"Evaluation of neprilysin activity in Adipose-Derived stem cells from Alzheimer's disease patients".

INTRODUCTION: The antibody drugs targeting ß-amyloid in Alzheimer's disease pose risks of inflammation and vascular damage. It is known that neprilysin, an endogenous enzyme responsible for ß-amyloid degradation, is reduced in areas with ß-amyloid deposition. Supplementation of neprilysin could potentially contribute to Alzheimer's disease treatment. When considering the use of adipose tissue-derived stem cells (ADSCs) for Alzheimer's disease therapy, it is crucial to ensure that Alzheimer's disease patient-derived ADSCs maintain neprilysin activity. If so, the use of autologous ADSCs may lead to a treatment with minimal risks of rejection or infection. Therefore, we investigated the neprilysin activity in Alzheimer's disease patient-derived adipose tissue-derived stem cells to assess their potential in Alzheimer's disease treatment. METHODS: Five Alzheimer's disease patients (MSC1-5) and two Chronic Obstructive Pulmonary Disease (COPD) patients (MSC6-7) were enrolled. ADSCs were cultured for 6 days with varying seeding densities. On the 3rd day, the medium was replaced, and on the 6th day, ADSCs were harvested. Cells were stained for PE-Cy7 Mouse IgG1 κ Isotype control and PE-Cy Mouse Anti-Human CD10, and CD10 expression was assessed by flow cytometry. Ethical approval and informed consent were obtained. RESULTS: Neprilysin activity, crucial for ß-amyloid degradation, was assessed in ADSCs. Positivity rates for CD10 expression in ADSCs from Alzheimer's patients were consistently high: 99.6%, 99.5%, 99.9%, 99.3%, 99.8%, and 100.0%. Control ADSCs from COPD patients (MSC6-7) exhibited comparable positivity rates. Flow cytometry plots for all seven cases are presented in Figures 1-7. DISCUSSION: This study confirms the presence and maintenance of neprilysin activity in ADSCs from Alzheimer's disease patients. The high positivity rates for CD10 expression in these cells suggest that neprilysin, a key enzyme in ß-amyloid degradation, remains active. The implications are significant, as ADSCs offer immune-compatible and low infection risk advantages. The study underscores the potential of autologous ADSCs as a therapeutic approach in Alzheimer's disease. Their ability to naturally harbor neprilysin activity, coupled with their safety profile, makes them a promising candidate for further exploration. While acknowledging the need for larger, more diverse cohorts and long-term studies, these findings contribute to the growing body of evidence supporting the development of stem cell-based interventions in Alzheimer's disease treatment.

Feasibility and Safety of Adjuvant Chemotherapy for Resected Colorectal Cancer in Patients With Renal Insufficiency: A Pooled Analysis of Individual Patient Data from Five Japanese Large-scale Clinical Trials.

BACKGROUND/AIM: The incidence of chemotherapy-related adverse events in colorectal cancer patients with renal insufficiency has been compared to patients with normal renal function in only a few studies. The purpose of this analysis was to verify the feasibility and safety of adjuvant chemotherapy for postoperative colorectal cancer patients with renal insufficiency. PATIENTS AND METHODS: Adverse events and discontinuation of adjuvant chemotherapy for patients with curatively resected locally advanced colorectal cancer were examined using a combined database of individual patient data obtained from five large-scale clinical trials (n=4,106). The renal function of patients was classified into Level (L) 1-2: ≥60 ml/min and L3-4: <60 ml/min. RESULTS: As Grade 3 adverse events, hematological toxicities, such as neutropenia and anemia, and gastrointestinal disorders, such as diarrhea and vomiting, were significantly more frequent in the L3-4 group. Moreover, the time-to-treatment discontinuation in the L3-4 group was higher (hazard ratio=1.21, p=0.0012). T factor, N factor, and creatinine clearance level were found to be independent risk factors for the discontinuation of adjuvant chemotherapy. In the subgroup analysis of FOLFOX, neutropenia and diarrhea were significantly common in the L3-4 group, but neurotoxicities were not different. There was no significant difference in the discontinuation of adjuvant FOLFOX. CONCLUSION: Adverse events of adjuvant chemotherapy in patients with resected colorectal cancer were associated with renal insufficiencies. Since adverse events have the potential to shorten the duration of treatment, especially when using chemotherapy without oxaliplatin, careful management, including dose reduction, may be important in patients with renal insufficiency.

Final Analysis of 3 Versus 6 Months of Adjuvant Oxaliplatin and Fluoropyrimidine-Based Therapy in Patients With Stage III Colon Cancer: The Randomized Phase III ACHIEVE Trial.

PURPOSE: The phase III ACHIEVE trial conducted in Japan was one of six prospective studies included in the International Duration Evaluation of Adjuvant Therapy collaboration, which explored whether 3 months of adjuvant fluorouracil, leucovorin, and oxaliplatin (FOLFOX) or capecitabine and oxaliplatin (CAPOX) therapy would be noninferior to 6 months of treatment in patients with curatively resected stage III colon cancer. We report the final analyses of survival and long-term safety. PATIENTS AND METHODS: Eligible patients were randomly assigned (1:1) to either 3 or 6 months of adjuvant chemotherapy (modified [m]FOLFOX6 or CAPOX, as selected by the treating physician). Random assignment was stratified according to number of involved lymph nodes, center, regimen, primary site, and age. The primary end point was disease-free survival, assessed in the modified intention-to-treat population. Overall survival (OS) was a secondary end point. RESULTS: The modified intention-to-treat population comprised 1,291 patients: 641 in the 6-month treatment group and 650 in the 3-month treatment group. Median follow-up for this analysis was 74.7 months. Five-year OS rates were comparable: 87.0% in the 3-month treatment group and 86.4% in the 6-month treatment group (hazard ratio, 0.91; 95% CI, 0.69 to 1.20; P = .51). Subgroup analysis of OS did not reveal a significant interaction between baseline characteristics and treatment duration. Peripheral sensory neuropathy lasting longer than 5 years was more common in the 6- compared with 3-month treatment group (16% v 8%, respectively), and in those receiving mFOLFOX6 compared with CAPOX (14% v 11%, respectively). CONCLUSION: In Asian patients, shortening adjuvant therapy duration from 6 to 3 months did not compromise efficacy and reduced the rate of long-lasting peripheral sensory neuropathy. In this setting, 3 months of CAPOX therapy is an appropriate adjuvant treatment option.

Perspectives on Stem Cell-Based Regenerative Medicine with a Particular Emphasis on Mesenchymal Stem Cell Therapy.

Regenerative medicine is a medical treatment that aims to restore lost human body functions by regenerating missing or dysfunctional organs and tissues using stem cells, etc. There are three major types of stem cells used in regenerative medicine: induced pluripotent stem cells (iPS cells), embryonic stem cells (ES cells), and mesenchymal stem cells (MSCs). MSCs are expected to be widely applied to regenerative medicine because of their ability to differentiate into various types of cells, repair cells and tissues; anti-inflammatory effects; secretion of various growth factors; and resolution of abnormally accumulated protein amyloid. MSCs can be derived from bone marrow, dental pulp, and other sources, but adipose tissue-derived stem cells (ADSCs) may be superior in that they can be harvested with the least amount of invasion, and therefore, a sufficient amount of stem cells can be cultured relatively easily. When MSCs are administered systemically by intravenous infusion, they tend to accumulate at the site of disease, a property known as "homing," which is extremely advantageous for clinical applications. In Japan, stem cell therapy can be performed only after the research or treatment plan has been reviewed and approved by the "Committee for Specific Approval of Regenerative Medicine" and submitted to the Ministry of Health, Labor and Welfare for approval in accordance with the "Act on Securing the Safety of Regenerative Medicine" and after approval by the ethics committee of the facility where the therapy is performed. In this review, the characteristics of MSCs, the actual status of their clinical application, and their future prospects are presented.

Repeated infusion of autologous adipose tissue-derived stem cells for Parkinson's disease.

BACKGROUND: Mesenchymal stem cells are expected to have a therapeutic effect on progressive neurodegenerative diseases for which there is currently no fundamental treatment. AIMS OF THE STUDY: The aim is to confirm that repeated infusion of autologous adipose tissue-derived stem cells (ADSCs) can be safely administered to patients with Parkinson's disease, and to investigate the effects of this as a pilot study. METHODS: Three patients with Parkinson's disease received five or six repeated infusions of ADSCs at intervals of approximately one month. Observations were based on medical examinations by a neurologist and interviews with the patient and caregivers. The severity of Parkinson's disease was assessed using the Hoehn & Yahr staging scale and Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). RESULTS: No adverse events were observed during the observation period from the start of treatment to six months after the end of the last dose. MDS-UPDRS improved in all three patients. CONCLUSIONS: Repeated administration of Autologous ADSCs for Parkinson's disease was safe and feasible. The results of this pilot study provide insight into the value of further research.

Hypothesis: Intravenous administration of mesenchymal stem cells is effective in the treatment of Alzheimer's disease.

We propose the intravenous administration of autologous adipose-derived stem cells as a new treatment for Alzheimer's disease. We hypothesize that the stem cells will secrete neprilysin in the brain to break down and remove amyloid deposits in the Alzheimer's brain. We have shown a case of skin amyloid deposition that disappeared after stem cell administration and confirmed that the stem cells administered had neprilysin activity. In addition to neprilysin secretion, other mechanisms of action of stem cells include nerve regeneration, nerve repair, growth factor secretion, anti-inflammatory effects, and angiogenesis. The harvesting of adipose-derived stem cells is minimally invasive, and intravenous administration can be safely repeated. We hope that the efficacy of this new treatment will be verified and that it will bring a ray of hope to patients suffering from this incurable disease.

Isolation of adipose tissue-derived stem cells by direct membrane migration and expansion for clinical application.

Mesenchymal stem cells (MSCs) have recently made significant progression in multiple clinical trials targeting several clinical disorders and in the modulation of immune responses. In the present study, we isolated human adipose tissue-derived stem cells (ADSCs) by direct membrane migration method without using enzymatic digestion via collagenase, and tried to extract adequate number of cells for clinical application. Hydroxyapatite-treated nonwoven fabric membrane made up of synthetic macromolecular fiber materials, polyethylene and polyester terephthalene was used. Expansion culture of ADSCs having plastic flask adherent characteristic in serum-free condition was successfully established, and adequate number of cells were obtained for clinical application. They were found to be positive for CD44, CD73, CD90 and CD105 and negative for CD11b, CD34, CD45, CD80 and HLA-DR. The resulting immunological marker profile satisfied the immunophenotype of previously reported MSCs. Also, microscopic findings demonstrated trilineage differentiation into adipogenic, osteogenic and chondrogenic cells as the characteristics of MSCs. The isolation by nonwoven fabric membrane and expanded cells under serum-free condition satisfied the criteria of MSCs, as proposed by the International Society for Cellular Therapy. Our direct membrane migration method without enzyme digestion is useful as ADSCs can be obtained from small pieces of adipose tissue and expanded under serum-free culture condition. This method was considered to be feasible for clinical application.

[A new strategy for locally advanced rectal cancer using a nerve-regeneration tube].

In surgery for the treatment of locally advanced rectal cancers affecting the intrapelvic nerves, when an affected nerve is resected in extended surgery to achieve radical cure, the resection results in functional disturbance in the organ it controls. On the other hand, when the nerve remains intact after function-preserving surgery, the risk of local recurrence is high because of possible remnant cancer cells. Thus in performing surgery to treat such cancers, there is a dilemma between the selection of extended surgery or function-preserving surgery. To resolve this, we devised a new strategy in which the cancer is removed radically in extended surgery and organ function is recovered by regeneration of the resected nerve using a nerve-regenerating tube. After animal experiments had confirmed the regeneration of nerve functions with nerve-regenerating tubes, we followed this new strategy to treat 17 patients with locally advanced cancers who underwent extended surgery plus the regeneration of the resected nerve using the nerve-regenerating tube. Nerve function was restored to a significant degree in 16 of the 17 patients.

Multipeptide immune response to cancer vaccine IMA901 after single-dose cyclophosphamide associates with longer patient survival.

IMA901 is the first therapeutic vaccine for renal cell cancer (RCC) consisting of multiple tumor-associated peptides (TUMAPs) confirmed to be naturally presented in human cancer tissue. We treated a total of 96 human leukocyte antigen A (HLA-A)*02(+) subjects with advanced RCC with IMA901 in two consecutive studies. In the phase 1 study, the T cell responses of the patients to multiple TUMAPs were associated with better disease control and lower numbers of prevaccine forkhead box P3 (FOXP3)(+) regulatory T (T(reg)) cells. The randomized phase 2 trial showed that a single dose of cyclophosphamide reduced the number of T(reg) cells and confirmed that immune responses to multiple TUMAPs were associated with longer overall survival. Furthermore, among six predefined populations of myeloid-derived suppressor cells, two were prognostic for overall survival, and among over 300 serum biomarkers, we identified apolipoprotein A-I (APOA1) and chemokine (C-C motif) ligand 17 (CCL17) as being predictive for both immune response to IMA901 and overall survival. A randomized phase 3 study to determine the clinical benefit of treatment with IMA901 is ongoing.

Regeneration and functional recovery of intrapelvic nerves removed during extensive surgery by a new artificial nerve conduit: a breakthrough to radical operation for locally advanced and recurrent rectal cancers.

PURPOSE: In the current strategy against locally advanced and recurrent rectal cancers possibly involving intrapelvic nerves, there has been a serious dilemma between extensive surgery and limited surgery. The former can attain high tumor curability by sacrificing the nerve functions while the latter prioritizes the patient quality of life by preserving the nerve functions but with a compromised curability. Here we present a new surgical strategy for locally advanced and recurrent rectal cancers, which realize both high tumor curability and good quality of life. METHODS: A new artificial nerve conduit (polyglycolic acid collagen tube) developed by in site tissue engineering technology was applied to recovery the disturbed functions after removing the nerves from 11 patients undergoing extensive surgery for intrapelvic advanced or recurrent colorectal cancers. The reconstructed nerves included eight autonomic nerves which are essential for the genitourinary function and three somatic nerves which control the sensation and mobility of the legs. RESULTS: Out of ten cases followed up more than 2 years and evaluated fully, eight including two report cases showed a functional recovery of the disturbed autonomic and somatic nerves clinically. The nerve function started to recover from 3 to 6 months after the operation and continued to improve with times. No specific complications associated with the nerve repair have been noted. CONCLUSIONS: The new strategy utilizing the nerve conduit can be a breakthrough in radical operations for locally advanced and recurrent rectal cancers to resolve the problems between tumor curability and the patient quality of life.

Multicenter phase II study of weekly paclitaxel plus S-1 combination chemotherapy in patients with advanced gastric cancer.

BACKGROUND: A multicenter phase II study was conducted to evaluate the efficacy and safety of a combination regimen of weekly paclitaxel plus S-1 in patients with advanced gastric cancer. METHODS: Patients with previously untreated metastatic or recurrent gastric cancer received intravenous paclitaxel 50 mg/m(2) on days 1, 8, and 15, plus oral S-1 40 mg/m(2) b.i.d. on days 1 to 14 followed by 2 weeks off, in a 28-day cycle. RESULTS: A total of 54 patients were registered. All of them had measurable disease and were determined to be eligible for the present study. Two complete responses and 23 partial responses were confirmed, giving an overall response rate of 46.3%. At a final follow up of 3 years, the median progression-free survival and median overall survival were 6.0 and 14.3 months, respectively. Grade 3 neutropenia occurred in 14 patients, and grade 4 in 1 patient (total, 27.8%). The most serious nonhematological toxicity was diarrhea, where grade 3 occurred in 5 patients (9.3%). There were no treatment-related deaths. CONCLUSION: A combination of weekly paclitaxel plus S-1 was found to be well tolerated and effective in patients with advanced gastric cancer. Further investigation with comparative trials is needed for confirmation.

Regeneration of peritoneum using amniotic membrane to prevent postoperative adhesions.

BACKGROUND/AIMS: Adhesions following intraperitoneal surgery are frequent causes of small bowel obstruction. Attempts to prevent postoperative adhesions have mostly proven disappointing clinically. Currently used by ophthalmologists in ocular surface disorders, amniotic membrane transplantation can reduce inflammation and promote re-epithelization. We used amniotic membrane for facilitating peritoneal regeneration and prevention of adhesions with surgical trauma. METHODOLOGY: 20 rats were randomized in equal number into treatment or control groups. Seven days after operation, the incidence and severity of adhesions were evaluated. Histologic and immunohistochemical analyses were examined at 1, 4, 10 weeks after operation. RESULTS: While severe adhesions were observed after 1 week between the cecum and surrounding organs in the control group, adhesion formation was significantly reduced in the amniotic membrane group. Histologic examination demonstrated that free-floating myofibroblasts in the peritoneal cavity attached to surfaces of amniotic membrane grafts to form a layered structure. Free-floating mesothelial cells were incorporated into the regenerating mesothelium on the myofibroblast layer in 4 weeks, while implanted amniotic membrane grafts were absorbed by 10 weeks. In the amniotic membrane group the cecum appeared nearly normal. CONCLUSIONS: Amniotic membrane grafts reduced intraperitoneal adhesions after surgical trauma, were well absorbed, and served as a substrate for regenerating mesothelium.

Histologic and electrophysiological study of nerve regeneration using a polyglycolic acid-collagen nerve conduit filled with collagen sponge in canine model.

OBJECTIVES: To determine the rate of achieving electrophysiologically proved functional recovery by autonomic nerve regeneration, with the aid of an artificial nerve conduit. METHODS: A polyglycolic acid (PGA) collagen nerve conduit filled with collagen sponge was interposed in a 10-mm-long gap of the right hypogastric nerve (HGN) in 16 dogs. Histologic evaluation of nerve regeneration and electrophysiological analysis at 2 weeks and 2, 3, 4, 5, 6, 7, and 8 months (n = 2, each) after surgery was performed, measuring the responses for the spermatic ducts (SD), bladder neck (BN), and prostate contraction, by stimulating the right lumbar splanchnic nerves (LSNs) from L2 to L4, after transection of the left HGN to eliminate substitutive pathways. RESULTS: Two months after implantation, the regenerated neurofilaments were successfully extended through the graft from the proximal-to-distal direction. In 2 control dogs, electrostimulation of the right LSNs induced elevation of the intraluminal pressure of the SD, elevation of the BN pressure, and prostate contraction. No responses were observed in all dogs up to 6 months of follow-up after implantation. In 1 dog with a 7-month follow-up, electrostimulation elicited elevation of BN pressure alone. In both dogs with an 8-month follow-up, electrostimulation induced similar responses to control in all SD, BN, and prostate; however, after excision of the area of the interposed right HGN, no response was observed. CONCLUSIONS: These results proved that regeneration of a 10-mm gap of the HGN, using a novel PGA-collagen nerve conduit could be achieved within 8 months.

Intrathoracic esophageal replacement by in situ tissue-engineered esophagus.

OBJECTIVE: This study aimed to evaluate in situ tissue-engineered esophagus in a canine model after experimental resection and replacement of a full circumferential defect of the intrathoracic esophagus. METHODS: Two types of scaffolding were fabricated. In the KF(+) group (n = 6), oral keratinocytes and fibroblasts cultured on human amniotic membrane were sheeted on polyglycolic acid felt with smooth muscle tissue and were then rolled around tubes. In the KF(-) group (n = 6), the same procedure was followed, but the keratinocytes and fibroblasts were omitted. Both scaffolds were wrapped in omentum and implanted in the abdomen. In the KF(+) group, at 3 weeks after implantation, the scaffold developed into a tube with a well-differentiated lumen of stratified squamous cells surrounded by a thick smooth muscle-like tissue (in situ tissue-engineered esophagus). A part of the esophagus was resected and replaced by the graft in the same dogs. RESULTS: In the KF(-) group, strictures developed after esophageal replacement, with almost complete obstruction within 2 to 3 weeks. In contrast, in the KF(+) group, the in situ tissue-engineered esophagus showed good distensibility and the dogs remained without feeding problems through 420 days. Esophageal peristalsis transferred food to the stomach, despite the absence of peristaltic activity in the in situ tissue-engineered esophagus itself. The thickness of the squamous epithelial layer and the smooth muscle layer of the in situ tissue-engineered esophagus were similar to that of the adjacent native esophagus. CONCLUSION: The in situ tissue-engineered esophagus can successfully replace the intrathoracic esophagus, and this procedure may offer a promising surgical approach to esophageal diseases.

Novel interventional treatment technique for intractable pancreatic fistula due to dehiscence of pancreatico-jejunal anastomosis following pancreaticoduodenectomy.

Despite recent technological advances in the treatment of hepatobiliary pancreatic disease, intractable external pancreatic fistula is still a major critical complication after pancreaticoduodenectomy, and the treatment strategy is not well defined. We report here a case that was successfully treated by our novel interventional internal drainage technique. A 62-year-old woman underwent pylorus-preserving pancreaticoduodenectomy for carcinoma of the papilla of Vater, with reconstruction by a modified Child's procedure. One year later, she was readmitted to our hospital because of external pancreatic fistula. Both computed tomography and fistulography demonstrated a pancreatic fistula derived from dehiscence of the pancreatico-jejunal anastomosis. The pancreatic fistula persisted for 1 week with conservative management. Therefore, we performed repeated fistulography and cannulation, using two comparatively stiff guidewires introduced into the main pancreatic duct and stenotic anastomosed jejunal lumen, respectively, and we placed an endoprosthesis, using bilateral guidewires to connect the two lumens. Consequently, the pancreatic fistula was successfully closed within a few days. Our novel technique is simple, rapid, and not costly. Therefore, it should be considered an effective treatment strategy for persistent pancreatic fistula following pancreaticoduodenectomy that fails to respond to initial conservative management and an endoscopic approach. Also, this technique is applicable to other intractable fistulous situations.

Efficacy of prophylactic extended lymphadenectomy with gastrectomy for patients with node-negative advanced gastric carcinoma.

BACKGROUND/AIMS: Extended lymphadenectomy with gastrectomy is widely performed for patients with advanced gastric carcinoma. However, the therapeutic value of prophylactic extensive lymphadenectomy in patients with node-negative advanced gastric cancer is controversial. METHODOLOGY: We retrospectively analyzed 221 patients who underwent curative gastrectomy for advanced gastric carcinoma without lymph node metastasis to evaluate the effect of prophylactic extended lymphadenectomy on postoperative survival. The postoperative survival rate of patients who underwent extended lymphadenectomy was compared with that of patients who underwent limited lymphadenectomy. Predictive risk factors for tumor recurrence and recurrent patterns also were analyzed. RESULTS: Extended lymphadenectomy improved the postoperative survival rate of patients with advanced tumors even when lymph node spread was absent. Whether or not prophylactic extended lymphadenectomy was performed significantly affected tumor recurrence in patients with node-negative advanced gastric carcinoma. CONCLUSIONS: Extensive lymphadenectomy with gastrectomy prolongs survival of patients with node-negative advanced tumors.

Quality of surgical randomized controlled trials for acute cholecystitis: assessment based on CONSORT and additional check items.

BACKGROUND/PURPOSE: In this study, we conducted a limited survey of reports of surgical randomized controlled trials, using the consolidated standards of reporting trials (CONSORT) statement and additional check items to clarify problems in the evaluation of surgical reports. METHODS: A total of 13 randomized trials were selected from two latest review articles on biliary surgery. Each randomized trial was evaluated according to 28 quality measures that comprised items from the CONSORT statement plus additional items. Analysis focused on relationships between the quality of each study and the estimated effect gap ("pooled estimate in meta-analysis" -- "estimated effect of each study"). RESULTS: No definite relationships were found between individual study quality and the estimated effect gap. The following items could have been described but were not provided in almost all the surgical RCT reports: "clearly defined outcomes"; "details of randomization"; "participant flow charts"; "intention-to-treat analysis"; "ancillary analyses"; and "financial conflicts of interest". The item, "participation of a trial methodologist in the study" was not found in any of the reports. CONCLUSIONS: Although the quality of reporting trials is not always related to a biased estimation of treatment effect, the items used for quality measures must be described to enable readers to evaluate the quality and applicability of the reporting. Further development of an assessment tool is needed for items specific to surgical randomized controlled trials.

Nanogel DDS enables sustained release of IL-12 for tumor immunotherapy.

For a valid cytokine immunotherapy of malignancies, a suitable delivery system that ensures slow-release of cytokines is required, because short half-life in vivo of the molecules ruins therapeutic efficacy while causing severe systemic toxic effects. We previously showed that the cholesterol-bearing pullulan (CHP)-based hydrogel nanoparticles, or nanogel, encapsulates, stabilizes and releases various molecules. Here we applied this nanogel to administration in vivo of interleukin-12 (IL-12). Recombinant murine IL-12 (rmIL-12) was successfully incorporated into CHP nanogel simply by incubated with CHP at room temperature. After subcutaneously injected into mice, the CHP/rmIL-12 complex led to a prolonged elevation in IL-12 concentration in the sera. Repetitive administrations of the CHP/rmIL-12, but not rmIL-12 alone, induced drastic growth retardation of preestablished subcutaneous fibrosarcoma without causing any serious toxic event. The present study proposes a novel therapeutic intervention technology, taking advantage of slow and sustained release of bioactive cytokines from the self-assembling biocompatible nanoparticles.