3D printing of gellan-dextran methacrylate IPNs in glycerol and their bioadhesion by RGD derivatives

The ever-growing need for new tissue and organ replacement approaches paved the way for tissue engineering. Successful tissue regeneration requires an appropriate scaffold, which allows cell adhesion and provides mechanical support during tissue repair. In this light, an interpenetrating polymer network (IPN) system based on biocompatible polysaccharides, dextran (Dex) and gellan (Ge), was designed and proposed as a surface that facilitates cell adhesion in tissue engineering applications. The new matrix was developed in glycerol, an unconventional solvent, before the chemical functionalization of the polymer backbone, which provides the system with enhanced properties, such as increased stiffness and bioadhesiveness. Dex was modified introducing methacrylic groups, which are known to be sensitive to UV light. At the same time, Ge was functionalized with RGD moieties, known as promoters for cell adhesion. The printability of the systems was evaluated by exploiting the ability of glycerol to act as a co-initiator in the process, speeding up the kinetics of crosslinking. Following semi-IPNs formation, the solvent was removed by extensive solvent exchange with HEPES and CaCl2, leading to conversion into IPNs due to the ionic gelation of Ge chains. Mechanical properties were investigated and IPNs ability to promote osteoblasts adhesion was evaluated on thin-layer, 3D-printed disk films. Our results show a significant increase in adhesion on hydrogels decorated with RGD moieties, where osteoblasts adopted the spindle-shaped morphology typical of adherent mesenchymal cells. Our findings support the use of RGD-decorated Ge/Dex IPNs as new matrices able to support and facilitate cell adhesion in the perspective of bone tissue regeneration.

Polysaccharide-Based Nanogels to Overcome Mucus, Skin, Cornea, and Blood-Brain Barriers: A Review

Nanocarriers have been extensively developed in the biomedical field to enhance the treatment of various diseases. However, to effectively deliver therapeutic agents to desired target tissues and enhance their pharmacological activity, these nanocarriers must overcome biological barriers, such as mucus gel, skin, cornea, and blood-brain barriers. Polysaccharides possess qualities such as excellent biocompatibility, biodegradability, unique biological properties, and good accessibility, making them ideal materials for constructing drug delivery carriers. Nanogels, as a novel drug delivery platform, consist of three-dimensional polymer networks at the nanoscale, offering a promising strategy for encapsulating different pharmaceutical agents, prolonging retention time, and enhancing penetration. These attractive properties offer great potential for the utilization of polysaccharide-based nanogels as drug delivery systems to overcome biological barriers. Hence, this review discusses the properties of various barriers and the associated constraints, followed by summarizing the most recent development of polysaccharide-based nanogels in drug delivery to overcome biological barriers. It is expected to provide inspiration and motivation for better design and development of polysaccharide-based drug delivery systems to enhance bioavailability and efficacy while minimizing side effects.

Polyacrylate-Cholesterol Amphiphilic Derivative: Formulation Development and Scale-up for Health Care Applications

The novel amphiphilic polyacrylate grafted with cholesterol moieties, PAAbCH, previously synthesized, was deeply characterized and investigated in the lab and on a pre-industrial scale. Solid-state NMR analysis confirmed the polymer structure, and several water-based pharmaceutical and cosmetic products were developed. In particular, stable oil/water emulsions with vegetable oils, squalene, and ceramides were prepared, as well as hydrophilic medicated films loaded with diclofenac, providing a prolonged drug release. PAAbCH also formed polyelectrolyte hydrogel complexes with chitosan, both at the macro- and nano-scale. The results demonstrate that this polymer has promising potential as an innovative excipient, acting as a solubility enhancer, viscosity enhancer, and emulsifying agent with an easy scale-up transfer process.

Prevalence of mood disturbance in Australian adults with chronic spinal cord injury

BACKGROUND

There is little understanding of the prevalence of mental health issues in people with spinal cord injury (SCI) after they leave rehabilitation or how mental health issues can alter over time.

AIM

The aims were to (i) determine the prevalence of mood disturbance in adults with chronic SCI living in the community, (ii) ascertain whether the prevalence of mood disturbance had changed since a previous study in 2004-2005 and (iii) establish whether people with chronic SCI remain vulnerable to mood disturbance, irrespective of time since injury.

METHODS

Prospective, open-cohort case series. Participants were 573 community-based adults with a chronic SCI. The depression, anxiety and stress scale - short version was used. Analyses included simple descriptors, Chi-squared and repeated measures t-tests.

RESULTS

Nearly half of participants (n = 263/573; 46%) reported symptoms indicating mood disturbance, which was similar to the level found in the previous study. While the presence of mood disturbance persisted in 23% of adults (n = 26) and 46 (41%) were in the 'below threshold' category, just over a third of the adults who participated in both studies (n = 111) experienced a change (n = 21, 19% mood disturbance resolved and n = 18, 16% mood disturbance developed).

CONCLUSION

Both resilience and change are common. At no time after SCI is the risk of mental health problems considered reduced or even stable. These results highlight the importance of regular mental health reviews even in those who have previously displayed good resilience.

A randomised control trial of an Internet-based cognitive behaviour treatment for mood disorder in adults with chronic spinal cord injury

STUDY DESIGN

Prospective parallel waitlist randomised controlled trial.

OBJECTIVES

Evaluate the feasibility and effectiveness of an Internet-based psychological intervention treating comorbid mood disorder in adults with spinal cord injury (SCI). Improved mood and satisfaction with life were primary outcomes.

SETTING

Victoria, Australia.

INTERVENTION

Electronic Personal Administration of Cognitive Therapy (ePACT).

MEASURES

Depression, Anxiety and Stress Scale-Short Form (DASS21), Personal Well-being Index, Helplessness subscale of the Spinal Cord Lesion Emotional Well-being Scale v1 Australia, at each time point.Participant qualifying criteria:Adults (18-70 years), chronic SCI, attend SCI review clinic at Austin or Caulfield Hospital and score above normative threshold of the Depression, Anxiety and Stress Scale-Short Form (DASS21).

METHODS

Forty-eight participants completed Time 2 post intervention (n=23) or time equivalent for waitlist control group (n=25) telephone interviews. The measures were repeated a third time (Time 3) for a small subgroup (n=12) at 6 months post intervention within the study implementation time frame.

RESULTS

Univariate within group analyses revealed significant improvement in mood in the intervention group at Time 2: (lower depression (effect size (ES)=0.4), anxiety (ES=0.4) and stress (ES=0.3)) and higher satisfaction with life (ES=0.2). Waitlist control group improved in depression only (ES=0.3) by Time 2. Multilevel variance components analyses, although not as positive, were still encouraging. Improvement in mood symptoms was maintained in the small group reinterviewed at Time 3.

CONCLUSION

Although Internet-based interventions for mental health issues in SCI not a solution for all, our results indicate that they are a potentially valuable addition to the currently available options.

Multimodal imaging of pancreatic beta cells in vivo by targeting transmembrane protein 27 (TMEM27)

AIMS/HYPOTHESIS

Non-invasive diagnostic tools specific for pancreatic beta cells will have a profound impact on our understanding of the pathophysiology of metabolic diseases such as diabetes. The objective of this study was to use molecular imaging probes specifically targeting beta cells on human samples and animal models using state-of-the-art imaging modalities (fluorescence and PET) with preclinical and clinical perspective.

METHODS

We generated a monoclonal antibody, 8/9-mAb, targeting transmembrane protein 27 (TMEM27; a surface N-glycoprotein that is highly expressed on beta cells), compared its expression in human and mouse pancreas, and demonstrated beta cell-specific binding in both. In vivo imaging was performed in mice with subcutaneous insulinomas overexpressing the human TMEM27 gene, or transgenic mice with beta cell-specific hTMEM27 expression under the control of rat insulin promoter (RIP-hTMEM27-tg), using fluorescence and radioactively labelled antibody, followed by tissue ex vivo analysis and fluorescence microscopy.

RESULTS

Fluorescently labelled 8/9-mAb showed beta cell-specific staining on human and mouse pancreatic sections. Real-time PCR on islet cDNA indicated about tenfold higher expression of hTMEM27 in RIP-hTMEM27-tg mice than in humans. In vivo fluorescence and PET imaging in nude mice with insulinoma xenografts expressing hTMEM27 showed high 8/9-mAb uptake in tumours after 72 h. Antibody homing was also observed in beta cells of RIP-hTMEM27-tg mice by in vivo fluorescence imaging. Ex vivo analysis of intact pancreas and fluorescence microscopy in beta cells confirmed these findings.

CONCLUSIONS/INTERPRETATION

hTMEM27 constitutes an attractive target for in vivo visualisation of pancreatic beta cells. Studies in mouse insulinoma models and mice expressing hTMEM27 demonstrate the feasibility of beta cell-targeted in vivo imaging, which is attractive for preclinical investigations and holds potential in clinical diagnostics.

Taspoglutide, a novel human once-weekly GLP-1 analogue, protects pancreatic β-cells in vitro and preserves islet structure and function in the Zucker diabetic fatty rat in vivo

AIM

Glucagon-like peptide-1 (GLP-1) has protective effects on pancreatic β-cells. We evaluated the effects of a novel, long-acting human GLP-1 analogue, taspoglutide, on β-cells in vitro and in vivo.

METHODS

Proliferation of murine pancreatic β (MIN6B1) cells and rat islets in culture was assessed by imaging of 5-ethynyl-2'-deoxyuridine-positive cells after culture with taspoglutide. Apoptosis was evaluated with the transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labelling assay in rat insulinoma (INS-1E) cells and isolated human islets exposed to cytokines (recombinant interleukin-1β, interferon-γ, tumour necrosis factor-α) or lipotoxicity (palmitate) in the presence or absence of taspoglutide. Islet morphology and survival and glucose-stimulated insulin secretion in perfused pancreata were assessed 3-4 weeks after a single application of taspoglutide to prediabetic 6-week-old male Zucker diabetic fatty (ZDF) rats.

RESULTS

Proliferation was increased in a concentration-dependent manner up to fourfold by taspoglutide in MIN6B1 cells and was significantly stimulated in isolated rat islets. Taspoglutide almost completely prevented cytokine- or lipotoxicity-induced apoptosis in INS-1E cells (control 0.5%, cytokines alone 2.2%, taspoglutide + cytokines 0.6%, p < 0.001; palmitate alone 8.1%, taspoglutide + palmitate 0.5%, p < 0.001) and reduced apoptosis in isolated human islets. Treatment of ZDF rats with taspoglutide significantly prevented β-cell apoptosis and preserved healthy islet architecture and insulin staining intensity as shown in pancreatic islet cross sections. Basal and glucose-stimulated insulin secretion of in situ perfused ZDF rat pancreata was normalized after taspoglutide treatment.

CONCLUSIONS

Taspoglutide promoted β-cell proliferation, prevented apoptosis in vitro and exerted multiple β-cell protective effects on islet architecture and function in vivo in ZDF rats.

Taspoglutide, a novel human once-weekly analogue of glucagon-like peptide-1, improves glucose homeostasis and body weight in the Zucker diabetic fatty rat

AIM

Glucagon-like peptide-1 (GLP-1) receptor agonists are a novel class of pharmacotherapy for type 2 diabetes. We investigated the effects of a novel, long-acting human GLP-1 analogue, taspoglutide, in the Zucker diabetic fatty (ZDF) rat, an animal model of type 2 diabetes.

METHODS

Blood glucose and plasma levels of insulin, peptide YY (PYY), glucose-dependent insulinotropic polypeptide (GIP) and triglycerides were measured during oral glucose tolerance tests (oGTT) conducted in ZDF rats treated acutely or chronically with a single long-acting dose of taspoglutide. Pioglitazone was used as a positive control in the chronic study. Postprandial glucose, body weight, glycaemic control and insulin sensitivity were assessed over 21 days in chronically treated animals.

RESULTS

Acute treatment with taspoglutide reduced glucose excursion and increased insulin response during oGTT. In chronically treated rats, glucose excursion and levels of GIP, PYY and triglycerides during oGTT on day 21 were significantly reduced. Postprandial glucose levels were significantly lower than vehicle controls by day 15. A significant reduction in body weight gain was noticed by day 8, and continued until the end of the study when body weight was approximately 7% lower in rats treated with taspoglutide compared to vehicle. Glycaemic control (increased levels of 1,5-anhydroglucitol) and insulin sensitivity (Matsuda index) were improved by taspoglutide treatment.

CONCLUSIONS

Taspoglutide showed typical effects of native GLP-1, with improvement in glucose tolerance, postprandial glucose, body weight, glycaemic control and insulin sensitivity.

Combined effects of botulinum toxin and casting treatments on lower limb spasticity after stroke

Optimal treatment of spasticity requires a combination of pharmacotherapy and muscle lengthening. We evaluated 13 stroke patients with equinovarus foot randomized to treatment with either botulinum toxin A (BTA) injection plus ankle-foot casting (n=6) or BTA alone (n=7). The tibialis posterior and calf muscles (range of BTA injection: 190 to 320 U) were treated in each patient. Castings were worn at night for four months. Each patient was examined before, and at two and four months after BTA injection using the static and dynamic baropodometric tests, the Modified Ashworth Scale and the 10-meter walking test. At two months, therapeutic effects were observed in both groups. At four months, the study group showed further clinical improvement, while the control group returned to baseline performance. Thus, prolonged stretching of spastic muscles after BTA injection affords long-lasting therapeutic benefit, enhancing the effects of the toxin alone.

Regioselective enzymatic diol esterification in batch and fixed-Bed adsorptive reactors: experiments and modeling

The dynamic behavior of batch and fixed-bed adsorptive reactors is studied for the enzyme-catalyzed regioselective esterification of propionic acid and 2-ethyl-1,3-hexanediol in hexane. The reaction is equilibrium-limited with an apparent equilibrium constant of 0.6 +/- 0.1 at 22 degrees C. Moreover, accumulation of water produced in the reaction onto the biocatalyst causes a decrease in the catalytic activity. As a result, improvements in both reaction rate and final conversion can be achieved by operating in an adsorptive-reactor mode. Control of water in the reactor is achieved with a catalytically inert ion-exchange resin in Na-form. The resin prevents an excessive accumulation of water on the biocatalyst and reduces equilibrium limitations. The thermodynamic activity of water is identified as a key parameter for the design of such reactors. A mathematical model capable of predicting the water activity as a function of the varying concentrations of reactants and products is thus developed and found to successfully predict the experimental behavior observed in laboratory reactors. Substantial improvements in performance predicted by the model are seen experimentally in batch reactions and during the transient operation of continuous-flow fixed-bed reactors combining adsorptive and catalytic functions.

p53 tumour suppressor gene and RAS oncogenes: molecular analysis in the chronic and leukaemic phases of essential thrombocythaemia

A panel of 51 cases of essential thrombocythaemia (ET), in chronic or leukaemic phase, was investigated for p53 gene and RAS oncogenes mutations by PCR-SSCP-direct sequencing. No RAS oncogenes mutations were detected, but p53 mutations were identified in three cases: 1/27 cases (approximately 4%) in chronic phase not undergoing chemotherapy, 1/19 cases (approximately 5%) in chronic phase undergoing chemotherapy, and 1/5 cases (20%) which had progressed to leukaemia. Our results suggest that: (1) p53 gene mutations occur sporadically in the chronic phase of ET, independent of chemotherapy, and may contribute to the progression to the leukaemic phase in a limited number of ET patients; (2) the RAS genes family does not seem to be involved in the pathogenesis of ET, unlike other bcr/abl negative chronic myeloproliferative diseases (CMPDs).