Table 2a.
General Characteristics of Included Studies. List of in vitro and in vivo studies
| Author, Year (Ref.) | Type(s) of Cancer | Nature of Study | Study Design | H2 Form (Concentration) | Duration of H2 Treatment | Treatment Outcomes |
|---|---|---|---|---|---|---|
| Yu Jiang et al., 2018 | Non-small cell lung cancer (NSCLC) | Combination of H2 with LY294002, PI3K inhibitor | in vitro | Hydrogen saline (Concentration maintained at >0.6 mmol/l) | 24 hours | - Antiproliferation and apoptotic effectiveness was increased after hydrogen saline treatment on the NSCLC A549 cell lines. |
| Yuanren Gao et al., 2021 | Liver cell injury and liver cancer | Independent H2 study | in vitro | Hydrogen-rich water (HRW) (Concentration not stated) | 24 hours | - HRW provided a protective impact against liver cell injury as well as an anti-proliferative effect on liver cancer cells. - It promotes normal liver cell proliferation in a co-culture system to resist the invasion of normal cells by liver cancer cells. |
| Ye Yang et al., 2020 | Endometrial cancer | Independent H2 study | in vitro | HRW (0.7 ppm) | 24 hours | - TNF/NF- κB signaling pathways, as well as apoptotic pathways, were activated by HRW treatment. |
| Ye Yang et al., 2020 | Endometrial cancer | Independent H2 study | in vitro & in vivo | HRW (1.0 ppm) | 24 days | - H2 upregulated ROS generation in association with upregulated expression of NLPR3 inflammasome. - HRW inhibits xenograft volume and weight of endometrial cancers via the pyroptotic pathway. There is a significant difference in tumour volume and weight between hydrogen culture media and normal culture media. |
| Runtuwene J. et al., 2015 | Colon cancer | Combination of H2 and 5-fluorouracil treatment (FU) | in vitro & in vivo | HRW (0.8mM) | 10 days | - HRW treatment showed strong anti-oxidative effects and increased survival rate of the treated mice for 16 days on hydrogen water alone. - The treatment enhanced 5-FU effectiveness through increased anticancer activity and cell death with a survival rate of 25 days. |
| Daisuke Kawai et al., 2012 | Nonalcoholic steatohepatitis and accompanying hepatocarcinoge-nesis | Independent H2 study | in vivo | HRW (Concentration not stated) | 8 weeks | - The number of hepatic tumours was much lower (from 20 to 5), with smaller maximum tumour size (from 3mm to 2mm) in the HRW group than the control group. |
| Fang-Yin Li et al., 2013 | Ferric nitrilotriacetate-induced nephrotoxicity (renal injury/cancer) | Combination of H2 and ferric nitrilotriacetate treatment | in vivo | HRW (Concentration maintained at more than 0.8mg/l) | 12 weeks | - Fe-NTA-induced inflammation, oxidative stress and renal mitochondrial dysfunction were reduced significantly after HRW therapy. - Reduced renal damage and suppressed early tumour promoting events. |
| Leyuan Liu et al., 2020 | Lung cancer | Independent H2 study | in vitro | Hydrogen gas (20%, 40%, 60%) | 48 hours | - Molecular hydrogen lowered STAT3/Bcl2 signaling, hence promoting lung cancer cell death and autophagy. - Autophagy suppression improves H2 involvement in inducing lung cancer cell death. |
| Yayoi Murakami et al., 2017 | Neuroblastoma cells | Independent H2 study | in vitro | Hydrogen gas (50% H2) | - | - Pretreatment inhibited H2O2-induced cell death. - Hydrogen gas enhanced mitochondrial membrane potential and cellular ATP levels. - Treatment with hydrogen gas induced weak oxidative stress and the system's anti-oxidative defense mechanism. |
| Meng-yu Liu et al., 2019 | Glioblastoma growth | Independent H2 study | in vitro & in vivo | Hydrogen gas (67% H2) | - | - Glioma growth was inhibited while glioma stem-like cell development was reduced by hydrogen gas therapy. - Glioma cell migration, invasion, and colony formation were inhibited after the hydrogen gas treatment. |
| Baocheng Zhu et al., 2021 | Gastric cancer cells | Independent H2 study | in vitro & in vivo | Hydrogen gas (67% H2) | 5 weeks | - Hydrogen treatment greatly reduced gastric tumour development in vivo. - Cell proliferation, migration, and lncRNA MALAT1 and EZH2 expression were inhibited by hydrogen gas while miR-124-3p expression was upregulated. |
| Jing Chu et al., 2021 | Cervical cancer | Independent H2 study | in vitro & in vivo | Hydrogen gas (67% H2) | 7 days | - Treatment with hydrogen promoted apoptosis while decreasing cell growth and oxidative stress. - Tumour growth and cell proliferation was reduced, along with increased cell death. |
| Dongchang Wang et al., 2018 | Lung cancer | Independent H2 study | in vitro & in vivo | Hydrogen gas (20%, 40%, 60%, 80% H2) | - | - Cell viability, migration, and invasion were reduced by hydrogen treatment, while cell apoptosis was accelerated via the downregulation of SMC3 expression. - Reduction in tumour weight and protein expression were also observed. |
| Jinghong Meng et al., 2020 | Lung cancer | Independent H2 study | in vitro & in vivo | Hydrogen gas (20%, 40%, 60% H2) | 4 weeks | - Hydrogen treatment increased apoptosis of cancer cells while suppressing cell proliferation, invasion, and migration. - Macrophage-mediated phagocytosis and the overall role of H2 in lung cancer inhibition was enhanced via down-regulating CD47. |
| Lei Shang et al., 2018 | Ovarian cancer | Independent H2 study | in vitro & in vivo | Hydrogen gas (66.7% H2) | 6 weeks | - Growth of tumour was inhibited, as are cancer cell proliferation, invasion, migration, and colony formation after hydrogen treatment. - PA-1 and Hs38.T cells' capacity to form spheres was significantly inhibited, along with reduced CD34 expression, showing anti-angiogenesis actions from the hydrogen gas. |