Melatonin improves hyperglycemia induced damages in rat brain

BACKGROUND

Diabetes mellitus is an endocrine disorder which is characterized by the development of resistance to the cellular activity of insulin or inadequate insulin production. It leads to hyperglycemia, prolonged inflammation, and oxidative stress. Oxidative stress is assumed to play an important role in the development of diabetic complications. Melatonin is the hormone that interacts with insulin in diabetes. Therefore, in this study, the effects of melatonin treatment with or without insulin were examined in diabetic rat brain.

METHODS

Rats were divided into five groups as control, diabetes, diabetes + insulin, diabetes + melatonin, and diabetes + melatonin + insulin. Experimental diabetes was induced by streptozotocin (60 mg/kg, i.p.). Twelve weeks after diabetes induction, rats were decapitated. Malondialdehyde, glutathione, sialic acid and nitric oxide levels, superoxide dismutase, catalase, glutathione-S-transferase, myeloperoxidase, and tissue factor activities were determined in brain tissue.

RESULTS

Melatonin alone showed its antioxidant effect by increasing brain glutathione level, superoxide dismutase, catalase, and glutathione-S-transferase activities and decreasing malondialdehyde level in experimental diabetes. Although insulin did not have a significant effect on glutathione and glutathione-S-transferase, its effects on lipid peroxidation, superoxide dismutase, and catalase were similar to melatonin; insulin also decreased myolopeoxidase activity and increased tissue factor activity. Combined melatonin and insulin treatment mimicked the effects of insulin.

CONCLUSION

Addition of melatonin to the insulin treatment did not change the effects of insulin, but the detailed role of melatonin alone in the treatment of diabetes merits further experimental and clinical investigation.

The Protective Effect of Radix Polygoni Multiflori on Diabetic Encephalopathy via Regulating Myosin Light Chain Kinase Expression

Currently there has been no effective treatment of diabetic encephalopathy. Radix Polygoni Multiflori, a famous traditional Chinese medicine, is widely used in antiaging treatment, especially in prevention and treatment of Alzheimer's diseases. In this study we tried to explore the effect of Radix Polygoni Multiflori on cognitive function among diabetic rats with demonstrated cognitive impairment. SD rats were divided into group A (control group), group B (diabetes), group C (treated with Radix Polygoni Multiflori at the dose of 2 g/kg/d), and group D (treated with same drug at the dose of 1 g/kg/d). The results showed that 8 weeks of Radix Polygoni Multiflori treatment could improve the cognitive dysfunction of diabetic rats (P < 0.01), recover the ultrastructure of hippocampal neurons, and increase the number of synapses in a dose-dependent manner. Further experiment also suggested that the neuroprotective effect of Radix Polygoni Multiflori was partly achieved by downregulating MLCK expression in hippocampus via ERK signaling.

[Delirium in the clinical practice of a therapist]

Delirium is a neuropsychiatric condition that may complicate any visceral disease. Its rate is especially high among patients with inflammatory diseases or metabolic disturbances and in the elderly. Brain injury concurrent with an abnormal stress response underlies the development of delirium. The clinical picture of delirium is characterized by clouding of consciousness accompanied by global cognitive and behavioral changes. According to the nature of changes in motor behavior, delirium is divided into hyperactive, hypoactive, and mixed subtypes. Special scales, such as Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), are used to identify delirium. Management of delirium includes specific therapy for the underlying disease and adequate care. Low-dose neuroleptics, haloperidol in particular, are recommended to correct behavioral changes.

Epidermal growth factor receptor transactivation is necessary for glucagon-like peptide-1 to protect PC12 cells from apoptosis

AIM

Patients with long-standing diabetes commonly develop diabetic encephalopathy, which is characterized by cognitive impairment and dementia. To identify potential treatments for diabetic encephalopathy, we focused on the protective action of glucagon-like peptide-1 (GLP-1) against neural cell apoptosis. In this study, we evaluated whether exposure of cells to GLP-1 leads to epidermal growth factor receptor (EGFR) transactivation and signaling through the PI3K/Akt/mTOR/GCLc/redox pathway, which we previously reported.

METHODS

We monitored the phosphorylation of EGFR and Akt in PC12 cells exposed to MG and GLP-1 that had been first incubated in the presence or absence of various inhibitors of EGFR transactivation.

RESULTS

DAPI staining revealed that pretreatment of cells with BiPS, HB-EGF and anti-TGF-α neutralization antibodies or AG1478 abrogated the ability of GLP-1 to rescue cells from MG-induced apoptosis. We show that exposure of PC12 cells to GLP-1 induces EGFR phosphorylation and that this effect was inhibited by prior exposure of the cells to BiPS, HB-EGF and anti-TGF-α neutralization antibodies or AG1478. Interestingly, these agents also diminished the capacity of GLP-1 to protect cells from MG-induced apoptosis. Moreover, these agents reduced GLP-1-induced phosphorylation of Akt. EGF itself also protected the cells from MG-induced apoptosis and induced phosphorylation of Akt, which was inhibited by LY294002.

CONCLUSION

The neuroprotective effects of GLP-1 against MG-induced apoptosis are mediated by EGFR transactivation, which signals through the PI3K/Akt/mTOR/GCLc/redox pathway in PC12 cells.

Pathology supported genetic testing and treatment of cardiovascular disease in middle age for prevention of Alzheimer's disease

Chronic, multi-factorial conditions caused by a complex interaction between genetic and environmental risk factors frequently share common disease mechanisms, as evidenced by an overlap between genetic risk factors for cardiovascular disease (CVD) and Alzheimer's disease (AD). Single nucleotide polymorphisms (SNPs) in several genes including ApoE, MTHFR, HFE and FTO are known to increase the risk of both conditions. The E4 allele of the ApoE polymorphism is the most extensively studied risk factor for AD and increases the risk of coronary heart disease by approximately 40%. It furthermore displays differential therapeutic responses with use of cholesterol-lowering statins and acetylcholinesterase inhibitors, which may also be due to variation in the CYP2D6 gene in some patients. Disease expression may be triggered by gene-environment interaction causing conversion of minor metabolic abnormalities into major brain disease due to cumulative risk. A growing body of evidence supports the assessment and treatment of CVD risk factors in midlife as a preventable cause of cognitive decline, morbidity and mortality in old age. In this review, the concept of pathology supported genetic testing (PSGT) for CVD is described in this context. PSGT combines DNA testing with biochemical measurements to determine gene expression and to monitor response to treatment. The aim is to diagnose treatable disease subtypes of complex disorders, facilitate prevention of cumulative risk and formulate intervention strategies guided from the genetic background. CVD provides a model to address the lifestyle link in most chronic diseases with a genetic component. Similar preventative measures would apply for optimisation of heart and brain health.

Neuroprotective properties of aucubin in diabetic rats and diabetic encephalopathy rats

In this study, we determined the neuroprotective effect of aucubin on diabetes and diabetic encephalopathy. With the exception of the control group, all rats received intraperitoneal injections of streptozotocin (STZ; 60 mg/kg) to induce type 1 diabetes mellitus (DM). Aucubin (1, 5, 10 mg/kg ip) was used after induction of DM (immediately) and diabetic encephalopathy (65 days after the induction of diabetes). The diabetic encephalopathy treatment groups were divided into short-term and long-term treatment groups. Treatment responses to all parameters were examined (body weight, plasma glucose, Y-maze error rates and proportion of apoptotic cells). In diabetic rats, aucubin controlled blood glucose levels effectively, prevented complications, and improved the quality of life of diabetic rats. In diabetic encephalopathy, aucubin significantly rescued neurons in the hippocampal CA1 subfield and reduced working errors during behavioral testing. The significant neuroprotective effect of aucubin could be seen not only in the short term (15 days) but also in the long term (45 days), which was a highly encouraging finding. These data suggest that aucubin may be a potential neuroprotective agent.

The development of a global program for the elimination of brain damage due to iodine deficiency

Iodine deficiency is the most common preventable cause of brain damage with more than 2 billion people from 130 countries at risk. The global problem of iodine deficiency has been redefined by a readily transmitted population concept, with an easy acronym - the concept of the iodine deficiency disorders (IDD) - referring to all the effects of iodine deficiency in a population, that can be totally prevented by correction of iodine deficiency with special emphasis on brain damage and not just to goitre and cretinism (1983). This was followed by the creation of the International Council for Control of Iodine Deficiency Disorders (ICCIDD) supported by WHO and UNICEF with 700 multidisciplinary professionals from more than 100 countries, committed to providing technical assistance to national programs for the elimination of IDD (1986). The WHO policy of Universal Salt Iodization (USI) has been widely adopted which requires iodization of all food for human and animal consumption by the use of iodized salt (25-40 mg I/kilo). Simple practical methods for monitoring - by the measurement of salt iodine and urine iodine were developed and promoted on a large scale with the technical assistance of the ICCIDD.

[Bio-ecological control of chronic liver disease and encephalopathy]

Minimal encephalopathy was originally associated with chronic liver disease but is increasingly associated with most other chronic diseases and particularly with diabetes and also chronic disorders in other organs: kidneys, lungs, thyroid and with obesity. It is increasingly with dramatically increased and more or less permanent increase in systemic inflammation, most likely a result of Western lifestyle. Frequent physical exercise and intake of foods rich in vitamins, antioxidants, fibres, lactic acid bacteria etc in combination with reduction in intake of refined and processed foods is known to reduce systemic inflammation and prevent chronic diseases. Some lactic acid bacteria, especially Lb paracasei, lb plantarum and pediococcus pentosaceus have proven effective to reduce inflammation and eliminate encephalopathy. Significant reduction in blood ammonia levels and endotoxin levels were reported in parallel to improvement of liver disease. Subsequent studies with other lactic acid bacteria seem to demonstrate suppression of inflammation and one study also provides evidence of clinical improvement.

Low incidence of neurologic events during long-term support with the HeartMate XVE left ventricular assist device

Neurologic events during left ventricular assist device (LVAD) support are associated with significant morbidity and death. To evaluate this problem, we analyzed neurocognitive function and the frequency and incidence of neurologic events in 21 consecutive patients who were undergoing long-term support with the HeartMate XVE LVAD (Thoratec Corporation; Pleasanton, Calif). The mean duration of LVAD support was 531 days (range, 55-1, 309 d); the cumulative support time was 11,188 days (30.7 yr). No patients received anticoagulant therapy, and most received aspirin. None experienced strokes or transient ischemic attacks. Twenty patients were discharged from the hospital; 2 were later readmitted because of transient changes in neurologic status (metabolic encephalopathy) that ultimately resolved. Neurologic function, as measured by the National Institutes of Health Stroke Scale (NIHSS) and the Modified Rankin Score (MRS), was abnormal before LVAD implantation but normal 6 and 12 months after (mean NIHSS, 23.6 before vs 0 after; mean MRS, 0.68 before vs 0.18 after). Neurocognitive function, as evaluated by the Boston Naming Test, Trail Making Test part B, and Block Design Test, also improved during LVAD support. Together, these findings indicate that few neurologic events occur during long-term HeartMate XVE LVAD support in the absence of anticoagulation therapy. They also suggest that modifications made to the HeartMate LVAD since the REMATCH trial have resulted in fewer complications, and that better patient selection and supportive care have improved outcomes.

Age and high-dose methotrexate are associated to clinical acute encephalopathy in FRALLE 93 trial for acute lymphoblastic leukemia in children

The objective of the study was to assess acute neurotoxicity associated with triple intrathecal therapy (TIT)+/-high-dose methotrexate (HD MTX) in children with acute lymphoblastic leukemia (ALL). 1395 children were enrolled on FRALLE 93 protocol from 1993 to 1999. Lower-risk group (LR, n=182) were randomized to weekly low-dose MTX at 25 mg/m(2)/week (LD MTX, n=81) or HD MTX at 1.5 g/m(2)/2 weeks x 6 (n=77). Intermediate-risk group (IR, n=672) were randomized to LD MTX (n=290) or HD MTX at 8 g/m(2)/2 weeks x 4 (n=316). Higher-risk group (HR, n=541) prednisone-responder patients received LD MTX and cranial radiotherapy. HR group steroid resistant cases were grafted (autologous or allogenic). TIT (MTX, cytarabine and methylprednisolone) was given every 2 weeks during 16-18 weeks and every 3 months during maintenance therapy in LR and IR patients. 52 patients (3.7%) developed neurotoxicity. Isolated seizures: n=15 (1.1%), peripheral and spinal neuropathy: n=17 (1.2%) and encephalopathy: n=20 (1.4%). Age >10 years was significantly associated with neurotoxicity (P=0.01) and use of HD MTX is associated with encephalopathy (P=0.03). Sequels are reported respectively in 60 and 33% of spinal neuropathy and encephalopathy cases. Current strategies tailoring risk of neurological sequels has to be defined.

Aprotinin to Improve Cerebral Outcome after Hypothermic Circulatory Arrest: A Study in a Surviving Porcine Model

BACKGROUND

Aprotinin is a serine protease inhibitor, which is usually used during cardiac surgery to reduce blood loss. There is evidence that aprotinin has neuroprotective effects during ischemia. We planned this study to evaluate its potential neuroprotective efficacy during hypothermic circulatory arrest (HCA).

METHODS

Twenty piglets with a median weight of 25.7 kg (interquartile range, 23.9-26.6) were randomly assigned to receive aprotinin or placebo prior to a 75-minute period of HCA at 18 degrees C. Brain microdialysis parameters and neurological and histological scores were the primary outcome measures.

RESULTS

Changes in brain metabolic parameters and histopathological findings were favorable in the aprotinin group. Brain lactate concentrations were significantly lower in the aprotinin group during the experiment (P = .02) along with blood lactate concentrations in the aprotinin group (P = .023). Brain glucose was significantly higher during the experiment (P = 0.02). Intracranial pressure tended to be higher in the control group. Two of 10 animals in the aprotinin group and 4 of 10 in the control group failed to reach full recovery on the seventh postoperative day. Four animals of 10 in the aprotinin group and 6 animals of 10 in the control group had brain infarction (P = .40).

CONCLUSIONS

The present data suggest that aprotinin mitigates cerebral damage and improves neurological outcome following a period of HCA.

Arguments for a lower carbohydrate-higher fat diet in patients with a short small bowel

Short small bowel patients suffer from malabsorption due to a strongly reduced small bowel surface. These patients usually get a high caloric high carbohydrate-low fat diet at oral or enteral feeding. At several points our studies demonstrate that the effect of this formula is doubtful. In these patients the intestinal flora has strongly been changed and even become characteristic due to abundant presence of lactobacilli (up to nearly 100%). In many patients with a high carbohydrate-low fat diet these bacteria both produce massive amounts of d-lactic acid and gaseous CO2, and they destroy the primary bile acids that are necessary for uptake of lipids. Thus, they cause (i) an increased risk of D-lactic acidosis and D-lactic acid-associated encephalopathy, (ii) flatulence, abdominal pain and non-infectious diarrhoea, and (iii) low uptake of fat and lipophilic vitamins. It is argued that by gradually converting the diet to a low carbohydrate-high fat diet growth of the characteristic lactobacilli can be strongly reduced and so also the mentioned inconveniences.

Preventing hyponatremic encephalopathy: comparison of serum sodium and osmolality during operative hysteroscopy with 5.0% mannitol and 1.5% glycine distention media

STUDY OBJECTIVE

To determine whether isotonic 5.0% mannitol is superior to 1.5% glycine in preventing development of hyponatremic encephalopathy.

DESIGN

Prospective, comparative study (Canadian Task Force classification II=2).

SETTING

Gynecology department of a community hospital.

PATIENTS

One hundred twenty-two women undergoing operative hysteroscopy.

INTERVENTIONS

Eighteen blood serum chemical indicators analyzed preoperatively and postoperatively in 61 women undergoing operative hysteroscopy with 1. 5% glycine (group 1) were compared with those of 61 women having similar surgery with 5.0% mannitol (group 2). Fluid deficit (difference between input and output volume of distention fluid) was recorded, and differences between presurgical and postsurgical indicators of the two groups (mean difference score) were compared.

MEASUREMENTS AND MAIN RESULTS

Mean +/- SEM sodium difference scores of groups 1 and 2 were -1.73 +/- 0.42 mEq/L (range -7.00 to 2.00 mEq/L) and -5.04 +/- 1.07 mEq/L (range -36.00 to 3.00 mEq/L), respectively (p <0.01). Serum osmolality difference scores were -6. 88 +/- 1.36 mmol/L (range -13.00 to -1.00 mmol/L) and -1.87 +/- 0.35 mmol/L (range -3 to 15 mmol/L), respectively (p <0.01). Distention fluid deficits were 0.435 +/- 0.071 L (range 0-2.448 L) and 0.473 +/- 0.084 L (range 0-3.640 L), respectively (p = 0.862). Two women (3.4%) in group 1 and five (8.2%) in group 2 developed postoperative asymptomatic dilutional hyponatremia (p = 0.211), which was the only complication. Two of the five women in group 2 developed severe dilutional hyponatremia.

CONCLUSION

We found that 5.0% mannitol distention fluid produces greater postoperative dilutional hyponatremia than 1.5% glycine, but hypo-osmolality does not occur with mannitol. Its use should lessen the risk of hyponatremic encephalopathy.

Reinduction of hyponatremia improves survival in rats with myelinolysis-related neurologic symptoms

Brain myelinolysis occurs after excessive correction (delta SNa > 20 mEq/1/24 hours) of chronic hyponatremia. However, we showed recently that the mechanisms leading to brain myelinolysis remain reversible. Indeed, reinduction of the hyponatremia by water administration despite 12 hours of sustained excessive correction could prevent the development of demyelination in rats still asymptomatic at that time. Whether this therapeutic maneuver could be also beneficial to rats with preexisting myelinolysis-related neurologic symptoms is unknown. Therefore we evaluated here the effect of reinduction of the hyponatremia on the survival and on brain damage in rats presenting obvious neurologic symptoms after excessive correction of hyponatremia. After 3 days of severe hyponatremia induced by 2.5 D-glucose in water and continuous infusion of AVP, rats were submitted to a large correction (delta SNa approximately 30 mEq/l) by 2 i.p. injections of hypertonic saline given over 24 hours. In group I (n = 15) the rats developing neurologic symptoms during the first 24 hours of correction received one i.p. injection of distilled water which rapidly decreased the natremia to a final correction gradient <20 mEq/l/24 hour. In group II (n = 13, controls) the symptomatic rats were left permanently overcorrected. In group I, after water administration, the neurological manifestations were generally attenuated or disappeared. Seven of the 15 rats (47%) in this group survived up to day 10 with a mean survival time of 7.5 +/- 2 days, an outcome clearly improved as compared to group II (controls): only 1 of the 13 rats (7%, p < 0.03) was still alive on day 10 and the mean survival time was 3.3 +/- 2 days (p < 0.001) in this group II. The duration of the symptoms also influences the prognosis. In group I, in 9 rats the water administration was performed 4 hours after symptoms onset. These rats had a better outcome than the 6 rats with more sustained (8-10 hours) neurologic symptoms before water loading. Brain analysis in the 7 surviving rats of group I demonstrated demyelinating lesions in only 2 of them, suggesting the reversibility of the process even when neurologic manifestation developed. In conclusion, after exposure to an excessive correction of chronic hyponatremia, even when rats have developed myelinolysis-related neurologic symptoms, hypotonic fluids administration could improve survival and could prevent the subsequent development of brain myelinolysis.

Pathogenesis and prevention of hyponatremic encephalopathy

Hyponatremia is the most common in-hospital electrolyte abnormality, and it has recently become apparent that there are at least two hyponatremia-associated mechanisms that may induce brain injury. They are hyponatremic encephalopathy and brain damage associated with therapy. The diagnosis of hyponatremia is established easily at virtually no risk to the patient by evaluation of plasma electrolytes. Rapid and appropriate therapy with hypertonic NaCl is indicated prior to respiratory insufficiency to prevent brain damage.