ATPases and lipid peroxidation in the rat sciatic nerve in the course of experimental neoplastic disease

Neurological paraneoplastic syndromes in lung cancer patients

Lung cancer is recognized among the most frequent causes of paraneoplastic neurological syndromes (PNS). Neurological syndromes in subjects with systemic malignancy remain a clinical and diagnostic challenge. The aim of the study was to evaluate the frequency of NPS, their clinical manifestation and association with onconeural antibodies in patients with lung cancer. Fifty patients hospitalized with the diagnosis of PNS participated in the study. Neurological evaluation consisted of the Rankin scale (mRS), the Barthel index (BI), and testing for the presence of onconeural antibodies by means of indirect immunofluorescence, as screening, and Western blotting as confirmation. The majority of lung cancer patients (64%) aged 62 ± 10 had NPS symptoms. Their neurological condition and daily living activities were reasonable: mRS (1.0; 0.0-4.0) and BI (100; 7.4-100) scores. Classical PNS were found in 30% of cases and included sensory neuropathy (16%), paraneoplastic cerebellar degeneration (12%) as the most frequent symptoms. Autoimmune reaction was observed in 42% of lung cancer patients and in 20% was represented by well-characterized onconeural antibodies. Anti-Hu antibody was identified as the most frequent. In conclusion, PNS signs in lung cancer patients have both classical and non-classical features. In the course of SCLC only well-characterized onconeural antibodies were identified. The presence of well-characterized onconeural antibodies is strongly associated with classical features of PNS.

Onconeuronal and antineuronal antibodies in patients with neoplastic and non-neoplastic pulmonary pathologies and suspected for paraneoplastic neurological syndrome

Objective

Onconeuronal antibodies are important diagnostic tool in patients with suspicion of paraneoplastic neurological syndromes (PNS). However, their role in PNS pathophysiology and specificity for particular neurological manifestation remains unclear. The aim of this study was to evaluate onconeuronal and antineuronal antibodies in patients with pulmonary pathologies and suspected for PNS.

Materials and methods

Twenty one patients with pulmonary pathologies were selected from the database of 525 consecutive patients with suspicion of PNS. Patients' sera were screened for the presence of onconeuronal and antineuronal antibodies by means of indirect immunofluorescence; the presence was confirmed by Western blotting. Clinical data were obtained from medical records, hospital data base, and questionnaire-based direct telephone contact with patients.

Results

Among 21 patients, aged 54 ± 11, with pulmonary pathologies, the most frequent neurological manifestations were neuropathies. Typical PNS included paraneoplastic cerebellar degeneration (PCD) and limbic encephalitis (LE). We found cases with multiple onconeuronal antibodies (anti-Ri and anti-Yo) and coexisting PNS (PCD/LE). Well-defined onconeuronal antibodies were identified in 23.8% of patients. Among antineuronal antibodies, the most frequent were anti-MAG (23.8%). ROC curves analysis revealed high sensitivity of onconeuronal and antineuronal antibodies for typical PNS and lower for pulmonary malignancies.

Conclusions

Tests for antibodies are highly sensitive for the diagnosis of typical paraneoplastic neurological syndromes. Anti-myelin and anti-MAG antibodies are associated with non-neoplastic pulmonary diseases. Patients with well-defined onconeuronal antibodies require careful screening and follow-up, because the PNS diagnosis indicates a high probability of an underlying malignancy.

Lipid oxidation and peroxidation in CNS health and disease: from molecular mechanisms to therapeutic opportunities

Reactive oxygen species (ROS) are produced at low levels in mammalian cells by various metabolic processes, such as oxidative phosphorylation by the mitochondrial respiratory chain, NAD(P)H oxidases, and arachidonic acid oxidative metabolism. To maintain physiological redox balance, cells have endogenous antioxidant defenses regulated at the transcriptional level by Nrf2/ARE. Oxidative stress results when ROS production exceeds the cell's ability to detoxify ROS. Overproduction of ROS damages cellular components, including lipids, leading to decline in physiological function and cell death. Reaction of ROS with lipids produces oxidized phospholipids, which give rise to 4-hydroxynonenal, 4-oxo-2-nonenal, and acrolein. The brain is susceptible to oxidative damage due to its high lipid content and oxygen consumption. Neurodegenerative diseases (AD, ALS, bipolar disorder, epilepsy, Friedreich's ataxia, HD, MS, NBIA, NPC, PD, peroxisomal disorders, schizophrenia, Wallerian degeneration, Zellweger syndrome) and CNS traumas (stroke, TBI, SCI) are problems of vast clinical importance. Free iron can react with H(2)O(2) via the Fenton reaction, a primary cause of lipid peroxidation, and may be of particular importance for these CNS injuries and disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Atherosclerosis, the major risk factor for ischemic stroke, involves accumulation of oxidized LDL in the arteries, leading to foam cell formation and plaque development. This review will discuss the role of lipid oxidation/peroxidation in various CNS injuries/disorders.