Secretory leukocyte protease inhibitor as a novel predictive biomarker in patients with diabetic kidney disease.

Background: Secretory leukocyte protease inhibitor (SLPI) is a multifunctional protein involved in the chronic inflammatory process, implicated in the pathogenesis of diabetic kidney disease (DKD). However, its potential as a diagnostic and prognostic biomarker of DKD has yet to be evaluated. This study explored the clinical utility of SLPI in the diagnosis and prognosis of renal endpoint events in patients with DKD. Methods: A multi-center cross-sectional study comprised of 266 patients with DKD and a predictive cohort study comprised of 120 patients with stage IV DKD conducted between December 2016 and January 2022. The clinical parameters were collected for statistical analysis, a multivariate Cox proportional hazards model was used to evaluate the independent risk factors for renal endpoints. Results: Serum SLPI levels gradually increased with DKD progression (p<0.01). A significant correlation was observed between serum SLPI levels and renal function in patients with DKD. The mean follow-up duration in this cohort study was 2.32 ± 1.30 years. Multivariate Cox regression analysis showed SLPI levels≥51.61ng/mL (HR=2.95, 95% CI[1.55, 5.60], p<0.01), 24h urinary protein levels≥3500 mg/24h (HR=3.02, 95% CI[1.66, 5.52], p<0.01), Alb levels<30g/l (HR=2.19, 95% CI[1.12, 4.28], p<0.05), HGB levels<13g/dl (HR=3.18, 95% CI[1.49, 6.80], p<0.01), and urea levels≥7.1 mmol/L (HR=8.27, 95% CI[1.96, 34.93], p<0.01) were the independent risk factors for renal endpoint events in DKD patients. Conclusions: Serum SLPI levels increased with DKD progression and were associated with clinical parameters of DKD. Moreover, elevated SLPI levels showed potential prognostic value for renal endpoint events in individuals with DKD. These findings validate the results of previous studies on SLPI in patients with DKD and provide new insights into the role of SLPI as a biomarker for the diagnosis and prognosis of DKD that require validation.

Secretory leukocyte protease inhibitor protects against severe urinary tract infection in mice.

Millions suffer from urinary tract infections (UTIs) worldwide every year with women accounting for the majority of cases. Uropathogenic Escherichia coli (UPEC) causes most of these primary infections and leads to 25% becoming recurrent or chronic. To repel invading pathogens, the urinary tract mounts a vigorous innate immune response that includes the secretion of antimicrobial peptides (AMPs), rapid recruitment of phagocytes, and exfoliation of superficial umbrella cells. Here, we investigate secretory leukocyte protease inhibitor (SLPI), an AMP with antiprotease, antimicrobial, and immunomodulatory functions, known to play protective roles at other mucosal sites, but not well characterized in UTIs. Using a preclinical model of UPEC-caused UTI, we show that urine SLPI increases in infected mice and that SLPI is localized to bladder epithelial cells. UPEC-infected SLPI-deficient (Slpi-/-) mice suffer from higher urine bacterial burdens, prolonged bladder inflammation, and elevated urine neutrophil elastase (NE) levels compared to wild-type (Slpi+/+) controls. Combined with bulk bladder RNA sequencing, our data indicate that Slpi-/- mice have a dysregulated immune and tissue repair response following UTI. We also measure SLPI in urine samples from a small group of female subjects 18-49 years old and find that SLPI tends to be higher in the presence of a uropathogen, except in patients with a history of recent or recurrent UTI, suggesting a dysregulation of SLPI expression in these women. Taken together, our findings show SLPI promotes clearance of UPEC in mice and provides preliminary evidence that SLPI is likewise regulated in response to uropathogen exposure in women.IMPORTANCEAnnually, millions of people suffer from urinary tract infections (UTIs) and more than $3 billion are spent on work absences and treatment of these patients. While the early response to UTI is known to be important in combating urinary pathogens, knowledge of host factors that help curb infection is still limited. Here, we use a preclinical model of UTI to study secretory leukocyte protease inhibitor (SLPI), an antimicrobial protein, to determine how it protects the bladder against infection. We find that SLPI is increased during UTI, accelerates the clearance of bacteriuria, and upregulates genes and pathways needed to fight an infection while preventing prolonged bladder inflammation. In a small clinical study, we show SLPI is readily detectable in human urine and is associated with the presence of a uropathogen in patients without a previous history of UTI, suggesting SLPI may play an important role in protecting from bacterial cystitis.

Recombinant human secretory leukocyte protease inhibitor (rhSLPI) coated titanium enhanced human osteoblast adhesion and differentiation.

Osseointegration is vital to success in orthopedic and dental reconstructions with implanted materials. The bone matrix or cells-particularly osteoblasts-are required to achieve functional contact on the implant surface. Osteoblast induction is therefore essential for osteogenesis to occur. Enhancement of osteoblast adhesion, proliferation, and differentiation, particularly by implant surface modifications, have been found challenging to develop. Secretory Leukocyte Protease Inhibitor (SLPI), a cation ionic protein with anti-inflammatory and anti-bacterial activities, showed activation in osteoblast proliferation and differentiation. However, the effects of coating recombinant human (rh) SLPI on a titanium alloy surface on human osteoblast adhesion, proliferation, and differentiation has never been investigated. In this study, titanium alloys (Ti-6Al-4V) were coated with rhSLPI, while human osteoblast adhesion, proliferation, differentiation, actin cytoskeletal organization, and gene expressions involved in cell adhesion and differentiation were investigated. The results indicate that coating titanium with 10-100 µg/ml rhSLPI enhanced the physical properties of the Ti surface and enhanced human osteoblast (hFOB 1.19) cell adhesion, activated actin dynamic, enhanced adhesive forces, upregulated integrins α1, α2, and α5, enhanced cell proliferation, mineralization, alkaline phosphatase activity, and upregulated ALP, OCN, and Runx2. This is the first study to demonstrate that coating SLPI on titanium surfaces enhances osseointegration and could be a candidate molecule for surface modification in medical implants.

Salivary concentrations of secretory leukocyte protease inhibitor and matrix metallopeptidase-9 following a single bout of exercise are associated with intensity and hydration status.

AIM: To investigate the effects of exercise on salivary concentrations of inflammatory markers by analyzing a panel of 25 inflammatory markers in subjects who had participated in bicycle ergometer tests varying in workload and hydration status. METHODS: Fifteen healthy young men (20-35 years) had performed 4 different exercise protocols of 1 hour duration in a randomly assigned cross-over design, preceded by a rest protocol. Individual workloads depended on participant's pre-assessed individual maximum workload (Wmax): rest (protocol 1), 70% Wmax in hydrated (protocol 2) and dehydrated (protocol 3) state, 50% Wmax (protocol 4) and intermittent 85%/55% Wmax in 2 min blocks (protocol 5). Saliva samples were collected before (T0) and immediately after exercise (T1), and at several time points after exercise (2 hours (T3), 3 hours (T4), 6 hours (T5) and 24 hours (T6)). Secretory Leukocyte Protease Inhibitor (SLPI), Matrix Metallopeptidase-9 (MMP-9) and lactoferrin was analyzed using a commercial ELISA kit, a panel of 22 cytokines and chemokines were analyzed using a commercial multiplex immunoassay. Data was analyzed using a multilevel mixed linear model, with multiple test correction. RESULTS: Among a panel of 25 inflammatory markers, SLPI concentrations were significantly elevated immediately after exercise in all protocols compared to rest and higher concentrations reflected the intensity of exercise and hydration status. MMP-9 showed a significant increase in the 70% Wmax dehydrated, 50% Wmax and intermittent protocols. CONCLUSIONS: Salivary concentrations of SLPI and MMP-9 seem associated with exercise intensity and hydration status and may offer non-invasive biomarkers to study (local) inflammatory responses to different exercise intensities in human studies.

Secretory leucocyte protease inhibitor (SLPI) as an adjunct prognostic biomarker for canine pyometra.

Pyometra is a potentially life-threatening condition that affects intact female dogs in their middle to advance age. Timely diagnosis and appropriate treatment are critical for the survival of patients, especially when pyometra advances to sepsis. This study aimed to investigate the prognostic potential of certain haematology, serum biochemical and inflammatory biomarker, secretory leucocyte protease inhibitor (SLPI) for pyometra in bitches (n = 41). Blood samples were collected after clinical diagnosis of pyometra for haematology and serum biochemistry. Based on the prognosis following medical/surgical treatment, animals were retrospectively categorized into survivor (n = 29) and dead (n = 12). Endometrial tissue sections were obtained from the bitches undergoing ovariohysterectomy (n = 21). Serum concentration of SLPI was quantified using sandwich ELISA and its expression in the endometrium was investigated using RT-qPCR. A marked increase in the total leucocyte count (TLC), neutrophils, blood urea nitrogen (BUN) and serum creatinine was observed in the female dogs that did not survive. Significant elevation in the serum SLPI concentration (3.49 ± 0.44 vs. 2.38 ± 0.13 ng/mL) was observed in the bitches those died after the treatment, in comparison to those survived (p < .01). Additionally, there was a notable upregulation of SLPI in the endometrium in the bitches those died due to pyometra. Based on the ROC analysis results, it was observed that a cut-off concentration of 2.93 ng/mL for SLPI, 27.77 mg/dL for BUN and 16.3 × 103 /µL for TLC could effectively distinguish the prognosis of pyometra-affected dogs. From this study, it can be concluded that upregulation of SLPI in the endometrium and its elevated concentration in peripheral circulation along with TLC and BUN concentration could serve as valuable indicators for predicting the prognosis of pyometra in bitches.

A novel immune modulator IM33 mediates a glia-gut-neuronal axis that controls lifespan.

Aging is a complex process involving various systems and behavioral changes. Altered immune regulation, dysbiosis, oxidative stress, and sleep decline are common features of aging, but their interconnection is poorly understood. Using Drosophila, we discover that IM33, a novel immune modulator, and its mammalian homolog, secretory leukocyte protease inhibitor (SLPI), are upregulated in old flies and old mice, respectively. Knockdown of IM33 in glia elevates the gut reactive oxygen species (ROS) level and alters gut microbiota composition, including increased Lactiplantibacillus plantarum abundance, leading to a shortened lifespan. Additionally, dysbiosis induces sleep fragmentation through the activation of insulin-producing cells in the brain, which is mediated by the binding of Lactiplantibacillus plantarum-produced DAP-type peptidoglycan to the peptidoglycan recognition protein LE (PGRP-LE) receptor. Therefore, IM33 plays a role in the glia-microbiota-neuronal axis, connecting neuroinflammation, dysbiosis, and sleep decline during aging. Identifying molecular mediators of these processes could lead to the development of innovative strategies for extending lifespan.

Secretory leukocyte protease inhibitor modulates FcεRI-dependent but not Mrgprb2-dependent mastocyte function in psoriasis.

Psoriasis, which involves mast cells, is a chronic inflammatory skin disorder whose pathophysiology is still not fully understood. We investigated the role of secretory leukocyte protease inhibitor (SLPI), a potential inhibitor of mastocyte serine proteases, on mast cell-dependent processes of relevance to the skin barrier defense in psoriasis. Here, we demonstrate that the dermal mast cells of patients with psoriasis express SLPI but not those of healthy donors. Moreover, SLPI transcripts were found to be markedly upregulated in murine mast cells by mediators derived from psoriasis skin explant cultures. Using mast cells from SLPI-deficient mice and their SLPI+ wild-type controls, we show that SLPI inhibits the activity of serine protease chymase in mastocytes. SLPI was also found to enhance the degranulation of mast cells activated via anti-IgE Abs but not Mrgprb2 ligands. Finally, we demonstrate that the expression and function of Mrgprb2 in mast cells are suppressed by a normal and, to a larger extent, psoriatic skin environment. Together, these findings reveal mechanisms underlying FcεRI- and Mrgprb2-dependent mast cell function that have not been described previously.

Dietary iron modulates gut microbiota and induces SLPI secretion to promote colorectal tumorigenesis.

Dietary iron intake is closely related to the incidence of colorectal cancer. However, the interactions among dietary iron, gut microbiota, and epithelial cells in promoting tumorigenesis have rarely been discussed. Here, we report that gut microbiota plays a crucial role in promoting colorectal tumorigenesis in multiple mice models under excessive dietary iron intake. Gut microbiota modulated by excessive dietary iron are pathogenic, irritating the permeability of the gut barrier and causing leakage of lumen bacteria. Mechanistically, epithelial cells released more secretory leukocyte protease inhibitor (SLPI) to combat the leaked bacteria and limit inflammation. The upregulated SLPI acted as a pro-tumorigenic factor and promoted colorectal tumorigenesis by activating the MAPK signaling pathway. Moreover, excessive dietary iron significantly depleted Akkermansiaceae in the gut microbiota; while supplementation with Akkermansia muciniphila could successfully attenuate the tumorigenic effect from excessive dietary iron. Overall, excessive dietary iron perturbs diet - microbiome-epithelium interactions, which contributes to intestinal tumor initiation.

Afterbirth oral fluid secretory leukocyte protease inhibitor decreased in acute histologic chorioamnionitis in preterm birth.

BACKGROUND: Secretory leukocyte protease inhibitor (SLPI) is an innate anti-inflammatory and anti-microbial peptide and produced in amnion of fetal membranes during pregnancy. However, studies on the association between SLPI levels in amniotic fluid and acute chorioamnionitis are limited. Afterbirth oral fluid (AOF) of the baby could be useful for representing the intra-amniotic environment precisely just before delivery. This study aimed to determine the relationship between SLPI levels in AOF and acute histologic chorioamnionitis (HC). METHODS: AOF of the baby was obtained during delivery from 24(0/7) to 36(6/7) weeks of gestational age (preterm group, n = 94) and from 37(0/7) to 41(6/7) weeks of gestational age (term group, n = 27) just after birth. SLPI expression levels among five classifications were compared to the intensity of acute HC as follows: no inflammation, acute subchorionitis, acute chorionitis, acute chorioamnionitis, and funisits. The SLPI and matrix metalloproteinase-8 (MMP-8) concentrations of AOF were determined using Enzyme Linked Immunosorbent Assay. Histologic examination of the placenta and membranes was performed after delivery. RESULTS: SLPI concentrations in AOF inversely decreased according to the intensity of acute HC (161.62 ng/mL in funisitis, 134.83 ng/mL in acute chorioamnionitis, 749.35 ng/mL in acute chorionitis, 953.05 ng/mL in acute subchorionitis, and 1126.77 ng/mL in no inflammation [p = .021]). The MMP-8 concentrations in AOF and maternal serum C-reactive protein were the highest in funisitis. The SLPI/ MMP-8 ratio was low in subgroup with acute chorioamnionitis and funisitis. CONCLUSION: Along with increased MMP-8 levels, decreased SLPI levels in AOF of the baby could be an additional factor in predicting acute HC immediately after birth.

Secretory leukocyte protease inhibitor (SLPI) in cancer pathophysiology: Mechanisms of action and clinical implications.

Cancer is a multifaceted disorder frequently linked to the dysregulation of several biological processes. The SLPI is a multifunctional protein involved in the modulation of immunological response and the inhibition of protease activities. SLPI acts as an inhibitor of proteases, exerts antibacterial properties, and suppresses the transcription of proinflammatory genes through the nuclear factor-kappa B (NF-κB) pathway. The role of this protein as a regulatory agent has been implicated in various types of cancer. Recent research has revealed that SLPI upregulation in cancer cells enhances the metastatic capacity of epithelial malignancies, indicating the deleterious effects of this protein. Furthermore, SLPI interacts intricately with other cancer-promoting factors, including matrix metalloproteinase-2 (MMP-2), MMP-9, the NF-κB and Akt pathways, and the p53-upregulated modulator of apoptosis (PUMA). This review provides an overview of the role of SLPI in cancer pathophysiology, emphasizing its expression in cancer cells and tissues, its potential as a prognostic biomarker, and its therapeutic promise as a target in cancer treatment. The mechanisms of SLPI action in cancer, including its anti-inflammatory effects, regulation of cell proliferation and angiogenesis, and modulation of the tumor microenvironment, have been investigated. The clinical implications of SLPI in cancer have been discussed, including its potential as a diagnostic and prognostic biomarker, its role in chemoresistance, and its therapeutic potential in several types of cancer, such as hepatocellular carcinoma (HCC), colorectal cancer (CRC), pancreatic cancer, head and neck squamous cell carcinoma (HNSCC), ovarian cancer (OvCa), prostate cancer (PC), gastric cancer (GC), breast cancer, and other cancers. In addition, we emphasized the significance of SLPI in cancer, which offers fresh perspectives on potential targets for cancer therapy.

Serum concentrations of secretory leukocyte protease inhibitor and IL6 can predict the onset of sepsis in pyometra bitches.

As onset of sepsis adversely affects the prognosis of canine pyometra, finding biomarkers that would distinguish sepsis status would be useful in the clinical management. Accordingly, we hypothesized that differential expression of endometrial transcripts and circulating concentration of certain inflammatory mediators would discriminate pyometra-led sepsis (P-sepsis+) from those of pyometra without sepsis (P-sepsis-). Bitches with pyometra (n = 52) were classified into P-sepsis+ (n = 28) and P-sepsis- (n = 24) based on vital clinical score and total leukocyte count. A group of non-pyometra bitches (n = 12) served as control. The relative fold changes in the transcripts of IL6, IL8, TNFα, IL10, PTGS2, mPGES1 and PGFS, SLPI, S100A8, S100A12 and eNOS were determined by quantitative polymerase chain reaction. Furthermore, the serum concentrations of IL6, IL8, IL10, SLPI and prostaglandin F2α metabolite (PGFM) were assayed by ELISA. The relative fold changes in S100A12 and SLPI and mean concentrations of IL6 and SLPI were significantly (p < .05) higher in P-sepsis+ than that of P-sepsis- group. Receiver operating characteristic analysis revealed that serum IL6 had a diagnostic sensitivity of 78.6% and a positive likelihood ratio (LR+) of 2.09, at a cut-off value of 15.7 pg/mL to diagnose P-sepsis+ cases. Similarly, serum SLPI had a sensitivity of 84.6% and an LR+ of 2.23, at a cut-off value of 2.0 pg/mL. It was concluded that SLPI and IL6 would serve as putative biomarkers for pyometra-led sepsis in bitches. Monitoring SLPI and IL6 would be a useful adjunct to the established haemato-biochemical parameters in customizing the treatment strategies and arriving at the decision for management of pyometra bitches with critical illness.

Up-regulation of secretory leukocyte protease inhibitor in human samples might have a potential role of predicting prostate cancer recurrence and progression after surgery and hormonal therapy.

Using new castration-resistant prostate cancer (CRPC) cell lines developed from LNCaP cells as a model for CRPC, we searched for novel biomarkers by analyzing the proteins secreted in culture supernatants. The results showed that the levels of secretory leukocyte protease inhibitor (SLPI) in these cell lines were 4.7-6.7 times higher than those secreted in parental LNCaP. Patients with localized prostate cancer (PC) and who expressed SLPI had a significantly lower prostate-specific antigen (PSA) progression-free survival rate than those who did not. Multivariate analysis revealed that SLPI expression was an independent risk factor for PSA recurrence. By contrast, when immunostaining of SLPI was performed on consecutive prostate tissue samples obtained from 11 patients, both in hormone naive (HN) and castration resistant (CR) conditions, only one patient expressed SLPI in the HNPC state; however, four of the 11 patients expressed SLPI in the CRPC state. In addition, two of these four patients were resistant to enzalutamide, and there was a discrepancy between their serum PSA levels and radiographic progression of the disease. These results suggest that SLPI can be a predictor of prognosis in patients with localized PC and disease progression in CRPC patients.

Pathological roles of antimicrobial peptides and pro-inflammatory factors secreted from the cervical epithelium in Gardnerella vaginalis-abundant vaginal flora in pregnancy.

Bacterial vaginosis due to Gardnerella vaginalis (GV) is one of the main causes of preterm birth. Antimicrobial function of the cervical glands prevents ascending pathogen infection. This study investigated the effect of GV on the cervical gland cells. We examined the correlation between GV and neutrophil elastase in the cervical mucous obtained from pregnant women's clinical samples. Culture supernatants (sup) of GV and Lactobacillus crispatus (LC) were added to human immortalized cervical gland cells (EndoCx). Quantitative reverse transcription PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine the effects on the production of antimicrobial peptides (AMPs), secretory leukocyte peptidase inhibitor (SLPI), and Elafin. mRNA microarray analysis revealed the expression profile of GV-exposed EndoCx. Moreover, the antimicrobial activity of Elafin against LC and GV was investigated. In the clinical samples, neutrophil elastase was increased in the GV-positive cervical mucous. In an in vitro assay, RT-qPCR and ELISA showed that GV-sup enhanced the secretion of Elafin, but not SLPI, from EndoCx, whereas LC-sup did not. mRNA microarray assay and ELISA results demonstrated that GV-sup enhanced the proinflammatory pathway and interleukin (IL)- 8 secretion from EndoCx as well as cell adhesion and tight junction pathways. Moreover, GV-sup directly enhanced Elafin and IL-8 secretion from the cervical gland cells. In the GV-abundant vaginal flora, IL-8 level increased the neutrophil elastase activity and Elafin inhibited the elastase activity to protect from tissue damage and infection. Thus, the balance of IL-8-induced neutrophil and Elafin-induced antiprotease activities may be crucial in preterm labor.

Secretory leukocyte protease inhibitor and risk of heart failure in the Multi-Ethnic Study of Atherosclerosis.

Circulating protease inhibitors are important regulators of inflammation that are implicated in the pathophysiology of heart failure (HF). Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor which protects pulmonary tissues against inflammatory damage; however, its role in HF is not well understood. We sought to evaluate associations of circulating SLPI and genetically-mediated serum SLPI with incident HF and its subtypes in a multi-ethnic cohort of adults using clinical and genetic epidemiological approaches. Among 2,297 participants in the Multi-Ethnic Study of Atherosclerosis (MESA), each doubling of serum SLPI was independently associated with incident HF (HR 1.77; 95% CI 1.02-3.02; P = 0.04), particularly incident HF with preserved ejection fraction (HFpEF; HR 2.44; 95% CI 1.23-4.84; P = 0.01) but not HF with reduced ejection fraction (HFrEF; HR 0.95; 95% CI 0.36-2.46; P = 0.91). Previously reported circulating SLPI protein quantitative trait loci (pQTLs) were not associated with serum SLPI levels or incident HF among MESA participants. In conclusion, baseline serum SLPI levels, but not genetically-determined serum SLPI, were significantly associated with incident HF and HFpEF over long-term follow-up in a multi-ethnic cohort. Serum circulating SLPI may be a correlate of inflammation that sheds insight on the pathobiology of HFpEF.

Endogenous secretory leukocyte protease inhibitor inhibits microbial-induced monocyte activation.

In the intestine, epithelial factors condition incoming immune cells including monocytes to adapt their threshold of activation and prevent undesired inflammation. Colonic epithelial cells express Secretory Leukocyte Protease Inhibitor (SLPI), an inhibitor of NF kappa light chain enhancer of activated B cells (NF-κB) that mediates epithelial hyporesponsiveness to microbial stimuli. Uptake of extracellular SLPI by monocytes has been proposed to inhibit monocyte activation. We questioned whether monocytes can produce SLPI and whether endogenous SLPI can inhibit monocyte activation. We demonstrate that human THP-1 monocytic cells produce SLPI and that CD68+ SLPI-producing cells can be detected in human intestinal lamina propria. Knockdown of SLPI in human THP-1 cells significantly increased NF-κB activation and subsequent C-X-C motif chemokine ligand 8 (CXCL8) and TNF-α production in response to microbial stimulation. Reconstitution of SLPI-deficient cells with either full-length SLPI or SLPI lacking its signal peptide rescued inhibition of NF-κB activation and cytokine production, demonstrating that endogenous SLPI inhibits monocytic cell activation. Unexpectedly, exogenous SLPI did not inhibit CXCL8 or TNF-α production, despite efficient uptake. Our data argue that endogenous SLPI can regulate the threshold of activation in monocytes, thereby preventing activation by commensal bacteria in mucosal tissues.

Differential expression of inflammatory cytokines, prostaglandin synthases and secretory leukocyte protease inhibitor in the endometrium and circulation in different graded CEH-pyometra in bitch.

Cystic endometrial hyperplasia (CEH)-pyometra (CEH-P) is one of the most common reproductive disorders in bitches, posing a risk to both future fertility and life. The aims of the current study were to elucidate the differential expression patterns of inflammatory mediators at transcript and protein levels in the endometrium and to assess the concentrations of key inflammatory mediators in the peripheral circulation of bitches with different graded CEH-P. A total of 25 client-owned intact mixed breed bitches of 3-10 years presented to the outpatient department of RVP-TVCC of the institute were considered for the study. Of which, 22 cases suggestive of pyometra and 3 cases of CEH obtained during routine elective ovariohysterectomy were subjected to histopathological examination. Uteri were categorized into CEH (n = 3), moderate CEH-P (mCEH-P, n = 9), severe CEH-P (sCEH-P, n = 6) and atrophic pyometra (AT-P, n = 7). A group of age matched (n = 12) bitches without pyometra served as control. Endometrial transcripts such as IL6, IL8, PTGS2, PGFS, and SLPI were expressed differentially in the CEH and CEH-P bitch. In addition, a strong immunoreactivity (IR) of IL6, IL8, PTGS2, and mPGES1 was recorded in the sCEH-P uterus, while expression of IL10 was noticed in AT-P. In circulation, serum IL6 was the most relevant marker with high sensitivity of 96.2% and specificity of 84.6% at a cut off concentration 8.5 pg/mL followed by SLPI with 95.2% sensitivity, and 84.6% specificity at cut off concentration of 1.3 ng/mL. Serum IL10, PGFM and SLPI concentration in the peripheral circulation were 1.5-2.23 fold higher in mCEH-P, 0.87-2.5 fold higher in sCEH-P and 2.9-3.5 fold higher in AT-P than that of control. It is concluded that monitoring the serum concentration of IL6, IL10 and SLPI would be useful adjunct to the established hematobiochemical parameters in the management of pyometra in the bitch with critical illness.

Salivary secretory leukocyte protease inhibitor levels in patients with stage 3 grade C periodontitis: a comparative cross-sectional study.

Secretory leukocyte protease inhibitor (SLPI) is an anti-protease that protects mucosal tissue integrity owing to its anti-microbial and immunomodulatory properties. This study aimed to investigate SLPI levels in periodontal diseases, and analyze the potential correlation with clinical periodontal parameters. Whole saliva samples were obtained from healthy (n = 24), gingivitis (n = 24) and patients with stage 3 grade C periodontitis (n = 24). SLPI was measured by ELISA and normalized by total protein. Receiver operating characteristics (ROC) curve was used for estimating the area under the curve (AUC). The normalized SLPI levels were significantly reduced in periodontitis compared with gingivitis (4.84-fold) or health (1.83-fold) and negatively correlated with periodontal parameters. The ROC curves showed a good predictor value of the SLPI for differentiation of periodontitis versus health or gingivitis (AUC ≥ 0.80). This study demonstrates that the levels of SLPI are high in periodontal health, further elevated in gingivitis, but eventually decreased in severe periodontitis beyond the former two states. This observation may have broader implications in the context of inflammatory diseases affecting the oral mucosa, as it shows that the bacterial burden is disturbing the homeostatic balances of anti-microbial and anti-protease factors in the oral cavity.

Secretory Leucoprotease Inhibitor (SLPI) Promotes Survival during Acute Pseudomonas aeruginosa Infection by Suppression of Inflammation Rather Than Microbial Killing.

Secretory leucoprotease inhibitor (SLPI) has multifaceted functions, including inhibition of protease activity, antimicrobial functions, and anti-inflammatory properties. In this study, we show that SLPI plays a role in controlling pulmonary Pseudomonas aeruginosa infection. Mice lacking SLPI were highly susceptible to P. aeruginosa infection, however there was no difference in bacterial burden. Utilising a model of P. aeruginosa LPS-induced lung inflammation, human recombinant SLPI (hrSLPI) administered intraperitoneally suppressed the recruitment of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and resulted in reduced BALF and serum levels of inflammatory cytokines and chemokines. This anti-inflammatory effect of hrSLPI was similarly demonstrated in a systemic inflammation model induced by intraperitoneal injection of LPS from various bacteria or lipoteichoic acid, highlighting the broad anti-inflammatory properties of hrSLPI. Moreover, in bone-marrow-derived macrophages, hrSLPI reduced LPS-induced phosphorylation of p-IkB-α, p-IKK-α/ß, p-P38, demonstrating that the anti-inflammatory effect of hrSLPI was due to the inhibition of the NFκB and MAPK pathways. In conclusion, administration of hrSLPI attenuates excessive inflammatory responses and is therefore, a promising strategy to target inflammatory diseases such as acute respiratory distress syndrome or sepsis and could potentially be used to augment antibiotic treatment.

The anticancer effect of EGFR-targeting artificial microRNA controlled by SLPI promoter in nasopharyngeal carcinoma.

BACKGROUND: This study intends to use artificial microRNA (recombinant adenovirus vector) targeting epidermal growth factor receptor (EGFR) to inhibit the overexpressed EGFR in nasopharyngeal carcinoma, thereby inhibiting the proliferation and metastasis of nasopharyngeal carcinoma. METHOD: The research group verified the expression of EGFR in nasopharyngeal carcinoma through databases, clinical tissues, and cellular pathways. The team first tested the transfection of the recombinant adenovirus by fluorescence microscopy. After adenovirus treatment with different multiplicity of infection (MOI), EGFR level and cell viability in cells were examined by Western blot and MTT assay. Next, the effects of adenovirus (Ad)-SLPI-EGFR on cell proliferation, migration, apoptosis, and related proteins were sequentially examined by EdU, scratch, Transwell, and Western blot. In vivo experiments were performed to evaluate the biological function of EGFR in nasopharyngeal carcinoma. RESULT: All three validation pathways showed the increase in EGFR expression in nasopharyngeal carcinoma. Transfection tests showed that the SLPI promoter was specific in CNE2 cells. With the increase in MOI, the inhibition of EGFR expression and cancer cell viability by Ad-SLPI-EGFR was enhanced. Meanwhile, Ad-SLPI-EGFR effectively reduced the proliferation and metastasis of CNE2 cells and affected the expression of related proteins. Furthermore, Ad-SLPI-EGFR inhibited the invasion and metastasis of nasopharyngeal carcinoma in vivo. CONCLUSION: Ad-SLPI-EGFR inhibits the expression of EGFR in nasopharyngeal carcinoma cells, and finally achieves the purpose of inhibiting the proliferation and metastasis of cancer cells, which may provide novel targeted intervention for the treatment of nasopharyngeal carcinoma.