Association between lactic acidosis and multiple organ dysfunction syndrome after cardiopulmonary bypass.

Background: The relationship between hyperlactatemia and prognosis after cardiopulmonary bypass (CPB) is controversial, and some studies ignore the presence of lactic acidosis in patients with severe hyperlactacemia. This study explored the association between lactic acidosis (LA) and the occurrence of multiple organ dysfunction syndrome (MODS) after cardiopulmonary bypass. Methods: This study was a post hoc analysis of patients who underwent cardiac surgery between February 2017 and August 2018 and participated in a prospective study at Taizhou Hospital. The data were collected at: ICU admission (H0), and 4, 8, 12, 24, and 48 h after admission. Blood lactate levels gradually increased after CPB, peaking at H8 and then gradually decreasing. The patients were grouped as LA, hyperlactatemia (HL), and normal control (NC) based on blood test results 8 h after ICU admission. Basic preoperative, perioperative, and postoperative conditions were compared between the three groups, as well as postoperative perfusion and oxygen metabolism indexes. Results: There were 22 (19%), 73 (64%), and 19 (17%) patients in the LA, HL, and NC groups, respectively. APACHE II (24h) and SOFA (24h) scores were the highest in the LA group (P < 0.05). ICU stay duration was the longest for the LA group (48.5 (42.5, 50) h), compared with the HL (27 (22, 48) h) and NC (27 (25, 46) h) groups (P = 0.012). The LA group had the highest incidence of MODS (36%), compared with the HL (14%) and NC (5%) groups (P = 0.015). In the LA group, the oxygen extraction ratio (O2ER) was lower (21.5 (17.05, 32.8)%) than in the HL (31.3 (24.8, 37.6)%) and the NC group (31.3 (29.0, 35.4) %) (P = 0.018). In the univariable analyses, patient age (OR = 1.054, 95% CI [1.003-1.109], P = 0.038), the LA group (vs. the NC group, (OR = 10.286, 95% CI [1.148-92.185], P = 0.037), and ΔPCO2 at H8 (OR = 1.197, 95% CI [1.022-1.401], P = 0.025) were risk factor of MODS after CPB. Conclusions: We speculated that there was correlation between lactic acidosis and MODS after CPB. In addition, LA should be monitored intensively after CPB.

Measuring affinity constants of 1450 monoclonal antibodies to peptide targets with a microarray-based label-free assay platform.

Monoclonal antibodies (mAbs) are major reagents for research and clinical diagnosis. For their inherently high specificities to intended antigen targets and thus low toxicity in general, they are pursued as one of the major classes of new drugs. Yet binding properties of most monoclonal antibodies are not well characterized in terms of affinity constants and how they vary with presentations and/or conformational isomers of antigens, buffer compositions, and temperature. We here report a microarray-based label-free assay platform for high-throughput measurements of monoclonal antibody affinity constants to antigens immobilized on solid surfaces. Using this platform we measured affinity constants of over 1410 rabbit monoclonal antibodies and 46 mouse monoclonal antibodies to peptide targets that are immobilized through a terminal cysteine residue to a glass surface. The experimentally measured affinity constants vary from 10 pM to 200 pM with the median value at 66 pM. We compare the results obtained from the microarray-based platform with those from a benchmarking surface-plasmon-resonance-based (SPR) sensor (Biacore 3000).

Development of humanized rabbit monoclonal antibodies against vascular endothelial growth factor receptor 2 with potential antitumor effects.

Vascular endothelial growth factor-A (VEGF-A) plays a critical role in physiologic and pathologic angiogenesis through its receptors especially through VEGFR2. The lack of cross-reactivity of monoclonal antibodies with human VEGFR2/mouse Flk-1 is a major obstacle in preclinical developments. In this study, using a unique hybridoma technique, we generated a panel of 30 neutralization anti-VEGFR2 rabbit monoclonal antibodies (RabMAbs) either blocking VEGF/VEGFR2 interaction or inhibiting VEGF-stimulated VEGFR2 tyrosine kinase phosphorylation. Among 18 RabMAbs with human/mouse VEGFR2 cross-reactivity, we humanized one lead candidate RabMAb by Mutational Lineage Guided (MLG) method and further demonstrated its potent inhibition of tumor growth in xenograft mouse model. Our study suggests that RabMAbs are highly relevant for therapeutic applications.

A humanized anti-VEGF rabbit monoclonal antibody inhibits angiogenesis and blocks tumor growth in xenograft models.

Rabbit antibodies have been widely used in research and diagnostics due to their high antigen specificity and affinity. Though these properties are also highly desirable for therapeutic applications, rabbit antibodies have remained untapped for human disease therapy. To evaluate the therapeutic potential of rabbit monoclonal antibodies (RabMAbs), we generated a panel of neutralizing RabMAbs against human vascular endothelial growth factor-A (VEGF). These neutralizing RabMAbs are specific to VEGF and do not cross-react to other members of the VEGF protein family. Guided by sequence and lineage analysis of a panel of neutralizing RabMAbs, we humanized the lead candidate by substituting non-critical residues with human residues within both the frameworks and the CDR regions. We showed that the humanized RabMAb retained its parental biological properties and showed potent inhibition of the growth of H460 lung carcinoma and A673 rhabdomyosarcoma xenografts in mice. These studies provide proof of principle for the feasibility of developing humanized RabMAbs as therapeutics.

Nck proteins maintain the adult glomerular filtration barrier.

Within the glomerulus, the scaffolding protein nephrin bridges the actin-rich foot processes that extend from adjacent podocytes to form the slit diaphragm. Mutations affecting a number of slit diaphragm proteins, including nephrin, cause glomerular disease through rearrangement of the actin cytoskeleton and disruption of the filtration barrier. We recently established that the Nck family of Src homology 2 (SH2)/SH3 cytoskeletal adaptor proteins can mediate nephrin-dependent actin reorganization. Formation of foot processes requires expression of Nck in developing podocytes, but it is unknown whether Nck maintains podocyte structure and function throughout life. Here, we used an inducible transgenic strategy to delete Nck expression in adult mouse podocytes and found that loss of Nck expression rapidly led to proteinuria, glomerulosclerosis, and altered morphology of foot processes. We also found that podocyte injury reduced phosphorylation of nephrin in adult kidneys. These data suggest that Nck is required to maintain adult podocytes and that phosphotyrosine-based interactions with nephrin may occur in foot processes of resting, mature podocytes.

Expression of Src and FAK in hepatocellular carcinoma and the effect of Src inhibitors on hepatocellular carcinoma in vitro.

The expressions of c-Src and focal adhesion kinase (FAK) were studied in 65 Chinese patients with hepatocellular carcinoma (HCC) by immunohistochemistry using rabbit monoclonal antibodies. Expressions of total Src, an active form of Src, and FAK were found in 44/65 (67.7%), 36/45 (55.4%), and 33/56 (58.9%) HCC cases, respectively. There was a good correlation between the expression of total Src, active form of Src, and FAK in these HCC cases (P < 0.001). Expression of Src was not correlated to any clinical parameters, cancer cell phenotypic markers, and pathologic features apart from a positive correlation with alpha-fetoprotein (P < 0.01). The expression of FAK was correlated with earlier onset and the expression of Ki-67 but not proliferating cell nuclear antigen (PCNA) in these HCC cases. Four liver-cancer-derived cell lines (three derived from HCC and one from hepatoblastoma) were then tested with inhibitors against Src. A small molecule, KX2-391, designed to target the substrate binding pocket of Src, was found to have more broad-spectrum activity and better potency than Dasatinib, an adenosine triphosphate (ATP)-competitive inhibitor in vitro. Our data indicates that Src and FAK expression are both elevated and active in Chinese patients with HCC and that Src may play a key role in supporting HCC progression. Src antagonism with specific inhibitors may be an attractive treatment paradigm for patients with HCC.

Minocycline inhibits 5-lipoxygenase activation and brain inflammation after focal cerebral ischemia in rats.

AIM: To determine whether the anti-inflammatory effect of minocycline on postischemic brain injury is mediated by the inhibition of 5-lipoxygenase (5-LOX) expression and enzymatic activation in rats. METHODS: Focal cerebral ischemia was induced for 30 min with middle cerebral artery occlusion, followed by reperfusion. The ischemic injuries, endogenous IgG exudation, the accumulation of neutrophils and macrophage/microglia, and 5-LOX mRNA expression were determined 72 h after reperfusion. 5-LOX metabolites (leukotriene B4 and cysteinyl leukotrienes) were measured 3 h after reperfusion. RESULTS: Minocycline (22.5 and 45 mg/kg, ip, for 3 d) attenuated ischemic injuries, IgG exudation, and the accumulation of neutrophils and macrophage/microglia 72 h after reperfusion. It also inhibited 5-LOX expression 72 h after reperfusion and the production of leukotrienes 3 h after reperfusion. CONCLUSION: Minocycline inhibited postischemic brain inflammation, which might be partly mediated by the inhibition of 5-LOX expression and enzymatic activation.

Spatio-temporal expression of cysteinyl leukotriene receptor-2 mRNA in rat brain after focal cerebral ischemia.

Cysteinyl leukotrienes (CysLTs) induce inflammatory responses mediated by activating CysLT(1) and CysLT(2) receptors. We have recently reported that CysLT(1) receptor expression is increased in rat brain after focal cerebral ischemia and the increased expression is spatio-temporally related to acute neuronal injury and late astrocyte proliferation. Here we report spatio-temporal expression of CysLT(2) receptor mRNA in rat brain after focal cerebral ischemia induced by 30min of middle cerebral artery occlusion. We found that the neuron density was gradually decreased or disappeared in the ischemic core and boundary zone during 14 days after reperfusion, and the astrocyte population in the boundary zone was increased 3-14 days after reperfusion. In the ischemic core, the expression of CysLT(2) receptor mRNA was increased at 6, 12 and 24h and then recovered at 3, 7 and 14 days after reperfusion. In the boundary zone, the expression was significantly increased 3, 7 and 14 days after reperfusion. The results suggest that CysLT(2) receptor may be related to the acute neuronal injury and late astrocyte proliferation in the ischemic brain.

[Incomplete protective effects of minocycline on traumatic brain injury in rats and mice].

OBJECTIVE: To evaluate protective effect of minocycline,a semisynthetic tetracycline derivative on different traumatic brain injuries in rats and mice. METHODS: The opened brain trauma was induced in rats and the closed head injury and cold brain injury were induced in mice. In 3 brain trauma models, minocycline (45 mg/kg, ip) was administered twice daily for 2 d before the operation, at 30 min before and 1 h after the operation, and once daily for 2 d following the operation (totally 8 doses in 5 d). After the operation, the behavioral alteration was observed daily, lesion area and survival neuron density were measured at the end of the experiments (14 d after the injuries). RESULT: For rat opened traumatic injury, minocycline promoted the recovery of hindlimb motor activity (inclined board angle), but did not alter other indexes. For mouse closed head traumatic injury, minocycline reduced the neuron loss, but did not improve behavioral dysfunction. For mouse cold injury-induced trauma, minocycline reduced death rate and lesion area, but did not remarkably improve behavior and neuron loss. CONCLUSION: Minocycline only has an incomplete neuroprotective effect on different brain traumatic injuries in rats and mice.

Spatio-temporal properties of 5-lipoxygenase expression and activation in the brain after focal cerebral ischemia in rats.

The role of 5-lipoxygenase (5-LOX) in brain injury after cerebral ischemia has been reported; however, the spatio-temporal properties of 5-LOX expression and the enzymatic activation are unclear. To determine these properties, we observed post-ischemic 5-LOX changes from 3 h to 14 days after reperfusion in rats with transient focal cerebral ischemia induced by 30 min of middle cerebral artery occlusion. We found that the expression of 5-LOX, both mRNA and protein, was increased in the ischemic core 12-24 h after reperfusion, and in the boundary zone adjacent to the ischemic core 7-14 days after reperfusion. The increased 5-LOX was primarily localized in the neurons in the ischemic core at 24 h, but in the proliferated astrocytes in the boundary zone 14 days after reperfusion. As 5-LOX metabolites, the level of cysteinyl-leukotrienes in the ischemic brain was substantially increased 3 h to 24 h, near control at 3 days, and moderately increased again 7 days after reperfusion; whereas the level of LTB(4) was increased mildly 3 h but substantially 7-14 days after reperfusion. Thus, we conclude that 5-LOX expression and the enzymatic activity are increased after focal cerebral ischemia, and spatio-temporally involved in neuron injury in the acute phase and astrocyte proliferation in the late phase.

Pranlukast reduces neutrophil but not macrophage/microglial accumulation in brain after focal cerebral ischemia in mice.

AIM: To determine whether pranlukast, a cysteinyl leukotriene receptor-1 antagonist, exerts an anti-inflammatory effect on focal cerebral ischemia in mice. METHODS: Focal cerebral ischemia in mice was induced by permanent middle cerebral artery occlusion (MCAO). In addition to neurological deficits, infarct volume, degenerated neurons and endogenous IgG exudation, we detected accumulation of neutrophils and macrophage/microglia in the ischemic brain tissue 72 h after MCAO. Pranlukast was ip injected 30 min before and after MCAO. RESULTS: Pranlukast significantly attenuated neurological deficits, infarct volume, neuron degeneration and IgG exudation. Importantly, pranlukast (0.01 and 0.1 mg/kg) inhibited myeloperoxidase-positive neutrophil, but not CD11b-positive macrophage/microglial accumulation in the ischemic cortical tissue. CONCLUSION: Pranlukast exerts an anti-inflammatory effect on focal cerebral ischemia in the subacute phase that is limited to neutrophil recruitment through the disrupted blood-brain barrier.

[Photomacrography of brain surface for evaluating blood-brain barrier disruption within 24 h after focal cerebral ischemia in mice].

OBJECTIVE: To establish a new photomacrographic analysis of morphological changes on brain surface to evaluate blood-brain barrier (BBB) disruption. METHODS: Permanent focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in mice. Brains were removed 10 min, 0.5, 1, 3, 6, 12 and 24 h after MCAO. The whole brains and brain slices were photographed by a digital camera. BBB disruption was evaluated by hemorrhage and traced Evans blue (EB) on the brain surface. Fluoremetric quantitation of EB and water content in the brains were also performed at various time points. RESULT: Photomacrographic morphological analysis showed that hemorrhage and traced EB on the surface of the brains significantly increased from 3 h after focal cerebral ischemia,which were correlated to the results in the brain slices. EB content in the ischemic hemispheres was significantly increased from 0.5 h after MCAO, and water content was increased from 1 h after MCAO. CONCLUSION: Photomacrographic measurement is a simple and useful method for evaluating BBB disruption semi-quantitatively, and can detect BBB disruption earlier after focal cerebral ischemia in mice.

Pranlukast, a cysteinyl leukotriene receptor-1 antagonist, protects against chronic ischemic brain injury and inhibits the glial scar formation in mice.

We have recently reported the neuroprotective effect of pranlukast (ONO-1078), a cysteinyl leukotriene receptor-1 (CysLT1) antagonist, on cerebral ischemia in rats and mice. In this study, we further determined whether the effect of pranlukast is long lasting and related to the formation of a glial scar in cerebral ischemic mice. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). After ischemia, pranlukast (0.1 mg/kg) was injected intraperitoneally for 5 consecutive days. Neurological deficits and sensorimotor function were determined during 70 days after ischemia. Brain lesion and glial scar formation were detected at the end of the experiment. Pranlukast did not reduce mortality, but significantly improved neurological deficits and promoted sensorimotor recovery during 70 days. At the end of the experiment, pranlukast significantly reduced lesion volume, and increased neuron densities in the cortex and hippocampal CA1 region in the ischemic hemispheres. Importantly, pranlukast also remarkably reduced the thickness of a scar wall in the ischemic hemispheres. These findings indicate that pranlukast has a long-lasting protective effect on focal cerebral ischemia in mice, and inhibit the ischemia-induced glial scar formation, providing further evidence of the therapeutic potential of pranlukast in the treatment of ischemic stroke.

Montelukast, a cysteinyl leukotriene receptor-1 antagonist, dose- and time-dependently protects against focal cerebral ischemia in mice.

Our previous studies showed that cysteinyl leukotriene receptor-1 (CysLT1) antagonist pranlukast has a neuroprotective effect on cerebral ischemia in rats and mice. However, whether the neuroprotective effect of pranlukast is its special action or a common action of CysLT1 receptor antagonists remains to be clarified. This study was performed to determine whether montelukast, another CysLT1 receptor antagonist, has the neuroprotective effect on focal cerebral ischemia in mice, and to observe its dose- and time-dependent properties. Permanent focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). Montelukast was injected intraperitoneally either as multiple doses (once a day for 3 days and 30 min before MCAO) or as a single dose (at 30 min before, 30 min after, or 1 h after MCAO), respectively, and pranlukast and edaravone were used as controls. The neurological deficits, infarct volumes, brain edema, neuron density, and Evans blue extravasation in the brain were determined 24 h after MCAO. Pretreatments with multiple doses or a single dose of montelukast (0.1 and 1.0 mg/kg) before MCAO significantly attenuated all the ischemic insults. Post-treatment with a single dose of montelukast (0.1 and 1.0 mg/kg) at 30 min after MCAO also significantly decreased brain edema and infarct volume, but not neurological deficits. However, post-treatment with a single dose of montelukast at 1 h after MCAO had no significant effect. Pranlukast showed the same effects as montelukast, but edaravone attenuated the ischemic insults only with multiple doses before MCAO. Thus, montelukast has a dose- and time-dependent neuroprotective effect on permanent focal cerebral ischemia in mice, with an effective dose range of 0.1-1.0 mg/kg and a therapeutic window of 30 min. These findings further support the therapeutic potential of CysLT1 receptor antagonists in the treatment of cerebral ischemia at earlier phases.

[Macrophotographic measurement of brain surface area for evaluating brain edema after focal cerebral ischemia in mice].

OBJECTIVE: To establish a new macrophotographic measurement of brain surface area to evaluate brain edema after focal cerebral ischemia in mice. METHODS: Permanent focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in mice. The brains were removed 10,30 min,1,3,6,12 and 24 h after MCAO, and photographed in dorsal and lateral views by a digital camera. Then, 6 coronal slices of 1 mm thick were cut and photographed. Finally, the water content of brain tissue was measured by heating at 110 degrees C for 24 h. The left and right hemisphere areas of the brains and the brain slices were analyzed and calculated by MedBrain 2 imaging analyzer to evaluate brain edema. RESULT: The macrophotographic measurement showed that the ischemic hemisphere areas significantly increased from 1 h after focal cerebral ischmia, which was similar to the measurement of water content. This measurement for brain edema correlated well with those of water content and brain slice volume. CONCLUSION: The macrophotographic measurement is an objective and quantitative method for evaluating brain edema after focal cerebral ischemia.