Effects of plateau hypoxia on population pharmacokinetics and pharmacodynamics of metformin in patients with Type 2 diabetes / 中南大学学报(医学版)

OBJECTIVES@#Metformin is the basic drug for treating diabetes, and the plateau hypoxic environment is an important factor affecting the pharmacokinetics of metformin, but there have been no reports of metformin pharmacokinetic parameters in patients with diabetes mellitus type 2 (T2DM) in the high-altitude hypoxic environment. This study aims to investigate the effect of the hypoxic environment on the pharmacokinetics and assess the efficacy and safety of metformin administration in patients with Type 2 diabetes mellitus (T2DM).@*METHODS@#A total of 85 patients with T2DM taking metformin tablets in the plateau group (n=32, altitude: 1 500 m) and control group (n=53, altitude: 3 800 m) were enrolled according to the inclusion and exclusion criteria, and 172 blood samples were collected in the plateau group and the control Group. A ultra-performance liquid chromatography/tandem mass spectrometry (UFLC-MS/MS) method was established to determine the blood concentration of metformin, and Phoenix NLME software was used to establish a model of pharmacokinetics of metformin in the Chinese T2DM population. The efficacy and serious adverse effects of metformin were compared between the 2 groups.@*RESULTS@#The population pharmacokinetic modeling results showed that plateau hypoxia and age were the main covariates for model building, and the pharmacokinetic parameters were significantly different between the plateau and control groups (all P<0.05), including distribution volume (V), clearance (CL), elimination rate constant (Ke), half-life(T1/2), area under the curve (AUC), time to reach maximum concentration (Tmax). Compared with the control group, AUC was increased by 23.5%, Tmax and T1/2 were prolonged by 35.8% and 11.7%, respectively, and CL was decreased by 31.9% in the plateau group. The pharmacodynamic results showed that the hypoglycaemic effect of T2DM patients in the plateau group was similar to that in the control group, the concentration of lactic acid was higher in the plateau group than that in the control group, and the risk of lactic acidosis was increased after taking metformin in the plateau population.@*CONCLUSIONS@#Metformin metabolism is slowed down in T2DM patients in the hypoxic environment of the plateau; the glucose-lowering effect of the plateau is similar, and the attainment rate is low, the possibility of having serious adverse effects of lactic acidosis is higher in T2DM patients on the plateau than on the control one. It is probably suggested that patients with T2DM on the plateau can achieve glucose lowering effect by extending the interval between medication doses and enhancing medication education to improve patient compliance.

Anti-hypoxic pharmacological effects of betelnut polyphenols / 中南大学学报(医学版)

Areca catechu L. medicinal materials and their preparations are widely used in clinical practice. Betelnut polyphenol is one of the main chemical components with antioxidant, anti-inflammatory, and antibacterial effects. With continuous increase of high altitude activities, tissue oxidative damage caused by high altitude hypoxia seriously affects the ability to work, and the studies on anti-hypoxia drugs are particularly important. Recent studies have shown that betelnut polyphenols have protective effects on oxidative stress injury caused by hypoxia via improving blood gas index of hypoxic organism, increasing superoxide dismutase glutathione catalase activity, and scavenging excessive free radicals. The effects of betelnut polyphenols against hypoxia and oxidative damage protection suggest that betelnut polyphenols can be used as potential anti-hypoxia drugs and posses clinical prospects.

Research progress of pharmacokinetic factors of metformin / 中国药房

Metformin is the most common first-line oral hypoglycemic drug ，but there are large individual differences in pharmacokinetic parameters and pharmacodynamics during clinical use. The dosage of some patients should be adjusted to achieve satisfactory therapeutic effect. Pharmacokinetic parameters of metformin are affected by many factors ，including respects of transporter gene polymorphism ，drug interaction ，intestinal flora ，plateau hypoxia and physiological function and so on. In order to guide the clinical individualized use of metformin ，this study reviews the research progress on the influencing factors of metformin pharmacokinetics.

Klotho, an aging-suppression protein, inhib its TLR4/NF-kB p65/NGAL pathways in rat mesangial cells cultured with high glucose and its mechanism / 中华内分泌代谢杂志

Objective To explore the changes in expression of Klotho, an aging-suppression protein, and neutrophil gelatinase associated lipocalin ( NGAL) and their relationship with rat mesangial cells ( RMCs) cultured with high glucose in vitro, and to explore the role played by Toll-like receptor-4 (TLR4) / nuclear factor-kB(NF-kB) p65 pathways in this process. Methods Three NGAL-siRNA sequences were designed and synthesized. The effective sequence in subsequent experiments was chosen. RMCs were preincubated with pyrrolidinedithiocarbamate (PDTC)or exogenously added Klotho prior to high glucose treatment. Realtime PCR was used to analyze Klotho, TLR4, NGAL mRNA expressions. Western blot was used to observe Klotho, TLR4,NF-kB p65, NGAL,fibronectin (FN), and connective tissue growth factor ( CTGF) protein expression. ELISA assay was used to detect monocyte chemoattractant protein-1 ( MCP-1) and CXCL5 secretions. Results High glucose suppressed Klotho expression significantly(P<0. 05) and activated TLR4 / NF-kB p65 pathway. Meanwhile,the levels of NGAL,FN,CTGF, MCP-1, and CXCL5 were highly expressed ( P < 0. 01). NGAL gene silencing obviously down-regulated the increased expressions of FN, CTGF, MCP-1, and CXCL5 ( P < 0. 01). After PDTC treatment the overexpression of NGAL protein was markedly lowered(P<0. 01). In addition, Klotho treatment significantly inhibited the activity of TLR4 /NF-kB p65 pathways and down-regulated the expressions of NGAL, FN, CTGF, MCP-1 and CXCL5 stimulated by high glucose(P<0. 01). Conclusion Klotho inhibits the activity of TLR4 / NF-kB p65 pathways and thus inhibits NGAL expression in RMCs cultured with high glucose in vitro. And then it suppresses the expressions of FN, CTGF, MCP-1, and CXCL5. This provides a new basis to illustrate the protection mechanism of the anti-aging protein Klotho in diabetic nephropathy, and may provide new ideas and therapeutic targets for prevention and treatment.

Factors affecting the progression from ocular to generalized myasthenia gravis / 中华神经科杂志

Objective To explore thc clinical manifestation of secondary generalized myasthenia gravis(GMG) and analyze the factors affecting the progression from ocular myasthenia gravis(OMG) to GMG.Methods This research constitutes a single-center,retrospectively-collected prospective cohort study.We comprehensively reviewed our self-managed myasthenia gravis (MG) database drawn from personal clinical experience from January 2000 to Junc 2013.Patients underwent series of examination including repetitive nerve stimulation (RNS) tests,measurement of serum acetylcholine receptors antibody and serum muscle-specific tyrosine kinase antibodies,thymus computer tomography scan etc.Patients were treated with pyridostigmine bromide,corticosteroid therapy and (or) thymectomy based on a nonrandomization pattern and they were documented for their respective symptoms of OMG and GMG and date of GMG conversion.Logistic regression analysis was adopted to determine the influencing factors correlated with the development of GMG during the follow-up.Results Totally 770 patients initially diagnosed with OMG were included,among whom 573 (74％) patients remained with OMG (R-OMG group) and 197(26％) patients developed into GMG (GMG group) during the follow-up.(1) In comparison with their R-OMG counterparts,patients with secondary GMG were older at onset; Displayed more frequent RNS abnormality of facial nerve,accessory nerve and ulnar nerve ; Showed higher incidence of thymoma and were less treated by early corticosteroids.(2) For GMG group,81％ (160/197) of them displayed bulbar MG; 67％ (132/197) of GMG conversion occurred within 2 years,and 84％ (166/197) within 5 years.In comparison with the patients with onset of≤ 14-year-old,both of patients with15-49-year-old and≥ 50-year-old displayed higher conversion rate and shorter conversion duration (median:10 years versus 1 year and 6.5 months).(3) RNS abnormality of accessory nerve(OR =6.650,95％ CI 3.547-12.471 ; P ＜ 0.05) and thymoma(OR =7.924,95％ CI 2.554-24.585 ; P ＜ 0.05) were prognostic factors for the development of GMG,while early corticosteroid(OR =0.232,95％ CI 0.119-0.452 ; P ＜ 0.05) predicted the reduction of the risk of generalization.Conclusions Multiple factors including abnormal RNS of proximal limb muscles,thymoma,early corticosteroids therapy and possibly even onset age of over 15-year-old may involve the generalization in patients with OMG at onset.

Postintervention status in ocular myasthenia gravis: effects of treatment / 中华神经科杂志

ObjectiveTo assess the differences of short- and long-term postintervention status on ocular and systemic symptoms for patients with ocular myasthenia gravis (OMG) after pyridostigmine bromide, corticosteroid, thymectomy, or thymectomy-corticosteroid combination therapy ( combination ).MethodsThis retrospective plus prospective study included 180 OMG patients, whose age of onset ≥ 15 years, treated non-randomly with above therapies separately: thymectomy group (60 cases ), corticosteroid group (39 cases), combination group ( 31 cases ), symptomatic group ( 50 cases ). Postintervention status complying with Myasthenia Gravis Foundation of America (MGFA)complete stable remission ,pharmacologic remission, or minimal manifestations was considered as desirable response, which was used as statistical indicator. Results ①Corticosteroid group showed higher desirable response rates on ptosis, ophthalmoplegia and general weakness at 3-6 months after treatment than other groups, and 42. 1％( 16/38 ) of them at 3 months achieved the desired state of ptosis, higher than the symptomatic group (7/48,14. 6％, ×2 = 8. 200, P = 0. 004 ). ② Ascending ideal rates had been presented in both combination and thymectomy groups since 1 year after treatments, while a little bit higher rate was presented in the former. At the end of observation, 21.7％ ( 13/60 )of patients in thymectomy group achieved complete stable remission.By paired longitudinal comparisons,thymectomy group showed higher ideal rates on ptosis (22/40,55.0％ ), ophthalmoplegia ( 16/27,59. 3％ ) and general weakness (20/40,50. 0％ ) at 2 years than that at 3 months( 11/59,18.6％ ;11/44,25.0％ ;9/60,15.0％ ;P =0. 002, 0. 031,0.000). ③For those patients by symptomatic treatment, the average age of onset was (51.9 ± 18.0) years, higher than that by other 3 therapies (F = 10. 563 ,P =0. 000). ④OMG patients with ophthalmoplegia more likely select corticosteroid or combined therapy. Ophthalmoplegia in combination group was higher than that in symptomatic and surgery groups( ×2 = 12. 939,14. 380, P =0. 000 in both). Ophthalmoplegia in corticosteroid group was higher than that in surgery group ( ×2 = 8. 017, P = 0. 005 ).Conclusions Corticosteroid appears to early overcome ptosis, ocular motor dysfunction and general weakness for patient with OMG in early-to-middle adulthood.Thymectomy andsurgery-corticosteroid combinationtherapies bothshowlong-term effectonthem.