Development and internal validation of a prognostic model for loss of balance and falls in mid- to late-stage Parkinson's disease

BACKGROUND

Mid- to late-stage Parkinson's disease (PD) is often linked with worsened and significant impairment of motor activities, but existing prognostic markers do not adequately capture the risk of loss of balance in PD patients. This study aims to develop a risk prognostic model for mid- to late-stage PD and identify prognostic factors that are indicative of impending loss of balance and falls.

METHODS

The study included 307 participants of which 75 were diagnosed with idiopathic PD and 232 were neurological or non-neurological controls. Among the PD group, 46 were early-stage (Hoehn and Yahr [H&Y] = 1,2) with no significant loss of balance while 29 were mid- to late-stage (H&Y = 3,4,5) which is characterized by loss of balance and falls. Multivariable logistic regression (MLR) was used to develop a prognostic model for mid- to late-stage PD. Model discrimination was assessed by ROC curves. The model was internally validated through bootstrapping and calibration plots.

RESULTS

The relevant factors identified and included in the final MLR model were shortness of breath, age, swollen joints, heme oxygenase-1 (HO-1) protein, and total salivary protein. The model had an AUC of 0.82 (95% CI = 0.71-0.92) and was well calibrated (calibration slope = 0.77, intercept = 0.03). The likelihood of shortness of breath (OR = 7.91, 95% CI = 1.63-45.12) was significantly higher among mid- to late-stage PD than early-stage. Age and total salivary protein were also significantly higher among mid- to late-stage PD.

CONCLUSION

The MLR prognostic model for mid- to late-stage PD may assist physicians in identifying patients at high risk for loss of balance and falls.

Craniofacial anomalies in schizophrenia-relevant GFAP.HMOX10-12m mice

Subtle craniofacial dysmorphology has been reported in schizophrenia patients. This dysmorphology includes midline facial elongation, frontonasal anomalies and a sexually dimorphic deviation from normal directional asymmetry of the face, with male patients showing reduced and female patients showing enhanced facial asymmetry relative to healthy control subjects. GFAP.HMOX10-12m transgenic mice (Mus musculus) that overexpress heme oxygenase-1 in astrocytes recapitulate many schizophrenia-relevant neurochemical, neuropathological and behavioral features. As morphogenesis of the brain, skull and face are highly interrelated, we hypothesized that GFAP.HMOX10-12m mice may exhibit craniofacial anomalies similar to those reported in persons with schizophrenia. We examined craniofacial anatomy in male GFAP.HMOX10-12m mice and wild-type control mice at the early adulthood age of 6-8 months. We used computer vision techniques for the extraction and analysis of mouse head shape parameters from systematically acquired 2D digital images, and confirmed our results with landmark-based geometric morphometrics. We performed skull bone morphometry using digital calipers to take linear distance measurements between known landmarks. Relative to controls, adult male GFAP.HMOX10-12m mice manifested craniofacial dysmorphology including elongation of the nasal bones, alteration of head shape anisotropy and reduction of directional asymmetry in facial shape features. These findings demonstrate that GFAP.HMOX10-12m mice exhibit craniofacial anomalies resembling those described in schizophrenia patients, implicating heme oxygenase-1 in their development. As a preclinical mouse model, GFAP.HMOX10-12m mice provide a novel opportunity for the study of the etiopathogenesis of craniofacial and other anomalies in schizophrenia and related disorders.

Salivary Heme Oxygenase-1: A Potential Biomarker for Central Neurodegeneration

BACKGROUND

Parkinson disease (PD) is the second most common neurodegenerative disease, affecting 2% of the population over 65 years of age. PD diagnosis is based on clinical examination and can only be confirmed during autopsy. In 2018, we reported that heme oxygenase-1 (HO-1), an inducible stress response protein important for heme catabolism and implicated in PD pathology, was higher in PD saliva relative to healthy controls, suggesting that salivary HO-1 may serve as a potential biomarker of PD.

OBJECTIVES

To ascertain whether HO-1 protein levels are elevated in PD saliva relative to degenerative neurological, non-degenerative neurological and healthy controls.

METHODOLOGY

The study included 307 participants comprising 75 participants with idiopathic PD and 3 control groups: 162 non-neurological, 37 non-PD degenerative neurological, and 33 non-degenerative neurological participants. Salivary HO-1 and total protein concentrations were measured using ELISA and BCA assay, respectively. Receiver operating characteristic (ROC) curves were used to estimate model discrimination. Analyses were adjusted by age, sex, total protein, and relevant comorbidities.

RESULTS

Elevated HO-1 concentrations were observed in the PD group and other neurodegenerative conditions compared to subjects with no neurological or non-degenerative neurological conditions. ROC curves using HO-1 levels and covariates yielded areas under the curve above 85% in models for PD or neurodegenerative conditions versus controls.

CONCLUSIONS

Salivary HO-1 concentrations in combination with covariates may provide a biomarker signature that distinguishes patients with neurodegenerative conditions from persons without.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that salivary HO-1 multivariable models can distinguish neurodegenerative conditions.

Characterization and heme oxygenase-1 content of extracellular vesicles in human biofluids

Heme oxygenase-1 (HO-1), a highly inducible stress protein that degrades heme to biliverdin, carbon monoxide, and free ferrous iron, is increased in blood and other biofluids of subjects with various systemic and neurological disorders. HO-1 does not contain an N-terminal signal peptide and the mechanism responsible for its secretion remains unknown. Extracellular vesicles (EVs) are membrane-bound inclusions that transport microRNAs, messenger RNAs, lipids, and proteins among diverse cellular and extracellular compartments. The objective of the current study was to determine whether EVs in human biofluids contain HO-1, and whether the latter may be transported in EVs from brain to periphery. Total, L1 cell adhesion molecule protein (L1CAM)-enriched (neuron-derived), and glutamate aspartate transporter 1 (GLAST)-enriched (astrocyte-derived) EVs were purified from five different human biofluids (saliva [n = 40], plasma [n = 14], serum [n = 10], urine [n = 10], and cerebrospinal fluid [n = 11]) using polymer precipitation and immuno-affinity-based capture methods. L1CAM-enriched, GLAST-enriched, and L1CAM/GLAST-depleted (LGD) EV, along with EV-depleted (EVD), fractions were validated by nanoparticle tracking analysis, enzyme-linked immunosorbent assay (ELISA), and western blot. HO-1 was assayed in all fractions using ELISA and western blot. The majority of HO-1 protein was localized to LGD, L1CAM-enriched, and GLAST-enriched EVs of all human biofluids surveyed after adjusting for age and sex, with little HO-1 protein detected in EVD fractions. HO-1 protein in human biofluids is predominantly localized to EV compartments. A substantial proportion of EV HO-1 in peripheral human biofluids is derived from the central nervous system and may contribute to the systemic manifestations of various neurological conditions.

Strategic Timing of Glial HMOX1 Expression Results in Either Schizophrenia-Like or Parkinsonian Behavior in Mice

Aims: In this original research communication, we assess the impact of shifting the window of glial HMOX1 overexpression in mice from early-to-midlife to mid-to-late life, resulting in two disparate conditions modeling schizophrenia (SCZ) and Parkinson's disease (PD). Mesolimbic hyperdopaminergia is a widely accepted feature of SCZ, while nigrostriatal hypodopaminergia is the sine qua non of idiopathic PD. Although the advent of parkinsonian features in SCZ patients after treatment with antidopaminergic agents is intuitive, subtle features of parkinsonism commonly observed in young, drug-naïve schizophrenics are not. Similarly, emergent psychosis in PD subjects receiving levodopa replacement is not unusual, whereas spontaneous hallucinosis in nonmedicated persons with idiopathic PD is enigmatic. Investigations using GFAP.HMOX1 mice may shed light on these clinical paradoxes. Results: Astroglial heme oxygenase-1 (HO-1) overexpression in mice throughout embryogenesis until 6 or 12 months of age resulted in hyperdopaminergia, hyperkinesia/stereotypy ameliorated with clozapine, deficient prepulse inhibition of the acoustic startle response, reduced preference for social novelty, impaired nest building, and cognitive dysfunction reminiscent of SCZ. On the contrary, astroglial HO-1 overexpression between 8.5 and 19 months of age yielded a PD-like behavioral phenotype with hypodopaminergia, altered gait, locomotor incoordination, and reduced olfaction. Innovation: We conjecture that region-specific disparities in the susceptibility of dopaminergic and other circuitry to the trophic and degenerative influences of glial HMOX1 induction may permit the concomitant expression of mixed SCZ and PD traits within affected individuals. Conclusion: Elucidation of these converging mechanisms may (i) help better understand disease pathogenesis and (ii) identify HO-1 as a potential therapeutic target in neurodevelopmental and neurodegenerative disorders.

Development and validation of a salivary tau biomarker in Alzheimer's disease

INTRODUCTION

Total tau (t-tau) and phosphorylated tau (p-tau) are abnormally elevated in the brain and cerebrospinal fluid of individuals with Alzheimer's disease (AD). Tau is also present in the salivary gland tissue and saliva, and salivary measures might produce an accurate, accessible, and inexpensive biomarker.

METHODS

Using unstimulated saliva and Western blot analysis, we quantified the p-tau/t-tau ratio at different phosphorylation sites.

RESULTS

We found that for one phosphorylation site, S396, p-tau/t-tau ratio was significantly elevated in patients with AD compared with normal elderly control subjects. The elevation in saliva, however, did not correlate with cerebrospinal fluid tau or with brain measures such as hippocampal volume.

DISCUSSION

There is significant elevation of p-tau/t-tau ratio for the S396 phosphorylation site. Large variation in the AD salivary tau levels, however, limits the utility of this test as a clinical biomarker.

Glial HMOX1 expression promotes central and peripheral α-synuclein dysregulation and pathogenicity in parkinsonian mice

α-Synuclein is a key player in the pathogenesis of Parkinson disease (PD). Expression of human heme oxygenase-1 (HO-1) in astrocytes of GFAP.HMOX1 transgenic (TG) mice between 8.5 and 19 months of age results in a parkinsonian phenotype characterized by neural oxidative stress, nigrostriatal hypodopaminergia associated with locomotor incoordination, and overproduction of α-synuclein. We identified two microRNAs (miR-), miR-153 and miR-223, that negatively regulate α-synuclein in the basal ganglia of male and female GFAP.HMOX1 mice. Serum concentrations of both miRNAs progressively declined in the wild-type (WT) and GFAP.HMOX1 mice between 11 and 19 months of age. Moreover, at each time point surveyed, circulating levels of miR-153 were significantly lower in the TG animals compared to WT controls, while α-synuclein protein concentrations were elevated in erythrocytes of the GFAP.HMOX1 mice at 19 months of age relative to WT values. Primary WT neurons co-cultured with GFAP.HMOX1 astrocytes exhibited enhanced protein oxidation, mitophagy and apoptosis, aberrant expression of genes regulating the dopaminergic phenotype, and an imbalance in gene expression profiles governing mitochondrial fission and fusion. Many, but not all, of these neuronal abnormalities were abrogated by small interfering RNA (siRNA) knockdown of α-synuclein, implicating α-synuclein as a potent, albeit partial, mediator of HO-1's neurodystrophic effects in these parkinsonian mice. Overexpression of HO-1 in stressed astroglia has previously been documented in the substantia nigra of idiopathic PD and may promote α-synuclein production and toxicity by downmodulating miR-153 and/or miR-223 both within the CNS and in peripheral tissues.

Greater palatine block for V2 trigeminal neuralgia: Case report

AIMS

This study describes a novel nerve block directed at the maxillary (V2) division of the fifth cranial nerve as treatment for medication-refractory trigeminal neuralgia (TN).

METHODS AND RESULTS

The authors present three cases of TN treated with V2 nerve block using commonly available local anesthetics injected through the greater palatine foramen. Patients' medications were noted before and after the procedure. Following the injection, patients were followed over time and outcome was assessed. Patients experienced rapid and long-lasting pain relief allowing for significant reduction in antineuralgia medications. This was done with the objective of breaking the pain cycle with subsequent discontinuation or reduction of analgesic medications.

CONCLUSION

This technique may be an effective treatment for medication-refractory V2 TN. By interrupting the pain cycle, this renders the condition amenable to long-term control using diminished doses of standard antineuralgia pharmaceuticals. The practical implications of the described procedure are that it is simple, safe, and well-tolerated with few or no adverse effects. This novel technique is a diagnostic feature for the dentist to differentiate between sources of facial pain.

Dentate Gyrus Immaturity in Schizophrenia

Hippocampal abnormalities have been heavily implicated in the pathophysiology of schizophrenia. The dentate gyrus of the hippocampus was shown to manifest an immature molecular profile in schizophrenia subjects, as well as in various animal models of the disorder. In this position paper, we advance a hypothesis that this immature molecular profile is accompanied by an identifiable immature morphology of the dentate gyrus granule cell layer. We adduce evidence for arrested maturation of the dentate gyrus in the human schizophrenia-affected brain, as well as multiple rodent models of the disease. Implications of this neurohistopathological signature for current theory regarding the development of schizophrenia are discussed.

Evaluation of salivary heme oxygenase-1 as a potential biomarker of early Parkinson's disease

BACKGROUND AND HYPOTHESIS

To date, there are no chemical analytes, including biochemical indices of oxidative stress, metabolites of α-synuclein protein, and differential protein expression patterns on proteomic profiling, for use in clinics as a diagnostic biomarker of idiopathic PD.

OBJECTIVES

Heme oxygenase-1 has been implicated in the pathogenesis of PD. The objective of this study is to ascertain whether salivary heme oxygenase-1 may serve as a biomarker for early idiopathic PD.

METHODS

Fifty-eight PD patients and 59 non-neurological disease controls were recruited. Levels of heme oxygenase-1 expression were assayed using enzyme-linked immunosorbent assay and western blot analysis of whole, unstimulated saliva. Analyses were adjusted by sex, l-dopa exposure, and relevant comorbidities.

RESULTS

We documented: (1) the presence of 32-kDa heme oxygenase-1 protein in human saliva; (2) significantly higher mean heme oxygenase-1 protein concentrations in saliva of PD patients relative to control values; (3) no variability in salivary heme oxygenase-1 levels with sex, age, l-dopa equivalence, or comorbidities; and (4) significantly higher mean salivary heme oxygenase-1 concentrations in patients with H & Y stage 1 PD (early) than control subjects and stage 2 and stage 3 PD patients. The area under the receiver operating characteristic curve that separated controls from PD H & Y stage 1 was 76% (95% confidence interval: 63-90).

CONCLUSIONS

Salivary heme oxygenase-1 concentrations may provide a useful, noninvasive, and relatively inexpensive biomarker of early idiopathic PD. © 2018 International Parkinson and Movement Disorder Society.

Cysteine-rich whey protein isolate (Immunocal®) ameliorates deficits in the GFAP.HMOX1 mouse model of schizophrenia

Schizophrenia is a neuropsychiatric disorder that features neural oxidative stress and glutathione (GSH) deficits. Oxidative stress is augmented in brain tissue of GFAP.HMOX1 transgenic mice which exhibit schizophrenia-relevant characteristics. The whey protein isolate, Immunocal® serves as a GSH precursor upon oral administration. In this study, we treated GFAP.HMOX1 transgenic mice daily with either Immunocal (33mg/ml drinking water) or equivalent concentrations of casein (control) between the ages of 5 and 6.5 months. Immunocal attenuated many of the behavioral, neurochemical and redox abnormalities observed in GFAP.HMOX1 mice. In addition to restoring GSH homeostasis in the CNS of the transgenic mice, the whey protein isolate augmented GSH reserves in the brains of wild-type animals. These results demonstrate that consumption of whey protein isolate augments GSH stores and antioxidant defenses in the healthy and diseased mammalian brain. Whey protein isolate supplementation (Immunocal) may constitute a safe and effective modality for the management of schizophrenia, an unmet clinical imperative.

Astrocyte heme oxygenase-1 reduces mortality and improves outcome after collagenase-induced intracerebral hemorrhage

Pharmacotherapies that increase CNS expression of heme oxygenase-1 (HO-1) and other antioxidant proteins have improved outcome in experimental models of spontaneous intracerebral hemorrhage (ICH). In order to more specifically investigate the relationship between HO-1 and ICH outcome, mice expressing human HO-1 driven by the glial fibrillary acidic protein (GFAP) promoter (GFAP·HMOX1 mice) were tested in a model of in situ parenchymal hemorrhage. Injection of collagenase into the striata of wild-type (WT) mice resulted in a 26.3% mortality rate, with deaths equally distributed between males and females. Mortality was reduced to 4.48% in GFAP·HMOX1 mice. Cell viability in the injected striata of surviving WT mice was reduced by about half at one week and was significantly increased in transgenics; this benefit persisted over a 22day observation period. Cell counts guided by design-based stereology indicated loss of ~40% of neurons in WT hemorrhagic striata at one week, which was decreased by half in transgenics; no significant differences in microglia or astrocyte numbers were observed. Blood-brain barrier disruption and short-term neurological deficits were also mitigated in GFAP·HMOX1 mice, but long-term outcome did not differ from that of WT survivors. These results suggest that astrocyte HO-1 overexpression provides robust neuroprotection after acute intracerebral hemorrhage. Further investigation of drug or genetic therapies that selectively increase astrocyte HO-1 is warranted.

Assessing neuronal density in peri-infarct cortex with PET: Effects of cortical topology and partial volume correction

The peri-infarct cortex (PIC) is the site of long-term physiologic changes after ischemic stroke. Traditional methods for delineating the peri-infarct gray matter (GM) have used a volumetric Euclidean distance metric to define its extent around the infarct. This metric has limitations in the case of cortical stroke, i.e., those where ischemia leads to infarction in the cortical GM, because the vascularization of the cerebral cortex follows the complex, folded topology of the cortical surface. Instead, we used a geodesic distance metric along the cortical surface to subdivide the PIC into equidistant rings emanating from the infarct border and compared this new approach to a Euclidean distance metric definition. This was done in 11 patients with [F-18]-Flumazenil ([18-F]-FMZ) positron emission tomography (PET) scans at 2 weeks post-stroke and at 6 month follow-up. FMZ is a PET radiotracer with specific binding to the alpha subunits of the type A γ-aminobutyric acid (GABAA) receptor. Additionally, we used partial-volume correction (PVC) of the PET images to compensate for potential cortical thinning and long-term neuronal loss in follow-up images. The difference in non-displaceable binding potential (BPND ) between the stroke unaffected and affected hemispheres was 35% larger in the geodesic versus the Euclidean peri-infarct models in initial PET images and 48% larger in follow-up PET images. The inter-hemispheric BPND difference was approximately 17-20% larger after PVC when compared to uncorrected PET images. PET studies of peri-infarct GM in cortical strokes should use a geodesic model and include PVC as a preprocessing step. Hum Brain Mapp 38:326-338, 2017. © 2016 Wiley Periodicals, Inc.

Altered Levels of Salivary 8-oxo-7-hydrodeoxyguanosine in Breast Cancer

Oxidative stress has been implicated in the pathogenesis of breast cancer (BC). To determine whether BC is associated with altered salivary redox homeostasis, we performed a case-control study assessing the relationship between BC and 8-oxo-7-hydrodeoxyguanosine (8-oxodG), a marker for oxidative damage to DNA. Enzyme-linked immunosorbent assay for 8-oxodG was used on whole, unstimulated saliva of 134 BC patients and 226 healthy controls. Associations of the redox data were assessed by analysis of variance and logistic regression analysis. Our results revealed that there were 1) significantly lower mean levels of salivary 8-oxodG in BC patients versus controls ( P = 0.0005), 2) significantly lower levels among participants who did not receive radiotherapy and/or chemotherapy as compared with controls ( P < 0.0001), 3) significantly lower levels among BC patients who did not receive these treatments than among those who did ( P < 0.02), 4) and no significant differences in mean 8-oxodG levels among BC patients positive or negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 ( P ≥ 0.08). Our results suggest that BC is associated with decreased levels of oxidatively modified DNA in saliva. Knowledge Transfer Statement: The results of our current case-control study indicate that the molecular biomarker of oxidative stress 8-oxo-7-hydrodeoxyguanosine, measured from saliva, is associated with breast cancer. Our findings may provide the basis for future studies on molecular biomarkers of oxidative stress and breast cancer using saliva as an accessible and noninvasive tissue.

The Impact of Gonadal Hormones on the Expression of Human Neurological Disorders

The effects of gonadal steroids on neurological well-being and disease constitute a rich and rapidly expanding area of basic and clinical neuroscience. Gonadal hormones exert potent effects on monoaminergic, cholinergic and peptidergic pathways as well as neurosteroidogenesis which, in turn, impact normal brain organization and function. A spectrum of human neurological conditions are influenced by hormonal fluctuations associated with the menstrual cycle, pregnancy, the menopause and use of oral contraceptives. An appreciation of these relationships may facilitate the development of specific hormonal and anti-hormonal therapies for neurological disorders as disparate as catamenial epilepsy and acute intermittent porphyria.

Salivary biomarkers of oxidative stress: A critical review

Human saliva is an increasingly attractive medium for biomarker discovery due to its amenability to noninvasive and repeated sampling, ease of collection and processing, and suitability for single analyte or metabolomic measurements. Salivary biomarkers of oxidative stress reflect local and systemic pathologies and may inform on the diagnosis, prognosis, and therapeutic responsiveness of numerous human diseases. However, for many of the disorders investigated, data reporting on alterations in salivary redox homeostasis are often highly conflicted across studies. We surveyed the available biomedical literature on this topic and noted significant discrepancies in the study designs, target populations, and operating procedures which likely contribute to the discordant data sets reported. Based on these observations, guidelines are provided to minimize interlaboratory variability in redox biomarker discovery based on human saliva.

Heme oxygenase-1 modulates microRNA expression in cultured astroglia: implications for chronic brain disorders

BACKGROUND

Over-expression of the heme-degrading enzyme, heme oxygenase-1 (HO-1) promotes iron deposition, mitochondrial damage, and autophagy in astrocytes and enhances the vulnerability of nearby neuronal constituents to oxidative injury. These neuropathological features and aberrant brain microRNA (miRNA) expression patterns have been implicated in the etiopathogeneses of various neurodevelopmental and aging-related neurodegenerative disorders.

OBJECTIVE

To correlate glial HO-1 overexpression with altered miRNA patterns, which have been linked to the aforementioned "core" neuropathological features.

METHODS

miRNA microchip assays were performed on HMOX1- and sham-transfected primary rat astroglia and affected miRNAs were further validated by qPCR. The roles of the heme degradation products, carbon monoxide (CO), iron (Fe) and bilirubin on miRNA expression were assessed and salient mRNA targets of the impacted miRNAs were ascertained.

RESULTS

In HMOX1-transfected astrocytes, rno-miR-140*, rno-miR-17, and rno-miR-16 were significantly up-regulated, and rno-miR-297, rno-miR-206, rno-miR-187, rno-miR-181a, rno-miR-138 and rno-miR-29c were down-regulated, compared to sham-transfected controls. CO and Fe were implicated in the HMOX1 effects, whereas bilirubin was inert or counteracted the HMOX1-related changes. mRNA levels of Ngfr, Vglut1, Mapk3, Tnf-α, and Sirt1, known targets of the down-regulated miRNAs and abnormal in various human brain disorders, were significantly increased in the HMOX-1-transfected astrocytes.

CONCLUSIONS

In chronic CNS disorders, altered expression of salient miRNAs and their mRNA targets may contribute to the neural damage accruing from the over-expression of glial HO-1.

Astrocyte overexpression of heme oxygenase-1 improves outcome after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Heme oxygenase-1 (HO-1) catalyzes the rate-limiting reaction of heme breakdown and may have both antioxidant and pro-oxidant effects. In previous studies, HO-1 overexpression protected astrocytes from heme-mediated injury in vitro. In the present study, we tested the hypothesis that selective astrocyte overexpression of HO-1 improves outcome after intracerebral hemorrhage.

METHODS

Male and female transgenic mice overexpressing human HO-1 driven by the GFAP promoter (GFAP.HMOX1) and wild-type controls received striatal injections of autologous blood (25 μL). Blood-brain barrier disruption was assessed by Evans blue assay and striatal cell viability by methylthiazolyldiphenyl-tetrazolium bromide assay. Neurological deficits were quantified by digital analysis of spontaneous cage activity, adhesive removal, and elevated body swing tests.

RESULTS

Mortality rate for wild-type mice was 34.8% and was similar for males and females; all GFAP.HMOX1 mice survived. Striatal Evans blue leakage at 24 hours was 23.4±3.2 ng in surviving wild-type mice, compared with 10.9±1.8 ng in transgenics. Perihematomal cell viability was reduced to 61±4% of contralateral at 3 days in wild-type mice, versus 80±4% in transgenics. Focal neurological deficits were significantly reduced and spontaneous cage activity was increased in GFAP.HMOX1 mice.

CONCLUSIONS

Selective HO-1 overexpression in astrocytes reduces mortality, blood-brain barrier disruption, perihematomal cell injury, and neurological deficits in an autologous blood injection intracerebral hemorrhage model. Genetic or pharmacological therapies that acutely increase astrocyte HO-1 may be beneficial after intracerebral hemorrhage.

Plasma near-infrared spectroscopy for diagnosis of idiopathic Parkinson's disease: the SPIN-PD study

Aim: There are no established chemical biomarkers of idiopathic Parkinson's disease (PD). The results of a prior metabolomics-based biomarker study suggested that near-infrared spectroscopy of blood plasma samples may distinguish idiopathic PD from neurologically normal controls. Methods: Near-infrared spectroscopy was used to detect and quantify substrate modifications in blood plasma samples derived from 71 PD subjects enrolled in the PostCEPT observational study and 68 normal control subjects. Results: Near-infrared spectra values were significantly higher in the PD group compared with the control group when adjusted for age and gender (PD: adjusted mean 0.49 [95% CI: 0.45–0.53]; control: adjusted mean 0.40 [95% CI: 0.36–0.44]; p = 0.004, multiple regression). Conclusion: Near-infrared spectra of blood plasma in early-stage idiopathic PD differ from those of non-neurological control subjects. However, the degree of overlap between the groups limits the use of this technique in its present form as a PD biomarker for routine clinical practice.

Neural HO-1/sterol interactions in vivo: implications for Alzheimer's disease

BACKGROUND

Up-regulation of heme oxygenase-1 (HO-1) and altered cholesterol (CH) metabolism are characteristic of Alzheimer-diseased (AD) neural tissues. We previously provided evidence of significant HO-1/sterol interactions in vitro (cultured rat astroglia) and in post-mortem human AD brain (Religious Orders Study).

METHODS

The current experiments were designed to further delineate these interactions in vivo by comparing the behavior of HO-1/sterol interactions in two mouse models; (1) a novel HO-1 transgenic mouse (GFAP.HMOX1) engineered to selectively express human HO-1 in the astrocytic compartment and (2) the previously described triple transgenic AD mouse (3xTg-AD). In samples of frontal cortex, total CH, CH precursors and relevant oxysterols were quantified by gas chromatography-mass spectrometry (GC-MS) and HO-1 protein expression was assessed by ELISA. The relationships of HO-1 expression to total CH, CH precursors and total oxysterols were determined for both mouse models using linear regression analysis.

RESULTS

HO-1 expression is increased in GFAP.HMOX1 mice relative to wild type and in 11-12-month-old 3xTg-AD mice (with AD-like phenotype) relative to control mice and 5-6-month-old 3xTg-AD mice (no AD-like phenotype). Total oxysterols significantly decreased as HO-1 expression increased in GFAP.HMOX1 mice expressing high levels of HO-1, whereas total oxysterols increased as HO-1 expression increased in aged 3xTg-AD mice. Total CH and total CH precursors increased as HO-1 protein expression increased in 11-12-month-old 3xTg-AD mice relative to 5-6-month old 3xTg-AD mice.

CONCLUSIONS

Our findings indicate a differential impact of HO-1 on patterns of brain sterol and redox homeostasis that is contingent on the presence or absence of AD-like neuropathology. These data provide fresh insight concerning the regulation of sterol homeostasis within the aging and degenerating CNS which may inform the development of novel therapeutic and preventive strategies for the management of AD and related conditions.

Neurotherapeutic effects of novel HO-1 inhibitors in vitro and in a transgenic mouse model of Alzheimer's disease

Heme oxygenase-1 (HO-1) encoded by the HMOX1 gene is a 32-kDa stress protein that catabolizes heme to biliverdin, free iron, and carbon monoxide (CO). Glial HO-1 is over-expressed in the CNS of subjects with Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). The HMOX1 gene is exquisitely sensitive to oxidative stress and is induced in brain and other tissues in various models of disease and trauma. Induction of the glial HMOX1 gene may lead to pathological brain iron deposition, intracellular oxidative damage, and bioenergetic failure in AD and other human CNS disorders such as PD and MS. Therefore, targeted suppression of glial HO-1 hyperactivity may prove to be a rational and effective therapeutic intervention in AD and related neurodegenerative disorders. In this study, we report the effects of QC-47, QC-56, and OB-28, novel azole-based competitive and reversible inhibitors of HO-1, on oxidative damage to whole-cell and mitochondrial compartments in rat astrocytes transfected with the HMOX1 gene. We also report the effect of OB-28 on the behavior and neuropathology of APP(swe)/PS1(∆E9) mice. OB-28 was found to reduce oxidative damage to whole-cell and mitochondrial compartments in rat astrocytes transfected with the HMOX1 gene. Moreover, OB-28 was found to significantly counter behavioral deficits and neuropathological alterations in APP(swe)/PS1(∆E9) mice. Attenuation of AD-associated behavioral deficits and neuropathological changes suggests that HO-1 may be a promising target for neuroprotective intervention in AD and other neurodegenerative diseases. We propose that the targeted suppression of glial heme oxygenase-1 (HO-1) hyperactivity may prove to be a rational and effective therapeutic intervention in Alzheimer's disease (AD) and related neurodegenerative disorders. We report attenuation by a selective HO-1 inhibitor of oxidative damage to whole-cell and mitochondrial compartments in astrocytes in vitro and amelioration of behavioral anomalies in a transgenic mouse model of AD.

Increased microRNA-34c abundance in Alzheimer's disease circulating blood plasma

Circulating microRNAs, present either in the cellular component, peripheral blood mononuclear cells (PBMC), or in cell-free plasma, have emerged as biomarkers for age-dependent systemic, disease-associated changes in many organs. Previously, we have shown that microRNA (miR)-34a is increased in circulating PBMC of Alzheimer's disease (AD) patients. In the present study, we show that this microRNA's sister, miR-34c, exhibits even greater increase in both cellular and plasma components of AD circulating blood samples, compared to normal age-matched controls. Statistical analysis shows the accuracy of levels of miR-34c assayed by receiver operating characteristic (ROC) analysis: the area under the curve is 0.99 (p < 0.0001) and the 95% confidence level extends from 0.97 to 1. Pearson correlation between miR-34c levels and mild and moderate AD, as defined by the mini-mental state examination (MMSE), shows an r-value of −0.7, suggesting a relatively strong inverse relationship between the two parameters. These data show that plasma levels of microRNA 34c are much more prominent in AD than those of its sister, miR-34a, or than its own level in PBMC. Transfection studies show that miR-34c, as does its sister miR-34a, represses the expression of several selected genes involved in cell survival and oxidative defense pathways, such as Bcl2, SIRT1, and others, in cultured cells. Taken together, our results indicate that increased levels of miR-34c in both PBMC and plasma may reflect changes in circulating blood samples in AD patients, compared to age-matched normal controls.

Biomarker potential of heme oxygenase-1 in Alzheimer's disease and mild cognitive impairment

The advent of an accessible chemical biological marker that differentiates early, sporadic Alzheimer's disease (AD) from normal aging and other dementing illnesses, and identifies individuals with mild cognitive impairment who are destined to deteriorate to Alzheimer's dementia, would represent a major achievement in the evaluation and management of this common neurodegenerative disorder. Although several candidate biomarkers of sporadic AD have been identified and commercialized, none currently fulfill the criteria for an ideal test. In this article, we review evidence implicating blood heme oxygenase-1 mRNA/protein levels and a recently identified plasma heme oxygenase-1 suppressor factor as potential biomarkers of AD and mild cognitive impairment.

Unregulated brain iron deposition in transgenic mice over-expressing HMOX1 in the astrocytic compartment

The mechanisms responsible for pathological iron deposition in the aging and degenerating mammalian CNS remain poorly understood. The stress protein, HO-1 mediates the degradation of cellular heme to biliverdin/bilirubin, free iron, and CO and is up-regulated in the brains of persons with Alzheimer's disease and Parkinson's disease. HO-1 induction in primary astroglial cultures promotes deposition of non-transferrin iron, mitochondrial damage and macroautophagy, and predisposes cocultured neuronal elements to oxidative injury. To gain a better appreciation of the role of glial HO-1 in vivo, we probed for aberrant brain iron deposition using Perls' method and dynamic secondary ion mass spectrometry in novel, conditional GFAP.HMOX1 transgenic mice that selectively over-express human HO-1 in the astrocytic compartment. At 48 weeks, the GFAP.HMOX1 mice exhibited increased deposits of glial iron in hippocampus and other subcortical regions without overt changes in iron-regulatory and iron-binding proteins relative to age-matched wild-type animals. Dynamic secondary ion mass spectrometry revealed abundant FeO⁻ signals in the transgenic, but not wild-type, mouse brain that colocalized to degenerate mitochondria and osmiophilic cytoplasmic inclusions (macroautophagy) documented by TEM. Sustained up-regulation of HO-1 in astrocytes promotes pathological brain iron deposition and oxidative mitochondrial damage characteristic of Alzheimer's disease-affected neural tissues. Curtailment of glial HO-1 hyperactivity may limit iron-mediated cytotoxicity in aging and degenerating neural tissues.

Altered redox homeostasis in human diabetes saliva

BACKGROUND

Oxidative stress has been implicated in the pathogenesis of diabetes mellitus (DM). Levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-epi-prostaglandin-F(2α) (8-epi-PGF2α), and total protein carbonyls were measured to assess whether DM is associated with altered salivary redox homeostasis.

METHODS

A total of 215 patients with diabetes and 481 healthy controls were recruited from the Department of Endocrinology at the Jewish General Hospital in Montreal. Levels of oxidative biomarkers were assayed using enzyme-linked immunosorbent assay (ELISA) in whole unstimulated saliva. Associations of the redox data with exposure to insulin, metformin and dietary control were assessed by logistic regression analyses.

RESULTS

We observed (i) significantly higher mean levels of 8-OHdG and protein carbonyls in whole unstimulated saliva of patients with diabetes compared to controls, (ii) higher mean levels of protein carbonyls in type 1 diabetes as well as higher mean levels of 8-OHdG and protein carbonyls in type 2 diabetes compared to controls, (iii) elevated levels of protein carbonyls in diet-controlled patients and in patients with diabetes on insulin and metformin, (iv) elevated levels of 8-OHdG in patients on metformin, and (v) significant associations between subjects with DM and salivary 8-OHdG and protein carbonyls.

CONCLUSION

DM is associated with increased oxidative modification of salivary DNA and proteins. Salivary redox homeostasis is perturbed in DM and may inform on the presence of the disease and efficacy of therapeutic interventions.

MicroRNA: Implications for Alzheimer Disease and other Human CNS Disorders

Understanding complex diseases such as sporadic Alzheimer disease (AD) has been a major challenge. Unlike the familial forms of AD, the genetic and environmental risks factors identified for sporadic AD are extensive. MicroRNAs are one of the major noncoding RNAs that function as negative regulators to silence or suppress gene expression via translational inhibition or message degradation. Their discovery has evoked great excitement in biomedical research for their promise as potential disease biomarkers and therapeutic targets. Key microRNAs have been identified as essential for a variety of cellular events including cell lineage determination, proliferation, apoptosis, DNA repair, and cytoskeletal organization; most, if not all, acting to fine-tune gene expression at the post-transcriptional level in a host of cellular signaling networks. Dysfunctional microRNA-mediated regulation has been implicated in the pathogenesis of many disease states. Here, the current understanding of the role of miRNAs in the central nervous system is reviewed with emphasis on their impact on the etiopathogenesis of sporadic AD.

Neurodegeneration with brain iron accumulation - clinical syndromes and neuroimaging

Iron participates in a wide array of cellular functions and is essential for normal neural development and physiology. However, if inappropriately managed, the transition metal is capable of generating neurotoxic reactive oxygen species. A number of hereditary conditions perturb body iron homeostasis and some, collectively referred to as neurodegeneration with brain iron accumulation (NBIA), promote pathological deposition of the metal predominantly or exclusively within the central nervous system (CNS). In this article, we discuss seven NBIA disorders with emphasis on the clinical syndromes and neuroimaging. The latter primarily entails magnetic resonance scanning using iron-sensitive sequences. The conditions considered are Friedreich ataxia (FA), pantothenate kinase 2-associated neurodegeneration (PKAN), PLA2G6-associated neurodegeneration (PLAN), FA2H-associated neurodegeneration (FAHN), Kufor-Rakeb disease (KRD), aceruloplasminemia, and neuroferritinopathy. An approach to differential diagnosis and the status of iron chelation therapy for several of these entities are presented. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

Biological markers and Alzheimer disease: a canadian perspective

Decreased β-amyloid_1-42 and increased phospho-tau protein levels in the cerebrospinal fluid (CSF) are currently the most accurate chemical neurodiagnostics of sporadic Alzheimer disease (AD). A report (2007) of the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (2006) recommended that biological markers should not be currently requisitioned by primary care physicians in the routine investigation of subjects with memory complaints. Consideration for such testing should prompt patient referral to a specialist engaged in dementia evaluations or a Memory Clinic. The specialist should consider having CSF biomarkers (β-amyloid_1-42 and phospho-tau) measured at a reputable facility in restricted cases presenting with atypical features and diagnostic confusion, but not as a routine procedure in all individuals with typical sporadic AD phenotypes. We submit that developments in the field of AD biomarker discovery since publication of the 3rd CCCDTD consensus data do not warrant revision of the 2007 recommendations.

Near-infrared spectroscopy of blood plasma for diagnosis of sporadic Alzheimer's disease

There are currently no accepted blood-based biomarkers of sporadic Alzheimer's disease (AD). Augmented oxidative stress has been implicated in both neural and peripheral AD tissues. In this study, we determined whether short-wavelength near-infrared (NIR) spectrophotometry of blood plasma differentiates mild sporadic AD from normal aging. NIR analysis was conducted on 75 microl plasma samples from 19 AD, 27 amnestic MCI, and 17 normal elderly control (NEC) persons using an optical fiber-coupled, holographic grating-based NIR spectrograph. Five spectral bands associated with heme, R-CH, R-OH, H2O, and R-NH functional groups were sensitive to oxidative modification in pre-clinical studies and were pre-selected to develop a logistic regression model for sample classification. This model differentiated AD from NEC samples with a sensitivity of 80% and specificity of 77%. Fifteen and twelve MCI patients were classified with the NEC and AD groups, respectively. The spectra were not influenced by age, gender, exposure to cholinesterase inhibitors or vitamin E, or sample storage time. The NIR data further implicate oxidative stress in the systemic pathophysiology of sporadic AD and differentiate mild (and possibly pre-clinical) AD from NEC individuals with moderate-high accuracy. The procedure is minimally-invasive, rapid, relatively-inexpensive, and may provide a useful biological marker of sporadic AD.

Suppression of glial HO-1 activity as a potential neurotherapeutic intervention in AD

The mechanisms responsible for oxidative damage, pathological brain iron deposition and mitochondrial insufficiency in Alzheimer disease (AD) remain enigmatic. Heme oxygenase-1 (HO-1) is a 32 kDa stress protein that catabolizes heme to biliverdin, free iron and carbon monoxide. The HO-1 gene is exquisitely sensitive to oxidative stress and is induced in brain and other tissues in various models of disease and trauma. Our laboratory demonstrated that 1) HO-1 protein is significantly over-expressed in AD-affected temporal cortex and hippocampus relative to neurohistologically-normal control preparations, 2) in cultured astrocytes, HO-1 up-regulation by transient transfection of the human ho-1 gene, or stimulation of endogenous HO-1 expression by exposure to beta-amyloid, TNFalpha or IL-1beta, promotes intracellular oxidative stress, opening of the mitochondrial permeability transition pore and accumulation of non-transferrin iron in the mitochondrial compartment, and 3) the glial iron sequestration renders co-cultured neuron-like PC12 cells prone to oxidative injury. Induction of the astroglial ho-1 gene may constitute a 'common pathway' leading to pathological brain iron deposition, intracellular oxidative damage and bioenergetic failure in AD and other human CNS disorders.

HYPOTHESIS

Targeted suppression of glial HO-1 hyperactivity may prove to be a rational and effective neurotherapeutic intervention in AD and related neurodegenerative disorders. To begin testing this hypothesis, studies have been initiated to determine whether systemic administration of a novel, selective and brain-permeable inhibitor of HO-1 activity ameliorates cognitive dysfunction and neuropathology in a transgenic mouse model of AD.

A novel experimental heme oxygenase-1-targeted therapy for hormone-refractory prostate cancer

Heme oxygenase-1 (HO-1), a member of the heat shock protein family, plays a key role as a sensor and regulator of oxidative stress. Herein, we identify HO-1 as a biomarker and potential therapeutic target for advanced prostate cancer (PCA). Immunohistochemical analysis of prostate tissue using a progression tissue microarray from patients with localized PCA and across several stages of disease progression revealed a significant elevation of HO-1 expression in cancer epithelial cells, but not in surrounding stromal cells, from hormone-refractory PCA (HRPCA) compared with hormone-responsive PCA and benign tissue. Silencing the ho-1 gene in HRPCA cells decreased the HO-1 activity, oxidative stress, and activation of the mitogen-activated protein kinase-extracellular signal-regulated kinase/p38 kinase. This coincided with reduced cell proliferation, cell survival, and cell invasion in vitro, as well as inhibition of prostate tumor growth and lymph node and lung metastases in vivo. The effect of ho-1 silencing on these oncogenic features was mimicked by exposure of cells to a novel selective small-molecule HO-1 inhibitor referred to as OB-24. OB-24 selectively inhibited HO-1 activity in PCA cells, which correlated with a reduction of protein carbonylation and reactive oxygen species formation. Moreover, OB-24 significantly inhibited cell proliferation in vitro and tumor growth and lymph node/lung metastases in vivo. A potent synergistic activity was observed when OB-24 was combined with Taxol. Together, these results establish HO-1 as a potential therapeutic target for advanced PCA.

Brain sterol dysregulation in sporadic AD and MCI: relationship to heme oxygenase-1

The objective of this study was to ascertain the impact of aging and Alzheimer's disease (AD) on brain cholesterol (CH), CH precursors, and oxysterol homeostasis. Altered CH metabolism and up-regulation of heme oxygenase-1 (HO-1) are characteristic of AD-affected neural tissues. We recently determined that HO-1 over-expression suppresses total CH levels by augmenting liver X receptor-mediated CH efflux and enhances oxysterol formation in cultured astroglia. Lipids and proteins were extracted from postmortem human frontal cortex derived from subjects with sporadic AD, mild cognitive impairment (MCI), and no cognitive impairment (n = 17 per group) enrolled in the Religious Orders Study, an ongoing clinical-pathologic study of aging and AD. ELISA was used to quantify human HO-1 protein expression from brain tissue and gas chromatography-mass spectrometry to quantify total CH, CH precursors, and relevant oxysterols. The relationships of sterol/oxysterol levels to HO-1 protein expression and clinical/demographic variables were determined by multivariable regression and non-parametric statistical analyses. Decreased CH, increased oxysterol and increased CH precursors concentrations in the cortex correlated significantly with HO-1 levels in MCI and AD, but not no cognitive impairment. Specific oxysterols correlated with disease state, increasing neuropathological burden, neuropsychological impairment, and age. A model featuring compensated and de-compensated states of altered sterol homeostasis in MCI and AD is presented based on the current data set and our earlier in vitro work.

The Parkinson disease-associated A30P mutation stabilizes alpha-synuclein against proteasomal degradation triggered by heme oxygenase-1 over-expression in human neuroblastoma cells

Proteosomal degradation of proteins is one of the major mechanisms of intracellular protein turnover. Failure of the proteosome to degrade misfolded protein is implicated in the accumulation of alpha-synuclein in Parkinson's disease (PD). Heme oxygenase-1 (HO-1), an enzyme that converts heme to free iron, carbon monoxide (CO) and biliverdin (bilirubin precursor) is expressed in response to various stressors. HO-1 is up-regulated in PD- and Alzheimer's disease-affected neural tissues. In this study, we found that HO-1 over-expression engenders dose-dependent decreases in alpha-synuclein protein levels in human neuroblastoma M17 cells. When over-expression of HO-1 was silenced in HO-1 transfected cells, level of alpha-synuclein was restored. Likewise, treatment of HO-1 over-expressing cells with the HO-1 inhibitor, tin mesoporphyrin, the iron chelator deferoxamine or antagonist of CO-dependent cGMP activation, methylene blue, mitigated the HO-1-induced reduction in alpha-synuclein levels. Furthermore, when HO-1 over-expressing cells were treated with the proteosome inhibitors, lactacystin and MG132, level of alpha-synuclein was almost completely restored. In contrast to the effect on alpha-synuclein [wild-type (WT)] levels, HO-1 over-expression did not significantly impact PD-associated alpha-synuclein (A30P) levels in these cells. HO-1 also significantly reduced aggregation of alpha-synuclein (WT) but not that of A30P. Our results suggest that HO-1, which is expressed when neurons are exposed to toxic stimuli capable of inducing protein misfolding, triggers proteosomal degradation of proteins and prevents intracellular accumulation of protein aggregates and inclusions. Resistance to HO-1 induced proteosomal degradation may render the familial PD-associated A30P mutation prone to toxic intracellular aggregation.

Methodology for discovery of Alzheimer's disease blood-based biomarkers

Alzheimer's disease (AD) is a degenerative brain disorder. The disease also affects peripheral tissue such as peripheral blood mononuclear cells (PBMCs). Delineating biochemical alterations in AD blood constituents may possibly allow the identification of accessible footprints that reflect degenerative processes within the central nervous system. Here, we describe an integrated methodology for the generation of a blood-based molecular bio-repository, including the collection of clinical and demographic data for downstream stringent sample selection and stratification for the study of molecular signatures in AD. We report the simultaneous extraction of high quality and yield of DNA, RNA, and protein from PBMCs of individuals with sporadic AD, mild cognitive impairment, and normal elderly controls. We describe experimental designs and present examples for the discovery of underlying etiopathogenetic networks in sporadic AD. We suggest that PBMC-associated biomarkers may provide insights into the pathogenesis of AD and be used to monitor disease diagnosis and progression.

Salivary DNA, lipid, and protein oxidation in nonsmokers with periodontal disease

Reactive oxygen species (ROS) are implicated in the destruction of the periodontium during periodontitis. The imbalance in oxidant activity may be a key factor. The aim of this paper is to determine whether periodontitis is associated with increased oxidative damage to DNA, lipids, and proteins and modification of total antioxidant capacity (TAC) in saliva. Saliva was collected from 58 periodontitis patients and 234 healthy controls, all nonsmokers. Periodontal disease status was characterized using the Community Periodontal Index of Treatment Needs (CPITN). Assays for 8-OHdG (ELISA), 8-epi-PGF2alpha (ELISA), and total protein carbonyls (ELISA), and oxy-blotting (Western)/mass spectrometry were performed to quantify oxidative damage to nucleic acids, lipids, total and individual proteins, respectively, in whole nonstimulated saliva. Salivary TAC was measured by inhibition of ABTS oxidation by metmyoglobin. We observed (i) significantly higher levels of 8-OHdG, 8-epi-PGF2alpha, and carbonylated proteins in saliva of periodontal patients as compared with controls (P=0.0003, <0.0001 and <0.0001); (ii) 8-OHdG, 8-epi-PGF2alpha, and carbonylated proteins were independently negatively associated with CPITN (P=0.004, 0.02, and <0.0001); (iii) a positive correlation between salivary TAC and periodontal disease status in the study group (P<0.0001); and (iv) specific oxidation of transferrin, human IgG1 heavy chain fragment, and salivary amylase in periodontitis. Periodontal disease is associated with increased oxidative modification of salivary DNA, lipids, and proteins. Augmented salivary total antioxidant capacity may represent an adaptive response to oxidative stress. Salivary amylase, transferrin, and human IgG1 heavy chain fragments are particularly prone to enhanced oxidation in periodontitis.

Oxidative stress in diseases of the human cornea

Intense exposure to light, robust metabolic activity, and high oxygen tension render the human eye particularly vulnerable to oxidative damage and the list of ophthalmological disorders implicating reactive oxygen and nitrogen species is rapidly expanding. Here, we review the roles of oxidative stress in the etiopathogeneses and pathophysiology of diseases of the human cornea including pterygium, keratoconus, trauma and chemical injury, and a host of inflammatory, metabolic, degenerative, and iatrogenic conditions. Data from animal and tissue culture experimentation germane to these conditions are also adduced.