Dexmedetomidine's protective mechanism against hyperoxic injury in neonatal rats.

Bronchopulmonary dysplasia (BPD) is a common serious complication of premature babies. No effective means control it. Hyperoxia damage is one of the important mechanisms of BPD. The reaserach confirmed pyroptosis existed in BPD. Dexmedetomidine is a new, high-specific α2 receptor agonist. Previous research foundation found that dexmedetomidine has a protective effect on BPD. To investigate how dexmedetomidine improves hyperoxic lung injury in neonatal mice by regulating pyroptosis. Neonatal rats were randomly divided into four groups: normal control group, hyperoxic injury group, air plus dexmedetomidine group, and hyperoxia plus dexmedetomidine group. After seven days the lungs of rats in each group were extracted, and the wet-to-dry weight ratio of the lung was measured. The lung injury in rats was observed using hematoxylin-eosin staining. Additionally, the expression and localization of nucleotide-binding oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and gasdermin D (GSDMD) proteins were examined in the lungs of rats using immunofluorescence staining. The mRNA levels of NLRP3, ASC, caspase-1, and interleukin 18 (IL-18) in the lungs of rats were determined using real-time PCR. Moreover, the protein levels of NLRP3, ASC, caspase-1/cleaved caspase-1, interleukin 1beta (IL-1ß), IL-18, and tunor necrosis factor alpha (TNF-α) were detected in lungs of rats using Western blot. The extent of mitochondrial damage in lung tissues of each group was observed by transmission electron microscopy. The lung tissue injury of the neonatal rats was significantly improved in the hyperoxia plus dexmedetomidine group compared to the hyperoxic injury group. Furthermore, the expressions of pyroptosis-related proteins such as NLRP3, ASC, cleaved-caspase-1, and GSDMD were significantly decreased, along with the expressions of inflammatory factors in lung tissues. By inhibiting the NLRP3/caspase-1/GSDMD pyroptosis pathway, dexmedetomidine reduces the activation and release of inflammatory factors and provides a protective effect against hyperoxic lung injury in neonatal mice.

[Gastrointestinal tumors with SWI/SNF complex deficiency: a clinicopathological analysis of 36 cases].

Objective: To investigate the clinicopathological characteristics of gastrointestinal tumors with SWI/SNF complex deficiency and to perform a prognostic analysis of the patients. Methods: Gastrointestinal tumor cases with SWI/SNF complex deficiency expression diagnosed at the Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China from August 2021 to May 2023 were collected. Hematoxylin and eosin (HE) stained slides were reviewed, and immunohistochemical results were analyzed. Clinical and pathological information was recorded, and relevant literature was reviewed. Results: A total of 36 cases of gastrointestinal tumor with loss of SWI/SNF complex expression were identified, including 28 males (77.8%) and 8 females (22.2%). The average age at diagnosis was 70 years (range 48-85 years). Clinical staging showed 3 cases in stage Ⅰ (8.3%), 12 cases in stage Ⅱ (33.3%), 19 cases in stage Ⅲ (52.8%), and 2 cases in stage Ⅳ (5.6%). Complete or partial loss of ARID1A expression was observed in 20 cases (55.6%); complete or partial loss of SMARCA2 expression was observed in 24 cases (66.7%). SMARCA4 exhibited complete loss of expression in 4 cases (11.1%). Eleven cases (30.6%) showed concurrent complete or partial losses of both ARID1A and SMARCA2 expression. Twelve cases (33.3%) had mismatch repair protein deficiency, all of which were characterized by MLH1/PMS2 absence. Mismatch repair protein deficiency was associated with loss of ARID1A expression (P<0.01). Patients with mismatch repair protein deficiency were also associated with earlier clinical stage and a lower risk of lymph node metastasis compared to the ones with intact mismatch repair proteins (P<0.05). Conclusions: SWI/SNF complex deficiency in gastrointestinal tumors is associated with dedifferentiation and often accompanied by mismatch repair protein deficiency. Compared to the cases with intact mismatch repair proteins, the cases with defective mismatch repair protein have an earlier clinical stage and a lower risk of lymph node metastasis.

[Expression of endosialin in human hypertrophic scars and its regulation on fibroblast phenotype].

Objective: To explore the expression of endosialin, i.e., CD248 in human hypertrophic scars (HSs) and its regulatory effect on the phenotype of hypertrophic scar fibroblasts (HSFs). Methods: The method of experimental research was used. From March to May, 2023, 3 pediatric patients with HS were admitted to the Department of Burns and Cutaneous Surgery of the First Affiliated Hospital of Air Force Medical University, including 2 females and 1 male, aged one year ten months to two years. The HS tissue resected during the surgery and the remaining full-thickness skin graft, i.e., normal skin tissue after full-thickness skin grafting were collected from the aforementioned pediatric patients for subsequent experiments. Using the aforementioned two types of tissue, the histological structures were observed by hematoxylin-eosin staining, collagen distribution was observed by Masson staining, and the expression of CD248 was observed and measured by immunohistochemical staining. The primary HSFs were isolated from HS tissue using explant culture technique, and the 3rd to 5th passages of HSFs were used in subsequent experiments. According to the random number table, HSFs were divided into immunoglobulin G78 (IgG78)-treated group and IgG control group, which were treated with 200 nmol/L human CD248 monoclonal antibody IgG78 and human IgG control antibody for 24 h, respectively. The mRNA expressions of collagen type Ⅰ (Col Ⅰ) and α-smooth muscle actin (α-SMA) in HSFs were measured by real-time fluorescence quantitative reverse transcription polymerase chain reaction, the protein expressions of Col Ⅰ and α-SMA in HSFs were detected by Western blotting, and the intracellular location and protein expressions of Col Ⅰ and α-SMA were detected by immunofluorescence method. The number of samples in each experiment was 3. Data were statistically analyzed with paired sample t test and independent sample t test. Results: Compared with those in normal skin tissue, the epidermis and dermis in HS tissue were significantly thicker, with massive accumulation and disordered arrangement of collagen in the dermis. The expression of CD248 in HS tissue was significantly upregulated compared with that in normal skin tissue (t=5.29, P<0.05). At post treatment hour 24, the mRNA expressions of Col Ⅰ and α-SMA of HSFs in IgG78-treated group were 0.39±0.05 and 0.56±0.09, respectively, which were significantly lower than 1.00±0.07 and 1.00±0.08 in IgG control group, respectively (with t values of 11.87 and 6.49, respectively, P values all <0.05). The protein expressions of Col Ⅰ and α-SMA of HSFs in IgG78-treated group were 0.617±0.011 and 0.67±0.14, respectively, which were significantly lower than 1.259±0.052 and 1.23±0.16 in IgG control group, respectively (with t values of 20.92 and 4.52, respectively, P values all <0.05). At post treatment hour 24, immunofluorescence staining showed that Col Ⅰ and α-SMA mainly located in the cytoplasm of HSFs in the two groups, and the protein expressions of Col Ⅰ and α-SMA of HSFs in IgG78-treated group were obviously downregulated compared with those in IgG control group. Conclusions: The expression of CD248 is significantly upregulated in human HS. Targeted blockade of CD248 can significantly inhibit the collagen synthesis by HSFs and the transdifferentiation of HSFs into myofibroblasts.

Stimulated mast cells promote maturation of myocardial microvascular endothelial cell neovessels by modulating the angiopoietin-Tie-2 signaling pathway

Angiopoietin (Ang)-1 and Ang-2 interact in angiogenesis to activate the Tie-2 receptor, which may be involved in new vessel maturation and regression. Mast cells (MCs) are also involved in formation of new blood vessels and angiogenesis. The present study was designed to test whether MCs can mediate angiogenesis in myocardial microvascular endothelial cells (MMVECs). Using a rat MMVEC and MC co-culture system, we observed that Ang-1 protein levels were very low even though its mRNA levels were increased by MCs. Interestingly, MCs were able to enhance migration, proliferation, and capillary-like tube formation, which were associated with suppressed Ang-2 protein expression, but not Tie-2 expression levels. These MCs induced effects that could be reversed by either tryptase inhibitor [N-tosyl-L-lysine chloromethyl ketone (TLCK)] or chymase inhibitor (N-tosyl-L-phenylalanyl chloromethyl ketone), with TLCK showing greater effects. In conclusion, our data indicated that MCs can interrupt neovessel maturation via suppression of the Ang-2/Tie-2 signaling pathway.

Adipose tissue-derived stem cells promote pancreatic cancer cell proliferation and invasion

To explore the effects of adipose tissue-derived stem cells (ADSCs) on the proliferation and invasion of pancreatic cancer cells in vitro and the possible mechanism involved, ADSCs were cocultured with pancreatic cancer cells, and a cell counting kit (CCK-8) was used to detect the proliferation of pancreatic cancer cells. ELISA was used to determine the concentration of stromal cell-derived factor-1 (SDF-1) in the supernatants. RT-PCR was performed to detect the expression of the chemokine receptor CXCR4 in pancreatic cancer cells and ADSCs. An in vitro invasion assay was used to measure invasion of pancreatic cancer cells. SDF-1 was detected in the supernatants of ADSCs, but not in pancreatic cancer cells. Higher CXCR4 mRNA levels were detected in the pancreatic cancer cell lines compared with ADSCs (109.3±10.7 and 97.6±7.6 vs 18.3±1.7, respectively; P<0.01). In addition, conditioned medium from ADSCs promoted the proliferation and invasion of pancreatic cancer cells, and AMD3100, a CXCR4 antagonist, significantly downregulated these growth-promoting effects. We conclude that ADSCs can promote the proliferation and invasion of pancreatic cancer cells, which may involve the SDF-1/CXCR4 axis.