Malignant hyperthermia when dantrolene is not readily available.

BACKGROUND: Malignant hyperthermia is a rare but life-threatening pharmacogenetic muscle disorder characterized by abnormal hypermetabolic reactions and commonly triggered in susceptible individuals by volatile anesthetics or succinylcholine, or both. Unfortunately, the specific medicine dantrolene is not readily available in many countries including China. The aim of this study was to find the characteristics of malignant hyperthermia under the situation that dantrolene is not readily available. METHODS: The cases of malignant hyperthermia reported on the most commonly used databases in China from 1985 to 2020 were analyzed. The inclusion criteria were the MH episodes only related to anesthesia. The exclusion criteria were dubious MH episodes only caused by Ketamine administration or MH episodes irrelevant to anesthesia. Independent samples t-test and Pearson's chi-squared test were applied to assess the difference between the survived and death cases. RESULTS: Ninety-two cases of malignant hyperthermia reported on the most commonly used databases in China from 1985 to 2020 were analyzed. Median (IQR [range]) age was 18.5 (11.8-37.0 [0-70.0]) years. Compared with the survived cases, the death cases had higher maximum end-tidal partial pressure of CO2 (P = 0.033), the maximum arterial partial pressure of CO2 (P = 0.006), temperature first measured when the patient was first discovered abnormal (P = 0.012), and maximum temperature (P < 0.001). Besides, the death cases had less minimum pH (P < 0.001) and higher potassium (P < 0.001) and were more likely to have coagulation disorders (p = 0.018). Concerning treatment, cases used furosemide (P = 0.024), mannitol (P = 0.029), blood purification treatment (P = 0.017) had the advantage on the outcome. Creatine phosphokinase, myoglobin, and MB isoenzyme of creatine phosphokinase differed greatly among cases during the first week. 43 (46.7%) cases had congenital diseases. 12 (13.0%) cases were reported with abnormal laboratory test results or abnormal signs that are possibly relevant before anesthesia. CONCLUSIONS: In countries that dantrolene is not readily available, early warning, diagnosis, and prompt effective therapies are crucial for MH patients to survive.

Suppression of mitochondrial respiration with local anesthetic ropivacaine targets breast cancer cells.

BACKGROUND: Retrospective studies on cancer patients who have received local anesthesia show a favorable decrease in tumor metastasis and recurrence. However, the mechanisms underlying the benefits of local anesthesia on cancer recurrence are not well understood. METHODS: In this study, we investigated the biological effects of ropivacaine on breast cancer cells and the mechanisms of its action with emphasis on mitochondrial respiration. RESULTS: Ropivacaine significantly inhibited growth, survival, and anchorage-independent colony formation in two human breast cancer cell lines. It also acted synergistically with a 5-FU in breast cancer cells. Mechanistically, ropivacaine was found to inhibit mitochondrial respiration by suppressing mitochondrial respiratory complex I and II activities, leading to energy depletion, and oxidative stress and damage. The inhibitory effects of ropivacaine in breast cancer cells were abolished in mitochondrial respiration-deficient ρ0 cells, indicating that mitochondrial respiration is essential for the mechanism of action of ropivacaine. Ropivacaine inhibited phosphorylation of Akt, mTOR, rS6, and EBP1 in breast cancer cells, suggesting the association between Akt/mTOR signaling pathway and mitochondrial functions in breast cancer. CONCLUSIONS: Our work clearly demonstrates the inhibitory effects of ropivacaine in breast cancer by disrupting mitochondrial function. Our findings provide a proper understanding of how local anesthetics reduce the risk of tumor recurrence, and thus, support the use of ropivacaine for surgery and to control pain in patients with breast cancer.

Inhibition of gastric cancer by local anesthetic bupivacaine through multiple mechanisms independent of sodium channel blockade.

BACKGROUND: Retrospective studies of patients undergoing cancer surgery suggest the use of local anesthesia may decrease tumor recurrence and improve survival. The mechanisms on the benefits of local anesthesia on cancer recurrence are complex and remain to be elucidated. METHODS: This study investigated the effects of bupivacaine on various cellular activities of gastric cancer using proliferation, migration, apoptosis assay. The underlying mechanism was analyzed focusing on mitochondrial functions and the activities of Rho family members. RESULTS: We show that bupivacaine at low concentrations (eg, 0.01 and 0.05 mM) inhibits migration whereas only at high concentrations (1 and 5 mM) inhibits growth and survival in two human gastric cancer cell lines. Bupivacaine also significantly augments 5-Fluorouracil in inhibiting growth and survival but not migration in gastric cancer cells. In addition, the mechanisms of bupivacaine's action on the growth and survival are different from those on the migration. We demonstrate that bupivacaine inhibits gastric cancer cell growth and survival through inhibiting mitochondrial respiratory complex I and II, leading to decreased mitochondrial oxidation and ATP production. In contrast, bupivacaine inhibits gastric cancer cell migration through decreasing RhoA and Rac1 activities without affecting their expression. Particularly, we demonstrate that bupivacaine inhibits gastric cancer cell migration via inhibiting RhoA/ROCK/MLC pathway. We further show that the action of bupivacaine on mitochondrial functions, RhoA, and Rac1 activities are independent of sodium channel blockade. CONCLUSIONS: Our work demonstrates that bupivacaine has direct anti-cancer activities with the dominant inhibitory effects on gastric cancer migration rather than growth and survival. Our findings also guide a proper understanding and provide underlying mechanisms on how local aesthesis could affect cancer patients.