Covalent linking of proteins and cytokines to suture: Enhancing the immune response of head and neck cancer patients

Analysis of immune status after iodine-125 permanent brachytherapy in prostate cancer

Background

Permanent prostate brachytherapy (PPB) is an effective treatment choice for low and intermediate risk prostate cancer (PCa). However, the impact of PPB on tumor immune status is still poorly understood. This study aimed to assess the immune status in PCa patients before and at different time points after PPB (1, 3, 6, and 12 months).

Methods

Blood was collected from 32 patients with low and intermediate risk PCa and 12 healthy volunteers. The frequency of immunocompetent cells was identified by flow cytometry. The concentration of immunoglobulins and complements was detected by ELISA.

Results

Various immunocompetent cells were dysregulated in PCa patients compared with healthy volunteers. Peripheral serum prostate-specific antigen (PSA) decreased rapidly at the first month after PPB treatment, and the peripheral serum PSA became very low at 6 months after PPB treatment. CD3+ T cells, CD4+ T cells, CD3-CD16+/56+ natural killer (NK) cells were increased significantly at certain time points after PPB. Although the percentage of the CD8+ T cells did not change markedly, the ratio of CD4/CD8 increased significantly at 3 months after PPB (P=0.0196). There was no influence of PPB on B cells number, but the concentration of immunoglobulins IgM, IgG, and IgA, and complements C3 and C4 in patients increased at some time points after PPB.

Conclusion

The immunocompetent cells are dysregulated in PCa patients. PPB treatment could effectively kill tumor cells and then stimulate cellular immunity and humoral immunity in PCa patients.

VEGF-releasing suture material for enhancement of vascularization: development, in vitro and in vivo study

As it has been demonstrated that bioactive substances can be delivered locally using coated surgical suture materials, the authors developed a vascular endothelial growth factor (VEGF)-releasing suture material that should promote vascularization and potentially wound healing. In this context, the study focused on the characterization of the developed suture material and the verification of its biological activity, as well as establishing a coating process that allows reproducible and stable coating of a commercially available polydioxanone suture material with poly(l-lactide) (PLLA) and 0.1μg and 1.0μg VEGF. The in vitro VEGF release kinetics was studied using a Sandwich ELISA. The biological activity of the released VEGF was investigated in vitro using human umbilical vein endothelial cells. The potential of the VEGF-releasing suture material was also studied in vivo 5days after implantation in the hind limb of Wistar rats, when the histological findings were analyzed. The essential results, enhanced cell viability in vitro as well as significantly increased vascularization in vivo, were achieved using PLLA/1.0μg VEGF-coated suture material. Furthermore, ELISA measurements revealed a high reproducibility of the VEGF release behavior. Based on the results achieved regarding the dose-effect relationship of VEGF, the stability during its processing and the release behavior, it can be predicted that a bioactive suture material would be successful in later in vivo studies. Therefore, this knowledge could be the basis for future studies, where bioactive substances with different modes of action are combined for targeted, overall enhancement of wound healing.

Multifunctional polymeric microfibers with prolonged drug delivery and structural support capabilities

The strength and stability of hybrid fiber delivery systems, ones that perform a mechanical function and simultaneously deliver drug, are critical in the design of surgically implantable constructs. We report the fabrication of drug-eluting microfibers where drug loading and processing conditions alone increase microfiber strength and stability partially due to solvent-induced crystallization. Poly(L-lactic acid) microfibers of 64±7 μm diameter were wet spun by phase inversion. Encapsulation of a model hydrophobic anti-inflammatory drug, dexamethasone, at high loading provided stability to microfibers which maintained linear cumulative release kinetics up to 8 weeks in vitro. In our wet spinning process, all microfibers had increased crystallinity (13-17%) in comparison to unprocessed polymer without any mechanical stretching. Moreover, microfibers with the highest drug loading retained 97% of initial tensile strength and were statistically stronger than all other microfiber formulations, including control fibers without drug. Results indicate that the encapsulation of small hydrophobic molecules (<400 Da) may increase the mechanical integrity of microfilaments whose crystallinity is also increased as a result of the process. Multifunctional drug-eluting microfibers can provide an exciting new opportunity to design novel biomaterials with mechanical stability and controlled release of a variety of therapeutics with micron-scale accuracy.

Evaluation of a thyroid nodule

The thyroid specialist frequently evaluates thyroid nodules because they may represent malignancy. Nodules are typically found on physical examination or incidentally when other imaging studies are performed. Malignant or symptomatic nodules that compress nearby structures warrant surgical excision. Yet, the majority of thyroid nodules are asymptomatic and benign, so the thyroid surgeon must rely on diagnostic studies to determine when surgery is indicated. Ultrasound is the preferred imaging modality for thyroid nodules, and the ultrasound guided fine-needle aspiration biopsy (FNAB) is the preferred method of tissue sampling. Nodules 1 cm or larger or nodules with suspicious sonographic appearance warrant cytologic analysis to better quantify the risk for malignancy. Molecular biomarkers are a powerful adjunct to cytology. Detecting malignancy preoperatively allows total thyroidectomy in a single operation without the need for frozen section or a second operation for completion of a thyroidectomy if malignancy is found during the initial thyroid lobectomy.

Release kinetics of polymer-bound bone morphogenetic protein-2 and its effects on the osteogenic expression of MC3T3-E1 osteoprecursor cells

BACKGROUND

In an effort to augment scaffold performance, additives such as growth factors are under investigation for their ability to optimize the "osteopotential" of synthetic polymer scaffolds. In parallel research, bone morphogenetic protein-2 (BMP-2), a growth factor that initiates bone formation, has been locally delivered to augment fracture healing and spinal fusion. The authors hypothesize that BMP-2 can be covalently bound to a polymer substrate, increasing its concentration and bioavailability over longer periods, thus improving the efficacy of the growth factor and subsequently the bony matrix production. It would remain bound longer when compared with published controls. This prolonged binding would then increase the bioavailability of the growth factor and thus increase bony matrix production over a longer interval.

METHODS

Mouse preosteoblast MC3T3-E1 cells were cultured on poly(lactic-co-glycolic acid) and polycaprolactone polymer disks covalently bound with BMP-2 to assess the progression and quality of osteogenesis. Covalent binding of BMP-2 to each polymer was visualized by immunohistochemical analysis of polymer-coated microscope slides. The quantity of covalently bound BMP-2 was determined using enzyme-linked immunosorbent assay.

RESULTS

Polymerase chain reaction results showed elevated expression levels for alkaline phosphatase and osteocalcin genes. BMP-2 was released from polycaprolactone over 2 weeks, with 86 percent remaining covalently bound, in contrast to 93 percent retained by poly(lactic-co-glycolic acid).

CONCLUSIONS

BMP-2, proven to alter polymer osteogenicity, remained bound to poly(lactic-co-glycolic acid), which may render poly(lactic-co-glycolic acid) an ideal choice as a polymer for scaffold-based bone tissue engineering using growth factor delivery.

Bioactive Sutures

With the first wave of bioactive sutures already in the marketplace, research is ongoing in the development of future products. Such sutures could potentially have not only antimicrobial activity but also anesthetic and antineoplastic functions. Some clinical trials have already been completed in Russia. This technology is likely to become commonplace. This article reviews the progress made to date in the development of this technology.

Indicadores bioquímicos predictivos de fístula faringocutánea postlaringuectomía: un estudio clínico

The aim of this clinical study was to determinate biochemical predictor indicators of postlaryngectomy pharyngocutaneous fistula.

PATIENTS AND METHODS

We have studied 100 patients with T2- 4 a laryngeal and piryform sinus carcinoma who underwent a laryngectomy. All patients were ASA 2-3. We studied serum albumin, protein serum level, cholesterol and lymphocites in each patient. These variables underwent statistical analysis (p < 0.05).

RESULTS

19% of the patients developed a postlaryngectomy pharyngocutaneous fistula, with a long-stay of 25 days vs. 10 days of stay in patients without postlaryngectomy pharyngocutaneous fistula. 7 postlaryngectomy pharyngocutaneous fistula needed surgical repair. Low serum albumin (< 3.5 g/dL) and a low level of serum proteins (< 6.5 g/dL) were predictive indicators of postlaryngectomy pharyngocutaneous fistula (p < 0.05).

CONCLUSIONS

Our results suggest that a low-level of serum proteins and albumin are predictive clinical parameters of postlaryngeal pharyngocutaneous fistula.

Linking of Bone Morphogenetic Protein-2 To Resorbable Fracture Plates for Enhancing Bone Healing

OBJECTIVE

To test whether bone morphogenetic protein (BMP)-2 may be covalently linked to resorbable fracture repair plates using an ester-hydrolysis reaction and determining whether the linked compound can facilitate bone growth.

STUDY DESIGN

Laboratory in vitro experiments.

METHOD

Resorbable fracture repair plates were partially hydrolyzed using varying concentrations of acid or base. This intermediate was then reacted with EDAC (1-ethyl-3[-3-dimethylamino propyl carbodiimide) to form an EDAC intermediate, which was then reacted with either horseradish peroxidase (HRP), interleukin (IL)-2, or BMP-2. Compound binding to the plate was confirmed by immunofluorescent staining. Confirmation of protein function was determined by the following assays: HRP's ability to cleave peroxide, IL-2's ability to stimulate lymphocytes, and BMP-2's ability to stimulate C3H10T1/2 cells to generate alkaline phosphatase.

RESULTS

Three compounds (HRP, IL-2, and BMP-2) were successfully linked to plates as confirmed by immunofluorescence staining or functional testing. Compounds demonstrated better covalent linking to plates under basic conditions. HRP, IL-2, and BMP-2 retained function after binding as measured by cleaved peroxide levels, lymphocytes proliferation, and alkaline phosphatase production.

CONCLUSIONS

Covalent linking of compounds such as HRP, IL-2, and BMP-2 to resorbable plates is possible and represents a novel protein delivery technique. BMP-2 covalently linked to resorbable plates may be used to facilitate bone healing. Covalent linking of compounds to plates represents a novel method for delivering concentrated levels of growth factors to a specific site and potentially extending their half-life. Further investigation into this application for bone healing may lead to quicker healing.

Interferon alpha2b augments suppressed immune functions in tobacco-related head and neck squamous cell carcinoma patients by modulating cytokine signaling

We have examined the role of interferon alpha2b (IFNalpha2b) in augmentation of the suppressed immune functions and cytotoxicity of tobacco-related head and neck squamous cell carcinoma (HNSCC) patients. The suppressed killing activity of PBMC of HNSCC patients towards KB, MCF7 and K562 cell lines could be restored by in vitro treatment of PBMC with IFNalpha2b, as detected by LDH release assay. HNSCC patients with cisplatin + 5FU + IFNalpha2b treatment showed greater cytotoxic efficacy than corresponding pretreatment values. Analysis of culture supernatant of HNSCC-PBMC by ELISA revealed the lower secretion of IL-12 and IFNgamma with increased level of IL-4 and IL-10. This altered Th1/Th2 status was rectified after in vitro and in vivo IFNalpha2b stimulation. Increased secretion of monocyte derived IL-12 was observed after IFNalpha2b treatment that can enhance the IFNgamma release, a key regulator for cytotoxicity. IFNalpha2b stimulated enhancement of NK cells may be the source of greater amount of IFNgamma. IFNalpha2b activated STAT1 and STAT4 signaling is observed to be involved in the regulation and maintenance of cytokine milieu. We conclude that IFNalpha2b may be effective as a tool for adjuvant therapy along with conventional therapies to overcome the immunosuppression in HNSCC patients.

Bioactive Suture

PURPOSE

We have proposed to characterize the mechanism through which bioactive surgical sutures generate a T(H)1 immune response and to define the immune-stimulating half-life of the sutures.

EXPERIMENTAL DESIGN

Bioactive sutures of interferon gamma (IFNgamma), interleukin 2 (IL-2), anti-CD3/CD28, anti-CD3/CD28 + IL-2, or anti-CD3/CD28 + IFNgamma sutures were used to stimulate lymphocytes from normal donors and from head and neck cancer patients in vitro over a 24-day period. Cell supernatants were analyzed by ELISA, and T cells were phenotyped to characterize the immune response generated. Intracellular cytokine staining was performed to measure the expansion of flu-specific T cells. Electromobility shift assay and supershift assay were used to measure the intranuclear DNA binding activity of nuclear factor kappaB and its p65 subunit in T cells activated by sutures in the presence and absence of a proteasome inhibitor, MG-132.

RESULTS

Anti-CD3/CD28, anti-CD3/CD28 + IL-2, or anti-CD3/CD28 + IFNgamma generated a prolonged T(H)1 immune response for 18 days in vitro. Anti-CD3/CD28 expanded flu-specific T cells. Activated T cells demonstrated enhanced CD40 ligand (CD40L) expression within 72 hours of stimulation, which stimulated other cells to secrete IL-12. Stimulated T cells demonstrated increased intranuclear expression of nuclear factor-kappaB, which was blocked by MG-132, and also reduced CD40L and IL-12 expression.

CONCLUSIONS

This is the first report to demonstrate that bioactive surgical sutures can generate a prolonged T(H)1 immune response and expand flu-specific T cells. Bioactive sutures, which are primarily a T-cell stimulant, also stimulated other cells to secrete IL-12 and prolonged the immune response. Sutures may provide a novel in situ stimulating strategy for enhancing the immune system of cancer patients.

Progress in Head and Neck Cancer Immunotherapy: Can Tolerance and Immune Suppression Be Reversed?

The incidence of squamous cell carcinoma of the head and neck (SCCHN) is greater than 40,000 cases per year in the United States, and approximately 500,000 cases annually worldwide. Despite significant advances in detection, ablation, and reconstruction, survival has not improved appreciably over the past few decades. Therefore, novel approaches are necessary to provide head and neck oncologists with a more effective armamentarium against this challenging disease. Cancer immunotherapy describes various approaches to expand and activate the immune system to control tumor growth in vivo. So far, immunotherapy appears to have had applicability in conjunction with other therapeutic interventions that treat residual tumor cells after therapy or to reduce the occurrence of second primary tumors. In particular, diseases such as SCCHN are attractive candidates for novel therapeutic approaches, since the standard treatments have not yet successfully controlled this disease with sufficiently high success rates. This article reviews adjuvant immunotherapeutic strategies currently in trials or under development for SCCHN patients, including vaccination or cytokine immunostimulation.