Impact of metformin on immunological markers: Implication in its anti-tumor mechanism.

Metformin, an anti-hyperglycemic drug, has been known to have antitumor properties for around 15 years. Although there are a number of reports attributing the antitumor function of metformin to its impact on energy homeostasis and oxygen re-distribution in tumor microenvironment, detailed mechanisms remain largely unknown. In the past several years, there is an increasing number of publications indicating that metformin can affect various immunological components including lymphocytes, macrophages, cytokines and several key immunological molecules in both human and animal studies. These interesting results appear to be in line with emerging data that suggest associations between immune responses and energy homeostasis/oxygen re-distribution, which may explain effective impacts of metformin on immunotherapies against autoimmune diseases as well as cancers. This review article is to analyse and discuss recent development in the above areas with aim to justify metformin as a new adjuvant for immunotherapy against human cancers. We hope that our summary will help to optimize the application of metformin for various types of human cancers.

Phase I-II Clinical Trial Assessing Safety and Efficacy of Umbilical Cord Blood Mononuclear Cell Transplant Therapy of Chronic Complete Spinal Cord Injury.

Umbilical cord blood-derived mononuclear cell (UCB-MNC) transplants improve recovery in animal spinal cord injury (SCI) models. We transplanted UCB-MNCs into 28 patients with chronic complete SCI in Hong Kong (HK) and Kunming (KM). Stemcyte Inc. donated UCB-MNCs isolated from human leukocyte antigen (HLA ≥4:6)-matched UCB units. In HK, four patients received four 4-µl injections (1.6 million cells) into dorsal entry zones above and below the injury site, and another four received 8-µl injections (3.2 million cells). The eight patients were an average of 13 years after C5-T10 SCI. Magnetic resonance diffusion tensor imaging of five patients showed white matter gaps at the injury site before treatment. Two patients had fiber bundles growing across the injury site by 12 months, and the rest had narrower white matter gaps. Motor, walking index of SCI (WISCI), and spinal cord independence measure (SCIM) scores did not change. In KM, five groups of four patients received four 4-µl (1.6 million cells), 8-µl (3.2 million cells), 16-µl injections (6.4 million cells), 6.4 million cells plus 30 mg/kg methylprednisolone (MP), or 6.4 million cells plus MP and a 6-week course of oral lithium carbonate (750 mg/day). KM patients averaged 7 years after C3-T11 SCI and received 3-6 months of intensive locomotor training. Before surgery, only two patients walked 10 m with assistance and did not need assistance for bladder or bowel management before surgery. The rest could not walk or do their bladder and bowel management without assistance. At about a year (41-87 weeks), WISCI and SCIM scores improved: 15/20 patients walked 10 m ( p = 0.001) and 12/20 did not need assistance for bladder management ( p = 0.001) or bowel management ( p = 0.002). Five patients converted from complete to incomplete (two sensory, three motor; p = 0.038) SCI. We conclude that UCB-MNC transplants and locomotor training improved WISCI and SCIM scores. We propose further clinical trials.

Pseudoprogression of malignant glioma in Chinese patients receiving concomitant chemoradiotherapy.

OBJECTIVES: To investigate the frequency of pseudoprogression of glioblastoma in Chinese patients receiving concomitant chemoradiotherapy and investigate its association with pseudoprogression and tumour molecular marker O(6)-methylguanine-DNA methyltransferase promoter methylation status. DESIGN: Case series with internal comparisons. SETTING: University teaching hospital, Hong Kong. PATIENTS: Patients with glioblastoma treated with concomitant chemoradiotherapy during April 2005 to June 2010 were reviewed. Magnetic resonance imaging brain scans, pre- and post-concomitant chemoradiotherapy and 3-monthly thereafter were reviewed by an independent neuroradiologist according to Macdonald's criteria. Relevant patient information (clinical condition, performance score, development of new neurological deficits, use of steroids, and survival) was retrieved. For each patient, O(6)-methylguanine-DNA methyltransferase methylation status was investigated with genomic DNA from formalin-fixed or paraffin-embedded sections of tumour tissues by methylation-specific polymerase chain reaction. RESULTS: During the study period, 28 primary glioblastoma patients underwent concomitant chemoradiotherapy. The mean age of the patients was 48 (range, 16-71) years. Thirteen patients (13/28, 46%) developed early radiological progression of the tumour after completion of concomitant chemoradiotherapy, of whom five (39%) were subsequently found to have had pseudoprogression. Patients with pseudoprogression showed a trend towards longer survival (22 months in pseudoprogression vs 17 months in all others vs 11 months in those with genuine progression). Among the 27 patients tested for O(6)-methylguanine-DNA methyltransferase promoter status, 12 (44%) were methylated. Two (2/12, 17%) in the methylated group had pseudoprogression, while three (3/15, 20%) in the unmethylated group had pseudoprogression. CONCLUSIONS: Nearly half of all patients (46%) developed early radiological progression (within 3 months of completing concomitant chemoradiotherapy). Moreover, about one in three of such patients had pseudoprogression. Pseudoprogression is an important clinical condition to be aware of to prevent premature termination of an effective treatment.

Association of molecular marker O(6)Methylguanine DNA methyltransferase and concomitant chemoradiotherapy with survival in Southern Chinese glioblastoma patients.

OBJECTIVES: (1) To compare the survival of concomitant chemotherapy and radiotherapy with radiotherapy alone in Chinese patients with primary glioblastoma. (2) To determine the methylation status of O(6)Methylguanine DNA methyltransferase in Chinese primary glioblastoma, and to assess the prognostic value of O(6)Methylguanine DNA methyltransferase methylation status in such patients. DESIGN: Retrospective correlative analysis. SETTING: University teaching hospital, Hong Kong. PATIENTS: Patients diagnosed with histologically proven primary glioblastoma in the period of March 2005 to June 2007 were recruited. Genomic DNA was isolated from formalin-fixed and paraffin-embedded sections of glioblastoma tissues. Methylation-specific polymerase chain reaction for O(6)Methylguanine DNA methyltransferase was performed. Patients' information at presentation was collected (age, performance status, steroid use, extent of resection, complications, radiotherapy data, use of chemotherapy). Primary outcome was measured by overall survival while secondary outcome was measured by progression-free survival. Overall and progression-free survivals were estimated by the Kaplan-Meier technique. Outcomes were assessed for groups with and without concomitant chemoradiotherapy and for groups with and without O(6)Methylguanine DNA methyltransferase methylation. RESULTS: A total of 35 glioblastoma patients were recruited; 27 were male and 8 female. Their mean age was 50 years. In all, 17 received concomitant chemoradiotherapy, and 18 received radiotherapy only. Their median overall survival was 12 (range, 7-17) months and the median progression-free survival was 5 (range, 3-6) months. In the radiotherapy alone group, the median progression-free survival and overall survival was 4 (range, 3-5) months and 6 (range, 2-10) months, respectively. In the concomitant radiochemotherapy group, the median progression-free survival and overall survival was 6 (range, 2-10) months and 13 (range, 8-18) months, respectively. Fifteen (43%) of the tumour samples showed methylation of O(6)Methylguanine DNA methyltransferase. There was a trend towards overall longer survival in the group with methylated tumours compared to those with unmethylated tumours; respective values for median survival (ranges) were 17 (13-21) versus 10 (6-14) months (P=0.105). CONCLUSIONS: Our single-centre results indicated that Chinese glioblastoma patients who had received concomitant chemoradiotherapy showed a trend towards longer overall survival compared to those receiving radiotherapy alone. Approximately 43% of our Chinese glioblastoma samples showed methylation of O(6)Methylguanine DNA methyltransferase. O(6)Methylguanine DNA methyltransferase methylation may be a significant prognostic factor in Chinese glioblastoma patients.

Intravenous magnesium sulphate for aneurysmal subarachnoid hemorrhage: an updated systemic review and meta-analysis.

INTRODUCTION: Previous meta-analyses of magnesium sulphate infusion in the treatment of aneurysmal subarachnoid hemorrhage (SAH) have become outdated due to recently published clinical trials. Our aim was thus to perform an up-to-date systemic review and meta-analysis of published data on the use of magnesium sulphate infusion in aneurysmal SAH patients. METHODS: A systemic review and meta-analysis of the literature was carried out on published randomized controlled clinical trials that investigated the efficacy of magnesium sulphate infusion in aneurysmal SAH patients. The results were analyzed with regard to delayed cerebral ischemia (DCI), delayed cerebral infarction, and favorable neurological outcomes at three and six months. The risks of bias were assessed using the Jadad criteria, with a Jadad score >3 indicating a lower such risk. Meta-analyses are presented in terms of relative risk (RR) with 95% confidence intervals (CIs). RESULTS: Six eligible studies with 875 patients were reviewed. The pooled RR for DCI was 0.87 (95% CI, 0.36 to 2.09; P = 0.75). That for delayed cerebral infarction was 0.58 (95% CI, 0.35 to 0.97; P = 0.04), although this result did not persist if only randomized clinical trials with a lower risk of bias were included (RR 0.61, 95% CI, 0.31 to 1.22; P = 0.17). The pooled RR for a favorable outcome at three months was 1.14 (95% CI, 0.99 to 1.31; P = 0.07), and that for a favorable outcome at six months was 1.08 (95% CI, 0.94 to 1.24; P = 0.29). CONCLUSIONS: The present findings do not lend support to a beneficial effect of magnesium sulphate infusion on delayed cerebral infarction. The reduction in DCI and improvement in the clinical outcomes of aneurysmal SAH patients following magnesium sulphate infusion observed in previous pilot studies are not confirmed, although a beneficial effect cannot be ruled out because of sample size limitation.

Health-related quality of life after aneurysmal subarachnoid hemorrhage: profile and clinical factors.

BACKGROUND: Health-related quality of life has recently been suggested as a supplement to the traditional neurological outcome measures from the patient's perspective according to the World Health Organization model and may capture the effects of other factors such as posttraumatic stress disorder and neuroendocrine dysfunction. OBJECTIVE: To explore the profile and clinical factors of quality of life after aneurysmal subarachnoid hemorrhage using the data we obtained from the recently completed Intravenous Magnesium Sulphate After Aneurysmal Subarachnoid Hemorrhage (IMASH) trial. METHODS: This study was registered at www.strokecenter.org/trials and www.ClinicalTrials.gov (NCT00124150). Data from a patient cohort obtained with the Short Form-36 questionnaire completed at 6 months were used for analysis. RESULTS: Patients with aneurysmal subarachnoid hemorrhage demonstrated a decrease in quality of life according to the Short Form-36 at 6 months. The physical and mental health scores correlated with the Extended Glasgow Outcome Scale and had the potential to avoid the ceiling effect. Multiple regression analyses showed that the physical component scores were related to age, World Federation of Neurological Surgeons grade, and chronic hydrocephalus and that the mental component scores were not related to the traditional prognostic factors. CONCLUSION: Subarachnoid hemorrhage caused a decrease in quality of life. Chronic hydrocephalus is related to a decrease in physical health quality of life.

Plasma magnesium concentrations and clinical outcomes in aneurysmal subarachnoid hemorrhage patients: post hoc analysis of intravenous magnesium sulphate for aneurysmal subarachnoid hemorrhage trial.

BACKGROUND AND PURPOSE: Conflicting data have been obtained on optimal plasma magnesium concentrations for clinical outcomes in patients with aneurysmal subarachnoid hemorrhage. METHODS: Adults (aged 18 years or older) who had acute aneurysmal subarachnoid hemorrhage diagnosed were randomly assigned to receive either an intravenous MgSO(4) infusion (80 mmol in 500 mL normal saline per day) or a placebo (500 mL normal saline per day) for up to 14 days. Post hoc multivariable binary logistic regression analyses were performed by dividing mean plasma magnesium concentrations into 4 quartiles according to treatment group and then comparing with the lowest quartiles. RESULTS: The worst clinical outcomes at 6 months were seen in MgSO(4) group patients, with mean plasma magnesium concentrations in the fourth quartile, and in placebo group patients, with mean such concentrations in the third and fourth quartiles. CONCLUSIONS: No evidence was found to suggest that a higher mean plasma magnesium concentration improves clinical outcomes. On the contrary, we found an association between high plasma magnesium concentration and worse clinical outcomes.

Intravenous magnesium sulphate for aneurysmal subarachnoid hemorrhage (IMASH): a randomized, double-blinded, placebo-controlled, multicenter phase III trial.

BACKGROUND AND PURPOSE: Pilot clinical trials using magnesium sulfate in patients with acute aneurysmal subarachnoid hemorrhage have reported trends toward improvement in clinical outcomes. This Phase III study aimed to compare intravenous magnesium sulfate infusion with saline placebo among such patients. METHODS: We recruited patients with aneurysmal subarachnoid hemorrhage within 48 hours of onset from 10 participating centers. The patients were randomly assigned to magnesium sulfate infusion titrated to a serum magnesium concentration twice the baseline concentration or saline placebo for 10 to 14 days. Patients and assessors were blinded to treatment allocation. The study is registered at www.strokecenter.org/trials (as Intravenous Magnesium Sulphate for Aneurysmal Subarachnoid Hemorrhage [IMASH]) and www.ClinicalTrials.gov (NCT00124150). RESULTS: Of the 327 patients recruited, 169 were randomized to receive treatment with intravenous magnesium sulfate and 158 to receive saline (placebo). The proportions of patients with a favorable outcome at 6 months (Extended Glasgow Outcome Scale 5 to 8) were similar, 64% in the magnesium sulfate group and 63% in the saline group (OR, 1.0; 95% CI, 0.7 to 1.6). Secondary outcome analyses (modified Rankin Scale, Barthel Index, Short Form 36, and clinical vasospasm) also showed no significant differences between the 2 groups. Predefined subgroups included age, admission World Federation of Neurological Surgeons grade, pre-existing hypertension, intracerebral hematoma, intraventricular hemorrhage, location of aneurysm, size of aneurysm, and mode of aneurysm treatment. In none of the subgroups did the magnesium sulfate group show a better outcome at 6 months. CONCLUSIONS: The results do not support a clinical benefit of intravenous magnesium sulfate infusion over placebo infusion in patients with acute aneurysmal subarachnoid hemorrhage.

The impact of ventricular catheter impregnated with antimicrobial agents on infections in patients with ventricular catheter: interim report.

INTRODUCTION: Previous prospective study in our unit had shown that the use of dual antibiotic prophylaxis in patients with external ventricular drain was associated with decreased incidence of cerebrospinal fluid infection but complicated with opportunistic extracranial infection. In recent years, cerebrospinal fluid shunt catheters impregnated with antimicrobial agents have become available. Theoretically, these catheters provide antibiotic prophylaxis locally without the associated complications of systemic opportunistic infection. METHODS: We carried out a prospective randomized, controlled clinical trial in a regional neurosurgical center in Hong Kong. We recruited patients admitted for emergency neurosurgical operation after informed consent was obtained from next-of-kin. Eligible patients were randomized to receive an antibiotic-impregnated ventricular catheter or plain ventricular catheter Dual prophylactic antibiotic coverage was given to the patients randomized for plain ventricular catheter only. Patients who received antibiotic impregnanted catheters were not treated with systematic prophylactic antibiotics. Here we present the analysis of 110 patients, recruited over a 2-year period, to receive antibiotic-impregnanted ventricular catheters versus non-impregnated ventricular cathethers with prophylactic antibiotic coverage. FINDINGS: Fifty-two patients were randomized to antibiotic-impregnated ventricular catheter with no systemic antibiotic prophylaxis (Group A) and 58 patients were randomized to plain ventricular catheters with prophylactic dual antibiotics (Group B). There was no ventriculostomy-related infection in either groups of patients. There was also no statistical significant difference in incidences of extracranial infections between the two groups, p = 0.617. CONCLUSIONS: In this analysis, antibiotic-impregnation of ventricular catheters was as effective as systemic antibiotics in the prevention of ventriculostomy infections, with the potential advantage of avoiding the systemic side-effects of prophylactic antibiotics.

Ischemic events after carotid interventions in relationship to baseline cerebrovascular reactivity.

BACKGROUND: We aimed to investigate whether baseline cerebrovascular reactivity could predict subsequent ischemic event after intervention and identify the patient group for more aggressive medical and interventional management paradigms. METHODS: Patients with more than 70% cervical carotid stenosis (from ultrasonography) were reviewed. Patients, who had baseline cerebrovascular reactivity test before intervention and had either carotid endarterectomy (CEA) or carotid angioplasty and stenting (CAS) performed, were recruited for analysis. Transcranial Doppler ultrasonography was used to examine the reactivity of the middle cerebral artery in response to 5% carbon dioxide in oxygen. The mean follow up period was 66 months. FINDINGS: Twenty-six patients had symptomatic carotid stenosis and ten patients had asymptomatic carotid stenosis. There were four subsequent ischemic events during follow up. None of the nine patients with impaired baseline ipsilateral cerebrovascular reactivity had subsequent ischemic event. CONCLUSIONS: In this current study, impaired baseline cerebrovascular reactivity did not predict the subsequent stroke risk after carotid intervention. Cerebrovascular reactivity testing may not serve as an indicator for aggressive medical and surgical treatments.