Long-term Therapeutic Effects Research Articles

A DNA Methylation Signature of Addiction in T Cells and Its Reversal With DHEA Intervention.

Previous studies in animal models of cocaine craving have delineated broad changes in DNA methylation profiles in the nucleus accumbens. A crucial factor for progress in behavioral and mental health epigenetics is the discovery of epigenetic markers in peripheral tissues. Several studies in primates and humans have associated differences in behavioral phenotypes with changes in DNA methylation in T cells and brain. Herein, we present a pilot study (n = 27) showing that the T cell DNA methylation profile differentiates persons with a substance use disorder from controls. Intervention with dehydroepiandrosterone (DHEA), previously shown to have a long-term therapeutic effect on human addicts herein resulted in reversal of DNA methylation changes in genes related to pathways associated with the addictive state.

Follow-up study of 116 cases of transjugular intrahepatic portosystemic shunt in the treatment of cirrhotic portal hypertension

Objective: To investigate the incidence rate of transjugular intrahepatic portosystemic shunt (TIPS) complications in the treatment of cirrhotic portal hypertension, and analyze the cause of complication to management methods. Methods: Data of 116 patients obtained from Zhongnan Hospital of Wuhan University were retrospectively analyzed. Portal venous pressure, routine blood test, coagulation test, liver and kidney function test, ammonia blood test, imaging and endoscopy reports were collected before and after procedure. The incidence rate of hepatic encephalopathy, gastrointestinal bleeding, ascites and shunt dysfunctions were observed. Data were expressed as mean ± Standard deviation and analyzed by t-test. A chi-squared test was used for comparison between categorical variables. Results: The success rate of TIPS operation was 97.41% (113/116). Two patients underwent prompt TIPS procedure due to active bleeding. Bleeding was successfully stopped. Portal venous pressure of 113 patients decreased from (42.73 ± 7.64) cmH(2)O to (24.92 ± 7.60) cmH(2)O, and the difference was statistically significant (P < 0.01). Twenty cases were of hepatic encephalopathy. Preoperative level of Child-pugh class C patients was more susceptible to hepatic encephalopathy within 3 months after procedure than class A and B. After TIPS procedure, there were 22 cases of gastrointestinal bleeding, 18 cases of shunt dysfunctions and 26 cases of disease related death. Conclusion: Rational patient selection strategies can effectively reduce portal venous pressure, incidence of hepatic encephalopathy, improve mid-and long-term therapeutic effects, and provide opportunities for liver transplantation.

Baseline Investigation of HIV-1 Primary Drug Resistance Among Newly Diagnosed Treatment-Naïve HIV-1 Individuals in Hebei, China.

Human immunodeficiency virus (HIV) primary drug resistance (PDR) has influenced the long-term therapeutic effects of antiretroviral drugs. However, for the overall PDR prevalence in China, no report was found in published articles. In our study, an extensive cross-sectional investigation based on all newly diagnosed treatment-naive HIV-infected individuals was conducted. The overall prevalence of HIV-1 PDR among newly diagnosed treatment-naive HIV-1 individuals was 8.3% (60/720), obviously beyond the warning line (5.0%) set by WHO. The prevalence of PDR to PIs, nucleoside reverse transcriptase inhibitors, and non-nucleoside reverse transcriptase inhibitors was 4.9% (35/720), 0.4% (3/720), and 2.5% (18/720), respectively. Moreover, the occurrence of HIV-1 PDR strains was random among different prefectures. HIV-1 PDR strains were extensively circulating among the sexual contact population inside and outside the Hebei province, especially between neighboring provinces and Hebei. Hebei province has become the moderate level PDR epidemic area. Enhanced surveillance for PDR is necessary among treatment-naïve individuals in Hebei, and we must take effective measures to cut off the spread of HIV PDR strains.

Advances in gene therapy for hemophilia: basis, current status, and future perspectives.

Hemophilia is a congenital hemorrhagic disease caused by genetic abnormalities in coagulation factor VIII or factor IX. Current conventional therapy to prevent bleeding requires frequent intravenous injections of coagulation factor concentrates from early childhood. Accordingly, gene therapy for hemophilia remains an exciting future prospect for patients and their families, due to its potential to cure the disease through a one-time treatment. After a series of successes in basic research, recent clinical trials have demonstrated clear efficacy of gene therapy for hemophilia using adeno-associated virus (AAV) vectors. Although this is likely to alter the paradigm of hemophilia care in the near future, it will be important to overcome immune responses against AAV. Gene therapy for hemophilia cannot be given to patients with anti-AAV capsid-neutralizing antibodies, and cellular immunity with CD8+ T cells should be controlled for sustained expression. Furthermore, long-term therapeutic effects should be closely observed because of the failure of the AAV vector genome to replicate during cell division. This review focuses on the basis of gene therapy, current successes of clinical trials, and the future direction of hemophilia gene therapy.

Laparoscopic sleeve gastrectomy combined with single-anastomosis duodenal-jejunal bypass in the treatment of type 2 diabetes mellitus of patients with body mass index higher than 27.5 kg/m2 but lower than 32.5 kg/m2.

This study aimed to introduce this surgical technique laparoscopic sleeve gastrectomy combined with single-anastomosis duodenal-jejunal bypass (LDJB-LSG), and to confirm this new surgical technique was safe in the treatment of type 2 diabetes mellitus (T2DM) of patients with body mass index (BMI) higher than 27.5 kg/m2 but lower than 32.5 kg/m2.A total of 34 T2DM patients with (BMI) higher than 27.5 kg/m2 but lower than 32.5 kg/m2 were admitted to our department between January 2014 and October 2016, of whom 25 received laparoscopic gastric bypass surgery (LRYGB) and 9 received LDJB-LSG. The efficacy and safety were compared between the 2 groups.None in both groups died and had severe postoperative complications. All the surgeries were performed by laparoscopy, and none received switching to open surgery. Patients received regular follow-up after surgery and none were lost to follow-up.Our study indicates LDJB-LSG is similar to LRYGB in the improvements of the body weight, blood glucose, insulin resistance, islet β cell function, blood lipid profile and serum uric acid, and thus LDJB-LSG is applicable in T2DM patients with 27.5 kg/m2 ≤ BMI ≤ 32.5 kg/m2 and risk for gastric cancer. However, long-term therapeutic effects need to be evaluated by studies with multicenter, large sample size, and long-term follow-ups.

Spatial Confined Synergistic Enzymes with Enhanced Uricolytic Performance and Reduced Toxicity for Effective Gout Treatment.

Confinement of urate oxidase with detoxifying enzymes into multienzyme architecture is an appealing approach for gout treatment due to its capability to decompose serum uric acid without generation of H2 O2 . However, most of these strategies involve chemical modifications to the enzymes and barely consider enhancing the stability of the multienzyme architectures particularly against proteolysis, which significantly dampened its catalytic activity and in vivo stability. Herein, a novel strategy to prepare multienzyme nanoclusters with highly uricolytic activity and enhanced stability is demonstrated. With the close proximation, catalase can effectively decompose the H2 O2 generated by uricase during uricolysis. Moreover, with a shell structure constructed with polyethylene glycol, the nanocluster achieves great performance in reducing the nonspecific serum protein adsorptions and proteases digestion, leading to an enhanced circulation time after the intravenous administration. Such complementary multienzyme nanoclusters realize the long-term therapeutic effect in the management of serum uric acid level, without any toxicity or undesired immune responses in vivo. This work mimics the synergistic effect of protein complex in nature and can be further developed to a general method for the construction of multienzyme nanoclusters, which provides new opportunities for utilizing therapeutic enzymes for the treatment of metabolic diseases.

Comparison of Therapeutic Effects of TREK1 Blockers and Fluoxetine on Chronic Unpredicted Mild Stress Sensitive Rats

The animal model for depressive behavior due to chronic unpredicted mild stress (CUMS) is commonly used to evaluate antidepressant treatments. The CUMS model has faced some criticism because of the heterogeneity of behavioral effects. Spadin and SID1900 are TREK1 blockers with a quick antidepressant effect. However, to date, their effectiveness and the long-term therapeutic mechanisms are not known. We hypothesize that early intervention with TREK1 blockers can fully reverse depressive-like behaviors, that the chronic administration of TREK1 blockers has a more pronounced effect than the SSRI fluoxetine, and that its long-term therapeutic effects may be mediated by improvement of impaired neurogenesis. Furthermore, we optimized the use of the CUMS model for increased homogeneity by screening the rats after the CUMS induction procedure. Depressive-like behavior was assessed by a forced swimming test, sucrose preference, and open field tests. To evaluate neurogenesis, cell proliferation and newly generated cell apoptosis were measured in the hippocampal dentate gyrus. Of 32 rats that underwent the CUMS procedure, 26 rats that exhibited depressive-like behaviors were grouped as CUMS sensitive rats (CUMSS), while six that did not were grouped as CUMS resistant ones (CUMSR). The CUMSR rats exhibited minor neurogenesis impairments, while the CUMSS rats had a more pronounced effect. Treatment with TREK1 blockers could reverse depressive-like behaviors at least 1 week earlier than that of fluoxetine. Chronic administration of both the TREK1 blockers and fluoxetine could restore neurogenesis impairments. This study underlines the importance of model validation by determination of CUMS sensitivity. The TREK1 blockers were found to have an effect that was more rapid and more pronounced than that of fluoxetine. Therapeutic benefits after chronic administration were associated with a restoration of impaired neurogenesis.

Time Course of Radiologic Changes After Lumbar Total Disc Replacement: Experience of Single Institute With Minimum 5-Year Follow-up.

This was a retrospective observatory analysis study. The purpose of this study was to evaluate long-term safety and therapeutic effectiveness of the lumbar total disc replacement (TDR) using ProDisc-L by analyzing the radiologic changes at the index and adjacent levels in minimum 5-year follow-up. Early successful clinical results of lumbar TDR have been reported. However, few reports have published its therapeutic effectiveness and radiologic degenerative changes at the index and adjacent segments in the long term. Forty-three patients were followed-up for at least 60 months. Radiologic changes were assessed by segmental range of motion (ROM) at the index and adjacent levels, global lumbar lordosis, and disc space height (DSH). The magnetic resonance imaging and computed tomographic scans were used to determine the facet arthrosis and intervertebral disc degeneration at the index and adjacent levels. Gradual decrements of DSH restoration were observed until the last follow-up. Mean global and segmental ROM of index segments were significantly reduced (P=0.044, 0.00) at the last visit. There were 21 patients (48.8%) with no motion at index segment (ROM<0.5 degrees) at the last visit. Among the 56 segments operated on, progression of facet arthrosis was observed in 30.3% of index segments and 10.9% of adjacent segments. None of the postoperative radiologic parameters included in the present study presented significant correlation with clinical outcome. The study demonstrates that only half of the lumbar TDR patients can maintain segmental motion at the index level >5-year after surgery and TDR provides a good clinical outcome postoperatively regardless of motion preservation or DSH height preservation at the last follow-up. After TDR, the degenerative changes in the index and adjacent segments advanced as compared with our previous report of 2-year follow-up, however, these changes did not appear to exert negative influence upon clinical outcomes.

Health Informatics Analysis of Long-Term Therapeutic Effect of Non-Penetrating Trabecular Surgery Based on Ultrasound Biomicroscopy

Health Informatics Analysis of Long-Term Therapeutic Effect of Non-Penetrating Trabecular Surgery Based on Ultrasound Biomicroscopy

CRISPR-LbCpf1 prevents choroidal neovascularization in a mouse model of age-related macular degeneration

LbCpf1, derived from Lachnospiraceae bacterium ND2006, is a CRISPR RNA-guided endonuclease and holds promise for therapeutic applications. Here we show that LbCpf1 can be used for therapeutic gene editing in a mouse model of age-related macular degeneration (AMD). The intravitreal delivery of LbCpf1, targeted to two angiogenesis-associated genes encoding vascular endothelial growth factor A (Vegfa) and hypoxia inducing factor 1a (Hif1a), using adeno-associated virus, led to efficient gene disruption with no apparent off-target effects in the retina and retinal pigment epithelium (RPE) cells. Importantly, LbCpf1 targeted to Vegfa or Hif1a in RPE cells reduced the area of laser-induced choroidal neovascularization as efficiently as aflibercept, an anti-VEGF drug currently used in the clinic, without inducing cone dysfunction. Unlike aflibercept, LbCpf1 targeted to Vegfa or Hif1a achieved a long-term therapeutic effect on CNV, potentially avoiding repetitive injections. Taken together, these results indicate that LbCpf1-mediated in vivo genome editing to ablate pathologic angiogenesis provides an effective strategy for the treatment of AMD and other neovascularization-associated diseases.

Engineered U7 snRNA mediates sustained splicing correction in erythroid cells from β-thalassemia/HbE patients

Repair of a splicing defect of β-globin pre-mRNA harboring hemoglobin E (HbE) mutation was successfully accomplished in erythroid cells from patients with β-thalassemia/HbE disorder by a synthetic splice-switching oligonucleotide (SSO). However, its application is limited by short-term effectiveness and requirement of lifelong periodic administration of SSO, especially for chronic diseases like thalassemias. Here, we engineered lentiviral vectors that stably express U7 small nuclear RNA (U7 snRNA) carrying the splice-switching sequence of the SSO that restores correct splicing of βE-globin pre-mRNA and achieves a long-term therapeutic effect. Using a two-step tiling approach, we systematically screened U7 snRNAs carrying splice-switching SSO sequences targeted to the cryptic 5′ splice site created by HbE mutation. We tested this approach and identified the most responsive element for mediating splicing correction in engineered U7 snRNAs in HeLa-βE cell model cell line. Remarkably, the U7 snRNA lentiviral vector (U7 βE4+1) targeted to this region effectively restored the correctly-spliced βE-globin mRNA for at least 5 months. Moreover, the effects of the U7 βE4+1 snRNA lentiviral vector were also evident as upregulation of the correctly-spliced βE-globin mRNA in erythroid progenitor cells from β-thalassemia/HbE patients treated with the vector, which led to improvements of pathologies in erythroid progenitor cells from thalassemia patients. These results suggest that the splicing correction of βE-globin pre-mRNA by the engineered U7 snRNA lentiviral vector provides a promising, long-term treatment for β-thalassemia/HbE.

Evaluation of the therapeutic effects of QuickOpt optimization in Chinese patients with chronic heart failure treated by cardiac resynchronization

In this trial, long-term therapeutic effects and clinical improvements in Chinese chronic heart failure patients optimized by QuickOpt or echocardiography were compared for atrioventricular (AV) and interventricular (VV) delay optimizations after cardiac resynchronization therapy (CRT) with pacing (CRT-P) or with pacing and defibrillator (CRT-D) therapy. One hundred and ninety-six subjects (50%) had dilated cardiomyopathy, 108 (27.6%) had ischemic heart disease and 112 (28.6%) were hypertensive and were randomized into QuickOpt (198) or echocardiographic optimization (control) (194) groups at ≤2-weeks post-implantation. Programmed AV/VV delay was optimized at baseline and at 3 and 6 months. Left ventricular end-systolic volume (LVESV), New York Heart Association (NYHA) class, specific activity scale (SAS), and the six-minute walk tests (6MWT) were evaluated by blinded researchers at 12 months. Of the QuickOpt group, LVESV decreased significantly by 24.7% ± 33.9% compared with baseline, while LVESV of Controls decreased by 25.1% ± 36.1% (P = 0.924). NYHA class, SAS and 6MWT also improved similarly in both groups at 12 months. Mortality in both groups was not significantly different (11.0% vs 7.6%, P = 0.289). However, there was a significant difference in the time required for optimization by QuickOpt compared with echocardiography (3.33 ± 3.11 vs 58.79 ± 27.03 minutes, P < 0.000).

A Longitudinal Mapping Study on Cortical Plasticity of Peripheral Nerve Injury Treated by Direct Anastomosis and Electroacupuncture in Rats.

We used functional magnetic resonance imaging to provide a longitudinal description of cortical plasticity caused by electroacupuncture (EA) of sciatic nerve transection and direct anastomosis in rats. Sixteen rats in a sciatic nerve transection and direct anastomosis model were randomly divided into intervention and control groups. EA intervention in the position of ST-36, GB-30 was conducted continuously for 4 months in the intervention group. Functional magnetic resonance imaging and gait assessment were performed every month after intervention. The somatosensory area was more activated in the first 2 months and then deactivated in the rest 2 months when EA was applied. The pain-related areas had the same activation pattern as the somatosensory area. The limbic/paralimbic areas fluctuated more during the EA intervention, which was not constantly activated or deactivated as previous studies reported. We attributed such changes in somatosensory and pain-related areas to the gradual reduction of sensory afferentation. The alterations in limbic/paralimbic system might be associated with the confrontation between the upregulating effect of paresthesia or pain and the downregulating effect of EA intervention through the autonomic nerve system. The gait analysis showed significantly higher maximum contact mean intensity in the intervention group. The alterations in the brain brought about by the long-term therapeutic effect of EA could be described as a synchronized activation pattern in the somatosensory and pain-related areas and a fluctuating pattern in the limbic/paralimbic system.

NATRIURETIC PEPTIDES AS PREDICTIVE BIOMARKERS OF TREATMENT RESPONSE IN CLINICAL TRIALS OF HEART FAILURE

The lack of reliable predictors of efficacy of HF drugs and devices has presented a major hurdle to the evaluation of novel therapies. We explore whether short-term treatment-related changes in natriuretic peptides (NP) predict long-term therapeutic effects using a) patient-level data from PARADIGM

A single, extinction-based treatment with a kappa opioid receptor agonist elicits a long-term reduction in cocaine relapse

Kappa opioid receptor (KOR) agonists have known anti-addiction properties and can reduce drug seeking. Their potential for clinical use has largely been daunted by their aversive properties mediated through p38 MAPK signaling. Here we examined the therapeutic potential of the KOR agonist U50,488 (U50) to reduce cocaine seeking in a self-administration model. Following cocaine self-administration and 7 days of forced home-cage abstinence, rats were administered a single dose of U50 (5 mg/kg, i.p.) 30 min prior to the first extinction training session, wherein cocaine and the discrete cocaine-paired cues were no longer available. U50 reduced cocaine seeking on this first extinction session, but did not alter extinction training over subsequent days. 2 weeks after U50 treatment, rats underwent a test of cue-induced reinstatement, and rats that had received U50 reinstated less than controls. Central inhibition of p38 MAPK at the time of U50 administration prevented its long-term therapeutic effect on reinstatement, but not its acute reduction in drug seeking on extinction day 1. The long-term therapeutic effect of U50 required operant extinction during U50 exposure, extended to cocaine-primed reinstatement, and was not mimicked by another aversive drug, lithium chloride (LiCl). These data suggest U50 elicits its long-term anti-relapse effects through a KOR-p38 MAPK-specific aversive counterconditioning of the operant cocaine-seeking response. A single, albeit aversive treatment that is able to reduce relapse long-term warrants further consideration of the therapeutic potential of KOR agonists in the treatment of addiction.

Development of gene therapy for hemophilia: current states and future perspectives

Hemophilia is congenital hemorrhagic disease due to genetic abnormality of blood coagulation factor VIII or factor IX. Hemophilia appears suitable for gene therapy because it is caused by a single gene abnormality, and therapeutic coagulation factor levels vary across a broad range. Since the success of gene therapy eliminates the need for regular administration of factor concentrates, the development has been met with great expectation from patients and their families. In fact, several clinical trials using adeno-associated virus (AAV) vectors have been started in Western countries, and long-term therapeutic effect could be obtained by single injection. More recently, the modifications of therapeutic gene and AAV serotypes have further improved therapeutic effects, and it appears to have reached the level of "cure". However, gene therapy using AAV vectors presents difficulties such as the existence of anti AAV capsid neutralizing antibody and hepatic injury due to cellular immunity with CD8+ T cells. Thus, it is essential to develop technologies adapted to a wide range of hemophilia patients, and to observe long-term safety and therapeutic effect after the gene therapy.

Abstract WP311: A Widely Accepted Metric (Telephone Assessment of the Modified Rankin Scale Score at 90 Days) May Not Accurately Reflect the Real-Life Outcome of Endovascular Stroke Treatment

Introduction: The modified Rankin Score (mRS) collected at approximately 90 days after stroke onset is a reliable and reproducible measure of stroke outcome. It was utilized in the randomized controlled trials that established the safety and efficacy of endovascular stroke treatment. It has been incorporated as a core metric for measuring quality of care in comprehensive stroke centers. We aimed to evaluate the value of the 90-day mRS considering that a certain percentage of patients may fail to respond to coordinator phone calls. Methods: We retrospectively analyzed patients who received endovascular stroke treatment in a comprehensive stroke center from January 2015 to March 2017, and who were prospectively enrolled in the Get With The Guidelines-Stroke Registry. We calculated the response rates to coordinator phone calls at approximately 90 days from stroke onset. Several calls were placed according to the established institutional policy. We compared the response rates of patients who had successful or unsuccessful recanalization, as reported by the endovascular specialist at the time of the procedure. Results: We identified 79 patients who received endovascular treatment, and who were contacted by the coordinators at approximately 90 days after stroke onset. 58 patients had successful recanalization (as defined by reported TICI grades IIb and III), whereas 21 patients had unsuccessful recanalization (as defined by reported TICI grades O, I, and IIa). 44/58 patients with successful recanalization responded to coordinator calls, compared to 11/21 patients with unsuccessful recanalization. The difference in proportions was statistically significant (p=0.045). Conclusions: Patients who have unsuccessful recanalization after endovascular stroke treatment are significantly less likely to respond to coordinator calls. Therefore, their mRS cannot be estimated, and the long-term outcome of the endovascular procedure cannot be assessed. Since these patients are more likely to have died, or be in a supervised facility (and therefore not accessible at their previous phone number), the telephone assessment of the mRS is likely not an accurate measure for the long-term therapeutic effect of endovascular stroke treatment.

Tumor-suppressing miR-141 gene complex-loaded tissue-adhesive glue for the locoregional treatment of hepatocellular carcinoma.

microRNAs (miRNAs) regulate gene expression post-transcriptionally and have been extensively tested as therapeutic molecules against several human diseases. In vivo delivery of miRNAs needs to satisfy the following conditions: safety, efficiency, and long-term therapeutic effectiveness. To satisfy these conditions, we developed a tissue-adhesive nucleotide-polymer complex (NPX-glue) for in vivo delivery of miRNAs to treat hepatocellular carcinoma (HCC).Methods: Polyallylamine (PAA), a cationic polymer, was mixed with tumor-suppressing miR-141 to form NPX and then mixed with partially oxidized alginate (OA) to form NPX-glue. Delivery efficiency of miR-141:NPX-glue was determined in cultured HCC cells and in an implanted HCC tumor model. In vivo tumor-suppressive effects of miR-141 on HCC were examined in mice upon intratumoral injection of miR-141:NPX-glue.Result: NPX-glue was generated by mixing of NPX with OA, which eliminated the inherent cytotoxic effect of NPX. NPX-glue led to the efficient delivery of miR-141 and plasmid to cultured cells and solid tumors in mice, where their expression was maintained for up to 30 days. Upon intratumoral injection of miR-141:NPX-glue, the growth of the tumors was dramatically retarded in comparison with the negative control, NCmiR:NPX-glue, (p < 0.05). Molecular examination proved miR-141:NPX-glue efficiently regulated the target genes including MAP4K4, TM4SF1, KEAP1, HDGF, and TIAM1 and finally induced apoptosis of cancer tissues.Conclusion: Here, we show that NPX-glue delivers therapeutic miR-141 to solid tumors in a safe, stable, and long-term manner and prove that locoregional treatment of HCC is possible using the NPX-glue system.

Comparative Analysis of Modern Methods of Psychotherapy for Patients with Borderline Personality Disorder

This literature review aims to evaluate the evidence in the extant literature of practical and evidence-based psychotherapy methods for overcoming personality disorders and to compare them with one another. For a systematic review, we used the following databases: ScienceDirect, ResearchGate, Cochrane, PsyNet, CrossRef, PubMed. As a result, 33 articles were selected. Dialectic Behavioral Therapy (DBT), Mentalization-based Therapy (MBT) and Schema-focused Therapy (SFT) have better evidence-based efficacy in the context of therapeutic effects on reducing the severity of diagnostic criteria and comorbid states. In the context of application in an outpatient setting the highest positive effect and compliances are demonstrated by DBT and SFT. The majority of trials of DBT and TFP showed the effectiveness of psychotherapy with a treatment duration of at least 12 months. The longest term without recurrence of comorbid states and drop out (36 months) was observed with the use of Transfer-focused Psychotherapy (TFP) and SFT, which in the context of the long-term therapeutic effect may give people benefits along with other therapies. The present review shows initial evidence that long-term psychotherapy can be a useful and evidence-based intervention for people with borderline personality disorder. These results provide promising evidence to support people who suffer from a personality disorder. DBT, MBT, and SFT can be proposed as methods of the first line as a nonpharmacological intervention.

Influence of crosslinker concentration on the characteristics of erythropoietin-alginate microspheres

Context: Microspheres have several advantages including protecting proteins from degradation and clearance after administration and produce a long-term therapeutic effect. Erythropoietin as a neuroprotectant agent has protein-like properties, which are susceptible to degradation and have low in vivo bioavailability. Microspheres formulations is one of potential drug delivery system for erythropoietin. Aims: To evaluate the effect of CaCl2 concentration on the characteristics (particle size, morphology, swelling index, and yield) of erythropoietin-alginate microspheres. Methods: Erythropoietin-alginate microspheres prepared by ionotropic gelation method with aerosolization technique using sodium alginate as polymer and CaCl2 as crosslinker were dried using freeze drying method with maltodextrin as lyoprotectant. The concentrations of alginate used were 2%, and CaCl2 concentrations were 0.5 M(F1), 0.75 M(F2) and 1 M(F3). Results: Results showed smooth and spherical microspheres for all formula with average particle size were 3.23 ± 0.05 μm (F1); 2.99 ± 0.07 μm (F2); and 2.86 ± 0.03 μm (F3). Mass swelling index at 24 h were 1.25 ± 0.10 (F1), 1.18 ± 0.11 (F2), and 1.11 ± 0.10 (F3); at 30 h were 2.00 ± 1.25 (F1), 1.85 ± 0.14 (F2), and 1.72 ± 0.15 (F3) while particle size swelling index at 24 h were 1.15 ± 0.10 (F1), 1.11 ± 0.10 (F2), and 0.97 ± 0.10 (F3); at 30 h were 1.81 ± 0.09 (F1), 1.73 ± 0.15 (F2), and 1.54 ± 0.14 (F3). Respectively yield percentages were 77.76 ± 6.49, 80.01 ± 3.53, and 82.97 ± 4.22. By using One Way ANOVA, it was found that there were significantly differences between three formulas. Conclusions: The particle size of formulas decreased by increasing concentration of CaCl2, whereas no significant difference on swelling index and yield from microspheres with increasing CaCl2 concentration simultaneously.