Hormetic shifting of redox environment by pro-oxidative resveratrol protects cells against stress

AbstractResveratrol has gained tremendous interest owing to multiple reported health-beneficial effects. However, the underlying key mechanism of action of this natural product remained largely controversial. Here, we demonstrate that under physiologically relevant conditions major biological effects of resveratrol can be attributed to its generation of oxidation products such as reactive oxygen species (ROS). At low nontoxic concentrations (in general <50µM), treatment with resveratrol increased viability in a set of representative cell models, whereas application of quenchers of ROS completely truncated these beneficial effects. Notably, resveratrol treatment led to mild, Nrf2-specific gene expression reprogramming. For example, in primary epidermal keratinocytes derived from human skin this coordinated process resulted in a 1.3-fold increase of endogenously generated glutathione (GSH) and subsequently in a quantitative reduction of the cellular redox environment by 2.61mVmmol GSH per g protein. After induction of oxidative stress by using 0.78% (v/v) ethanol, endogenous generation of ROS was consequently reduced by 24% in resveratrol pre-treated cells. In contrast to the common perception that resveratrol acts mainly as a chemical antioxidant or as a target protein-specific ligand, we propose that the cellular response to resveratrol treatment is essentially based on oxidative triggering. In physiological microenvironments this molecular training can lead to hormetic shifting of cellular defense towards a more reductive state to improve physiological resilience to oxidative stress

Data of oxygen- and pH-dependent oxidation of resveratrol

AbstractWe show here if under physiologically relevant conditions resveratrol (RSV) remains stable or not. We further show under which circumstances various oxidation products of RSV such as ROS can be produced. For example, in addition to the widely known effect of bicarbonate ions, high pH values promote the decay of RSV. Moreover, we analyse the impact of reduction of the oxygen partial pressure on the pH-dependent oxidation of RSV. For further interpretation and discussion of these focused data in a broader context we refer to the article “Hormetic shifting of redox environment by pro-oxidative resveratrol protects cells against stress” (Plauth et al., in press) [1]

Association of seizures with cortical spreading depression and peri-infarct depolarisations in the acutely injured human brain

OBJECTIVE: To test the co-occurrence and interrelation of ictal activity and cortical spreading depressions (CSDs) - including the related periinfarct depolarisations in acute brain injury caused by trauma, and spontaneous subarachnoid and/or intracerebral haemorrhage. METHODS: 63 patients underwent craniotomy and electrocorticographic (ECoG) recordings were taken near foci of damaged cortical tissue for up to 10 days. RESULTS: 32 of 63 patients exhibited CSDs (5 to 75 episodes), and 11 had ECoGraphic seizure activity (1-81 episodes). Occurrence of seizures was significantly associated with CSD, as 10 of 11 patients with seizures also had CSD (p=0.007, 2-tailed Fishers exact test). Clinically overt seizures were only observed in one patient. Each patient with CSD and seizures displayed one of four different patterns of interaction between CSD and seizures. In four patients CSD was immediately preceded by prolonged seizure activity. In three patients the two phenomena were separated in time: multiple CSDs were replaced by ictal activity. In one patient seizures appeared to trigger repeated CSDs at the adjacent electrode. In two patients ongoing repeated seizures were interrupted each time CSD occurred. CONCLUSIONS: Seizure activity occurs in association with CSD in the injured human brain. SIGNIFICANCE: ECoG recordings in brain injury patients provide insight into pathophysiological mechanisms that is not accessible by scalp EEG recordings

Immunoglobulin M deposition in cutaneous nerves of anti-myelin-associated glycoprotein polyneuropathy patients correlates with axonal degeneration

Anti-myelin-associated glycoprotein (MAG) neuropathy is an antibody-mediated polyneuropathy. We correlated clinical features, immunoglobulin (Ig) M blood levels, IgM deposition and axonal degeneration in skin biopsies of anti-MAG neuropathy patients. By confocal microscopy, IgM deposits were found exclusively within perineurium-enclosed nerves; they were not found on single, non-perineurium-ensheathed myelinated axons. There was a linear correlation between IgM accumulation in nerve fascicles with IgM blood levels but not with anti-MAG antibody titer or disease duration. Axons with specific IgM deposits had signs of axonal damage, including neurofilament disintegration. Nodal structures were intact even at sites where the axons showed pathologic changes. Ultrastructural analysis revealed degeneration of myelinating Schwann cells. Taken together, these findings suggest that in anti-MAG neuropathy patients, IgM deposits are entrapped within cutaneous perineurium-ensheathed nerve bundles where they accumulate in the endoneurial space. High local IgM levels in the endoneurium may be required for IgM deposition on myelin and subsequent axonal injury and degeneration. This study underlines the importance of early, effective anti-B-cell treatments for preventing progression of this neuropathy

Autologous peripheral blood stem cell transplantation for chronic acquired demyelinating neuropathy

Six patients with chronic acquired demyelinating neuropathy (CADP) were treated with autologous peripheral blood stem cell transplantation (PBSCT). Two with polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome improved-improvement was sustained in one but relapsed and required repeat transplant in the other. Two of the three with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and one with an IgM paraprotein and antibodies to nerve improved--of the responders, one relapsed after 18 months and the other was in remission after 6 months. Four developed neutropenic septicemia and pneumonia. The role of PBSCT in CADP refractory to other treatment deserves further investigation but the serious adverse events and lack of sustained response in some patients emphasize the need for caution