Elevated plasma homocysteine concentration in elderly patients with mental illness is mainly related to the presence of vascular disease and not the diagnosis

Hyperhomocysteinemia-Induced Oxidative Stress Exacerbates Cortical Traumatic Brain Injury Outcomes in Rats

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality among military service members and civilians in the United States. Despite significant advances in the understanding of TBI pathophysiology, several clinical reports indicate that multiple genetic and epigenetic factors can influence outcome. Homocysteine (HCY) is a non-proteinogenic amino acid, the catabolism of which can be dysregulated by stress, lifestyle, aging, or genetic abnormalities leading to hyperhomocysteinemia (HHCY). HHCY is a neurotoxic condition and a risk factor for multiple neurological and cardiovascular disorders that occurs when HCY levels is clinically > 15 µM. Although the deleterious impact of HHCY has been studied in human and animal models of neurological disorders such as stroke, Alzheimer's disease and Parkinson's disease, it has not been addressed in TBI models. This study tested the hypothesis that HHCY has detrimental effects on TBI pathophysiology. Moderate HHCY was induced in adult male Sprague Dawley rats via daily administration of methionine followed by impact-induced traumatic brain injury. In this model, HHCY increased oxidative stress, upregulated expression of proteins that promote blood coagulation, exacerbated TBI-associated blood-brain barrier dysfunction and promoted the infiltration of inflammatory cells into the cortex. We also observed an increase of brain injury-induced lesion size and aggravated anxiety-like behavior. These findings show that moderate HHCY exacerbates TBI outcomes and suggest that HCY catabolic dysregulation may be a significant biological variable that could contribute to TBI pathophysiology heterogeneity.

Rebuilding Microbiome for Mitigating Traumatic Brain Injury: Importance of Restructuring the Gut-Microbiome-Brain Axis

Traumatic brain injury (TBI) is a damage to the brain from an external force that results in temporary or permanent impairment in brain functions. Unfortunately, not many treatment options are available to TBI patients. Therefore, knowledge of the complex interplay between gut microbiome (GM) and brain health may shed novel insights as it is a rapidly expanding field of research around the world. Recent studies show that GM plays important roles in shaping neurogenerative processes such as blood-brain-barrier (BBB), myelination, neurogenesis, and microglial maturation. In addition, GM is also known to modulate many aspects of neurological behavior and cognition; however, not much is known about the role of GM in brain injuries. Since GM has been shown to improve cellular and molecular functions via mitigating TBI-induced pathologies such as BBB permeability, neuroinflammation, astroglia activation, and mitochondrial dysfunction, herein we discuss how a dysbiotic gut environment, which in fact, contributes to central nervous system (CNS) disorders during brain injury and how to potentially ward off these harmful effects. We further opine that a better understanding of GM-brain (GMB) axis could help assist in designing better treatment and management strategies in future for the patients who are faced with limited options.

Elevated plasma homocysteine level in vascular dementia reflects the vascular disease process

Background

Patients with vascular dementia (VaD) exhibit particularly elevated levels of plasma total homocysteine (tHcy) compared to patients with other psychogeriatric diseases.

Methods

We investigated the main determinants (age, renal impairment, cobalamin/folate status and presence of extracerebral vascular disease) of plasma tHcy in 525 patients with VaD. Furthermore, 270 patients with depression were used as a reference group to reveal the potential specificity of elevated plasma tHcy in patients with VaD.

Results

Elevated plasma tHcy levels in patients with VaD could only partly be attributed to cobalamin/folate deficiency or renal impairment. Plasma tHcy might also be related to the vascular disease process since patients with depression and vascular disease exhibited similar plasma tHcy levels to patients with VaD.

Conclusion

Our findings suggest that elevated plasma tHcy might be a sensitive marker for the vascular disease process in patients with VaD and that the level also is a reflection of changes in the other main determinants of plasma tHcy.

Elevated plasma homocysteine level is not primarily related to Alzheimer's disease

BACKGROUND

A moderate elevation of plasma total homocysteine (tHcy) is considered a potential risk factor for Alzheimer's disease (AD).

METHODS

We have investigated the main determinants (age, renal impairment, cobalamin/folate status and the presence of vascular disease) of plasma tHcy in 326 patients with AD, and also in 281 patients with mild cognitive impairment (MCI), since about half of these patients develop AD during the first 5 years.

RESULTS

Elevated plasma tHcy in patients with AD could mainly be attributed to cobalamin/folate deficiency or renal impairment. Younger patients (below 75 years) with AD and patients with MCI without cobalamin/folate deficiency or renal impairment showed normal levels of plasma tHcy.

CONCLUSION

Our findings suggest that plasma tHcy is not primarily involved in the pathogenesis of AD but rather a reflection of changes of the main determinants of plasma tHcy in AD patients.

Survival in a large elderly population of patients with dementia and other forms of psychogeriatric diseases

BACKGROUND

Dementia and other psychogeriatric diseases in elderly patients bring an increased risk of death. Better knowledge of prognosis in elderly patients affected by dementia or mental illness should be of great importance in order to improve care plans and assist in medical decisions.

METHODS

We have investigated the survival time in 2,112 patients with dementia and other forms of psychogeriatric diseases, enrolled during 1990 to 2005 and followed up until 2009, and the influence of diagnoses, plasma homocysteine level, presence of vascular disease and renal impairment.

RESULTS

The survival time after diagnosis in most diagnostic groups is about a third compared to an average population of similar age and sex. Age was the main predictor of survival time in all patients.

CONCLUSIONS

All diagnoses, except in patients with subjective cognitive impairments, showed an increased mortality. These estimates can be used for prognosis and planning for patients, carers, service providers and policy makers.

The use of N-terminal pro-brain natriuretic Peptide to evaluate vascular disease in elderly patients with mental illness

Background

Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) is regarded as a sensitive marker of cardiovascular disease. Vascular disease plays an important role in cognitive impairment.

Method

In 447 elderly patients with mental illness, serum NT-proBNP level and the presence or absence of vascular disease according to the medical record were used to categorize patients in different subgroups of vascular disease.

Results and Conclusion

Patients with vascular disease and elevated serum NT-proBNP level had a lower cognition level, shorter survival time, lower renal function and a higher percentage of pathological brain imaging than patients with vascular disease and normal NT-proBNP level. Thus, elevated serum NT-proBNP level might be helpful to detect patients who have a more severe cardiovascular disease.

Plasma homocysteine, apolipoprotein E status and vascular disease in elderly patients with mental illness

BACKGROUND

Total plasma homocysteine (tHcy) concentration is increased in elderly patients with mental illness. Also, patients with vascular disease have significantly higher plasma tHcy concentration compared with patients without vascular disease. Apolipoprotein E (apoE) status is associated with cardiovascular disease and a major genetic risk factor is inheritance of the e4 allele. In the present study, we investigated the association between plasma tHcy and apoE status.

METHODS

The relation between apoE status, plasma tHcy and vascular disease was investigated in a cohort of consecutively enrolled elderly patients with mental illness (n=328).

RESULTS

Plasma tHcy concentrations were increased (p<0.01) in carriers of APOE4 (13.6 micromol/L; 9.2-21.7 micromol/L) compared to non-carriers (12.4 micromol/L; 8.3-19.9 micromol/L). The proportion of patients with vascular disease was significantly (p<0.001) increased among carriers (61%) compared to non-carriers (42%). An increased percentage (p<0.001) of APOE4 carriers was observed in patients with Alzheimer's disease (AD) with (71%) or without vascular disease (42%), and in patients with vascular dementia (VaD) (54%) compared to a reference group (34%).

CONCLUSIONS

Since carriers of APOE4 showed an increased likelihood of vascular disease, these patients need more intensive control of other modifiable vascular risk factors. Furthermore, the association between plasma tHcy and the presence of APOE4 might be attributed to an increased proportion of vascular disease in APOE4 carriers.

Cognitive impairment after cerebrovascular stroke: Relationship to vascular risk factors

BACKGROUND

Cognitive decline after cerebrovascular stroke has adverse outcome consequences. Since some vascular causes can be prevented and treated, the identification of stroke-related cognitive impairment is a challenge. Patients with cognitive impairment and vascular diseases exhibit higher homocysteine (Hcy) concentrations. Whether Hcy is an independent risk factor for cognitive impairment after stoke is still in question. The objectives of this study were to determine: 1) the relative frequency of first-ever post-stroke dementia (PSD) (three months after onset) in a consecutive sample of our population, 2) the risk factors associated with PSD, and 3) the relationship between Hcy levels and PSD.

METHODS

Eighty-one inpatients with first-ever stroke were prospectively evaluated with a neuropsychological battery and event-related evoked potentials (P300) at onset and then after three months. A wide range of demographic, clinical, radiological and laboratory variables were examined. PSD was diagnosed if the clinical presentation fulfilled DSM-IV criteria of vascular dementia, the patient scored </=21 on Mini Mental State Examination (MMSE) and </=67 points on Cognitive Abilities Screening Instruments (CASI).

RESULTS

PSD was diagnosed in 21%. PSD was significantly associated with increasing age, low levels of education, large sized and lacunar infarctions, severity of stroke, prolonged P300 latency, smoking, hypertension, and elevated Hcy levels. High Hcy levels increased the odds ratio of PSD after adjustment of significantly relevant variables including age, smoking, size of infarction, and carotid stenosis.

CONCLUSIONS

Cognitive decline is common after stroke. The results of this study indicate that PSD may result from stroke and its related risk factors including possible direct association with high Hcy levels. Better knowledge of the risk factors for PSD should increase the effectiveness of preventive strategies in patients with this condition.

Is major depressive disorder a metabolic encephalopathy?

Metabolic encephalopathy is an acute disturbance in cellular metabolism in the brain evoked by conditions of hypoxia, hypoglycaemia, oxidative stress and/or inflammation. It usually develops acutely or subacutely and is reversible if the systemic disorder is treated. If left untreated, however, metabolic encephalopathy may result in secondary structural damage to the brain. Most encephalopathies are present with neuropsychiatric symptoms, one in particular being depression. However, mood disorders are often co-morbid with cardiovascular, liver, kidney and endocrine disorders, while increasing evidence concurs that depression involves inflammatory and neurodegenerative processes. This would suggest that metabolic disturbances resembling encephalopathy may underscore the basic neuropathology of depression at a far deeper level than currently realized. Viewing depression as a form of encephalopathy, and exploiting knowledge gleaned from our understanding of the neurochemistry and treatment of metabolic encephalopathy, may assist in our understanding of the neurobiology of depression, but also in realizing new ideas in the pharmacotherapy of mood disorders.