotic cell death [3]. In dementia model systems Cerebrolysin modulates kinase activities, which results in decreased amyloid β-peptide deposition and tau protein phosphorylation [4,5]. Positive effects on synaptic density and neuronal cytoarchitecture correlate with improved cognitive and behavioral performance [6,7]. In addition, Cerebrolysin promotes neurogenesis, an important self-repair mechanism of the brain [8,9]. Clinical trials have consistently shown that Cerebrolysin is an effective treatment for patients suffering from dementia of different origin. In vascular dementia, Cerebrolysin improved cognitive deficits and global clinical impression, which correlated with improvements in electroencephalogram activities [10, 11]. In patients with mild to moderate Alzheimer's disease Cerebrolysin has been shown to significantly improve cognition and the overall clinical response up to three months after active treatment [12,13]. Beneficial effects were also reported in activities of daily living and in behavioral performance [12-15]. Due to the observed long-lasting treatment effects Cerebrolysin seems to delay disease progression, which is in line with its pleiotropic mode of action targeting different molecular pathways in this pathologic cascade. Direct comparison of Cerebrolysin with cholinergic treatment resulted in comparable clinical efficacy in mild to moderate Alzheimer's disease and synergistic treatment effects were observed by combining both treatment strategies [16]. Stroke trials with Cerebrolysin have shown accelerated improvement in global, neurological, and motor functions, cognitive performance and activities of daily living. Cerebrolysin was effective in both early and late hospitalization [17-19]. However, early treatment start resulted in a faster and more efficient recovery of impaired neurological functions. Cerebrolysin had a fast onset of action with significant treatment effects as early as the first days. Safety data from clinical trials suggest an excellent benefit-to-risk ratio. Cerebrolysin was safe and well-tolerated also in hemorrhagic stroke, permitting early initiation of treatment even when exact type of stroke is not yet known. Most importantly, Cerebrolysin was also safe when used in combination with recombinant tissue-type plasminogen activator without enhancing the number or severity of side effects resulting from recombinant tissue-type plasminogen activator treatment [Lang, manuscript in preparation] or when given in combination with cholinesterase inhibitors such as donepezil [16] or rivastigmine [20]. In conclusion, clinical data have strongly shown that Cerebrolysin is an effective therapeutic option for patients diagnosed with dementia, stroke or traumatic brain injury....

Cardioprotective effect of the PPAR ligand tetradecylthioacetic acid in type 2 diabetic mice

Tetradecylthioacetic acid (TTA) is a novel peroxisome proliferator-activated receptor (PPAR) ligand with marked hypolipidemic and insulin-sensitizing effects in obese models. TTA has recently been shown to attenuate dyslipidemia in patients with type 2 diabetes, corroborating the potential for TTA in antidiabetic therapy. In a recent study on normal mice, we showed that TTA increased myocardial fatty acid (FA) oxidation, which was associated with decreased cardiac efficiency and impaired postischemic functional recovery. The aim of the present study was, therefore, to elucidate the effects of TTA treatment (0.5%, 8 days) on cardiac metabolism and function in a hyperlipidemic type 2 diabetic model. We found that TTA treatment increased myocardial FA oxidation, not only in nondiabetic (db/+) mice but also in diabetic (db/db) mice, despite a clear lipid-lowering effect. Although TTA had deleterious effects in hearts from nondiabetic mice (decreased efficiency and impaired mitochondrial respiratory capacity), these effects were not observed in db/db hearts. In db/db hearts, TTA improved ischemic tolerance, an effect that is most likely related to the antioxidant property of TTA. The present study strongly advocates the need for investigation of the cardiac effects of PPAR ligands used in antidiabetic/hypolipidemic therapy, because of their pleiotropic properties.

Reorganization of cerebral networks after stroke: new insights from neuroimaging with connectivity approaches.

The motor system comprises a network of cortical and subcortical areas interacting via excitatory and inhibitory circuits, thereby governing motor behaviour. The balance within the motor network may be critically disturbed after stroke when the lesion either directly affects any of these areas or damages-related white matter tracts. A growing body of evidence suggests that abnormal interactions among cortical regions remote from the ischaemic lesion might also contribute to the motor impairment after stroke. Here, we review recent studies employing models of functional and effective connectivity on neuroimaging data to investigate how stroke influences the interaction between motor areas and how changes in connectivity relate to impaired motor behaviour and functional recovery. Based on such data, we suggest that pathological intra- and inter-hemispheric interactions among key motor regions constitute an important pathophysiological aspect of motor impairment after subcortical stroke. We also demonstrate that therapeutic interventions, such as repetitive transcranial magnetic stimulation, which aims to interfere with abnormal cortical activity, may correct pathological connectivity not only at the stimulation site but also among distant brain regions. In summary, analyses of connectivity further our understanding of the pathophysiology underlying motor symptoms after stroke, and may thus help to design hypothesis-driven treatment strategies to promote recovery of motor function in patients.

Clinical presentation and some parameters of nonspecific resistance in Q-fever

The paper presents the results of a clinical observation and complex examination of 48 patients with Q-fever, the blood samples from 20 of them were tested for lysozyme, complement, and circulating immune complexes (CIC). The swing of the disease was characterized by the maximum clinical manifestations of the disease. Early reconvalescence was marked by a decrement in the clinical symptoms of the disease and a gradual recovery of the body's impaired functions. The study indicated a relationship between the level of nonspecific resistance factors and the stage of the pathologic process. The swing of the disease showed an increase in the amount of CIC with lower complement activity and normal lysozyme levels. In early reconvalescence, there was an increase in the levels of CIC and a decrease in total complementary activity as compared with those in the previous period. At the same time blood lysozyme activity substantially increased and exceeded the control values.

ANG II type I receptor antagonism improved nitric oxide production and enhanced eNOS and PKB/Akt expression in hearts from a rat model of insulin resistance

Exogenous insulin therapy improves endothelial function in insulin resistant patients, indirectly indicating that nitric oxide synthase activity and NO production may be impaired. Insulin stimulates production of NO by activating a signaling pathway including insulin receptor substrate-1, phosphatidylinositol-3-kinase and protein kinase B (PKB/Akt). Angiotensin II type I (AT1) receptor-evoked oxidative stress is implicated in the inactivation of NO, impairing endothelium-dependent vasodilatation. Blocking the actions of Angiotensin II with an AT1 receptor antagonist (Losartan), has beneficial effects in patients with insulin resistance or type 2 diabetes mellitus. This study investigated whether elevated Angiotensin II influences myocardial insulin resistance, insulin signaling and NO production in a rat model of diet-induced obesity (DIO) by antagonizing the actions of the AT1 receptor with Losartan. Isolated, perfused hearts, Western blotting and flow-cytometric methods were utilized to determine myocardial function, expression and phosphorylation of key proteins and NO production, respectively. Results showed that hearts from DIO rats are insulin resistant (higher serine phosphorylation of IRS-1, lower insulin-stimulated phosphorylation of PKB/Akt and eNOS, lower NO production) and had poorer functional recovery and larger infarct development after ischaemia/reperfusion. Losartan improved the impaired functional recovery, and NO production and enhanced eNOS expression and phosphorylation and reduced infarct size in hearts from the DIO animals. Data obtained from Losartan treatment also revealed that Angiotensin II signaling modulates myocardial PKB/Akt expression. We conclude that Angiotensin II signaling exacerbates inhibition of NO production in insulin resistance and that this can be improved by AT1 antagonism.

The Alternative and Terminal Pathways of Complement Mediate Post-Traumatic Spinal Cord Inflammation and Injury

Complement is implicated in the inflammatory response and the secondary neuronal damage that occurs after traumatic spinal cord injury (SCI). Complement can be activated by the classical, lectin, or alternative pathways, all of which share a common terminal pathway that culminates in formation of the cytolytic membrane attack complex (MAC). Here, we investigated the role of the alternative and terminal complement pathways in SCI. Mice deficient in the alternative pathway protein factor B (fB) were protected from traumatic SCI in terms of reduced tissue damage and demyelination, reduced inflammatory cell infiltrate, and improved functional recovery. In a clinically relevant paradigm, treatment of mice with an anti-fB mAb resulted in similarly improved outcomes. These improvements were associated with decreased C3 and fB deposition. On the other hand, deficiency of CD59, an inhibitor of the membrane attack complex, resulted in significantly increased injury and impaired functional recovery compared to wild-type mice. Increased injury in CD59-deficient mice was associated with increased MAC deposition, while levels of C3 and fB were unaffected. These data indicate key roles for the alternative and terminal complement pathways in the pathophysiology of SCI. Considering a previous study demonstrating an important role for the classical pathway in promoting SCI, it is likely that the alternative pathway plays a critical role in amplifying classical pathway initiated complement activation.

Importância da monitorização do delirium na unidade de terapia intensiva

Delirium is an acute confusional state associated with increased mortality in the intensive care unit and long-term impaired functional recovery. Despite its elevated incidence and major impact in the outcomes of critically ill patients, delirium remains under-diagnosed. Presently, there are validated instruments to diagnose and monitor delirium, allowing the detection of early organ dysfunction and treatment initiation. Beyond patient's non-modifiable risk factors, there are modifiable clinical and environmental aspects that should be accessed to reduce the occurrence and severity of delirium. As recent studies demonstrate that interventions aiming to reduce sedative exposure and to improve patients' orientation associated with early mobility have proved to reduce delirium, a low incidence of delirium should be targeted and considered as a measure of quality of care in the intensive care unit (ICU).

Extensive scarring induced by chronic intrathecal tubing augmented cord tissue damage and worsened functional recovery after rat spinal cord injury

Intrathecal infusion has been widely used to directly deliver drugs or neurotrophins to a lesion site following spinal cord injury. Evidence shows that intrathecal infusion is efficient for 7 days but is markedly reduced after 14 days, due to time dependent occlusion. In addition, extensive fibrotic scarring is commonly observed with intrathecal infusion. These anomalies need to be clearly elucidated in histology. In the present study, all adult Long-Evans rats received a 25 mm contusion injury on spinal cord T10 produced using the NYU impactor device. Immediately after injury, catheter tubing with an outer diameter of 0.38 mm was inserted through a small dural opening at L3 into the subdural space with the tubing tip positioned near the injury site. The tubing was connected to an Alzet mini pump, which was filled with saline solution and was placed subcutaneously. Injured rats without tubing served as control. Rats were behaviorally tested for 6 weeks using the BBB locomotor rating scale and histologically assessed for tissue scarring. Six weeks later, we found that the intrathecal tubing caused extensive scarring and inflammation, related to neutrophils, macrophages and plasma cells. The tubing's tip was occluded by scar tissue and inflammatory cells. The scar tissue surrounding the tubing consists of 20-70 layers of fibroblasts and densely compacted collagen fibers, seriously compressing and damaging the cord tissue. BBB scores of rats with intrathecal tubing were significantly lower than control rats (p<0.01) from 2 weeks after injury, implying serious impairment of functional recovery caused by the scarring.

Immunodeficiency reduces neural stem/progenitor cell apoptosis and enhances neurogenesis in the cerebral cortex after stroke

Acute inflammation in the poststroke period exacerbates neuronal damage and stimulates reparative mechanisms, including neurogenesis. However, only a small fraction of neural stem/progenitor cells survives. In this report, by using a highly reproducible model of cortical infarction in SCID mice, we examined the effects of immunodeficiency on reduction of brain injury, survival of neural stem/progenitor cells, and functional recovery. Subsequently, the contribution of T lymphocytes to neurogenesis was evaluated in mice depleted for each subset of T lymphocyte. SCID mice revealed the reduced apoptosis and enhanced proliferation of neural stem/progenitor cells induced by cerebral cortex after stroke compared with the immunocompetent wild-type mice. Removal of T lymphocytes, especially the CD4(+) T-cell population, enhanced generation of neural stem/progenitor cells, followed by accelerated functional recovery. In contrast, removal of CD25(+) T cells, a cell population including regulatory T lymphocytes, impaired functional recovery through, at least in part, suppression of neurogenesis. Our findings demonstrate a key role of T lymphocytes in regulation of poststroke neurogenesis and indicate a potential novel strategy for cell therapy in repair of the central nervous system.

Simulated urban carbon monoxide air pollution exacerbates rat heart ischemia-reperfusion injury

Myocardial damages due to ischemia-reperfusion (I/R) are recognized to be the result of a complex interplay between genetic and environmental factors. Epidemiological studies suggested that, among environmental factors, carbon monoxide (CO) urban pollution can be linked to cardiac diseases and mortality. The aim of this work was to evaluate the impact of exposure to CO pollution on cardiac sensitivity to I/R. Regional myocardial I/R was performed on isolated perfused hearts from rats exposed for 4 wk to air enriched with CO (30-100 ppm). Functional variables, reperfusion ventricular arrhythmias (VA) and cellular damages (infarct size, lactate dehydrogenase release) were assessed. Sarcomere length shortening and Ca(2+) handling were evaluated in intact isolated cardiomyocytes during a cellular anoxia-reoxygenation protocol. The major results show that prolonged CO exposure worsens myocardial I/R injuries, resulting in increased severity of postischemic VA, impaired recovery of myocardial function, and increased infarct size (60 +/- 5 vs. 33 +/- 2% of ischemic zone). The aggravating effects of CO exposure on I/R could be explained by a reduced myocardial enzymatic antioxidant status (superoxide dismutase -45%; glutathione peroxidase -49%) associated with impaired intracellular Ca(2+) handling. In conclusion, our results are consistent with the idea that chronic CO pollution dramatically increases the severity of myocardial I/R injuries.

Transfer of Bone Marrow Progenitors Prevents Coronary Insufficiency and Systolic Dysfunction in the Mechanical Unloaded Heart in Mice

Left ventricular-assist device (LVAD) can lead to improvement of cardiac performance in a subset of patients, but chronic mechanical unloading in this fashion may result in left ventricular (LV)-atrophy and impaired functional recovery. Here, we evaluate the efficacy of transferring bone-marrow KSL cells (Lin-/c-kit+/Sca1+), a fraction containing endothelial progenitor cells, for preventing LV-atrophy and malfunction in a mouse model of mechanical unloading of the heart. Recipients of an isogenic heart transplant received intramyocardial isogenic KSL cells or PBS in three different locations of the left ventricle (LV). Coronary blood flow and LV systolic function were evaluated by echocardiography, and morphologic changes were analyzed on d 7 and 56. PBS-treated mice showed severe systolic dysfunction and large thrombi in LV at both time points. In contrast, KSL cell transfer markedly reduced systolic dysfunction and thrombus size. Furthermore, in comparison with PBS control, KSL recipients had increased coronary blood flow (3-fold, P < 0.01) accompanied by increased LV capillary density and muscle mass. These results indicate that intramyocardial transfer of bone marrow KSL cells significantly protects against coronary insufficiency and systolic dysfunction in the chronic LV-unloading heart, suggesting that this approach may have clinical potential as a combination therapy with LVAD.

Involvement of Phosphoinositide 3-Kinase γ in Angiogenesis and Healing of Experimental Myocardial Infarction in Mice

Phosphoinositide 3-kinase (PI3K)gamma is expressed in hematopoietic cells, endothelial cells (ECs), and cardiomyocytes and regulates different cellular functions relevant to inflammation, tissue remodeling and cicatrization. Recently, PI3Kgamma inhibitors have been indicated for the treatment of chronic inflammatory/autoimmune diseases and atherosclerosis. We aimed to determine PI3Kgamma contribution to the angiogenic capacity of ECs and the effect of PI3Kgamma inhibition on healing of myocardial infarction (MI). Human umbilical ECs were treated with a selective PI3Kgamma inhibitor, AS605240, or a pan-phosphoinositide 3-kinases inhibitor, LY294002. Both inhibitory treatments and small interfering RNA-mediated PI3Kgamma knockdown strongly impaired ECs angiogenic capacity, because of suppression of the PI3K/Akt and mitogen-activated protein kinase pathways. Constitutive activation of Akt rescued the angiogenic defect. Reparative angiogenesis was studied in vivo in a model of MI. AS605240 did not affect MI-induced PI3Kgamma upregulation, whereas it suppressed Akt activation and downstream signaling. AS605240 strongly reduced inflammation, enhanced cardiomyocyte apoptosis, and impaired survival and proliferation of ECs in peri-infarct zone, which resulted in defective reparative neovascularization. As a consequence, AS605240-treated MI hearts showed increased infarct size and impaired recovery of left ventricular function. Similarly, PI3Kgamma-deficient mice showed impaired reparative neovascularization, enhanced cardiomyocyte apoptosis and marked deterioration of cardiac function following MI. Mice expressing catalytically inactive PI3Kgamma also failed to mount a proper neovascularization, although cardiac dysfunction was similar to wild-type controls. PI3Kgamma expression and catalytic activity are involved at different levels in reparative neovascularization and healing of MI.

Timing and duration of anti–α4β1 integrin treatment after spinal cord injury: effect on therapeutic efficacy

After spinal cord injury (SCI) leukocytes infiltrate the injured cord, causing significant damage and further impairment of functional recovery. The leukocyte integrin alpha4beta1 is crucial for their entry. The authors previously demonstrated that an anti-alpha4 monoclonal antibody (mAb) treatment attenuates leukocyte infiltration, improves motor and autonomic function, and reduces neuropathic pain when administered at 2 hours and 24 hours after SCI. The authors conducted 2 preclinical studies: the first determined effects of treatment commencing at 6 hours, a clinically relevant time after injury, and the second examined effects of long-lasting treatment (28 days) on neurological recovery after SCI, as current clinically used anti-inflammatory monoclonal antibodies have such longevity. In the first study (timing study), rats were treated with anti-alpha4 or control mAb (intravenously) at 6 hours and 48 hours after moderate (35 g) thoracic compression SCI. Effects on intraspinal inflammation and oxidative injury were assessed at 3 and 7 days after SCI; motor function and pain were examined for 6 weeks. In the second study (duration study), anti-alpha4 mAb was administered starting 2 hours after SCI and subsequently every 3 days for 4 weeks (total of 8 doses), using a schedule of decreasing doses to resemble the pharmacodynamics of long-lasting antibodies used clinically. Motor function and pain were examined for 6 weeks. Lesions were assessed for tissue sparing and inflammation at 6 weeks by histological examination and MR imaging. Anti-alpha4 mAb treatment at 6 hours and 48 hours after SCI (timing study) significantly decreased neutrophil and monocyte/macrophage influx at 3 days by 36% and 20%, respectively, but had no effect by at 7 days after SCI. Antibody treatment significantly reduced intraspinal myeloperoxidase activity by 48% and lipid peroxidation by 27% at 3 days post-injury. The treatment did not improve locomotor function but reduced mechanical allodynia elicited from the trunk and hind paw by ~50% at 3-6 weeks after SCI. In contrast, long-term mAb treatment commencing at 2 hours after SCI (duration study) significantly improved locomotor function at 2-6 weeks after SCI, (mean BBB scores +/- SE: treated rats, 8.3 +/- 0.16; controls, 7.3 +/- 0.2 at 6 weeks). At 3-6 weeks, mAb treatment decreased mechanical allodynia elicited from the trunk and hind paw by ~55%. This recovery correlated with 30% more myelin-containing white matter in treated rats than controls at 6 weeks. The lesion cavity was smaller in the treated rats when assessed by both histological (-37%) and imaging (-50%) methods. The accumulation of ED1-immunoreactive microglia/macrophages at the lesion was similar in treated and control rats. Although delayed treatment reduced intraspinal inflammation and pain, motor function was not improved, revealing decreased efficacy at the more clinically feasibly treatment onset. Long-term anti-alpha4 mAb treatment starting 2 hours after SCI improved neurological outcomes, with tissue sparing near the lesion and no impairment of the late immune response to injury. These findings reveal no disadvantage of long-lasting immunosuppression by the treatment but show that efficacy depends upon very early delivery.

Neuronal Circuit Remodeling in the Contralateral Cortical Hemisphere during Functional Recovery from Cerebral Infarction

Recent advances in functional imaging of human brain activity in stroke patients, e.g., functional magnetic resonance imaging, have revealed that cortical hemisphere contralateral to the infarction plays an important role in the recovery process. However, underlying mechanisms occurring in contralateral hemisphere during functional recovery have not been elucidated. We experimentally induced a complete infarction of somatosensory cortex in right hemisphere of mice and examined the neuronal changes in contralateral (left) somatosensory cortex during recovery. Both basal and ipsilateral somatosensory stimuli-evoked neuronal activity in left (intact) hemisphere transiently increased 2 d after stroke, followed by an increase in the turnover rate of usually stable mushroom-type synaptic spines at 1 week, observed by using two-photon imaging in vivo. At 4 weeks after stroke, when functional recovery had occurred, a new pattern of electrical circuit activity in response to somatosensory stimuli was established in intact ipsilateral hemisphere. Thus, the left somatosensory cortex can compensate for the loss of the right somatosensory cortex by remodeling neuronal circuits and establishing new sensory processing. This finding could contribute to establish the effective clinical treatments targeted on the intact hemisphere for the recovery of impaired functions and to achieve better quality of life of patients.