[Long-term outcomes of laparoscopic gastrectomy for locally advanced gastric cancer with serosa-invasion].

Objective: To evaluate the long-term outcomes and prognostic factors of locally advanced gastric cancer with serosa-invasion. Methods: This study is a retrospective cohort study. The clinical and pathological data of 495 patients with locally advanced gastric cancer with serosa-invasion who underwent laparoscopic radical gastrectomy in Department of General Surgery, the First Hospital Affiliated to Army Medical University from October 2012 to October 2018 was analyzed retrospectively. There were 356 males and 139 females with an age (M(IQR)) of 59 (16) years (range: 18 to 75 years). Observation indicators included postoperative results and long-term prognosis. The survival curve was drawn by the Kaplan-Meier method. Univariate and multivariate prognostic analysis was performed using the Cox proportional hazards model. Results: Among the 495 patients, a total of 57 patients (11.5%) were lost to follow-up, with a follow-up time of 89 (40) months (range: 23 to 134 months). The 5-year disease-free survival rate (DFS) and the 5-year overall survival rate (OS) were 56.0% and 58.2%, respectively. The 5-year DFS for patients with stage ⅡB, ⅢA, ⅢB, ⅢC were 71.2%, 60.5%, 51.6%, 33.3%, respectively. The 5-year OS for patients with stage ⅡB, ⅢA, ⅢB, ⅢC were 71.2%, 62.2%, 54.1%, 39.3%, respectively. Multivariate analysis showed that age >65 years (DFS: HR=1.402, 95%CI: 1.022 to 1.922, P=0.036; OS: HR=1.461, 95%CI: 1.057 to 2.019, P=0.022), lymph node dissection number less than 25 (DFS: HR=1.348, 95%CI: 1.019 to 1.779, P=0.036; OS: HR=1.376, 95%CI: 1.035 to 1.825, P=0.028), pathological stage Ⅲ (DFS: HR=2.131, 95%CI: 1.444 to 3.144, P<0.01; OS: HR=2.079, 95%CI: 1.406 to 3.074, P<0.01), and no postoperative chemotherapy (DFS: HR=3.127, 95%CI: 2.377 to 4.113, P<0.01; OS: HR=3.768, 95%CI: 2.828 to 5.020, P<0.01) were independent prognostic factors for the decrease in DFS and OS rates. Conclusions: Laparoscopic radical gastrectomy for locally advanced gastric cancer with serosa-invasion could achieve satisfactory long-term oncological outcomes. More lymph node dissection and standardized postoperative adjuvant chemotherapy are expected to further improve the prognosis of patients with locally advanced gastric cancer with serous invasion after laparoscopic radical surgery.

Long non-coding RNA FTX promotes gastric cancer progression by targeting miR-215.

OBJECTIVE: Gastric cancer (GC) is one of the most common malignant tumors in the world, which is seriously harmful to people's health. The increasing number of studies have shown that long non-coding RNA (lncRNA) is related to the occurrence of gastric cancer. In this study, we aimed at investigating the role of lnc FTX in the occurrence of gastric cancer. MATERIALS AND METHODS: The expression of FTX in gastric cancer patients and gastric cancer cell lines was detected by RT-qPCR. Univariate Kaplan-Meier method was used to analyze the relationship between FTX expression level, clinicopathological parameters and overall survival rate (OS). After transferring si-FTX and overexpression FTX plasmids into MGC-803 and SGC-7901, the expression of miR-215-3p was detected by RT-qPCR, and the changes of cell proliferation and cell cycle were detected by CCK-8 and flow cytometry. In addition, luciferase activity was used to detect whether miR-215-3p combined with FTX and SIVA1. Finally, Western blot (WB) was used to detect the change of SIVA1 protein expression by miR-215 mimic. RESULTS: We found that the expression of FTX in tumor tissues of 71 GC patients was higher than that in paracancerous tissues, and the prognosis of patients with high FTX was poor. The expression of FTX in gastric cancer cells was higher than that in normal human gastric epithelial cells (GES-1). Transferring overexpression plasmid of FTX into gastric cancer cells (MGC-803 and SGC-7901) promoted cell proliferation and the ratio of cells in G0-G1 phase was decreased. Transferring si-FTX to MGC-803 and SGC-7901 led to opposite results. There was a negative correlation between the expression of mi215-3p and FTX in MGC-803 and SGC-7901 gastric cancer cells, and luciferase results showed that mi215-3p could directly bind to FTX and regulate cell growth and cell cycle changes. In addition, luciferase results showed that mi215-3p could bind directly to SIVA1. What's more, RT-qPCR and WB results showed that mi215 mimic could promote the expression of MGC-803, SGC-7901 SIVA1mRNA and protein. CONCLUSIONS: According to these results, this study revealed that the previously neglected FTX-miR2153p-SIVA1 regulatory axis for the regulation of gastric cancer progression, which may be a potential target for the treatment of gastric cancer.

[Long-term efficacy of robotic radical total gastrectomy for gastric cancer and analysis of prognostic factors].

Objective: To analyze long-term outcomes and prognostic factors of gastric cancer patients after robotic radical total gastrectomy. Methods: A retrospective case-control study was conducted. Inclusion criteria: (1) receiving robotic radical total gastrectomy; (2) gastric adenocarcinoma was confirmed by postoperative pathology; (3) no previous history of other malignant tumors; (4) no preoperative chemotherapy or radiation therapy performed. Exclusion criteria: (1) age <18 years old or age >80 years old;(2)distant metastasis before surgery, or palliative surgery; (3) conversion to laparotomy;(4) R1 or R2 resection; (5)emergency surgery; (6) remnant gastric cancer or recurrence; (7)died of severe complications during hospitalization or within 1 month after surgery. Overall survival rates (OS) and disease-free survival rates (DFS) were evaluated using the Kaplan-Meier method. Cox regression analysis was used to identify prognosis factors for overall survival. Results: According to the above criteria, 166 gastric cancer patients who underwent robotic radical total gastrectomy between March 2010 and November 2018 were included in this study. Roux-en-Y reconstruction was performed in all patients. Reconstruction were achieved using extracorporeal method through a minilaparotomy in 149 case and intracorporeal anastomosis in 17 cases. The number of harvested lymph nodes was (34.8±17.5), and the number of harvested lymph nodes at group 2 was (10.1±6.7). The number of patients with lymph node metastasis of group 2 was 73 (44.0%). The median follow-up time was 25 months (range 2-109). There were 55 (33.1%) cases of recurrence during follow-up. The 3- and 5-year overall survival rates were 55.8% and 46.2% respectively. The 3- and 5-year disease-free survival rates were 53.4% and 45.4% respectively. The 5-year overall survival rates grouped based on TNM stage were 78.9% for stage I, 58.5% for stage II, and 37.1% for stage III. The 5-year disease-free survival rates grouped based on TNM stage were 78.9% for stage I, 59.2% for stage II, and 34.6% for stage III. Univariate analysis suggested that TNM stage, the number of harvested lymph nodes and number of harvested lymph nodes at group 2 were associated with overall survival rates (all P<0.05). Multivariate analyses revealed that TNM stage (P<0.001; stage IIIB: HR=5.357, 95%CI:1.182 to 24.275; stage IIIC: HR=11.937, 95%CI: 2.677 to 53.226) and number of harvested lymph nodes at group 2 (P=0.034; 6-10: HR=0.562,95%CI:0.326 to 0.969; >10: HR=0.388, 95%CI: 0.176 to 0.857) were independent prognostic factors for overall survival. Conclusion: The long-term outcomes of robotic radical total gastrectomy were satisfactory. TNM stage and number of harvested lymph nodes at group 2 were independent prognostic factors for overall survival.

The promotion of the transformation of quiescent gastric cancer stem cells by IL-17 and the underlying mechanisms.

Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells (CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26- and CXCR4-, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial-mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.

Geometric Parameter Analysis of Ruptured and Unruptured Aneurysms in Patients with Symmetric Bilateral Intracranial Aneurysms: A Multicenter CT Angiography Study.

BACKGROUND AND PURPOSE: Previous studies of geometric and morphologic parameters of intracranial aneurysms have been conducted to determine rupture risk, which remains incompletely defined due to patient-specific risk factors, such as sex, hypertension, and age. To this end, we compared characteristics of ruptured and unruptured aneurysms in the same patients with symmetric bilateral intracranial aneurysms. MATERIALS AND METHODS: Between January 2008 and March 2014, 2361 patients with 2674 aneurysms were diagnosed by CT angiography or surgical findings at 4 medical centers. Geometric and morphologic parameters examined for symmetric bilateral intracranial aneurysms comprised aneurysm wall regularity, size, neck width, aspect ratio, size ratio, neck-to-parent artery ratio, and area ratio. Univariate and multivariate statistical analyses were performed to determine independent risk factors for rupture. RESULTS: Sixty-three patients (48 women, 15 men; mean age, 62.5 ± 9.8 years) with symmetric bilateral aneurysms were eligible for the study and were included. The most frequent aneurysm location was the posterior communicating artery. Univariate analysis disclosed that aneurysm size, aspect ratio, size ratio, area ratio, and irregular wall differed between patients with ruptured and unruptured aneurysms. Multivariate analysis indicated that aspect ratio of ≥1.6 (adjusted OR, 9.521; 95% CI, 2.182-41.535), area ratio of ≥1.5 (adjusted OR, 4.089; 95% CI, 1.247-13.406), and irregular shape (adjusted OR, 10.443; 95% CI 3.394-32.135) were significant predictive factors for aneurysm rupture after adjustment for aneurysm size. CONCLUSIONS: An aspect ratio of ≥1.6, area ratio of ≥1.5, and irregular wall are associated with aneurysm rupture independent of aneurysm size and patient characteristics. These characteristics alone can help in distinguishing ruptured bilateral intracranial aneurysms from unruptured ones.

Hyperglycemia enhances DNA fragmentation after transient cerebral ischemia.

Previous histopathologic results have suggested that one mechanism whereby hyperglycemia (HG) leads to exaggerated ischemic damage involves fragmentation of DNA. DNA fragmentation in normoglycemia (NG) and HG rats subjected to 30 minutes of forebrain ischemia was studied by terminal deoxynucleotidyl transferase mediated DNA nick-labeling (TUNEL) staining, by pulse-field gel electrophoresis (PFGE), and by ligation-mediated polymerase chain reaction (LM-PCR). High molecular weight DNA fragments were detected by PFGE, whereas low molecular weight DNA fragments were detected using LM-PCR techniques. The LM-PCR procedure was performed on DNA from test samples with blunt (without Klenow polymerase) and 3'-recessed ends (with Klenow polymerase). In addition, cytochrome c release and caspase-3 activation were studied by immunocytochemistry. Results show that HG causes cytochrome c release, activates caspase-3, and exacerbates DNA fragments induced by ischemia. Thus, in HG rats, but not in control or NGs, TUNEL-stained cells were found in the cingulate cortex, neocortex, thalamus, and dorsolateral crest of the striatum, where neuronal death was observed by conventional histopathology, and where both cytosolic cytochrome c and active caspase-3 were detected by confocal microscopy. In the neocortex, both blunt-ended and stagger-ended fragments were detected in HG, but not in NG rats. Electron microscopy (EM) analysis was performed in the cingulate cortex, where numerous TUNEL-positive neurons were observed. Although DNA fragmentation was detected by TUNEL staining and electrophoresis techniques, EM analysis failed to indicate apoptotic cell death. It is concluded that HG triggers a cell death pathway and exacerbates DNA fragmentation induced by ischemia.

Free radical spin trap alpha-phenyl-N-tert-butyl-nitron inhibits caspase-3 activation and reduces brain damage following a severe forebrain ischemic injury.

It has been documented that alpha-phenyl-N-tert-butyl-nitron (PBN) possesses a potent neuroprotective effect when administered after transient focal cerebral ischemia. However, contradicting results were reported regarding its effect in transient global ischemia. To further elucidate the mechanism of PBN action, we have studied the effect of PBN on animal survival, histopathological outcome, and activation of caspase-3 following 30 min of global ischemia in vehicle- and PBN-treated rats. The results showed that 30 min of global ischemia was such a severe insult that no animal could survive beyond 2 d of reperfusion. Histopathological evaluation showed severe tissue edema and microinfarct foci in the neocortex and thalamus. Close to 100% damage was observed in the stratum and hippocampal CA1, CA3, and dentate gyrus subregions. Postischemic PBN treatment significantly enhanced animal survival and reduced damage in the neocortex, thalamus, and hippocampus. Immunohistochemistry demonstrated that caspase-3 was activated following ischemia in the striatum and the neocortex. PBN suppressed the activation of caspase-3 in both structures. It is concluded that PBN is a potent neuroprotectant against both focal and global ischemia; besides its function as a free radical scavenger, PBN may reduce ischemic brain damage by blocking cell death pathways that involve caspase-3 activation.

Necrosis of the substantia nigra, pars reticulate, in flurothyl-induced status epilepticus is ameliorated by the spin trap alpha phenyl-N-tert-butyl nitrone.

The objective of the present study was to explore whether a diffusible free radical scavenger can ameliorate the pan-neurotic lesions of the substantia nigra, pars reticulate (SNPR), which are incurred in rats subjected to status epilepticus of more than 30 min duration. Vehicle-injected animals had flurothyl seizures induced for 45 min. The seizures were then terminated and the animals were recovered for 7 d to allow histopathological evaluation of the SNPR lesions. Drug-treated animals, which were otherwise treated identically, were given either 100-800 mg/ kg of dimethylthiourea (DMTU), a diffusible hydroxyl ion scavenger, or the diffusible spin trap alpha-phenyl N-tert-butyl nitrone (PBN) in a dose of 100 mg/kg i.p.. All animals given DMTU died 2 to 8 h after status epilepticus, but PBN was tolerated well by the animals. The amount of flurothyl required to sustain the electrographic seizures was identical in the vehicle- and drug-injected groups, demonstrating that PBN did not suppress seizure activity. Vehicle-injected animals had large bilateral infarcts localized to the SNPR. Of the six animals treated with PBN, one had a small, unilateral lesions, and in all other animals the SNPR had a normal histological appearance. The results strongly suggest that the pan-necrotic lesions of the SNPR incurred during ongoing seizure activity represent a free radical-mediated lesion.

Production of hydroxyl free radical by brain tissues in hyperglycemic rats subjected to transient forebrain ischemia.

Preischemic hyperglycemia is known to aggravate brain damage resulting from transient ischemia. In the present study, we explored whether this aggravation is preceded by an enhanced formation of reactive oxygen species (ROS) during the early reperfusion period. To that end, normo- and hyperglycemic rats were subjected to 15 min of forebrain ischemia and allowed recovery periods of 5, 15, and 60 min. Sodium salicylate was injected intraperitoneally in a dose of 100 mg/kg, and tissues were sampled during recirculation to allow analyses of salicylic acid (SA) and its hydroxylation products, 2,3- and 2,5-dihydroxybenzoate (DHBA). Tissue sampled from thalamus and caudoputamen in normoglycemic animals failed to show an increase in 2,3- or 2,5-DHBA after 5 and 15 min of recirculation. However, such an increase was observed in the neocortex after 60 min of recirculation, with a suggested increase in the hippocampus as well. Hyperglycemia had three effects. First, it increased 2,5-DHBA in the thalamus and caudoputamen to values exceeding normoglycemic ones after 15 min of recirculation. Second, it increased basal values of 2,5- and total DHBA in the neocortex. Third, it increased the 60-min values for 2,5- and total DHBA in the hippocampus. These results hint that, at least in part, hyperglycemia may aggravate damage by enhancing basal- and ischemia-triggered production of ROS.

Posttreatment with low molecular weight heparin reduces brain edema and infarct volume in rats subjected to thrombotic middle cerebral artery occlusion.

Low molecular weight heparin (LMWH) has similar efficacy to unfractionated heparin with less hemorrhagic complications. We studied the neuroprotective effect of LMWH on a rat model of focal-ischemia. Our results revealed that treatment with LMWH at 1 and 3 h following thrombotic MCA occlusion reduced brain edema and infarct size and improved clinical outcome. Treatment with LMWH initiated at 6 h after thrombin injection only partially ameliorated brain damage.

Amelioration by cyclosporin A of brain damage following 5 or 10 min of ischemia in rats subjected to preischemic hyperglycemia.

It has recently been shown that the immunosuppressant cyclosporin A (CsA) dramatically ameliorates the selective neuronal necrosis which results from 10 min of forebrain ischemia in rats. Since CsA is a virtually specific blocker of the mitochondrial permeability transition (MPT) pore which is assembled under adverse conditions, such as mitochondrial calcium accumulation and oxidative stress, the results suggest that the delayed neuronal death is due to an MPT. In the present study we explored whether CsA can also ameliorate the aggravated brain damage which is observed in hyperglycemic subjects, and which encompasses rapidly evolving neuronal lesions, edema, and postischemic seizures. Anaesthetised rats with a plasma glucose concentration of approximately 13 mM were subjected to 10 min of forebrain ischemia, and allowed a recovery period of 7 days. In these animals, CsA prevented seizure from occurring and virtually eliminated neuronal necrosis. In order to allow even higher plasma glucose values (approximately 20 mM) to be studied, with long-term recovery, the duration of ischemia had to be reduced to 5 min. Again, CsA suppressed seizure activity and reduced neuronal damage. However, the effects were not as marked or consistent as in the 10 min group, suggesting that excessive tissue acidosis recruits mechanisms of damage which are not sensitive to CsA.

Effects of intracarotid arterial injection of cyclosporin A and spontaneous hypothermia on brain damage incurred after a long period of global ischemia.

A recent study showed that a single intracarotid arterial injection of cyclosporin A (CsA) can dramatically reduce infarct volume in rats subjected to transient focal ischemia. The present experiments were undertaken to investigate whether intracarotid arterial injection of CsA reduces brain damage after global ischemia. Since hypothermia is also an efficacious factor in preventing ischemic brain damage, in the second part of the experiments we tested whether a combination of hypothermia and CsA would provide additional brain protection. Global ischemia of a 30-min duration was induced in the rat. CsA (10 mg/kg) was injected into the carotid artery immediately after reperfusion. Hypothermia was instituted after ischemia by allowing spontaneous head temperature to fall to 30-32 degrees C, while body temperature was upheld at 37 degrees C. The results demonstrated that vehicle-treated animals could not survive beyond 1-2 days after reperfusion, and the histopathological outcome in a separate group of rats perfusion-fixed after 1 day reperfusion showed 80-100% brain damage in the caudoputamen, and in the hippocampal CA1, CA3, CA4 and dentate gyrus subregions. Microinfarction and grade 3 damage were frequently observed in the cingulate and parietal cortex and in the thalamus. CsA moderately prolonged animal survival to 3 days after reperfusion and reduced brain damage to grade 2 in the cortical areas and the thalamus. Hypothermia further increased animal survival to at least 6 days after reperfusion and reduced brain damage to 30% in the caudoputamen, to close to zero in the CA3, CA4, and dentate gyrus, and to grade 1-2 in the cortical areas and the thalamus. The combination of hypothermia and CsA did not give additional protection.

Does long-term glucose infusion reduce brain damage after transient cerebral ischemia?

A recent study reported that hyperglycemia of a brief duration worsens, and of long duration reduces, ischemic brain damage. To test whether this is a valid conception, we induced 10 min of transient forebrain ischemia, recorded postischemic seizures, and evaluated brain morphology. The results showed that administration of glucose 2 h before ischemia aggravated brain damage, induced seizures, and caused animal death in the same manner as was previously observed when glucose was given 30 min before ischemia. Thus, the conclusion that the influence of glucose on an ischemic transient is dependent upon the duration of hyperglycemia is unsubstantiated.

Cyclosporin A, but not FK506, prevents the downregulation of phosphorylated Akt after transient focal ischemia in the rat.

The two immunosuppressants, cyclosporin A (CsA) and FK506, when given 1 and 3 h after the start of reperfusion following 2 h of middle cerebral artery (MCA) occlusion, reduce infarct volume to 30% of control. This suggests a common effect, e.g. one due to suppression of the activation of calcineurin. However, when given by the intracarotid (i.c.) route after only 5 min of recirculation CsA, but not FK506, reduced infarct volume even further, to 10% of control. This was attributed to the fact that CsA, but not FK506, block the in vitro assembly of a mitochondrial permeability transition (MPT) pore. The present experiments were undertaken to further characterize the anti-ischemic effect of CsA, when given i.c. 5 min after recirculation and to explore why CsA, when given at that time, is more efficacious than FK506. It was established that the i.c. administration of CsA in a dose of 10 mg/kg increased the tissue concentration of CsA 2- to 3-fold, when compared to the i.v. administration. CsA proved to be effective in reducing infarct volume even when the tissue damage was assessed by histopathology after 7 days of recovery. MCA occlusion of 2 h duration caused a sustained decrease in the phosphorylation Akt at threonine 308. Since this down regulation of Akt was prevented by CsA, the results suggested a link between dephosphorylaltion of Bad, and cell death. Interestingly FK506 did not prevent down regulation of Akt, it thus seems unlikely that the anti-ischemic effect of CsA is related to its association with cytosolic cyclophilin.

Preischemic hyperglycemia leads to rapidly developing brain damage with no change in capillary patency.

The present experiments were undertaken to explore whether exaggeration of ischemic brain damage by preischemic hyperglycemia is due to lack of capillary patency in the postischemic period. Normo- and hyperglycemic rats were exposed to 10 min of forebrain ischemia. Histopathological changes were evaluated after 6 and 16-18 h of recovery by light microscopy, and capillary patency was assessed at the same time points by a double-staining technique, depicting perfused and morphologically identifiable capillaries. The results demonstrate that some neuronal damage was detectable after 6 h of recirculation which was aggravated after 16-18 h of recirculation in hyperglycemic rats. In contrast, the degree of capillary patency was similar in normo- and hyperglycemic rats. In both groups the perfusion marker, Evans blue, perfused about 95% of all capillaries when injected 10 s before decapitation. Since preischemic hyperglycemia exaggerates brain damage without cessation of capillary perfusion the primary targets of hyperglycemic brain damage may not be capillaries but neurons or glial cells.

Hyperglycemia-exaggerated ischemic brain damage following 30 min of middle cerebral artery occlusion is not due to capillary obstruction.

Transient focal ischemia of brief duration (15-30 min) gives rise to brain damage. In normoglycemic animals this damage usually consists of selective neuronal necrosis (SNN), and is largely confined to the lateral caudoputamen. In hyperglycemic subjects damage occurs more rapidly, involves also neocortical areas, and is often of the pan-necrotic type ('infarction'). Since experiments on forebrain ischemia of 30 min duration suggest that microcirculatory compromise develops during recirculation, we studied whether focal ischemia of the same duration, followed by reperfusion for 1, 2 or 4 h, leads to microcirculatory dysfunction. To test this possibility, we fixed the tissue by perfusion and counted the number of formed elements (leukocytes, macrophages and erythrocytes) in capillaries and postcapillary venules. Furthermore, capillary patency was evaluated following in vivo injection of Evan's blue. Histopathological examination of tissue fixed by perfusion after 1, 2 and 4 h of recirculation showed an increasing density of SNN in the caudoputamen of normoglycemic animals. Hyperglycemic, but not normoglycemic, animals showed pan-necrotic lesions ('infarction') after 4 h of recirculation. As a result, the total volume of tissue damage (SNN plus infarction) was larger in hyper- than in normoglycemic animals at 2 and 4 h of recirculation. In addition, hyperglycemic animals showed involvement of neocortex which increased with the time of reperfusion. In the ischemic hemisphere, between 5 and 10% of counted capillaries contained formed elements. However, since hyperglycemic animals contained an equal (or smaller) amount of cells the results did not suggest that capillary 'plugging' could explain the aggravated damage. Moreover, both normo- and hyperglycemic animals showed close to 100% capillary patency. The results thus fail to support the notion that the aggravation of focal ischemic damage by hyperglycemia is due to obstruction of microvessel by swelling or leukocyte adherence.

Amelioration by cyclosporin A of brain damage in transient forebrain ischemia in the rat.

The immunosuppressant drug cyclosporin A (CsA) is considered to be inherently protective in conditions of ischemia, e.g. in hepatic and cardiac tissue. However, investigations of effects of CsA on neuronal tissue have been contradictory, probably because the blood-brain barrier (BBB) is virtually impermeable to CsA. In the present study, we exploited the finding that the insertion of a syringe needle into brain parenchyma obviously disrupts the BBB and allows influx of CsA, and explored whether CsA, given as intraperitoneal injections daily for 1 week before and 1 week after forebrain ischemia of 7 or 10 min duration, ameliorates the damage incurred to the hippocampal CA 1 sector. In other experiments, the needle insertion and the first i.p. injection of CsA were made 30 min after the start of recirculation, with continued daily administration of CsA during the postinsult week. In animals which were injected with CsA in daily doses of 10 mg kg-1, but in which no needle was inserted, the drug failed to ameliorate CA1 damage, whether the ischemia had a duration of 7 or 10 min. Likewise, needle insertion had no effect on CA1 damage if CsA was not administered. In contrast, when CsA was given to animals with a needle insertion, CA1 damage was dramatically ameliorated, whether treatment was initiated 1 week before ischemia, or 30 min after the start of recirculation. The effect of CsA seemed larger than that of any other drug proposed to have an anti-ischemic effect in forebrain/global ischemia. Injection of tritiated CsA in one animal with BBB disruption lead to detectable radioactivity throughout the ventricular system, suggesting a generalised increase of the entry of CsA across the BBB. The results demonstrate that immunosuppressants of the type represented by CsA markedly ameliorate delayed neuronal damage after transient forebrain ischemia, provided that they can pass the BBB. It is discussed whether the effect of the drug is one involving calcineurin, a protein phosphatase, or if CsA counteracts a permeability transition of the inner mitochondrial membrane, assumed to occur in response to adverse conditions, e.g. gradual accumulation of Ca2+ in the mitochondria in the postischemic period.

Capillary patency after transient middle cerebral artery occlusion of 2 h duration.

Reperfusion after transient focal ischemia of 2 h duration is followed by secondary bioenergetic failure after 4 h of reperfusion. The objective of the present study was to explore whether or not this secondary deterioration is due to secondary microcirculatory compromise. Normal fasted rats were subjected to 2 h of MCA occlusion and allowed reperfusion for 2, 4, 6 and 8 h. At predetermined reperfusion times, rats were injected with Evans blue and decapitated. Capillary patency was determined using a fluorescent double-staining technique. No capillary perfusion deficits were detected in the ischemic neocortical penumbra, neocortical focus or striatal focus. We concluded that the secondary deterioration of bioenergetic state is not due to microcirculatory compromise. Since hyperglycemic animals show pan-necrotic lesions, a hyperglycemic group was added at 8 h of reperfusion to test if the adverse effect of hyperglycemia on ischemic damage is related to capillary compromise. The results showed that, in hyperglycemic rats, capillary perfusion in the striatal focus was compromised after 8 h of recirculation following 2 h of MCA occlusion. It is concluded that when normoglycemic rats are subjected to 2 h of MCA occlusion, capillary patency is not affected during the first 4-6 h of reflow. At 8 h of reflow, though, particularly in hyperglycemic rats, microcirculation is compromised in the caudoputamenal focus, probably reflecting infarction.

The influence of plasma glucose concentrations on ischemic brain damage is a threshold function.

To investigate whether aggravation of damage in hyperglycemic subjects is a continuous function of changes in intra- and extracellular pH during ischemia or whether there is a threshold value, preischemic plasma glucose was varied from 8.3-20.0 mM. 10 min forebrain ischemia was induced. The results showed that no animal with plasma glucose of < 13 mM developed seizures, and that all animals with glucose of > 16 mM died in status epilepticus. Half of the animals with plasma glucose in the range of 13-16 mM showed seizures and 50% of these died. In surviving animals, histological brain damage occurred in the hippocampal CA3 sector, cingulate cortex, thalamic nuclei and substantia nigra, structures normally not injured by 10 min ischemia. The data demonstrate that there is a glucose threshold of 10-13 mM, above which seizures develop and additional damage appears, and another one (> 16 mM), above which seizures are invariably fatal.

Postischemic treatment with calpain inhibitor MDL 28170 ameliorates brain damage in a gerbil model of global ischemia.

The newly-developed calpain inhibitor, MDL 28170 penetrates the blood-brain barrier and inhibits brain cysteine protease activity after systemic administration. This experiment was initiated to determine if the calpain inhibitor, MDL 28170 could, by these actions, reduce neuronal damage in an animal model of global cerebral ischemia in the gerbil. The calpain inhibitor, MDL 28170 (50 mg/kg), was initiated at 0.5 and 3 h of recirculation following 5min of global ischemia. Animals subjected to ischemia but without treatment or with vehicle treatment served as controls. Evaluation by light microscopy was carried out on paraffin-embedded brain sections of gerbils which were sacrificed 7 days post-operatively. The results show that the calpain inhibitor, MDL 28170, protects against cortical neuronal damage even if the treatment is delayed until 3 h after reperfusion. However, the neuroprotective effect of this agent is less pronounced in the hippocampal CA1 sector. The results suggest that calpain-mediated proteolysis plays an important role in neuronal death due to ischemia. However, additional mechanisms by which an increased intracellular calcium concentration leads to neuronal death may exist.