Hypoxic pre-conditioning increases the infiltration of endothelial cells into scaffolds for dermal regeneration pre-seeded with mesenchymal stem cells.

Many therapies using mesenchymal stem cells (MSC) rely on their ability to produce and release paracrine signals with chemotactic and pro-angiogenic activity. These characteristics, however, are mostly studied under standard in vitro culture conditions. In contrast, various novel cell-based therapies imply pre-seeding MSC into bio-artificial scaffolds. Here we describe human bone marrow-derived MSC seeded in Integra matrices, a common type of scaffold for dermal regeneration (SDR). We show and measured the distribution of MSC within the SDR, where cells clearly establish physical interactions with the scaffold, exhibiting constant metabolic activity for at least 15 days. In the SDR, MSC secrete VEGF and SDF-1α and induce transwell migration of CD34(+) hematopoietic/endothelial progenitor cells, which is inhibited in the presence of a CXCR4/SDF-1α antagonist. MSC in SDR respond to hypoxia by altering levels of angiogenic signals such as Angiogenin, Serpin-1, uPA, and IL-8. Finally, we show that MSC-containing SDR that have been pre-incubated in hypoxia show higher infiltration of endothelial cells after implantation into immune deficient mice. Our data show that MSC are fully functional ex vivo when implanted into SDR. In addition, our results strongly support the notion of hypoxic pre-conditioning MSC-containing SDR, in order to promote angiogenesis in the wounds

Regeneration of blood vessels within diabetic wounds after treatment with mesenchymal stem cells

Diabetes is a chronic disease that affects more than 30 million Americans. This disorder leads to a variety of acute and chronic complications, including diabetic ulcers (chronic wounds). Chronic wounds often persist due to poor regeneration of the blood supply which is essential to bring nutrients for healing. Particularly, diabetic individuals are prone to damage in their peripheral tissues which leads to a high prevalence of ulcers in their extremities, often leading to limb amputations. The aim of this study is to improve healing outcomes for diabetics through the use of mesenchymal stem cells (MSCs) to stimulate healing, in which vasculogenesis is an important aspect. Catecholamines such as epinephrine (adrenaline) are prevalent in diabetic foot ulcer tissue and have been shown to inhibit wound healing. In this study, healing rates of type II diabetic mice wounds were evaluated when human MSCs were delivered within a collagen scaffold (IntegraTM) and treated with Timolol, a beta blocker that inhibits the effects of epinephrine. We examined wounded mice after 7 days that had received either no MSCs (control), MSCs, or MSCs treated with timolol for blood vessel development using immunohistochemical staining and confocal fluorescence microscopy. Blood vessel biomarkers GSL-I Isolectin B4 and CD31 were used to stain the wound tissue and fluorescent imaging data was quantified using software. Our results indicate that wound tissue treated with MSCs and timolol had the highest blood vessel regeneration and it was statistically significant when compared to control levels. Additionally, a Fluorescent in situ Hybridization (FISH) protocol to identify human chromosomes was successfully implemented using positive and negative control slides so that human MSCs can be identified when delivered to mouse wound tissue. Future experiments will examine how long the MSCs persist and whether they migrate outside the wound tissue bed

Acute Wounding Alters the Beta2-Adrenergic Signaling and Catecholamine Synthetic Pathways in Keratinocytes

Keratinocyte migration is critical for wound re-epithelialization. Previous studies showed that epinephrine activates the beta2-adrenergic receptor (B2AR), impairing keratinocyte migration. Here, we investigated the keratinocyte catecholamine synthetic pathway in response to acute trauma. Cultured keratinocytes were scratch wounded and expression levels of the B2AR and catecholamine synthetic enzymes tyrosine hydroxylase and phenylethanolamine-N-methyltransferase were assayed. The binding affinity of the B2AR was measured. Wounding downregulated B2AR, tyrosine hydroxylase, and phenylethanolamine-N-methyltransferase expression, but pre-exposure to timolol, a beta-adrenergic receptor antagonist, delayed this effect. In wounded keratinocytes, B2AR-binding affinity remained depressed even after its expression returned to prewounding levels. Keratinocyte-derived norepinephrine increased after wounding. Norepinephrine impaired keratinocyte migration; this effect was abrogated with B2AR-selective antagonist ICI-118,551 but not with B1AR-selective antagonist bisoprolol. Finally, for clinical relevance, we determined that norepinephrine was present in freshly wounded skin, thus providing a potential mechanism for impaired healing by local B2AR activation in wound-edge keratinocytes. Taken together, the data show that keratinocytes modulate catecholamine synthetic enzymes and release norepinephrine after scratch wounding. Norepinephrine appears to be a stress-related mediator that impairs keratinocyte migration through activation of the B2AR. Future therapeutic strategies evaluating modulation of norepinephrine-related effects in the wound are warranted

Effects of Intermittent IL-2 Alone or with Peri-Cycle Antiretroviral Therapy in Early HIV Infection: The STALWART Study

The Study of Aldesleukin with and without antiretroviral therapy (STALWART) evaluated whether intermittent interleukin-2 (IL-2) alone or with antiretroviral therapy (ART) around IL-2 cycles increased CD4+ counts compared to no therapy

Research Priorities for Childhood Apraxia of Speech: A Long View

This article introduces the Journal of Speech, Language, and Hearing Research Special Issue: Selected Papers From the 2022 Apraxia Kids Research Symposium. The field of childhood apraxia of speech (CAS) has developed significantly in the past 15 years, with key improvements in understanding of basic biology including genetics, neuroscience, and computational modelling; development of diagnostic tools and methods; diversity of evidence-based interventions with increasingly rigorous experimental designs; and understanding of impacts beyond impairment-level measures. Papers in this special issue not only review and synthesize the some of the substantial progress to date but also present novel findings addressing critical research gaps and adding to the overall body of knowledge. A second aim of this prologue is to report the current research needs in CAS, which arose from symposium discussions involving researchers, clinicians, and Apraxia Kids community members (including parents of children with CAS). Four primary areas of need emerged from discussions at the symposium. These were: (a) What questions should we ask? (b) Who should be in the research? (c) How do we conduct the research? and (d) How do we move from research to practice? Across themes, symposium attendees emphasized the need for CAS research to better account for the diversity of people with CAS and improve the timeliness of implementation of high-level evidence-based practice across the lifespan. It is our goal that the articles and prologue discussion in this special issue provide an appreciation of advancements in CAS research and an updated view of the most pressing needs for future research

Hypoxic pre-conditioning increases the infiltration of endothelial cells into scaffolds for dermal regeneration pre-seeded with mesenchymal stem cells.

Many therapies using mesenchymal stem cells (MSC) rely on their ability to produce and release paracrine signals with chemotactic and pro-angiogenic activity. These characteristics, however, are mostly studied under standard in vitro culture conditions. In contrast, various novel cell-based therapies imply pre-seeding MSC into bio-artificial scaffolds. Here we describe human bone marrow-derived MSC seeded in Integra matrices, a common type of scaffold for dermal regeneration (SDR). We show and measured the distribution of MSC within the SDR, where cells clearly establish physical interactions with the scaffold, exhibiting constant metabolic activity for at least 15 days. In the SDR, MSC secrete VEGF and SDF-1α and induce transwell migration of CD34(+) hematopoietic/endothelial progenitor cells, which is inhibited in the presence of a CXCR4/SDF-1α antagonist. MSC in SDR respond to hypoxia by altering levels of angiogenic signals such as Angiogenin, Serpin-1, uPA, and IL-8. Finally, we show that MSC-containing SDR that have been pre-incubated in hypoxia show higher infiltration of endothelial cells after implantation into immune deficient mice. Our data show that MSC are fully functional ex vivo when implanted into SDR. In addition, our results strongly support the notion of hypoxic pre-conditioning MSC-containing SDR, in order to promote angiogenesis in the wounds