Interleukin-6 supplementation improves bovine conceptus elongation and transcriptomic indicators of developmental competence.

A high incidence of pregnancy failures occurs in cattle during the second week of pregnancy as blastocysts transition into an elongated conceptus. This work explored whether interleukin-6 (IL6) supplementation during in vitro embryo production would improve subsequent conceptus development. Bovine embryos were treated with 0 or 100 ng/mL recombinant bovine IL6 beginning on day 5 post-fertilization. At day 7.5 post-fertilization, blastocysts were transferred into estrus synchronized beef cows (n = 5 recipients/treatment, 10 embryos/recipient). Seven days after transfer (day 14.5), cows were euthanized to harvest reproductive tracts and collect conceptuses. Individual conceptus lengths and stages were recorded before processing for RNA-sequencing. Increases in conceptus recovery, length, and the proportion of tubular and filamentous conceptuses were detected in conceptuses derived from IL6-treated embryos. The IL6 treatment generated 591 differentially expressed genes (DEG) in conceptuses (n = 9-10/treatment). Gene ontology enrichment analyses revealed changes in transcriptional regulation, DNA-binding, and antiviral actions. Only a few DEG were associated with extraembryonic development, but several DEG were associated with embryonic regulation of transcription, mesoderm and ectoderm development, organogenesis, limb formation, and somatogenesis. To conclude, this work provides evidence that IL6 treatment before embryo transfer promotes pre-implantation conceptus development and gene expression in ways that resemble the generation of a robust conceptus containing favorable abilities to survive this critical period of pregnancy.

TGFß macrophage reprogramming: a new dimension of macrophage plasticity.

The August 2023 article in Science Signaling, "TGF-ß uncouples glycolysis and inflammation in macrophages and controls survival during sepsis," challenges the traditional M1/M2 macrophage classification by investigating the impact of transforming growth factor ß on macrophage metabolism and function. Despite its conventional anti-inflammatory role, transforming growth factor ß-treated macrophages exhibit a distinct phenotype marked by heightened glycolysis, suppressed proinflammatory cytokines, and increased coagulation factor expression. The study identifies phosphofructokinase, liver type as a crucial glycolytic enzyme regulated by transforming growth factor ß via the mTOR-c-MYC pathway. Epigenetic changes induced by transforming growth factor ß, such as increased Smad3 activation and reduced proinflammatory transcription factor motif enrichment, contribute to the anti-inflammatory profile. The research extends its implications to sepsis, revealing the role of transforming growth factor ß in exacerbating coagulation and reducing survival in mouse models. This effect involves upregulation of coagulation factor F13A1, dependent on phosphofructokinase, liver type activity and glycolysis in macrophages. Connections to COVID-19 pathology are drawn, as transforming growth factor ß-treated macrophages and SARS-CoV-2 E protein-exposed cells display similar metabolic profiles. Bioinformatic analysis of COVID-19 patient data suggests correlations between myeloid expression of TGFßR1, PFKL, and F13A1 with disease severity. The study challenges the M1/M2 classification, emphasizing the complexity of macrophage responses influenced by transforming growth factor ß, proposing transforming growth factor ß as a potential therapeutic target for conditions like sepsis and COVID-19 where dysregulated coagulation is significant. Overall, the research provides valuable insights into transforming growth factor ß-mediated immunometabolic regulation, paving the way for future investigations and potential therapeutic interventions.

Cold atmospheric plasma is bactericidal to wound-relevant pathogens and is compatible with burn wound healing.

Burn wound healing can be significantly delayed by infection leading to increased morbidity and hypertrophic scarring. An optimal antimicrobial agent would have the ability to kill bacteria without negatively affecting the host skin cells that are required for healing. Currently available products provide antimicrobial coverage, but may also cause reductions in cell proliferation and migration. Cold atmospheric plasma is a partially ionized gas that can be produced under atmospheric pressure at room temperature. In this study a novel handheld Aceso Plasma Generator was used to produce and test Aceso Cold Plasma (ACP) in vitro and in vivo. ACP showed a potent ability to eliminate bacterial load in vitro for a number of different species. Deep partial-thickness and full-thickness wounds that were treated with ACP after burning, after excision, after autografting, and at days 5, 7, and 9 did not show any negative effects on their wound healing trajectories. On par with in vitro analysis, bioburden was decreased in treated wounds vs. control. In addition, metrics of hypertrophic scar such as dyschromia, elasticity, trans-epidermal water loss (TEWL), and epidermal and dermal thickness were the same between the two treatment groups. It is likely that ACP can be used to mitigate the risk of bacterial infection during the phase of acute burn injury while patients await surgery for definitive closure. It may also be useful in treating wounds with delayed re-epithelialization that are at risk for infection and hypertrophic scarring. A handheld cold plasma device will be useful in treating all manner of wounds and surgical sites in order to decrease bacterial burden in an efficient and highly effective manner without compromising wound healing.

Treatment of hypopigmented burn hypertrophic scars with short-term topical tacrolimus does not lead to repigmentation.

OBJECTIVES: Dyschromia is an understudied aspect of hypertrophic scar (HTS). The use of topical tacrolimus has successfully shown repigmentation in vitiligo patients through promotion of melanogenesis and melanocyte proliferation. It was hypothesized that HTSs treated with topical tacrolimus would have increased repigmentation compared to controls. METHODOLOGY: Full-thickness burns in red Duroc pigs were either treated with excision and meshed split-thickness skin grafting or excision and no grafting, and these wounds formed hypopigmented HTSs (n = 8). Half of the scars had 0.1% tacrolimus ointment applied to the scar twice a day for 21 days, while controls had no treatment. Further, each scar was bisected with half incurring fractional ablative CO2 laser treatment before topical tacrolimus application to induce laser-assisted drug delivery (LADD). Pigmentation was evaluated using a noninvasive probe to measure melanin index (MI) at Days 0 (pretreatment), 7, 14, and 21. At each timepoint, punch biopsies were obtained and fixed in formalin or were incubated in dispase. The formalin-fixed biopsies were used to evaluate melanin levels by H&E staining. The biopsies incubated in dispase were used to obtain epidermal sheets. The ESs were then flash frozen and RNA was isolated from them and used in quantitative reverse transcription polymerase chain reaction for melanogenesis-related genes: Tyrosinase (TYR), TYR-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). Analysis of variance test with Sídák's multiple comparisons test was used to compare groups. RESULTS: Over time, within the grafted HTS and the NS group, there were no significant changes in MI, except for Week 3 in the -Tacro group. (+Tacro HTS= pre = 685.1 ± 42.0, w1 = 741.0 ± 54.16, w2 = 750.8 ± 59.0, w3 = 760.9 ± 49.8) (-Tacro HTS= pre = 700.4 ± 54.3, w1 = 722.3 ± 50.7, w2 = 739.6 ± 53.2, w3 = 722.7 ± 50.5). Over time, within the ungrafted HTS and the NS group, there were no significant changes in MI. (+Tacro HTS= pre = 644.9 ± 6.9, w1 = 661.6 ± 3.3, w2 = 650.3 ± 6.2, w3 = 636.3 ± 7.4) (-Tacro HTS= pre = 696.8 ± 8.0, w1 = 695.8 ± 12.3, w2 = 678.9 ± 14.0, w3 = 731.2 ± 50.3). LADD did not lead to any differential change in pigmentation compared to the non-LADD group. There was no evidence of increased melanogenesis within the tissue punch biopsies at any timepoint. There were no changes in TYR, TYRP1, or DCT gene expression after treatment. CONCLUSION: Hypopigmented HTSs treated with 0.1% tacrolimus ointment with or without LADD did not show significantly increased repigmentation. This study was limited by a shorter treatment interval than what is known to be required in vitiligo patients for repigmentation. The use of noninvasive, topical treatments to promote repigmentation are an appealing strategy to relieve morbidity associated with dyschromic burn scars and requires further investigation.

Neutrophil Extracellular Traps Are Induced by Coronavirus 2019 Disease-Positive Patient Plasma and Persist Longitudinally: A Possible Link to Endothelial Dysfunction as Measured by Syndecan-1.

Background: Neutrophil extracellular trap (NET) formation is a mechanism that neutrophils possess to respond to host infection or inflammation. However, dysregulation of NETosis has been implicated in many disease processes. Although the exact mechanisms of their involvement remain largely unknown, this study aimed to elucidate NET formation over the time course of coronavirus disease 2019 (COVID-19) infection and their possible role in endothelial injury. Patients and Methods: Plasma samples from COVID-19-positive patients were obtained at six timepoints during hospitalization. Neutrophils were extracted from healthy donors and treated with COVID-19-positive patient plasma. Myeloperoxidase (MPO) assay was used to assess for NETosis. Syndecan-1 (SDC-1) enzyme-linked immunosorbent assay (ELISA) was run using the same samples. Immunocytochemistry allowed for further quantification of NETosis byproducts MPO and citrullinated histone 3 (CitH3). The receiver operating characteristic (ROC) curve discriminated between admission levels of SDC-1 and MPO in predicting 30-day mortality and need for ventilator support. Results: Sixty-three patients with COVID-19 were analyzed. Myeloperoxidase was upregulated at day 3, 7, and 14 (p = 0.0087, p = 0.0144, p = 0.0421). Syndecan-1 levels were elevated at day 7 and 14 (p = 0.0188, p = 0.0026). Neutrophils treated with day 3, 7, and 14 plasma expressed increased levels of MPO (p < 0.001). Immunocytochemistry showed neutrophils treated with day 3, 7, and 14 plasma expressed higher levels of MPO (p < 0.001) and higher levels of CitH3 when treated with day 7 and 14 plasma (p < 0.01 and p < 0.05). Admission SDC-1 and MPO levels were found to be independent predictors of 30-day mortality and need for ventilator support. Conclusions: Neutrophil dysregulation can be detrimental to the host. Our study shows that COVID-19 plasma induces substantial amounts of NET formation that persists over the course of the disease. Patients also exhibit increased SDC-1 levels that implicate endothelial injury in the pathogenesis of COVID-19 infection. Furthermore, MPO and SDC-1 plasma levels are predictive of poor outcomes.

Developmental Hurdles That Can Compromise Pregnancy during the First Month of Gestation in Cattle.

Several key developmental events are associated with early embryonic pregnancy losses in beef and dairy cows. These developmental problems are observed at a greater frequency in pregnancies generated from in-vitro-produced bovine embryos. This review describes critical problems that arise during oocyte maturation, fertilization, early embryonic development, compaction and blastulation, embryonic cell lineage specification, elongation, gastrulation, and placentation. Additionally, discussed are potential remediation strategies, but unfortunately, corrective actions are not available for several of the problems being discussed. Further research is needed to produce bovine embryos that have a greater likelihood of surviving to term.

Progesterone-stimulated endometrial cell conditioned media increases in vitro produced bovine embryo blastocyst formation.

The early bovine embryo is supported by histotroph molecules secreted by endometrial epithelial (EPI) and stroma fibroblast (SF) cells in response to luteal progesterone (P4). We hypothesized that specific histotroph molecule transcript abundance depends on cell type and P4 concentration and that endometrial cell conditioned media (CM) could improve in vitro produced (IVP) embryo development in culture. Primary bovine EPI and SF cells from seven uteri were incubated for 12 h with RPMI medium containing 0 (Control), 1, 15, or 50 ng of P4. RPMI was also incubated without cells (N-CM) and CM from EPI or SF cultures (EPI- or SF-CM) or a combination of the two (1:1; EPI/SF-CM) was used to culture IVP embryos from days 4-8 of development (n = 117). There was an effect of cell type (SLC1A1, SLC5A6, SLC7A1, FGF-2, FGF-7, CTGF, PRSS23 and NID2) and/or P4 concentration (FGF-7 and NID2) on endometrial cell histotroph molecule mRNA (P < 0.05). Compared to N-CM, blastocyst development on day 7 was greater in the EPI or SF-CM (P ≤ 0.05) and tended to be greater in the EPI/SF-CM (P = 0.07). On day 8, blastocyst development was greater only in the EPI-CM (P < 0.05). Further, culturing embryos with endometrial cell CM reduced day 8 blastocyst transcript abundance of cell adhesion molecule LGALS1 (P < 0.01). In conclusion, endometrial cell CM or histotroph molecules may be used to improve IVP embryo development in cattle.

Laser-assisted drug delivery of synthetic alpha melanocyte stimulating hormone and L-tyrosine leads to increased pigmentation area and expression of melanogenesis genes in a porcine hypertrophic scar model.

OBJECTIVES: One symptom of hypertrophic scar (HTS) that can develop after burn injury is dyschromia with hyper- and hypopigmentation. There are limited treatments for these conditions. Previously, we showed there is no expression of alpha melanocyte stimulating hormone (α-MSH) in hypopigmented scars, and if these melanocytes are treated with synthetic α-MSH in vitro, they respond by repigmenting. The current study tested the same hypothesis in the in vivo environment using laser-assisted drug delivery (LADD). METHODS: HTSs were created in red Duroc pigs. At Day 77 (pre), they were treated with CO2 fractional ablative laser (FLSR). Synthetic α-MSH was delivered as a topical solution dissolved in  l-tyrosine (n = 6, treated). Control scars received LADD of  l-tyrosine only (n = 2, control). Scars were treated and examined weekly through Week 4. Digital images and punch biopsies of hyper, hypo-, and normally pigmented scar and skin were collected. Digital pictures were analyzed with ImageJ by tracing the area of hyperpigmentation. Epidermal sheets were obtained from punch biopsies through dispase separation and RNA was isolated. qRT-PCR was run for melanogenesis-related genes: tyrosinase (TYR), tyrosinase-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). Two-way ANOVA with multiple comparisons and Dunnett's correction compared the groups. RESULTS: The areas of hyperpigmentation were variable before treatment. Therefore, data is represented as fold-change where each scar was normalized to its own pre value. Within the LADD of NDP α-MSH + l-tyrosine group, hyperpigmented areas gradually increased each week, reaching 1.3-fold over pre by Week 4. At each timepoint, area of hyperpigmentation was greater in the treated versus the control (1.04 ± 0.05 vs. 0.89 ± 0.08, 1.21 ± 0.07 vs. 0.98 ± 0.24, 1.21 ± 0.08 vs. 1.04 ± 0.11, 1.28 ± 0.11 vs. 0.94 ± 0.25; fold-change from pre-). Within the treatment group, pretreatment, levels of TYR were decreased -17.76 ± 4.52 below the level of normal skin in hypopigmented scars. After 1 treatment, potentially due to laser fractionation, the levels decreased to -43.49 ± 5.52. After 2, 3, and 4 treatments, there was ever increasing levels of TYR to almost the level of normally pigmented skin (-35.74 ± 15.72, -23.25 ± 6.80, -5.52 ± 2.22 [p < 0.01, Week 4]). This pattern was also observed for TYRP1 (pre = -12.94 ± 1.82, Week 1 = -48.85 ± 13.25 [p < 0.01], Weeks 2, 3, and 4 = -34.45 ± 14.64, -28.19 ± 4.98, -6.93 ± 3.05 [p < 0.01, Week 4]) and DCT (pre = -214.95 ± 89.42, Week 1 = -487.93 ± 126.32 [p < 0.05], Weeks 2, 3, and 4 = -219.06 ± 79.33, -72.91 ± 20.45 [p < 0.001], -76.00 ± 24.26 [p < 0.001]). Similar patterns were observed for scars treated with LADD of  l-tyrosine alone without NDP α-MSH. For each gene, in hyperpigmented scar, levels increased at Week 4 of treatment compared to Week 1 (p < 0.01). CONCLUSIONS: A clinically-relevant FLSR treatment method can be combined with topical delivery of synthetic α-MSH and l-tyrosine to increase the area of pigmentation and expression of melanogenesis genes in hypopigmented HTS. LADD of  l-tyrosine alone leads to increased expression of melanogenesis genes. Future studies will aim to optimize drug delivery, timing, and dosing.

Endothelial damage occurs early after inhalation injury as measured by increased syndecan-1 levels.

Inhalation injury is a significant cause of morbidity and mortality in the burn patient population. However, the pathogenesis of inhalation injury and its potential involvement in burn shock is not well understood. Preclinical studies have shown endothelial injury, as measured by syndecan-1 (SDC-1) levels, to be involved in the increased vascular permeability seen in shock states. Furthermore, the lung has been identified as a site of significant SDC-1 shedding. Here we aim to characterize the contribution of endotheliopathy caused by inhalation alone in a swine model. When comparing injured animals, the fold change of circulating SDC-1 levels from preinjury was significantly higher at 2, 4, and 6 hours postinjury (P = .0045, P = .0017, and P < .001, respectively). When comparing control animals, the fold change of SDC-1 from preinjury was not significant at any timepoint. When comparing injured animals versus controls, the fold change of SDC-1 injured animals was significantly greater at 2, 4, 6, and 18 hours (P = .004, P = .03, P < .001, and P = .03, respectively). Histological sections showed higher lung injury severity compared to control uninjured lungs (0.56 vs 0.38, P < .001). This novel animal model shows significant increases in SDC-1 levels that provide evidence for the connection between smoke inhalation injury and endothelial injury. Further understanding of the mechanisms underlying inhalation injury and its contribution to shock physiology may aid in development of early, more targeted therapies.

Laser Treatment of Hypertrophic Scar in a Porcine Model Induces Change to Epidermal Histoarchitecture That Correlates to Improved Epidermal Barrier Function.

Mechanisms and timing of hypertrophic scar (HTS) improvement with laser therapy are incompletely understood. Epidermal keratinocytes influence HTS through paracrine signaling, yet they are understudied compared to fibroblasts. It was hypothesized that fractional ablative CO2 laser scar revision (FLSR) would change the fibrotic histoarchitecture of the epidermis in HTS. Duroc pigs (n = 4 FLSR and n = 4 controls) were injured and allowed to form HTS. HTS and normal skin (NS) were assessed weekly by noninvasive skin probes measuring trans-epidermal water loss (TEWL) and biopsy collection. There were 4 weekly FLSR treatments. Immediate laser treatment began on day 49 postinjury (just after re-epithelialization), and early treatment began on day 77 postinjury. Punch biopsies from NS and HTS were processed and stained with H&E. Epidermal thickness and rete ridge ratios (RRR) were measured. Gene and protein expression of involucrin (IVL) and filaggrin (FIL) were examined through qRT-PCR and immunofluorescent (IF) staining. After treatment, peeling sheets of stratum corneum were apparent which were not present in the controls. TEWL was increased in HTS vs NS at day 49, indicating decreased barrier function (P = .05). In the immediate group, TEWL was significantly decreased at week 4 (P < .05). The early group was not significantly different from NS at the prelaser timepoint. After four sessions, the epidermal thickness was significantly increased in treated scars in both FLSR groups (immediate: P < .01 and early: P < .001, n = 8 scars). Early intervention significantly increased RRR (P < .05), and immediate treatment trended toward an increase. There was no increase in either epidermal thickness or RRR in the controls. In the immediate intervention group, there was increased IVL gene expression in HTS vs NS that decreased after FLSR. Eight scars had upregulated gene expression of IVL vs NS levels pretreatment (fold change [FC] > 1.5) compared to four scars at week 4. This was confirmed by IF where IVL staining decreased after FLSR. FIL gene expression trended towards a decrease in both interventions after treatment. Changes in epidermal HTS histoarchitecture and expression levels of epidermal differentiation markers were induced by FLSR. The timing of laser intervention contributed to differences in TEWL, epidermal thickness, and RRR. These data shed light on the putative mechanisms of improvement seen after FLSR treatment. Resolution of timing must be further explored to enhance efficacy. An increased understanding of the difference between the natural history of HTS improvement over time and interventional-induced changes will be critical to justifying the continued approved usage of this treatment.

The Potential of Arterial Pulse Wave Analysis in Burn Resuscitation: A Pilot In Vivo Study.

While urinary output (UOP) remains the primary endpoint for titration of intravenous fluid resuscitation, it is an insufficient indicator of fluid responsiveness. Although advanced hemodynamic monitoring (including arterial pulse wave analysis [PWA]) is of recent interest, the validity of PWA-derived indices in burn resuscitation extremes has not been established. The goal of this paper is to test the hypothesis that PWA-derived cardiac output (CO) and stroke volume (SV) indices as well as pulse pressure variation (PPV) and systolic pressure variation (SPV) can play a complementary role to UOP in burn resuscitation. Swine were instrumented with a Swan-Ganz catheter for reference CO and underwent a 40% TBSA burns with varying resuscitation paradigms, and were monitored for 24 hours in an ICU setting under mechanical ventilation. The longitudinal changes in PWA-derived indices were investigated, and resuscitation adequacy was compared as determined by UOP vs PWA indices. The results indicated that PWA-derived indices exhibited trends consistent with reference CO and SV measurements: CO and SV indices were proportional to reference CO and SV, respectively (CO: postcalibration limits of agreement [LoA] = ±24.7 [ml/min/kg], SV: postcalibration LoA = ±0.30 [ml/kg]) while PPV and SPV were inversely proportional to reference SV (PPV: postcalibration LoA = ±0.32 [ml/kg], SPV: postcalibration LoA = ±0.31 [ml/kg]). The results also indicated that PWA-derived indices exhibited notable discrepancies from UOP in determining adequate burn resuscitation. Hence, it was concluded that the PWA-derived indices may have complementary value to UOP in assessing and guiding burn resuscitation.

Influences of Supplementing Selective Members of the Interleukin-6 Cytokine Family on Bovine Oocyte Competency.

This work explored whether supplementing selective members of the interleukin-6 (IL6) cytokine family during in vitro bovine oocyte maturation affects maturation success, cumulus-oocyte complex (COC) gene expression, fertilization success, and embryo development potential. Human recombinant proteins for IL6, IL11, and leukemia inhibitory factor (LIF) were supplemented to COCs during the maturation period, then fertilization and embryo culture commenced without further cytokine supplementation. The first study determined that none of these cytokines influenced the rate that oocytes achieved arrest at meiosis II. The second study identified that LIF and IL11 supplementation increases AREG transcript abundance. Supplementation with IL6 supplementation did not affect AREG abundance but reduced HAS2 transcript abundance. Several other transcriptional markers of oocyte competency were not affected by any of the cytokines. The third study determined that supplementing these cytokines during maturation did not influence fertilization success, but either LIF or IL11 supplementation increased blastocyst development. No effect of IL6 supplementation on subsequent blastocyst development was detected. The fourth experiment explored whether each cytokine treatment affects the post-thaw survivability of cryopreserved IVP blastocysts. None of the cytokines supplemented during oocyte maturation produced any positive effects on post-thaw blastocyst re-expansion and hatching. In conclusion, these outcomes implicate IL11 and LIF as potentially useful supplements for improving bovine oocyte competency.

Angiogenic gene characterization and vessel permeability of dermal microvascular endothelial cells isolated from burn hypertrophic scar.

Hypertrophic scar (HTS) formation is a common challenge for patients after burn injury. Dermal microvascular endothelial cells (DMVECs) are an understudied cell type in HTS. An increase in angiogenesis and microvessel density can be observed in HTS. Endothelial dysfunction may play a role in scar development. This study aims to generate a functional and expression profile of HTS DMVECs. We hypothesize that transcript and protein-level responses in HTS DMVECs differ from those in normal skin (NS). HTSs were created in red Duroc pigs. DMVECs were isolated using magnetic-activated cell sorting with ulex europaeus agglutinin 1 (UEA-1) lectin. Separate transwell inserts were used to form monolayers of HTS DMVECs and NS DMVECs. Cell injury was induced and permeability was assessed. Gene expression in HTS DMVECS versus NS DMVECs was measured. Select differentially expressed genes were further investigated. HTS had an increased area density of dermal microvasculature compared to NS. HTS DMVECs were 17.59% less permeable than normal DMVECs (p < 0.05). After injury, NS DMVECs were 28.4% and HTS DMVECs were 18.8% more permeable than uninjured controls (28.4 ± 4.8 vs 18.8 ± 2.8; p = 0.11). PCR array identified 31 differentially expressed genes between HTS and NS DMVECs, of which 10 were upregulated and 21 were downregulated. qRT-PCR and ELISA studies were in accordance with the array. DMVECs expressed a mixed profile of factors that can contribute to and inhibit scar formation. HTS DMVECs have both a discordant response to cellular insults and baseline differences in function, supporting their proposed role in scar pathology. Further investigation of DMVECs is warranted to elucidate their contribution to HTS pathogenesis.

Ruminant conceptus-maternal interactions: interferon-tau and beyond.

Embryonic or fetal loss in cattle is associated with problems that occur during oocyte maturation, early embryonic development, conceptus elongation, maternal recognition of pregnancy (MRP), and/or placental attachment and implantation. Many of these problems manifest as inadequate or asynchronous communication between the developing conceptus and endometrium, resulting in pregnancy failure. This review will provide an overview of how various conceptus-endometrial paracrine signaling systems control the fate of early pregnancy in cattle and other ruminants. We begin by summarizing the actions of interferon-tau, the classic MRP signal in ruminates, and then explore how other secretory factors derived from either the conceptus or endometrium influence establishment and maintenance of pregnancy. Insight into how the endometrium responds to male vs. female conceptuses or conceptuses produced by in vitro methods will also be described. Specific focus will be placed on describing how "omic" technologies and other cutting-edge techniques have assisted with identifying novel conceptus and/or endometrial factors and their functions. Recent findings indicate that the endometrial transcriptome and histotroph are altered by conceptus sex, quality, and origin, suggesting that the endometrium is a sensor of conceptus biochemistry. Although the endometrium has a certain level of flexibility in terms of conceptus-maternal interactions, this interplay is not sufficient to retain some pregnancies. However, new information inspires us to learn more and will help develop technologies that mitigate early embryonic loss and reproductive failure in ruminants and other animals.

Early pregnancy losses are common in cattle. This review describes how critical the interplay between the developing conceptus (embryo and extraembryonic membranes) and endometrium is to maintaining pregnancies in cattle and other ruminants. The discovery of interferon-tau more than 40 yr ago initiated a new field of reproductive biology focused on describing how the conceptus and endometrium communicate with one another through the secretion of paracrine factors, extracellular vesicles, and other molecules. The use of "omic" and gene editing technologies has assisted with identifying novel functions for many conceptus and endometrial secreted factors. This review provides examples of how conceptus sex, quality, and in vitro vs. in vivo development influences endometrial function. The endometrium appears to have some flexibility in its response to conceptuses, and this insight could be used to our advantage as we work towards developing schemes to rescue conceptuses that are in danger of experiencing pregnancy loss.

Evaluation of healing outcomes combining a novel polymer formulation with autologous skin cell suspension to treat deep partial and full thickness wounds in a porcine model: a pilot study.

Autologous skin cell suspensions (ASCS) can treat burns of varying depths with the advantage of reduced donor site wound burden. The current standard primary dressing for ASCS is a nonabsorbant, non-adherent, perforated film (control) which has limited conformability over heterogeneous wound beds and allows for run-off of the ASCS. To address these concerns, a novel spray-on polymer formulation was tested as a potential primary dressing in porcine deep partial thickness (DPT) and full thickness (FT) wounds. It was hypothesized that the polymer would perform as well as control dressing when evaluating wound healing and scarring. DPT or FT wounds were treated with either a spray-on poly(lactic-co-glycolic acid) (PLGA) and poly(lactide-co-caprolactone) (PLCL) formulation or control ASCS dressings. Throughout the experimental time course (to day 50), we found no significant differences between polymer and control wounds in % re-epithelialization, graft-loss, epidermal or dermal thickness, or % dermal cellularity in either model. Pigmentation, erythema, elasticity, and trans-epidermal water loss (TEWL), were not significantly altered between the treatment groups, but differences between healing wounds/scars and un-injured skin were observed. No cytotoxic effect was observed in ASCS incubated with the PLGA and PLCL polymers. These data suggest that the novel spray-on polymer is a viable option as a primary dressing, with improved ease of application and conformation to irregular wounds. Polymer formulation and application technique should be a subject of future research.

A Pilot Study of Negative Pressure Therapy with Autologous Skin Cell Suspensions in a Porcine Model.

BACKGROUND: Negative pressure wound therapy (NPWT) is an option for securing meshed split thickness skin grafts (mSTSGs) after burn excision to optimize skin graft adherence. Recently, the use of autologous skin cell suspension (ASCS) has been approved for use in the treatment of burn injuries in conjunction with mSTSGs.To date, limited data exists regarding the impact of NPWT on healing outcomes when the cellular suspension is utilized. It was hypothesized that NPWT would not negatively impact wound healing of ASCS+mSTSG. MATERIALS AND METHODS: A burn, excision, mSTSG, ASCS ± NPWT model was used. Two Duroc pigs were utilized in this experiment, each with 2 sets of paired burns. Four wounds received mSTSG+ASCS+NPWT through post-operative day 3, and 4 wounds received mSTSG+ACSC+ traditional ASCS dressings. Cellular viability was characterized prior to spraying. Percent re-epithelialization, graft-adherence, pigmentation, elasticity, and blood perfusion and blood vessel density were assessed at multiple time points through 2 weeks. RESULTS: All wounds healed within 14 days with minimal scar pathology and no significant differences in percent re-epithelialization between NPWT, and non-NPWT wounds were observed. Additionally, no differences were detected for pigmentation, perfusion, or blood vessel density. NPWT treated wounds had less graft loss and improved elasticity, with elasticity being statistically different. CONCLUSIONS: These data suggest the positive attributes of the cellular suspension delivered are retained following the application of negative pressure. Re-epithelialization, revascularization, and repigmentation are not adversely impacted. The use of NPWT may be considered as an option when using ASCS with mSTSGs for the treatment of full-thickness burns.