Heme Oxygenase Protects against Placental Vascular Inflammation and Abortion by the Alarmin Heme in Mice.

Both infectious as non-infectious inflammation can cause placental dysfunction and pregnancy complications. During the first trimester of human gestation, when palatogenesis takes place, intrauterine hematoma and hemorrhage are common phenomena, causing the release of large amounts of heme, a well-known alarmin. We postulated that exposure of pregnant mice to heme during palatogenesis would initiate oxidative and inflammatory stress, leading to pathological pregnancy, increasing the incidence of palatal clefting and abortion. Both heme oxygenase isoforms (HO-1 and HO-2) break down heme, thereby generating anti-oxidative and -inflammatory products. HO may thus counteract these heme-induced injurious stresses. To test this hypothesis, we administered heme to pregnant CD1 outbred mice at Day E12 by intraperitoneal injection in increasing doses: 30, 75 or 150 μmol/kg body weight (30H, 75H or 150H) in the presence or absence of HO-activity inhibitor SnMP from Day E11. Exposure to heme resulted in a dose-dependent increase in abortion. At 75H half of the fetuses where resorbed, while at 150H all fetuses were aborted. HO-activity protected against heme-induced abortion since inhibition of HO-activity aggravated heme-induced detrimental effects. The fetuses surviving heme administration demonstrated normal palatal fusion. Immunostainings at Day E16 demonstrated higher numbers of ICAM-1 positive blood vessels, macrophages and HO-1 positive cells in placenta after administration of 75H or SnMP + 30H. Summarizing, heme acts as an endogenous "alarmin" during pregnancy in a dose-dependent fashion, while HO-activity protects against heme-induced placental vascular inflammation and abortion

CXCL12-CXCR4 Interplay Facilitates Palatal Osteogenesis in Mice.

Cranial neural crest cells (CNCCs), identified by expression of transcription factor Sox9, migrate to the first branchial arch and undergo proliferation and differentiation to form the cartilage and bone structures of the orofacial region, including the palatal bone. Sox9 promotes osteogenic differentiation and stimulates CXCL12-CXCR4 chemokine-receptor signaling, which elevates alkaline phosphatase (ALP)-activity in osteoblasts to initiate bone mineralization. Disintegration of the midline epithelial seam (MES) is crucial for palatal fusion. Since we earlier demonstrated chemokine-receptor mediated signaling by the MES, we hypothesized that chemokine CXCL12 is expressed by the disintegrating MES to promote the formation of an osteogenic center by CXCR4-positive osteoblasts. Disturbed migration of CNCCs by excess oxidative and inflammatory stress is associated with increased risk of cleft lip and palate (CLP). The cytoprotective heme oxygenase (HO) enzymes are powerful guardians harnessing injurious oxidative and inflammatory stressors and enhances osteogenic ALP-activity. By contrast, abrogation of HO-1 or HO-2 expression promotes pregnancy pathologies. We postulate that Sox9, CXCR4, and HO-1 are expressed in the ALP-activity positive osteogenic regions within the CNCCs-derived palatal mesenchyme. To investigate these hypotheses, we studied expression of Sox9, CXCL12, CXCR4, and HO-1 in relation to palatal osteogenesis between E15 and E16 using (immuno)histochemical staining of coronal palatal sections in wild-type (wt) mice. In addition, the effects of abrogated HO-2 expression in HO-2 KO mice and inhibited HO-1 and HO-2 activity by administrating HO-enzyme activity inhibitor SnMP at E11 in wt mice were investigated at E15 or E16 following palatal fusion. Overexpression of Sox9, CXCL12, CXCR4, and HO-1 was detected in the ALP-activity positive osteogenic regions within the palatal mesenchyme. Overexpression of Sox9 and CXCL12 by the disintegrating MES was detected. Neither palatal fusion nor MES disintegration seemed affected by either HO-2 abrogation or inhibition of HO-activity. Sox9 progenitors seem important to maintain the CXCR4-positive osteoblast pool to drive osteogenesis. Sox9 expression may facilitate MES disintegration and palatal fusion by promoting epithelial-to-mesenchymal transformation (EMT). CXCL12 expression by the MES and the palatal mesenchyme may promote osteogenic differentiation to create osteogenic centers. This study provides novel evidence that CXCL12-CXCR4 interplay facilitates palatal osteogenesis and palatal fusion in mice

Excisional wounding of the soft palate.

<p>Excisional wounds (1 mm ø) were made in the soft palate, 7 mm behind the 9th palatal ruga. W: excisional wound, R: 9th ruga.</p

Anatomy of levator veli palatini and tensor veli palatini.

<p>Left: Schematic representation of the levator veli palatini and tensor veli palatini muscles. Right: (A) The levator veli palatini muscle arises from the inferior surface of the temporal bone, lateral and posterior from the tympanic bulla. The tympanic bulla is a bony projection of the temporal bone containing the tympanic cavity. (B) Posterior to the pterygoid process, the levator veli palatini continues towards the soft palate. The glossopharyngeal, vagus and hypoglossal nerves are visible between the levator veli palatini and the skull base. (C) The tensor veli palatini originates from the inferior surface of the sphenoid bone, the lateral surface of the perygoid plate, and the auditory tube. (D) The tendon of the tensor veli palatini turns around a curved process; the pterygoid hamulus. It continues medially towards the soft palate and forms the palatine aponeurosis. LVP: levator veli palatini muscle, TVP: tensor veli palatini muscle, IX: glossopharyngeus nerve, X: vagus nerve, XII: hypoglossus nerve, Ty: Tympanic bulla, At: auditory tube, H: pterygoid hamulus, Pt: pterygoid process, PNS: posterior nasal spine, S: soft palate.</p

Regeneration of the soft palate after wounding.

<p>Control and wound tissues from the soft palate were stained with AZAN, and with antibodies against myofibroblasts (ASMA) and fast muscle fibers (Fast MyHC). After 7 days, extensive granulation tissue with collagen and myofibroblasts had formed. (A) AZAN staining. Connective tissue is stained blue, muscle tissue red. Black arrows indicate muscle fibers, white arrows indicate initial regeneration of salivary glands. SG: Salivary glands. (B) ASMA (Brown). Myofibroblasts were not present in the controls, except in blood vessels and salivary glands. In contrast, large numbers of myofibroblasts were present in the wound area at 7 days in the experimental group. (C) Fast MyHC (brown). In both groups, almost all myofibers were of the fast-twitch type. Wound margins are indicated by the dotted lines. The bar represents 200 µm.</p

Satellite cells and myofibers after wounding.

<p>Control and wound tissues were stained with antibodies against Pax7, MyoD, and Myogenin. Large numbers of activated satellite cells and regenerating myofibers are present in the experimental group. (A) Satellite cells (arrows) express the transcription factor Pax7. (B) The myogenic determination factor 1 (MyoD, arrows) is expressed during satellite cell proliferation. (C) Differentiation is marked by a decline in Pax 7 expression, and the induction of myogenin (MyoG, arrows). Pax7-, MyoD-, and MyoG positive cells are stained brown. The bar represents 50 µm.</p

Histology of the soft palate.

<p>Paraffin sections were were cut from the tissue and stained with AZAN. (A) Midsagittal section of the soft palate. The anterior two thirds of the soft palate mainly contain salivary glands. The posterior third of the soft palate contains an additional layer of muscle tissue. (B) Coronal sections of the soft palate. The dotted lines in figure A indicate the position of the coronal sections. (B1) The palatine aponeurosis is the continuation of the tensor veli palatini and inserts into the posterior nasal spine. (B2) Posterior to the pterygoid hamulus, the levator veli platini fibers insert into the palatine aponeurosis. (B3) Most of muscle fibers of the levator veli palatini cross the midline and form a sling suspended from the skull base. N: nasal cavity, O: oral cavity, PA: palatine aponeurosis, SG: salivary glands, PNS: posterior nasal spine, LVP: levator veli palatini muscle, H: pterygoid hamulus. The bar represents 500 µm.</p

General aspect of the soft palate in rats.

<p>Left: Schematic representation of the soft palate (intraoral view). Right: The soft palate in the rat extends from the posterior edge of the hard palate (9^th ruga) towards the nasopharyngeal sphincter. In adult rats, the length of the soft palate is about 11 mm. Ns: nasopharygeal sphincter, R: 9th ruga, M: molar. The red circle indicates the location of the excisional wound (1 mm ø). The dotted lines indicate the location of the histological sections shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059193#pone-0059193-g004" target="_blank">Figure 4</a>. S: midsagittal section. B1, B2, and B 3 coronal sections.</p

Technology roadmap for the heterodyne receiver for origins (HERO)

No abstract availabl

A rat model for muscle regeneration in the soft palate

Contains fulltext : 118436.pdf (publisher's version ) (Open Access)BACKGROUND: Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. METHODS: Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4) and 2 (n = 2) were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6) was used for surgical wounding of the soft palate, and group 4 (n = 2) was used as unwounded control group. The wounds (1 mm) were evaluated by (immuno)histochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA) after 7 days. RESULTS: The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. CONCLUSIONS: This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery