Irradiation of the Subventricular Zone and Subgranular Zone in High- and Low-Grade Glioma Patients: an Atlas-based Analysis on Overall Survival

Background Neural stem cells in the subventricular- (SVZ) and subgranular zone (SGZ) are hypothesized to support growth of glioma. Therefore, irradiation of the SVZ and SGZ might reduce tumor growth and might improve overall survival (OS). However, it may also inhibit the repair capacity of brain tissue. The aim of this retrospective cohort study is to assess the impact of SVZ and SGZ radiotherapy doses on OS of patients with high-grade (HGG) or low-grade (LGG) glioma. Methods We included 273 glioma patients who received radiotherapy. We created an SVZ atlas, shared openly with this work, while SGZ labels were taken from the CoBRA atlas. Next, SVZ and SGZ regions were automatically delineated on T1 MR-images. Dose and OS correlations were investigated with Cox regression and Kaplan-Meier analysis. Results Cox regression analyses showed significant hazard ratios for SVZ dose (univariate: 1.029/Gy, p<0.001; multivariate: 1.103/Gy, p = 0.002) and SGZ dose (univariate: 1.023/Gy, p<0.001; multivariate: 1.055/Gy, p<0.001) in HGG patients. Kaplan-Meier analysis showed significant correlations between OS and high/low dose groups for HGG patients (SVZ: respectively 10.7 months (>30.33 Gy) vs 14.0 months (<30.33 Gy) median OS, p = 0.011; SGZ: respectively 10.7 months (>29.11 Gy) vs 15.5 months (<29.11 Gy) median OS, p<0.001). No correlations between dose and OS were found for LGG patients. Conclusion Irradiation doses on neurogenic areas correlate negatively with OS in patients with HGG. Whether sparing of the SVZ and SGZ during radiotherapy improves OS, should be subject of prospective studies.

Gastroprotective Mechanisms

Gastric ulcer (GU), a common type of peptic ulcer, results from an imbalance in the action of protective and aggressive agents. Gastroprotective mechanisms are mucus layer, gastric epithelium, gastric blood flow, gastric neurons, mucosal repair capacity, and immune system. Thus, the aim of this chapter was to provide an update on gastroprotective mechanisms. It was carried out through searches in PubMed covering the years 2016–2021 using several keywords. This survey resulted in 428 articles, of which 110 were cited in this chapter. It was reviewed the status of gastroprotective mechanisms and highlighted that mucins can act as a filter; gastric epithelial defenses are composed of the cell barrier, stem cells, and sensors on the mucosal surface; nitric oxide (NO) and hydrogen sulfide (H2S) act for gastric blood flow homeostasis (GBF); the main effector neurons in the gastric mucosa are cholinergic, nitrergic and VIPergic, and oxytocin can activate neurons; repair of the gastric mucosa requires complex biological responses; the immune system regulates the entry of antigens and pathogens. The main knowledge about gastroprotective mechanisms remains unchanged. However, we conclude that there has been progressing in this area.

Increased WIP1 Expression With Aging Suppresses the Capacity of Oocytes to Respond to and Repair DNA Damage

If fertilization does not occur for a prolonged time after ovulation, oocytes undergo a time-dependent deterioration in quality in vivo and in vitro, referred to as postovulatory aging. The DNA damage response is thought to decline with aging, but little is known about how mammalian oocytes respond to the DNA damage during in vitro postovulatory aging. Here we show that increased WIP1 during in vitro postovulatory aging suppresses the capacity of oocytes to respond to and repair DNA damage. During in vitro aging, oocytes progressively lost their capacity to respond to DNA double-strand breaks, which corresponded with an increase in WIP1 expression. Increased WIP1 impaired the amplification of γ-H2AX signaling, which reduced the DNA repair capacity. WIP1 inhibition restored the DNA repair capacity, which prevented deterioration in oocyte quality and improved the fertilization and developmental competence of aged oocytes. Importantly, WIP1 was also found to be high in maternally aged oocytes, and WIP1 inhibition enhanced the DNA repair capacity of maternally aged oocytes. Therefore, our results demonstrate that increased WIP1 is responsible for the age-related decline in DNA repair capacity in oocytes, and WIP1 inhibition could restore DNA repair capacity in aged oocytes.

Cryptomphalus aspersa Eggs Extract Potentiates Human Epidermal Stem Cell Regeneration and Amplification

Modern life and extended life expectancy have prompted the search for natural compounds alleviating skin aging. Evidence supports the beneficial effects on skin integrity and health from the topical administration of preparations of the mollusc Cryptomphalus aspersa eggs extract (IFC-CAF®) and suggests these effects are partly derived from an impact on skin renewal and repair mechanisms. The objective was to dissect in vitro the specific impact of IFC-CAF® on different parameters related to the regenerative potential, differentiation phenotype and exhaustion of skin stem cells. A prominent impact of IFC-CAF® was the induction of stratification and differentiated phenotypes from skin stem cells. IFC-CAF® slowed down the cell cycle at the keratinocyte DNA repair phase and, decelerated proliferation. However, it preserved the proliferative potential of the stem cells. IFC-CAF® reduced the DNA damage marker, γH2AX, and induced the expression of the transcription factor p53. These features correlated with significant protection in telomere shortening upon replicative exhaustion. Thus, IFC-CAF® helps maintain orderly cell cycling and differentiation, thus potentiating DNA repair and integrity. Our observations support the regenerative and repair capacity of IFC-CAF® on skin, through the improved mobilization and ordered differentiation of keratinocyte precursors and the enhancement of genome surveillance and repair mechanisms that counteract aging.

Amniotic Fluid-derived MSC Secretome Halts Action of IL-1β and TNF-α Through ERK/MAPK and Returns Cartilage Repair Under OA Inflammatory Stimuli

Background: Osteoarthritis (OA) is a degenerative cartilage disease. OA cartilage has a limited repair capacity due to the effect of IL-1β and TNF-α on the chondrocyte progenitor cells (CPC) in an OA joint. Mesenchymal stem cells (MSC) therapy is a therapeutic option for osteoarthritis that initiated by the ability of secretory growth factors and mediator molecules to heal OA. Amniotic fluid MSC (AF-MSC), an interesting MSC source, has been shown to secrete various growth factors and anti-inflammatory molecules promoting tissue repair and regeneration. However, the effect of AF-MSC secretory factors to inflammation and cartilage repair is still limited. The current study aims to explore the action of AF-MSC secretome to IL-1β and TNF-α, and the CPC function that encourages cartilage repair.Methods: The effect of AF-MSC secretome to OA inflammatory cytokines was observed via the CPC migration using scratch assay. Inhibitory action of AF-MSC secretome to IL-1β and TNF-α was determined through NF-κB and MAPK signaling pathways by western blot. The repaired function of OA cartilage was analyzed via the cartilage outgrowth study and the expression of chondrogenic and anabolic genes using qRT-PCR.Results: AF-MSC secretome can arrest inflammatory action of IL-1β and TNF-α and reduces production of NF-κB, pNF-κB, p38, pp38, ERK, COX-2, and iNOS signaling proteins. It significantly reduced the production of pERK (P = 0.0434). For cartilage repair, AF-MSC secretome promotes CPC outgrowth and migration in human OA cartilage, even under inflammatory stimuli. By the action of AF-MSC secretome, the inflamed CPC can restore Col II and anabolic genes; IGF1 expression, indicating reactivation of cartilage regeneration.Conclusion: AF-MSC secretory factors have the ability to halt inflammatory actions of IL-1β and TNF-α via the ERK/MAPK pathway and motivate CPC function and anabolic property.

The Art of War: Ferroptosis and Pancreatic Cancer

Pancreatic cancer is a devastating gastrointestinal cancer, characterized by late diagnosis, low treatment success rate, and poor survival prognosis. The most common pathological type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), which is mainly driven by the K-Ras oncogene. Ferroptosis was originally described as Ras-dependent cell death, but is now defined as lipid peroxidation-mediated regulated necrosis, accompanied by excessive activation of the autophagy degradation pathway and limited membrane repair capacity. The impaired ferroptotic pathway is involved in many types of cancer, including PDAC. On the one hand, the chronic inflammation caused by ferroptotic damage contributes to the formation of K-Ras-driven PDAC. On the other hand, drug-induced ferroptosis is an emerging strategy to suppress tumor growth in established PDAC. In this mini-review, we outline the core process of ferroptosis, discuss the regulatory mechanism of ferroptosis in PDAC, and highlight some of the challenges of targeting ferroptosis in PDAC therapy.

Fractionated Radiation Exposure Enhances DNA Repair Capacity to Amplify Radioresistance of Cancer Cells

Fractionated radiotherapy is widely used in cancer therapy for its advantages in the preservation of normal tissues, but may amplify radioresistance of cancer cells. To understand whether and how fractionated radiation exposure amplifies radioresistance, HCT-8 human colon cancer cells and MCF-7 human breast cancer cells were received a total dose of 5 Gy X-ray irradiation by a single exposure or fractionated exposures (1 Gy/day for 5 consecutive days), respectively. We then examined the radioresistance of cells. Underwent an additional exposing to 2 Gy, cells received fractionated exposures showed significantly better cell proliferation and clonogenic ability than cells received a single exposure. Compared to the intact cells without radiation exposure, the expression of γ-H2AX, pATM and PARP was significantly enhanced in only these cells received fractionated exposures. However, the expression of cyclin D1 and cyclin E1 was enhanced in only these HCT-8 cells received a single exposure. Otherwise, the expression of SOD1, SOD2 and caspase 3 was not significantly changed in both cells received either a single exposure or fractionated exposures. Fractionated radiation exposure amplifies radioresistance of cancer cells, predominantly by enhancing DNA repair capacity.