MITOCHONDRIAL AND NEUROPROTECTIVE EFFECTS OF PHENELZINE RELATED TO SCAVENGING OF NEUROTOXIC LIPID PEROXIDATION PRODUCTS

Lipid peroxidation is a key contributor to the pathophysiology of traumatic brain injury (TBI). Traditional antioxidant therapies are intended to scavenge the free radicals responsible for either the initiation or propagation of lipid peroxidation (LP). However, targeting free radicals after TBI is difficult as they rapidly react with other cellular macromolecules, and thus has a limited post-injury time window in which they may be intercepted by a radical scavenging agent. In contrast, our laboratory has begun testing an antioxidant approach that scavenges the final stages of LP i.e. formation of carbonyl-containing breakdown products. By scavenging breakdown products such as the highly reactive and neurotoxic aldehydes (often referred to as “carbonyls”) 4-hydroxynonenal (4-HNE) and acrolein (ACR), we are able to prevent the covalent modification of cellular proteins that are largely responsible for posttraumatic neurodegeneration. Without intervention, carbonyl additions render cellular proteins non-functional which initiates the loss of ionic homeostasis, mitochondrial failure, and subsequent neuronal death. Phenelzine (PZ) is an FDA-approved monoamine oxidase (MAO) inhibitor traditionally used for the treatment of depression. Phenelzine also possesses a hydrazine functional group capable of covalently binding neurotoxic carbonyls. The hypothesis of this dissertation is that carbonyl scavenging with PZ will exert an antioxidant neuroprotective effect in the traumatically injured rat brain mechanistically related to PZ’s hydrazine moiety reacting with the lipid peroxidation (LP)-derived reactive aldehydes 4-hydroxynonenal (4-HNE) and acrolein (ACR). Data from our ex vivo experiments demonstrate that the exogenous application of 4-HNE or ACR significantly reduced respiratory function and increased markers of oxidative damage in isolated non-injured rat cortical mitochondria, whereas PZ pre-treatment significantly prevented mitochondrial dysfunction and oxidative modification of mitochondrial proteins in a concentration-related manner. Additionally, PZ’s neuroprotective scavenging mechanism was confirmed to require the presence of a hydrazine moiety based on experiments with a structurally similar MAO inhibitor, pargyline, which lacks the hydrazine group and did not protect the isolated mitochondria from 4-HNE and ACR. Our in vivo work demonstrates that subcutaneous injections of PZ following TBI in the rat are able to significantly protect brain mitochondrial respiratory function, decrease markers of oxidative damage, protect mitochondrial calcium buffering capacity, and increase cortical tissue sparing without decreasing neuronal cytoskeletal spectrin degradation. These results confirm that PZ is capable of protecting mitochondrial function and providing neuroprotection after experimental TBI related to scavenging of neurotoxic LP degradation products

Human Brain Lipidomics: Utilities of Chloride Adducts in Flow Injection Analysis

Ceramides have been implicated in a number of disease processes. However, current means of evaluation with flow infusion analysis (FIA) have been limited primarily due to poor sensitivity within our high-resolution mass spectrometry lipidomics analytical platform. To circumvent this deficiency, we investigated the potential of chloride adducts as an alternative method to improve sensitivity with electrospray ionization. Chloride adducts of ceramides and ceramide subfamilies provided 2- to 50-fold increases in sensitivity both with analytical standards and biological samples. Chloride adducts of a number of other lipids with reactive hydroxy groups were also enhanced. For example, monogalactosyl diacylglycerols (MGDGs), extracted from frontal lobe cortical gray and subcortical white matter of cognitively intact subjects, were not detected as ammonium adducts but were readily detected as chloride adducts. Hydroxy lipids demonstrate a high level of specificity in that phosphoglycerols and phosphoinositols do not form chloride adducts. In the case of choline glycerophospholipids, the fatty acid substituents of these lipids could be monitored by MS2 of the chloride adducts. Monitoring the chloride adducts of a number of key lipids offers enhanced sensitivity and specificity with FIA. In the case of glycerophosphocholines, the chloride adducts also allow determination of fatty acid substituents. The chloride adducts of lipids possessing electrophilic hydrogens of hydroxyl groups provide significant increases in sensitivity. In the case of glycerophosphocholines, chloride attachment to the quaternary ammonium group generates a dominant anion, which provides the identities of the fatty acid substituents under MS2 conditions

Cognition based bTBI mechanistic criteria; a tool for preventive and therapeutic innovations

Blast-induced traumatic brain injury has been associated with neurodegenerative and neuropsychiatric disorders. To date, although damage due to oxidative stress appears to be important, the specific mechanistic causes of such disorders remain elusive. Here, to determine the mechanical variables governing the tissue damage eventually cascading into cognitive deficits, we performed a study on the mechanics of rat brain under blast conditions. To this end, experiments were carried out to analyse and correlate post-injury oxidative stress distribution with cognitive deficits on a live rat exposed to blast. A computational model of the rat head was developed from imaging data and validated against in vivo brain displacement measurements. The blast event was reconstructed in silico to provide mechanistic thresholds that best correlate with cognitive damage at the regional neuronal tissue level, irrespectively of the shape or size of the brain tissue types. This approach was leveraged on a human head model where the prediction of cognitive deficits was shown to correlate with literature findings. The mechanistic insights from this work were finally used to propose a novel helmet design roadmap and potential avenues for therapeutic innovations against blast traumatic brain injury

And Some, I Assume, Are Good People: A Closer Look At Hispanic Immigration And The Code Of The Street

Although research shows that increasing neighborhood levels of immigration tend to be associated with lower crime, little attention has been paid to why this is the case-- in essence what variables might help account for, or explain, these findings. Thus, the focus of this study is to explore a cultural explanation, specifically whether adherence to the code of the street helps to explain this relationship. Further, this study is looking to find the differences between immigrant generations as well as recent and established immigrants as it pertains to adherence to the code of the street. Using a random sample of 46 neighborhood clusters in El Paso, Texas, with merged survey and census data, the present research explores the relationship between a variety of neighborhood level measures of immigration and crime and to what extent the code of the street explains these relationships. The results and implications are discussed

And Some, I Assume, Are Good People: A Closer Look at Hispanic Immigration and the Code of the Street

Although research shows that increasing neighborhood levels of immigration tend to be associated with lower crime, little attention has been paid to why this is the case-- in essence what variables might help account for, or explain, these findings. Thus, the focus of this study is to explore a cultural explanation, specifically whether adherence to the code of the street helps to explain this relationship. Further, this study is looking to find the differences between immigrant generations as well as recent and established immigrants as it pertains to adherence to the code of the street. Using a random sample of 46 neighborhood clusters in El Paso, Texas, with merged survey and census data, the present research explores the relationship between a variety of neighborhood level measures of immigration and crime and to what extent the code of the street explains these relationships. The results and implications are discussed

Tear Film Amphiphilic and Anti-Inflammatory Lipids in Bovine Pink Eye

Background: Tear film fluid serves as a dynamic barrier that both lubricates the eye and protects against allergens and infectious agents. However, a detailed analysis of a bacteria-induced immune response on the tear film lipidome has not been undertaken. Methods: We undertook a high-resolution mass spectrometry lipidomics analysis of endogenous anti-inflammatory and structural tear film lipids in bovine pink eye. Results: Bovine pink eye resulted in dramatic elevations in tear fluid levels of the anti-inflammatory lipids resolvin E2, cyclic phosphatidic acid 16:0, and cyclic phosphatidic acid 18:0. In addition, there were elevated levels of the structural lipids (O-acyl)-ω-hydroxy-fatty acids, cholesterol sulfate, ethanolamine plasmalogens, and sphingomyelins. Lipid peroxidation also was augmented in pink eye as evidenced by the hydroperoxy derivatives of ethanolamine plasmalogens. Conclusions: Ocular infections with Moraxella bovis result in the induction of a number of endogenous anti-inflammatory lipids and augmentation of the levels of structural glycerophospholipids and sphingolipids. Increased levels of hydroperoxy glycerophospholipids also indicate that this bacterial infection results in lipid peroxidation

Reduced plasma levels of very-long-chain dicarboxylic acid 28:4 in italian and brazilian colorectal cancer patient cohorts

Background: There are currently no blood-based biomarkers for early diagnosis of colorectal cancer. Previous research has suggested that very-long-chain dicarboxylic acid (VLCDCA) 28:4 might be such a biomarker. Methods: Using high-resolution mass spectrometry, we analyzed VLCDCA 28:4 in the plasma of colorectal cancer patients in Italian [n = 62] and Brazilian [n = 52] cohorts. Additionally, we investigated individuals diagnosed with familial adenomatous polyposis (FAP; n = 27), one of the most important clinical forms of inherited susceptibility to colorectal cancer. Results: Decrements in plasma levels of VLCDCA 28:4 were monitored in colorectal cancer patients. These decreases were independent of the stage of tumor development and the individual’s age. However, no decrements in VLCDCA 28:4 were monitored in FAP patients. Conclusions: The plasma levels of VLCDCA 28:4 represent a potential biomarker of sporadic colorectal cancer. In addition, it is possible that resupply of this anti-inflammatory lipid may represent a new therapeutic strategy for CRC and inflammatory disorders

Reduced Plasma Levels of Very-Long-Chain Dicarboxylic Acid 28:4 in Italian and Brazilian Colorectal Cancer Patient Cohorts

Background: There are currently no blood-based biomarkers for early diagnosis of colorectal cancer. Previous research has suggested that very-long-chain dicarboxylic acid (VLCDCA) 28:4 might be such a biomarker. Methods: Using high-resolution mass spectrometry, we analyzed VLCDCA 28:4 in the plasma of colorectal cancer patients in Italian [n = 62] and Brazilian [n = 52] cohorts. Additionally, we investigated individuals diagnosed with familial adenomatous polyposis (FAP; n = 27), one of the most important clinical forms of inherited susceptibility to colorectal cancer. Results: Decrements in plasma levels of VLCDCA 28:4 were monitored in colorectal cancer patients. These decreases were independent of the stage of tumor development and the individual’s age. However, no decrements in VLCDCA 28:4 were monitored in FAP patients. Conclusions: The plasma levels of VLCDCA 28:4 represent a potential biomarker of sporadic colorectal cancer. In addition, it is possible that resupply of this anti-inflammatory lipid may represent a new therapeutic strategy for CRC and inflammatory disorders