Covering: 2000 to 2013 Oxidative stress is the central component of chronic diseases. The nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathway is vital in the up-regulation of cytoprotective genes and enzymes in response to oxidative stress and treatment with certain dietary phytochemicals. Herein, we classify bioactive compounds derived from natural products that are Nrf2/ARE pathway activators and recapitulate the molecular mechanisms for inducing Nrf2 to provide favorable effects in experimental models of chronic diseases. Moreover, pharmacological inhibition of Nrf2 signalling has emerged as promising strategy against multi-drug resistance thereby improving the treatment efficacy. We have also enlisted natural product-derived inhibitors of Nrf2/ARE pathway.

Neuroinflammation is a host-defense mechanism associated with restoration of normal structure and function of the brain and neutralization of an insult. Increasing neuropathological and biochemical evidence from the brains of individuals with Parkinson’s disease (PD) provides strong evidence for activation of neuroinflammatory pathways. Microglia, the resident innate immune cells, may play a major role in the inflammatory process of the diseased brain of patients with PD. Although microglia forms the first line of defense for the neural parenchyma, uncontrolled activation of microglia may directly affect neurons by releasing various molecular mediators such as inflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-6, and IL-1β), nitric oxide, prostaglandin E2, and reactive oxygen and nitrogen species. Moreover, recent studies have reported that activated microglia phagocytose not only damaged cell debris but also intact neighboring cells. This phenomenon further supports their active participation in self-enduring neuronal damage cycles. As the relationship between PD and neuroinflammation is being studied, there is a realization that both cellular and molecular mediators are most likely assisting pathological processes leading to disease progression. Here, we discuss mediators of neuroinflammation, which are known activators released from damaged parenchyma of the brain and result in neuronal degeneration in patients with PD.

Free radical production and their targeted action on biomolecules have roles in aging and age-related disorders such as Parkinson’s disease (PD). There is an age-associated increase in oxidative damage to the brain, and aging is considered a risk factor for PD. Dopaminergic neurons show linear fallout of 5–10% per decade with aging; however, the rate and intensity of neuronal loss in patients with PD is more marked than that of aging. Here, we enumerate the common link between aging and PD at the cellular level with special reference to oxidative damage caused by free radicals. Oxidative damage includes mitochondrial dysfunction, dopamine auto-oxidation, α-synuclein aggregation, glial cell activation, alterations in calcium signaling, and excess free iron. Moreover, neurons encounter more oxidative stress as a counteracting mechanism with advancing age does not function properly. Alterations in transcriptional activity of various pathways, including nuclear factor erythroid 2-related factor 2, glycogen synthase kinase 3β, mitogen activated protein kinase, nuclear factor kappa B, and reduced activity of superoxide dismutase, catalase and glutathione with aging might be correlated with the increased incidence of PD.

Adipose tissue-derived mesenchymal stem cells (AT-MSCs) offer potential as a therapeutic option for chronic discogenic low back pain (LBP) because of their immunomodulatory functions and capacity for cartilage differentiation. The goal of this study was to assess the safety and tolerability of a single intradiscal implantation of combined AT-MSCs and hyaluronic acid (HA) derivative in patients with chronic discogenic LBP. We performed a single-arm phase I clinical trial with a 12-month follow-up and enrolled 10 eligible chronic LBP patients. Chronic LBP had lasted for more than 3 months with a minimum intensity of 4/10 on a visual analogue scale (VAS) and disability level ≥ 30% on the Oswestry Disability Index (ODI). The 10 patients underwent a single intradiscal injection of combined HA derivative and AT-MSCs at a dose of 2 × 107 cells/disc (n = 5) or 4 × 107 cells/disc (n = 5). Safety and treatment outcomes were evaluated by assessing VAS, ODI, Short Form-36 (SF-36), and imaging (lumbar spine X-ray imaging and MRI) at regular intervals over 1 year. No patients were lost at any point during the 1-year clinical study. We observed no procedure or stem cell-related adverse events or serious adverse events during the 1-year follow-up period. VAS, ODI, and SF-36 scores significantly improved in both groups receiving both low (cases 2, 4, and 5) and high (cases 7, 8, and 9) cell doses, and did not differ significantly between the two groups. Among six patients who achieved significant improvement in VAS, ODI, and SF-36, three patients (cases 4, 8, and 9) were determined to have increased water content based on an increased apparent diffusion coefficient on diffusion MRI. Combined implantation of AT-MSCs and HA derivative in chronic discogenic LBP is safe and tolerable. However, the efficacy of combined AT-MSCs and HA should be investigated in a randomized controlled trial in a larger population. ClinicalTrials.gov NCT02338271 . Registered 7 January 2015.

Oxygen homeostasis reflects the constant body requirement to generate energy. Hypoxia (0.1–1% O₂), physioxia or physoxia (∼1–13%), and normoxia (∼20%) are terms used to define oxygen concentration in the cellular environment. A decrease in oxygen (hypoxia) or excess oxygen (hyperoxia) could be deleterious for cellular adaptation and survival. Hypoxia can occur under both physiological (e.g., exercise, embryonic development, underwater diving, or high altitude) and pathological conditions (e.g., inflammation, solid tumor formation, lung disease, or myocardial infarction). Hypoxia plays a key role in the pathophysiology of heart disease, cancers, stroke, and other causes of mortality. Hypoxia inducible factor(s) (HIFs) are key oxygen sensors that mediate the ability of the cell to cope with decreased oxygen tension. These transcription factors regulate cellular adaptation to hypoxia and protect cells by responding acutely and inducing production of endogenous metabolites and proteins to promptly regulate metabolic pathways. Here, we review the role of the HIF pathway as a metabolic adaptation pathway and how this pathway plays a role in cell survival. We emphasize the roles of the HIF pathway in physiological adaptation, cell death, pH regulation, and adaptation during exercise.