Improved anticancer delivery of paclitaxel by albumin surface modification of PLGA nanoparticles

Background

Nanoparticles (NPs) play an important role in anticancer delivery systems. Surface modified NPs with hydrophilic polymers such as human serum albumin (HSA) have long half-life in the blood circulation system.

Methods

The method of modified nanoprecipitation was utilized for encapsulation of paclitaxel (PTX) in poly (lactic-co-glycolic acid) (PLGA). Para-maleimide benzoic hydrazide was conjugated to PLGA for the surface modifications of PLGA NPs, and then HSA was attached on the surface of prepared NPs by maleimide attachment to thiol groups (cysteines) of albumin. The application of HSA provides for the longer blood circulation of stealth NPs due to their escape from reticuloendothelial system (RES). Then the physicochemical properties of NPs like surface morphology, size, zeta potential, and in-vitro drug release were analyzed.

Results

The particle size of NPs ranged from 170 to 190 nm and increased about 20–30 nm after HSA conjugation. The zeta potential was about -6 mV and it decreased further after HSA conjugation. The HSA conjugation in prepared NPs was proved by Fourier transform infrared (FT-IR) spectroscopy, faster degradation of HSA in Differential scanning calorimetry (DSC) characterization, and other evidences such as the increasing in size and the decreasing in zeta potential. The PTX released in a biphasic mode for all colloidal suspensions. A sustained release profile for approximately 33 days was detected after a burst effect of the loaded drug. The in vitro cytotoxicity evaluation also indicated that the HSA NPs are more cytotoxic than plain NPs.

Conclusions

HSA decoration of PLGA NPs may be a suitable method for longer blood circulation of NPs.     

肾病患儿联合检测尿中三种蛋白的临床意义

目的：探索尿白蛋白(Alb)、免疫球蛋白G(IgG)和β2-微球蛋白(β2-MG)联合测定在肾脏疾病(肾病)患儿早期诊断和病变部位的价值。方法127例肾脏疾病患儿,其中急性肾炎61例,为肾炎组,肾病综合征66例,为肾病组,另选取正常健康小儿50例,为对照组。采用RIA法对三组尿液中的Alb、IgG和β2-MG进行测定。结果肾炎组和肾病组尿中的Alb、IgG明显高于对照组(P<0.01);肾病组尿中的β2-MG明显高于对照组和肾炎组(P<0.01)。结论尿中的Alb、IgG和β2-MG联合测定能高灵敏早期反映肾脏的损伤,且能区分是肾小球还是肾小管的损害,并与病情呈正相关。     

Early serum albumin changes in patients with ulcerative colitis treated with tacrolimus will predict clinical outcome

BACKGROUNDOral tacrolimus is a therapeutic agent for moderate to severe steroid-dependent or resistant ulcerative colitis (UC), but remission induction is difficult, and it is necessary to treat the patient while considering the next treatment.AIMTo examine serum albumin (Alb) level as a prognostic factor for the therapeutic effect of tacrolimus in clinical practice.METHODSForty-seven patients with UC treated with tacrolimus at our institution were divided into remission and failure groups (colectomy or switch to biologics), and the biological data at the start of observation and at weeks 1 and 2 were retrospectively examined. Kaplan-Meier and multivariate analyses were performed using Alb as a prognostic factor in UC treatment.RESULTSDuring the three months observed, 17 (36.2%) patients failed treatment with tacrolimus. A comparison between the failure and remission groups showed a significant difference only in Alb in week 2, and in the week 2/week 0 Alb ratio, which showed the rate of change in Alb. The cut-off value of the week 2/week 0 Alb ratio that predicted failure was 1, and its area under the curve was 0.751 (95%CI: 0.604-0.898). In the Kaplan-Meier analysis, a week 2/week 0 Alb ratio ≤ 1 had a significantly higher failure rate than that of > 1; Cox proportional hazard regression analysis also showed that a week 2/week 0 Alb ratio ≤ 1 was an independent prognostic factor for failure within 3 mo after the start of tacrolimus treatment.CONCLUSIONA week 2/week 0 Alb ratio ≤ 1 predicts failure within 3 mo of tacrolimus administration for UC. High failure risk exists with week 2 Alb values ≤ 1 on admission.     

Incidence of new diabetic patients on dialysis in Piedmont,Italy: Major changes recorded over a 10-year period

Different incidence rates of new diabetic patients on dialysis are reported in various settings; although prevalence of this disease is often considered a marker of acceptance policy, rates are thought to be influenced also by genetic, epidemiological and other characteristics of a population (genetic composition, age distribution, lifestyle). Moreover, since features of a general population are often not stable (as in the setting analysed) changes at this level may have important reflections in the incidence of diabetics with end-stage renal disease (ESRD). In the region studied (Piedmont, northern Italy, about 4400 000 inhabitants, 20 dialysis centres, open acceptance since the mid-1970s, yearly information on 100% of patients, gathered by a Dialysis and Transplantation Registry) the incidence of diabetic patients with ESRD (389 cases recorded 1981–1990: 222 males, 167 females: mean age at start increasing from 55.5 years in 1981–1985 to 58.7 years in 1986–1990) differs according to age and sex. Incidence was higher in males, and rose from 6.23/year patients per million population (p.m.p.) in 1981–1982 to 12.88/year p.m.p. in 1989–1990, with a peak at age 60–69 (from 18.46/year p.m.p. in 1981–1982, to 46.12/year p.m.p. in 1989–1990). While relatively stable in the younger age groups from 1981 to 1990, incidence increased in the elderly (males age 70–79: 7.12/year p.m.p. in 1981–1982, 26.08/year p.m.p. in 1989–1990). As regards clinical and metabolic patterns, at the first update, in 1986–1990, 88.3% of diabetic patients were hypertensive or taking hypotensive drugs; albumin levels were below the normal range (<3.5 g/dl) in 30.3%; cholesterol levels were below the normal range (<150 mg/dl) in 16.15%. As regards entry criteria, creatinine clearances ranged from <1 to 14 ml/min (mean values at first update: 3.45±2.76 ml/min). In conclusion, presentation of diabetic patients with ESRD is changing. The stability of incidence in the younger age groups confirms the appropriateness of an open acceptance policy, at least for these ages. The increase in the elderly probably reflects the longer lifespan of diabetic patients in the overall population, while the influence of a hidden preselection must be further assessed. Since this cohort increasingly requires in-hospital high-tolerance treatment, future provision of dialysis needs must take into account the trend towards an increase in this high-risk elderly population.     

Contribution of superoxide to reduced antioxidant activity of glycoxidative serum albumin

Hyperglycemia increases oxidative stress in various tissues and leads to diabetic cardiovascular complication. Dyslipidemia, such as an increase in oxidized low-density lipoprotein (LDL), is well recognized in diabetic patients with hyperglycemia. However, the mechanism by which hyperglycemia causes the increased LDL oxidation remains unclear. Albumin is the most abundant protein in the circulation, and can function as an antioxidant. Therefore, we examined whether glycoxidative modification inhibits the antioxidant activity of albumin to LDL oxidation and clarified the mechanism by which this modification may suppress its antioxidant activity. Human serum albumin (HSA) was incubated in phosphate-buffered saline with and without glucose at 37°C for up to 8 weeks under aerobic conditions (referred to as glycoxidation (goHSA) and oxidation (oHSA), respectively). Metal chelator-treated, nonoxidative HSA (chHSA) and freshly prepared HSA (fHSA) were used as controls. N ^ε-(carboxymethyl)lysine (CML), a glycoxidative product, was determined by enzyme-linked immunosorbent assay. Oxidation was estimated by measuring the thiols of the HSA molecule. Copper-mediated oxidation of LDL was conducted in the presence or absence of modified HSAs at 37°C for 6 days. Malondialdehyde and negative charge of LDL were measured. To clarify the mechanism of reduced antioxidant activity of HSA, we examined firstly the binding activity of modified HSAs to copper, and secondly the effects of free radical scavengers on the formation of malondialdehyde. CML was formed in goHSA in a time- and concentration-dependent manner. Both goHSA and oHSA significantly decreased the contents of free thiol groups compared to ch- and fHSAs. The antioxidant activity of goHSA to LDL oxidation was the lowest among various modified HSAs. The oHSA showed a moderate decrease in antioxidant activity. The binding activity of go- and oHSAs to copper was lower than that of ch- and fHSAs. The formation of MDA from LDL oxidation in the presence of goHSA was completely inhibited by Tiron (1,2-dihydroxy-3,5-benzenedisulfonic acid) and superoxide dismutase. In contrast, catalase and mannitol had no effect. Our results indicate that in vitro glycoxidation of HSA induced a marked loss of antioxidant activity of this molecule to copper-mediated oxidation of LDL, which may be caused by the generation of superoxide. Received: December 17, 2001 / Accepted: June 28, 2002 Acknowledgments The authors thank Drs. Ryoji Nagai and Seikoh Horiuchi (Department of Biochemistry, Kumamoto University School of Medicine, Kumamoto, Japan) and Drs. Hiroyuki Itabe and Tatsuya Takano (Department of Microbiology and Molecular Pathology, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan) for kindly supplying antibodies. We also thank Associate Professor Takeo Yamaguchi (Department of Chemistry, Faculty of Science, Fukuoka University) for the ESR experiment and Miss Satoko Nagano for her excellent technical assistance. This work was supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan (No. 14570171) and in part by funds from the Central Research Institute of Fukuoka University (No. 016004). Correspondence to N. Sakata     

Angiotensinogen gene T235 variant: a marker for the development of persistent microalbuminuria in children and adolescents with type 1 diabetes mellitus

AIM: We examined genetic polymorphisms in the renin-angiotensin system (RAS) coding for angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) for angiotensinogen (AGT) M235T and angiotensin II receptor type 1 (AGTR1) A1166C as predictors for the development of microalbuminuria (MA) in children with type 1 diabetes mellitus (T1DM). METHODS: Four hundred fifty-three (215 males, 238 females) T1DM children [median (interquartile range): age, 16.7 years (13.9-18.3); diabetes duration, 6.9 years (3.3-10.8); age at diagnosis, 9.1 years (5.8-11.8)] were followed prospectively from diagnosis until the development of MA (two of three consecutive overnight urine samples with albumin excretion rates of > or =20 and <200 microg/min). Kaplan-Meier survival curves and Cox proportional multivariate model estimated the probability of developing MA and the relative risk for MA among different variables. RESULTS: MA developed in 41 (9.1%) subjects. The frequencies of genotypes were as follows: ACE-II 112 (25%), ACE-ID 221 (49%), and ACE-DD 117 (26%) (n=450); AGT-MM 144 (32%), AGT-MT 231 (51%), and AGT-TT 77 (17%) (n=452); AGTR1-AA 211 (47%), AGTR1-AC 204 (45%), and AGTR1-CC 37 (8%) (n=452). The cumulative risk for the development of MA was higher in ACE-DD versus ACE-ID/II groups (log-rank test, P=.05), and a trend was noticed when AGT-TT was compared to AGT-MT/MM groups (log-rank test, P=.08). AGT-TT polymorphism conferred a fourfold increased risk for MA compared to AGT-MM/MT (hazard ratio=3.8; 95% confidence interval=1.43-10.3; P=.008). INTERPRETATION: Our findings suggest that RAS gene polymorphism at AGT M235T is a strong predictor for early MA in young T1DM subjects.     

Recombinant human growth hormone increases albumin and prolongs survival in patients with chronic liver failure: A pilot open, randomized, and controlled clinical trial

OBJECTIVE: To evaluate the efficacy and safety of recombinant human growth hormone (rhGH) in the treatment of patients with chronic liver failure. SUBJECTS AND METHODS: One hundred and fourteen patients with chronic liver failure were randomly divided into two groups: (1) 56 patients in the rhGH treatment group received 4.5IU of rhGH intramuscularly daily for 4 weeks and (2) 58 patients in the control-treatment group. Fifteen healthy subjects served as normal controls. Symptoms and complications were recorded. The prognosis was analysed by Kaplan-Meier survival analysis. The serum GH, IGF-1, IGFBP-3, and insulin levels were determined using ELISA. RESULTS: The efficacy of rhGH treatment was 87.5% (vs. 38.1% in the controls-treatment group, p<0.01). The serum GH, IGF-1, IGFBP-3, and insulin levels in patients with chronic liver failure were significantly different than the levels in the normal controls (5.50+/-4.21 vs. 1.57+/-1.27, 80.45+/-69.99 vs. 172.97+/-78.12, 109.93+/-87.53 vs. 373.41+/-119.07, and 31.99+/-49.87 vs. 6.72+/-1.09, respectively, p<0.05-0.001). The serum IGF-1, IGFBP-3, albumin, proalbumin, and cholesterol levels were significantly increased after rhGH treatment; however, the serum GH and insulin levels were decreased. The survival rate of the rhGH treatment and control-treatment groups after 2 weeks, 1 month, 3 months, and 6 months of treatment was 98.21% vs.75.86%, 91.07% vs.62.07%, 66.07% vs.22.41%, and 55.36% vs.13.79%, respectively. Cox regression analysis showed that rhGH was an independent factor in predicting the survival of patients after 3 and 6 months of treatment with rhGH. CONCLUSIONS: rhGH replacement therapy increased albumin and tended to improve survival in adult patients with chronic liver failure.     

Low gradient ascites： A seven-year course review

AIM: To study the patients with low gradient ascites in hospitals of Guilan Province (northern Iran). METHODS: Patients admitted in hospitals of Guilan Province with low gradient ascites from 1993 to 2000 were enrolled in the study. Serum and ascitic fluid albumin levels were determined by biochemical reactions. The serum-ascitic albumin gradient (SAAG) less than 1.1 g/dL was considered low. Statistical analysis was performed with SPSS 9.0 software and P<0.05 was considered statistically significant. RESULTS: Of the 148 patients enrolled in the study, 72 (48.6%) were males and 76 (51.4%) were females with a mean age of 59.03±13.54 years. Tuberculous peritonitis was the most frequent cause of low gradient ascites in 68 (45.9%). Other most frequent causes were cancer in 62 (41.9%), nephrotic syndrome in 9 (6%), pancreatitis in 6 (4%). Peritoneal cancer was found in 22 (35%), ovarian and gastric cancers were found in 14 (22.5%) and 12 (19.3%), respectively. All of which were the causes of ascites. The mean SAAG was 0.68±0.19 g/dL. The mean serum and ascitic fluid albumin concentrations were higher in tuberculous patients (P<0.006), but lactate dehydrogenase (LDH) level was higher in cancer patients (P<0.0001). In peritoneal tuberculosis, mean ascitic glucose concentration was significantly lower than other patients (P<0.0001). CONCLUSION: Tuberculosis should be considered in all patients with low gradient ascites especially in developing countries (like Iran), as the first cause of ascites. In the approach to patients with low gradient ascites, ascitic fluid glucose, and LDH level are useful indicators for decision making.     

鞣酸蛋白酵母散对幼年大鼠腹泻的治疗作用及其机制研究

目的 研究鞣酸蛋白酵母散的治疗作用及其与保护肠黏膜、促进其修复的关系。方法 将48只21 d SD大鼠随机分为6组：对照组、模型组、蒙脱石散（阳性药,0.8 g/kg）组和鞣酸蛋白酵母散低、中、高剂量（0.1、0.3、0.9 g/kg）组。除对照组外,所有动物用4 g/kg番泻叶水煎剂连续ig 2周后,ig给药,对照组和模型组给予等体积的蒸馏水,每天2次,给药5 d。记录各组大鼠稀便率和腹泻指数。经治疗后,取各组大鼠空肠做苏木精-伊红染色和免疫组化,分别观察肠黏膜组织结构的改变和肠黏膜增殖细胞核抗原（PCNA）表达的变化。同时,刮取大鼠空肠黏膜分别测定DNA、总蛋白和IL-6的表达水平。结果 与模型组比较,经高剂量的鞣酸蛋白酵母散治疗后,大鼠稀便率和腹泻指数显著降低（P<0.001）,空肠绒毛结构基本恢复正常,空肠黏膜DNA含量显著增加（P<0.05）,PCNA表达显著增加（P<0.001）,IL-6表达减少。中剂量的鞣酸蛋白酵母散可改善大鼠腹泻,但对其他指标没有显著影响。而低剂量的鞣酸蛋白酵母散则无作用。结论 鞣酸蛋白酵母散对幼年大鼠腹泻有治疗作用,并可促进肠黏膜修复。