In Vitro and In Vivo Antiaggregant Effects of Magnesium Halogenates

The effects of subchronic intake of magnesium hydro-carbonate-rich mineral water on cardiometabolic markers and electrolytes in rats with streptozotocin-induced diabetes

Background/Aim: Hypomagnesaemia is one of the most detected electrolyte abnormalities in diabetics. Modulation of numerous cardiovascular pathophysiological processes is a potential goal for anti-diabetic therapy. Magnesium supplementation prevents subclinical tissue magnesium deficiency, thus delaying the onset of metabolic imbalance in diabetes, but long-term effects of magnesium supplementation in chronic diabetes and numerous pathophysiological processes remain unknown. Aim of this study was to determine the effects of subchronic intake of magnesium hydrocarbonate-rich mineral water on cardiometabolic markers and electrolytes in rats with streptozotocin-induced diabetes. Methods: A total of 28 Wistar, male rats, body weight 160 g at start, were divided into four groups of 7 each: two controls, group that drank tap water and received a single ip injection of saline (0.9 % NaCl) (TW-C), group that drank mineral water rich in magnesium hydrocarbonate and received a single ip injection of saline (0.9 % NaCl) (MW-C); and two experimental groups with streptozotocin-induced diabetes, group that drank tap water and received a single ip injection of streptozotocin (100 mg/kg) in saline (0.9 % NaCl, 1 mL) (TW-DM), group that drank mineral water rich in magnesium hydrocarbonate and received a single ip injection of streptozotocin (100 mg/kg) in saline (0.9 % NaCl, 1 mL) (MW-DM). Results: Regarding the biochemical parameters, a decrease was observed in the MW-C group for vitamin B12 and proteins, while triglycerides were higher compared to the TW-C group. By comparing the haemostatic biomarkers between TW-C and MW-C groups, a statistically significant decrease was found for fibrinogen, while the electrolyte analysis showed an increase in phosphates for the MW-C group. Biochemical value comparison between TW-DM and MWDM groups showed that magnesium hydrocarbonate usage in diabetic rats did not significantly reduce glycaemia although the average glycaemic values were lower in the group treated with magnesium hydrocarbonate. Regarding the electrolyte values, a statistically significant decrease was observed for sodium, potassium and phosphate in the MW-DM group. The MW-DM group also showed a significant increase in iron value compared to TW-DM group. Conclusion: Subchronic intake of magnesium hydrocarbonate-rich mineral water, as a form of magnesium supplementation, did not cause a significant improvement in glycaemia or normalisation of diabetes-induced dyslipidaemia. This study showed the reduction of fibrinogen value, thus indicating the possibility of usage of this form of magnesium supplementation in different pro-thrombogenic conditions.

Effects of perioperative magnesium sulfate infusion on intraoperative blood loss and postoperative analgesia in patients undergoing posterior lumbar spinal fusion surgery: A randomized controlled trial

OBJECTIVE

Many studies have suggested the anti-nociceptive role for magnesium either as an adjunct for postoperative pain. Although several studies have been carried out to evaluate the anti-nociceptive effect of magnesium, there is still considerable uncertainty.

PATIENTS AND METHODS

Eighty patients who underwent posterior spinal fusion were randomly divided into two groups (magnesium and saline). Changes in cell count, magnesium concentration and coagulation status were assessed one hour after operation at both group and compared to baseline. At recovery room, their pain score was assessed according to 10 points visual analogue scale (VAS). Morphine consumption was evaluated at regular times after the surgery by patient controlled analgesia (PCA) device.

RESULTS

VAS scores were significantly lower in the magnesium group. Cumulative PCA morphine consumption after the surgery was significantly lower in the magnesium group. Pre and postoperative values for haemoglobin, platelet count, Prothrombin Time (PT), fibrinogen were not significantly different. There was a significant increase in activated Partial Thromboplastin Time (aPTT), International Normalized Ratio (INR), and bleeding time (BT), one hour after the operation in the magnesium group but intraoperative blood loss was similar in both groups.

CONCLUSIONS

Perioperative magnesium sulfate infusion improves the postoperative analgesia, decreases the amount of morphine consumption after the operation and does not change the intraoperative bleeding in patients undergoing posterior spinal fusion surgery.

Antenatal magnesium sulphate neuroprotection in the preterm infant

Very preterm infants have high rates of neurological impairments and disabilities. These rates have not diminished as the survival rates have improved. Basic science research suggests that magnesium sulphate before birth can be neuroprotective for the preterm fetus. Some, but not all, observational studies in humans also suggest a protective effect of antenatal magnesium sulphate on cerebral palsy. Four randomised controlled trials of antenatal magnesium sulphate have reported long-term neurological effects in surviving infants, but only one of these was designed specifically to evaluate the long-term effects of treatment. These studies found that, overall, antenatal magnesium sulphate therapy had no significant effect on paediatric mortality or neurological outcomes in the first few years of life, including cerebral palsy, but it was found to lower the rate of motor problems at 2 years of age in one study. The role for antenatal magnesium sulphate therapy as a neuroprotective agent for the preterm fetus is not yet established.

Magnesium sulfate as a tocolytic agent

Although magnesium sulfate is widely used as a tocolytic agent in the hope of preventing spontaneous preterm birth, there is a paucity of data from large well-designed randomized clinical studies demonstrating the efficacy of magnesium sulfate therapy. Given the potential for untoward side effects and the inherent risks of magnesium sulfate therapy, a thorough understanding of the potential risks and benefits of this agent is needed. To accomplish this understanding we have provided a detailed review the history, pharmacology, physiology, maternal/fetal side effects, and tocolytic efficacy of magnesium sulfate.

The effect of magnesium on coagulation in parturients with preeclampsia

Preeclampsia is associated with complex coagulation abnormalities that include altered platelet function and consumption and activation of the fibrinolytic system. Magnesium sulfate, which is used as a therapeutic modality for the prevention of seizures in preeclamptic parturients, has anticoagulant and antiplatelet effects. We sought to determine the effects of magnesium on various components of the coagulation system in patients with preeclampsia. We assessed the coagulation status of 18 parturients with preeclampsia being treated with magnesium. The assessment was performed with the thromboelastograph test, which provides an overall assessment of blood coagulation via the coagulation index. Thromboelastography was performed before beginning magnesium therapy and 30 min and 2 h after a 6-g bolus of IV magnesium. The R value (time to first clot formation) was found to be significantly slower (P < 0.05) at 30 min after the magnesium bolus. This result suggests increased coagulant factor activity resulting from the magnesium bolus. However, there was no effect of magnesium on the overall coagulation, as evidenced by the lack of change in the coagulation index either at 30 min or at 2 h after the completion of the initial magnesium bolus. Therefore, this therapy should have no effect on the use of neuraxial techniques.

IMPLICATIONS

On the basis of the thromboelastography assessment, we found that the current practice of administering magnesium did not influence overall coagulation in preeclamptic women. Therefore, magnesium administration should not affect the use of neuraxial techniques.

The effect of magnesium sulfate on bleeding time in pregnancy

OBJECTIVE

The bleeding time is one of the most commonly used diagnostic tests to evaluate platelet-related hemorrhagic disorders. Magnesium has been shown in vitro to be a platelet antiaggregant. This study was conducted to evaluate the hypothesis that magnesium sulfate has no effect on the template bleeding time.

STUDY DESIGN

The study group consisted of 24 women who required magnesium sulfate in pregnancy. A blood cell count, platelet count, magnesium level, bleeding time, and mean arterial pressure were obtained before and 2 hours after magnesium sulfate infusion. Magnesium sulfate was infused beginning with a 6 gm intravenous bolus followed by 2 gm/hr. A template bleeding time was performed with a Simplate-II (Organon Teknika, Durham, N.C.) device. Two of the authors performed all the bleeding times. Data were analyzed with a paired t test and Wilcoxon rank test.

RESULTS

Fifteen (63%) patients received magnesium sulfate for tocolysis or before external cephalic version and nine (37%) for preeclampsia prophylaxis. No differences were found between the normotensive and hypertensive groups regarding maternal age, gestational age, initial bleeding time, or platelet count. Analysis of the entire study group revealed a prolongation of the bleeding time after magnesium sulfate (5.7 +/- 1.8 vs 6.6 +/- 1.9 minutes, p < 0.05); a lowering of the mean arterial pressure (p < 0.05), and a rise in the magnesium level (p < 0.05). Four patients (16.7%) had a postmagnesium bleeding time > 9 minutes.

CONCLUSION

Magnesium sulfate appears to prolong the bleeding time in pregnancy. The clinical significance remains to be determined.

Effect of magnesium on cocaine-induced, catecholamine-mediated platelet and vascular response in term pregnant ewes

Ten pregnant ewes were alternated in a study of the blocking effect of parenteral magnesium on the catecholamine response to cocaine. Indirect blood pressures were recorded at 1-minute intervals for 12 minutes before and after a bolus of 2 mg/kg of cocaine. Fetal heart rates were continuously recorded from skin electrodes. Platelet counts were performed before and 12 minutes after cocaine. Control ewes received lactated Ringer's solution, and test animals had 5 mg/kg of elemental magnesium in the form of MgSO4-7H2O in a rapid infusion. A semicrossover was also performed. Platelet counts fell precipitately in controls and rose after magnesium infusions. Fetal heart rates rose in controls at 5-minute intervals and were unchanged in magnesium-treated mothers. Because of disparity of the baseline mean arterial pressure, direct comparisons were not significant before and after cocaine. Alterations from the baseline were different in magnesium-treated versus control animals, with values in the latter rising by 28 +/- 10 mm Hg with lactated Ringer's solution plus cocaine and falling by 3 +/- 5 mm Hg with magnesium pretreatment. Values in test animals originally treated with magnesium rose 4 +/- 11 mm Hg for an overall significance of p less than 0.05. Low beginning serum magnesium levels were associated with ovine hypertension and reduced fetal weight and survival.