Sepsis is a crucial public health problem with a high mortality rate caused by a dysregulated host immune response to infection. Vascular endothelial cell injury is an important hallmark of sepsis, which leads to multiple organ failure and death. Early biomarkers to diagnose sepsis may provide early intervention and reduce risk of death. Damage-associated molecular patterns (DAMPs) are host nuclear or cytoplasmic molecules released from cells following tissue damage. We postulated that DAMPs could potentially be a novel sepsis biomarker. We used an in vitro model to determine suitable protein–DAMPs biomarkers for early sepsis diagnosis. Low and high lipopolysaccharide (LPS) doses were used to stimulate the human umbilical vein endothelial cell line EA.hy926 for 24, 48, and 72 h. Results showed that cell viability was reduced in both dose-dependent and time-dependent manners. Cell injury was corroborated by a significant increase in lactate dehydrogenase (LDH) activity within 24 h in cell-conditioned medium. Secreted protein–DAMPs in the supernatant, collected at different time points within 24 h, were characterized using shotgun proteomics LC-MS/MS analysis. Results showed that there were 2233 proteins. Among these, 181 proteins from the LPS-stimulated EA.hy926 at 1, 12, and 24 h were significantly different from those of the control. Twelve proteins were up-regulated at all three time points. Furthermore, a potential interaction analysis of predominant DAMPs-related proteins using STITCH 5.0 revealed the following associations with pathways: response to stress; bacterium; and LPS (GO:0080134; 0009617; 0032496). Markedly, alpha-2-HS-glycoprotein (AHSG or fetuin-A) and lactotransferrin (LTF) potentially presented since the first hour of LPS stimulation, and were highly up-regulated at 24 h. Taken together, we reported proteomic profiling of vascular endothelial cell-specific DAMPs in response to early an in vitro LPS stimulation, suggesting that these early damage-response protein candidates could be novel early biomarkers associated with sepsis.

Damage-associated molecular patterns (DAMPs) are well recognized as the molecular signature of immunogenic cell death (ICD). The efficacy of drug-induced ICD function may be impacted by the precise ratio between immunostimulatory and immunoinhibitory DAMPs. Tumor-derived DAMPs can activate tumor-expressed TLRs for the promotion of tumor cell motility, invasion, metastatic spread and resistance to chemotherapeutic treatment. Herein, drug-induced DAMPs’ expression and their role in tumor progression are utilized as one crucial point of evaluation regarding chemotherapeutic treatment efficacy in our study. Cisplatin and oxaliplatin, the conventional anticancer chemotherapy drugs, are emphasized as a cause of well-known DAMPs’ release from cholangiocarcinoma (CCA) cells (e.g., HSP family, S100, CRT and HMGB1), whereby they trigger Akt, ERK and Cyclin-D1 to promote tumor activities. These findings strengthen the evidence that DAMPs are not only involved in immunomodulation but also in tumor promotion. Therefore, DAMP molecules should be considered as either targets of cancer treatment or biomarkers to evaluate treatment efficacy and tumor recurrence.

Secretory Leukocyte Protease Inhibitor (SLPI), a protein functions as an anti-inflammatory molecule that maintains the protease-antiprotease balance. Although SLPI is gaining recognition as a potential biomarker, additional research is required to connect its levels with existing indicators and the quick Sepsis-related Organ Failure Assessment (qSOFA) score to determine its therapeutic value. This study included 50 patients with sepsis and 50 healthy controls recruited from Uttaradit Hospital. Plasma SLPI concentrations were assessed utilising a quantitative ELISA, and the results were compared with standard indicators including Procalcitonin (PCT), C-reactive protein (CRP), lactate, and white blood cell (WBC) count. The findings indicated that plasma SLPI concentrations were markedly increased in the sepsis group relative to healthy controls. ROC curve study of diagnostic accuracy revealed that PCT and CRP had the highest discriminative efficacy, while SLPI also proved to be a meaningful indicator. SLPI had a substantial moderate positive connection with the qSOFA score, in addition to CRP, PCT, and WBC count. A significant association was not observed between SLPI and lactate levels, indicating that SLPI is indicative of systemic inflammation and organ failure rather than direct metabolic distress. In conclusion, plasma SLPI could be a sepsis biomarker that corresponds with severity and inflammatory markers. The moderate association between SLPI and qSOFA scores suggests its possible application in monitoring organ dysfunction in septic patients. Traditional markers like PCT and CRP are reliable for initial diagnosis, but SLPI's unique regulatory capabilities may help diagnose and treat sepsis-related organ damage.