Tethered TGF-β1 in a Hyaluronic Acid-Based Bioink for Bioprinting Cartilaginous Tissues

In 3D bioprinting for cartilage regeneration, bioinks that support chondrogenic development are of key importance. Growth factors covalently bound in non-printable hydrogels have been shown to effectively promote chondrogenesis. However, studies that investigate the functionality of tethered growth factors within 3D printable bioinks are still lacking. Therefore, in this study, we established a dual-stage crosslinked hyaluronic acid-based bioink that enabled covalent tethering of transforming growth factor-beta 1 (TGF‑β1). Bone marrow-derived mesenchymal stromal cells (MSCs) were cultured over three weeks in vitro, and chondrogenic differentiation of MSCs within bioink constructs with tethered TGF‑β1 was markedly enhanced, as compared to constructs with non-covalently incorporated TGF‑β1. This was substantiated with regard to early TGF‑β1 signaling, chondrogenic gene expression, qualitative and quantitative ECM deposition and distribution, and resulting construct stiffness. Furthermore, it was successfully demonstrated, in a comparative analysis of cast and printed bioinks, that covalently tethered TGF‑β1 maintained its functionality after 3D printing. Taken together, the presented ink composition enabled the generation of high-quality cartilaginous tissues without the need for continuous exogenous growth factor supply and, thus, bears great potential for future investigation towards cartilage regeneration. Furthermore, growth factor tethering within bioinks, potentially leading to superior tissue development, may also be explored for other biofabrication applications.

Single-chain tandem macrocyclic peptides as a scaffold for growth factor and cytokine mimetics

Mimetics of growth factors and cytokines are promising tools for culturing large numbers of cells and manufacturing regenerative medicine products. In this study, we report single-chain tandem macrocyclic peptides (STaMPtides) as mimetics in a new multivalent peptide format. STaMPtides, which contain two or more macrocyclic peptides with a disulfide-closed backbone and peptide linkers, are successfully secreted into the supernatant by Corynebacterium glutamicum-based secretion technology. Without post-secretion modification steps, such as macrocyclization or enzymatic treatment, bacterially secreted STaMPtides form disulfide bonds, as designed; are biologically active; and show agonistic activities against respective target receptors. We also demonstrate, by cell-based assays, the potential of STaMPtides, which mimic growth factors and cytokines, in cell culture. The STaMPtide technology can be applied to the design, screening, and production of growth factor and cytokine mimetics.

Cytokine Profiling and Intra-Articular Injection of Autologous Platelet-Rich Plasma in Knee Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease leading to joint pain and stiffness. Due to lack of effective treatments, physical and psychological disabilities caused by OA have a detrimental impact on the patient’s quality of life. Emerging evidence suggests that intra-articular injection of platelet-rich plasma (PRP) may provide favorable results since PRP comprises not only a high level of platelets but also a huge amount of cytokines, chemokines, and growth factors. However, the precise mechanism and standardization method remain uncertain. This study aimed to examine cytokine profiling in both PRP and platelet-poor plasma (PPP) of knee OA patients and to determine the effects of PRP on OA chondrocytes and knee OA patients. PRP contained a wide variety of cytokines, chemokines, growth factors, and autologous intra-articular PRP injection resulted in favorable outcomes in knee OA patients. Significant increases in levels of IL-1, IL-2, IL-7, IL-8, IL-9, IL-12, TNF-α, IL-17, PDGF-BB, bFGF, and MIP-1β were detected in PRP compared to PPP (p < 0.001). An in vitro study showed a marked increase in proliferation in OA chondrocytes cultured with PRP, compared to PPP and fetal bovine serum (p < 0.001). In a clinical study, knee OA patients treated with PRP showed improvement of physical function and pain, assessed by physical performance, Western Ontario and McMaster Universities Arthritis Index and visual analog scale. Our findings from both in vitro and clinical studies suggest that intra-articular PRP injection in knee OA patients may be a potential therapeutic strategy for alleviating knee pain and delaying the need for surgery.

Optimization of Bacterial Concentrate Media for Lactobacillus Sakei

Two strains of lactic acid bacteria were selected for the study (Lactobacillus sakei Lsk-45andLactobacillus sakeiDSM 20017). Bacterial media, based on rice and rice flour, were tested as an alternative to media based on whey. A comparison of the different types of media showed that there was better growth of the selected strains on themedium based on rice flour.Statistical analyses, including factorial experiments and response surface analyses, were used to optimizethe composition of the bacterial medium for Lactobacillus sakei propagation. Bacteriological peptone and rice flour were found to be good growth factors for Lactobacillus sakei.For Lactobacillus sakei Lsk-45,better growth was obtained with the use of 7.75-10 g/L of peptone and 57.5-75 g/L of rice flour. For Lactobacillus sakei DSM 20017, better growth was obtained with the use of 7-10 g/L of peptone and 40-75 g/L of rice flour. Keywords: starters, media, Lactobacillus sakei, fermentation,fish products, bacterial strains, lactic acid bacteria

Allogeneic platelet-derived growth factors local injection in treatment of tennis elbow: a prospective randomized controlled study

Purpose The purpose of this study aimed to evaluate the efficacy of local injection of allogeneic platelet-derived growth factors in treatment of patients with tennis elbow. Patients and methods This study included 120 tennis elbow patients randomly divided into two groups. The patients were locally injected with allogeneic growth factors (treatment group) or with normal saline (control group). The outcomes were assessed using Patient-Related Tennis Elbow Evaluation (PRTEE) and quick Disabilities of the Arm, Shoulder and Hand (qDASH) scales. The clinical outcomes were accordingly classified as excellent, good and poor. The patient’s satisfaction and adverse effects were also recorded. Results There was no statistically significant difference between the two groups regarding the age, gender, dominant arm or the pre-injection scores. At three month follow-up, the reductions in the mean PRTEE and qDASH scores were 88.7% and 70.6% in the treatment group versus 21.8% and 14.9% in the control group, respectively. At the last follow-up, the outcomes in the treatment group were excellent in 85% of patients and good in 15%, versus 8% and 32% in the control group. Overall, 95% were satisfied in the treatment group compared to 25% in control group. Forty patients in the treatment group experienced mild transient post-injection pain. Conclusion This study strongly suggests that local injection of allogeneic platelet-derived growth factors could be a promising safe treatment option for tennis elbow with significant pain relief, functional improvement and patient’s satisfaction. Yet, additional larger studies are needed to assess the durability of these outcomes.

Reciprocal epigenetic Sox2 regulation by SMAD1-SMAD3 is critical for anoikis resistance and metastasis in cancer

Growth factors in the tumor environment are key regulators of cell survival and anoikis resistance during metastasis. Here we reveal significant dichotomy between TGF-β superfamily growth factors BMP and TGF-β/activin and their downstream SMAD effectors in regulation of anchorage-independent tumor cell survival in ovarian cancer. Gene expression profiling uncovered the transcription factor Sox2 as a key signaling node regulated in an opposing manner by anoikis-promoting BMP2 4 and 9 and anoikis-suppressing TGF-β and activin A. Mechanistically, repression of Sox2 by BMPs is mediated by type I receptors ALK2 and ALK3 induced SMAD1 activation, leading to SMAD1-dependent histone H3K27me3 recruitment and DNA methylation at SOX2s promoter. Conversely, TGF-β and activin A promote Sox2 expression directly by ALK5-mediated SMAD3 activation and histone H3K4me3 recruitment. Increased Sox2 expression promotes anoikis resistance, while decreasing Sox2 levels conversely reduces anoikis resistance and activates cell death pathways. Additionally, administrating BMP9 as a strategy to reduce Sox2 robustly inhibits intraperitoneal tumor burden and increases survival in multiple ovarian cancer xenograft models. Importantly, BMP-driven SMAD1 signaling can override the effects of TGF-β and activin on Sox2 regulation, which has potential clinical significance as we find high TGF-β levels in patient ascites. Our findings highlight the contrasting regulation of anoikis by distinct SMAD signaling pathways that are dependent on a novel dichotomous regulation of Sox2 and implicate the use of a subset of BMPs as a therapeutic strategy in cancer

Applications of the amniotic membrane in tissue engineering and regeneration: the hundred-year challenge

The amniotic membrane (Amnio-M) has various applications in regenerative medicine. It acts as a highly biocompatible natural scaffold and as a source of several types of stem cells and potent growth factors. It also serves as an effective nano-reservoir for drug delivery, thanks to its high entrapment properties. Over the past century, the use of the Amnio-M in the clinic has evolved from a simple sheet for topical applications for skin and corneal repair into more advanced forms, such as micronized dehydrated membrane, amniotic cytokine extract, and solubilized powder injections to regenerate muscles, cartilage, and tendons. This review highlights the development of the Amnio-M over the years and the implication of new and emerging nanotechnology to support expanding its use for tissue engineering and clinical applications. Graphical Abstract

Plasma Rich in Growth Factors in Macular Hole Surgery

The aim of this study was to evaluate the use of PRGF (plasma rich in growth factors) as an adjuvant to PPV (pars plana vitrectomy) in recurrent, persistent, or poor prognosis MH (macular hole). Patients with MH were treated with PPV plus adjuvant therapy (PRGF membrane (mPRGF) and injectable liquid PRGF (iPRGF)). The anatomical closure of MH and postoperative BCVA (best-corrected visual acuity) were evaluated. Eight eyes (eight patients) were evaluated: myopic MH (MMH, n = 4), idiopathic MH (IMH, n = 2), iatrogenic n = 1, traumatic n = 1. The mean age was 53.1 ± 19.3 years. Hence, 66.7% (n = 4) of patients previously had internal limiting membrane peeling. Five patients (62.5%) received mPRGF and iPRGF, and three patients (37.5%) received iPRGF. Gas tamponade (C3F8) was placed in seven cases and one case of silicone oil. Anatomic closure of MH was achieved in seven eyes (87.5%) and BCVA improved in six cases. In the MMH group, visual acuity improved in two lines of vision. Follow-up time was 27.2 ± 9.0 months. No adverse events or MH recurrences were recorded during follow-up. The use of PRGF as an adjuvant therapy to PPV can be useful to improve anatomical closure and visual acuity in MH surgery.

Collagen fibrous scaffolds for sustained delivery of growth factors for meniscal tissue engineering

Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-β1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis; and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.