LRP5 promotes cancer stem cell traits and chemoresistance in colorectal cancer

The overactivation of canonical Wnt/β‐catenin pathway and the maintenance of cancer stem cells (CSCs) are essential for the onset and malignant progression of most human cancers. However, their regulatory mechanism in colorectal cancer (CRC) has not yet been well demonstrated. Low‐density lipoprotein receptor‐related protein 5 (LRP5) has been identified as an indispensable co‐receptor with frizzled family members for the canonical Wnt/β‐catenin signal transduction. Herein, we show that activation of LRP5 gene promotes CSCs‐like phenotypes, including tumorigenicity and drug resistance in CRC cells, through activating the canonical Wnt/β‐catenin and IL‐6/STAT3 signalling pathways. Clinically, the expression of LRP5 is upregulated in human CRC tissues and closely associated with clinical stages of patients with CRC. Further analysis showed silencing of endogenous LRP5 gene is sufficient to suppress the CSCs‐like phenotypes of CRC through inhibiting these two pathways. In conclusion, our findings not only reveal a regulatory cross‐talk between canonical Wnt/β‐catenin signalling pathway, IL‐6/STAT3 signalling pathway and CD133‐related stemness that promote the malignant behaviour of CRC, but also provide a valuable target for the diagnosis and treatment of CRC.     

LncRNA SNHG1 promotes sepsis‐induced myocardial injury by inhibiting Bcl‐2 expression via DNMT1

Myocardial injury is a frequently occurring complication of sepsis. This study aims to investigate the molecular mechanism of long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1)‐mediated DNA methyltransferase 1/B‐cell lymphoma‐2 (DNMT1/Bcl‐2) axis in sepsis‐induced myocardial injury. Mice and HL‐1 cells were treated with lipopolysaccharide (LPS) to establish animal and cellular models simulating sepsis and inflammation. LncRNA SNHG1 was screened out as a differentially expressed lncRNA in sepsis samples through microarray profiling, and the upregulated expression of lncRNA SNHG1 was confirmed in myocardial tissues of LPS‐induced septic mice and HL‐1 cells. Further experiments suggested that silencing of lncRNA SNHG1 reduced the inflammation and apoptotic rate of LPS‐induced HL‐1 cells. LncRNA SNHG1 inhibited Bcl‐2 expression by recruiting DNMT1 to Bcl‐2 promoter region to cause methylation. Inhibition of Bcl‐2 promoter methylation reduced the inflammation and apoptotic rate of LPS‐induced HL‐1 cells. In vivo experiments substantiated that lncRNA SNHG1 silencing alleviated sepsis‐induced myocardial injury in mice. Taken together, lncRNA SNHG1 promotes LPS‐induced myocardial injury in septic mice by downregulating Bcl‐2 through DNMT1‐mediated Bcl‐2 methylation.     

Kcnh2 mediates FAK/AKT‐FOXO3A pathway to attenuate sepsis‐induced cardiac dysfunction

ObjectivesMyocardial dysfunction is a significant manifestation in sepsis, which results in high mortality. Even Kcnh2 has been hinted to associate with the pathological process, its involved signalling is still elusive.Materials and methodsThe caecal ligation puncture (CLP) surgery or lipopolysaccharide (LPS) injection was performed to induce septic cardiac dysfunction. Western blotting was used to determine KCNH2 expression. Cardiac function was examined by echocardiography 6 hours after CLP and LPS injection in Kcnh2 knockout (Kcnh2^+/‐) and NS1643 injection rats (n ≥ 6/group). Survival was monitored following CLP‐induced sepsis (n ≥ 8/group).ResultsSepsis could downregulate KCNH2 level in the rat heart, as well as in LPS‐stimulated cardiomyocytes but not cardiac fibroblast. Defect of Kcnh2 (Kcnh2^+/‐) significantly aggravated septic cardiac dysfunction, exacerbated tissue damage and increased apoptosis under LPS challenge. Fractional shortening and ejection fraction values were significantly decreased in Kcnh2^+/‐ group than Kcnh2^+/+ group. Survival outcome in Kcnh2^+/‐ septic rats was markedly deteriorated, compared with Kcnh2^+/+ rats. Activated Kcnh2 with NS1643, however, resulted in opposite effects. Lack of Kcnh2 caused inhibition of FAK/AKT signalling, reflecting in an upregulation for FOXO3A and its downstream targets, which eventually induced cardiomyocyte apoptosis and heart tissue damage. Either activation of AKT by activator or knockdown of FOXO3A with si‐RNA remarkably attenuated the pathological manifestations that Kcnh2 defect mediated.ConclusionKcnh2 plays a protection role in sepsis‐induced cardiac dysfunction (SCID) via regulating FAK/AKT‐FOXO3A to block LPS‐induced myocardium apoptosis, indicating a potential effect of the potassium channels in pathophysiology of SCID.     

Downregulation of muscle protein degradation in sepsis by eicosapentaenoic acid (EPA)

Eicosapentaenoic acid (EPA) has been shown to attenuate muscle atrophy in cancer, starvation and hyperthermia by downregulating the increased expression of the ubiquitin-proteasome proteolytic pathway leading to a reduction in protein degradation. In the current study EPA (0.5 g/kg) administered to septic mice completely attenuated the increased protein degradation in skeletal muscle by preventing the increase in both gene expression and protein concentration of the α- and β-subunits of the 20S proteasome, as well as functional activity of the proteasome, as measured by the ‘chymotrypsin-like’ enzyme activity. These results suggest that muscle protein catabolism in sepsis is mediated by the same intracellular signalling pathways as found in other catabolic conditions.     

IM156, a new AMPK activator,protects against polymicrobial sepsis

IM156, a novel biguanide with higher potency of AMP‐activated protein kinase activation than metformin, has inhibitory activity against angiogenesis and cancer. In this study, we investigated effects of IM156 against polymicrobial sepsis. Administration of IM156 significantly increased survival rate against caecal ligation and puncture (CLP)‐induced sepsis. Mechanistically, IM156 markedly reduced viable bacterial burden in the peritoneal fluid and peripheral blood and attenuated organ damage in a CLP‐induced sepsis model. IM156 also inhibited the apoptosis of splenocytes and the production of inflammatory cytokines including IL‐1β, IL‐6 and IL‐10 in CLP mice. Moreover, IM156 strongly inhibited the generation of reactive oxygen species and subsequent formation of neutrophil extracellular traps in response to lipopolysaccharide in neutrophils. Taken together, these results show that IM156 can inhibit inflammatory response and protect against polymicrobial sepsis, suggesting that IM156 might be a new treatment for sepsis.     

Combining bioinformatics techniques to explore the molecular mechanisms involved in pancreatic cancer metastasis and prognosis

This article aims to explore the underlying molecular mechanisms and prognosis‐related genes in pancreatic cancer metastasis. Pancreatic cancer metastasis‐related gene chip data were downloaded from GENE EXPRESSION OMNIBUS(GEO)database. Differentially expressed genes were screened after R‐package pre‐treatment. Functional annotations and related signalling pathways were analysed using DAVID software. GEPIA (Gene Expression Profiling Interactive Analysis) was used to perform prognostic analysis, and differential genes associated with prognosis were screened and validated using data from GEO. We screened 40 healthy patients, 40 primary pancreatic cancer and 40 metastatic pancreatic cancer patients, collected serum, designed primers and used qPCR to test the expression of prognosis‐related genes in each group. 109 differentially expressed genes related with pancreatic cancer metastasis were screened, of which 49 were up‐regulated and 60 were down‐regulated. Functional annotation and pathway analysis revealed differentially expressed genes were mainly concentrated in protein activation cascade, extracellular matrix construction, decomposition, etc In the biological process, it is mainly involved in signalling pathways such as PPAR, PI3K‐Akt and ECM receptor interaction. Prognostic analysis showed the expression levels of four genes were significantly correlated with the overall survival time of patients with pancreatic cancer, namely SCG5, CRYBA2, CPE and CHGB. qPCR experiments showed the expression of these four genes was decreased in both the primary pancreatic cancer group and the metastatic pancreatic cancer group, and the latter was more significantly reduced. Pancreatic cancer metastasis is closely related to the activation of PPAR pathway, PI3K‐Akt pathway and ECM receptor interaction. SCG5, CRYBA2, CPE and CHGB genes are associated with the prognosis of pancreatic cancer, and their low expression suggests a poor prognosis.     

Scaffold compound L971 exhibits anti‐inflammatory activities through inhibition of JAK/STAT and NFκB signalling pathways

JAK/STAT and NFκB signalling pathways play essential roles in regulating inflammatory responses, which are important pathogenic factors of various serious immune‐related diseases, and function individually or synergistically. To find prodrugs that can treat inflammation, we performed a preliminary high‐throughput screening of 18 840 small molecular compounds and identified scaffold compound L971 which significantly inhibited JAK/STAT and NFκB driven luciferase activities. L971 could inhibit the constitutive and stimuli‐dependent activation of STAT1, STAT3 and IκBα and could significantly down‐regulate the proinflammatory gene expression in mouse peritoneal macrophages stimulated by LPS. Gene expression profiles upon L971 treatment were determined using high‐throughput RNA sequencing, and significant differentially up‐regulated and down‐regulated genes were identified by DESeq analysis. The bioinformatic studies confirmed the anti‐inflammatory effects of L971. Finally, L971 anti‐inflammatory character was further verified in LPS‐induced sepsis shock mouse model in vivo. Taken together, these data indicated that L971 could down‐regulate both JAK/STAT and NFκB signalling activities and has the potential to treat inflammatory diseases such as sepsis shock.     

STARD3NL inhibits the osteogenic differentiation by inactivating the Wnt/β‐catenin pathway via binding to Annexin A2 in osteoporosis

Osteoporosis is one of the leading forms of systemic diseases related to bone metabolism in the world. STARD3 N‐terminal like (STARD3NL) showed robust association with osteoporosis‐related traits. Yet, the molecular functional mechanisms of STARD3NL in osteoblasts is still obscure. In this study, we demonstrated a high level of STARD3NL expression in the bone tissues from the patients with low bone mass and ovariectomized (OVX)‐induced osteoporotic mice. We identified Stard3nl as a potent factor that negatively and positively regulates osteoblast differentiation and cell proliferation, respectively. Furthermore, inhibition of Stard3nl induced β‐catenin gene expression and the nuclear translocation of β‐catenin, as well as Wnt signalling activities, contributing to the activation of Wnt/β‐catenin signalling. Mechanistic studies revealed that Stard3nl bound with Annexin A2 (Anxa2) to suppress β‐catenin expression, resulting into the suppression of Wnt signalling and downstream osteogenic differentiation. Moreover, adeno‐associated virus 9 (AAV9)‐mediated silencing of Stard3nl reversed bone loss in OVX‐induced osteoporotic mice by the injection into the knee joints. Collectively, our study revealed that Stard3nl suppressed osteogenesis via binding with Anxa2, resulting into the inactivation of Wnt signalling. It also highlights the preventive and therapeutic potential of STARD3NL as a specific and novel target for osteoporotic patients.     

Circulating microRNA profile in humans and mice with congenital GH deficiency

Reduced inflammation, increased insulin sensitivity, and protection against cancer are shared between humans and mice with GH/IGF1 deficiency. Beyond hormone levels, miRNAs are important regulators of metabolic changes associated with healthy aging. We hypothesized that GH deficiency in humans alters the abundance of circulating miRNAs and that a subset of those miRNAs may overlap with those found in GH‐deficient mice. In this study, subjects with untreated congenital isolated GH deficiency (IGHD; n = 23) and control subjects matched by age and sex (n = 23) were recruited and serum was collected for miRNA sequencing. Serum miRNAs from young (6 month) and old (22 month) Ames dwarf (df/df) mice with GH deficiency and their WT littermates (n = 5/age/genotype group) were used for comparison. We observed 14 miRNAs regulated with a genotype by age effect and 19 miRNAs regulated with a genotype effect independent of age in serum of IGHD subjects. These regulated miRNAs are known for targeting pathways associated with longevity such as mTOR, insulin signaling, and FoxO. The aging function was overrepresented in IGHD individuals, mediated by hsa‐miR‐31, hsa‐miR‐146b, hsa‐miR‐30e, hsa‐miR‐100, hsa‐miR‐181b‐2, hsa‐miR‐195, and hsa‐miR‐181b‐1, which target the FoxO and mTOR pathways. Intriguingly, miR‐181b‐5p, miR‐361‐3p, miR‐144‐3p, and miR‐155‐5p were commonly regulated in the serum of humans and GH‐deficient mice. In vitro assays confirmed target genes for the main up‐regulated miRNAs, suggesting miRNAs regulated in IGHD individuals can regulate the expression of age‐related genes. These findings indicate that systemic miRNAs regulated in IGHD individuals target pathways involved in aging in both humans and mice.     

Effects of Mild Cold Shock (25°C) Followed by Warming Up at 37°C on the Cellular Stress Response

Temperature variations in cells, tissues and organs may occur in a number of circumstances. We report here that reducing temperature of cells in culture to 25°C for 5 days followed by a rewarming to 37°C affects cell biology and induces a cellular stress response. Cell proliferation was almost arrested during mild hypothermia and not restored upon returning to 37°C. The expression of cold shock genes, CIRBP and RBM3, was increased at 25°C and returned to basal level upon rewarming while that of heat shock protein HSP70 was inversely regulated. An activation of pro-apoptotic pathways was evidenced by FACS analysis and increased Bax/Bcl2 and BclX_S/L ratios. Concomitant increased expression of the autophagosome-associated protein LC3II and AKT phosphorylation suggested a simultaneous activation of autophagy and pro-survival pathways. However, a large proportion of cells were dying 24 hours after rewarming. The occurrence of DNA damage was evidenced by the increased phosphorylation of p53 and H2AX, a hallmark of DNA breaks. The latter process, as well as apoptosis, was strongly reduced by the radical oxygen species (ROS) scavenger, N-acetylcysteine, indicating a causal relationship between ROS, DNA damage and cell death during mild cold shock and rewarming. These data bring new insights into the potential deleterious effects of mild hypothermia and rewarming used in various research and therapeutical fields.     

Medicarpin confers powdery mildew resistance in Medicago truncatula and activates the salicylic acid signalling pathway

Powdery mildew (PM) caused by the obligate biotrophic fungal pathogen Erysiphe pisi is an economically important disease of legumes. Legumes are rich in isoflavonoids, a class of secondary metabolites whose role in PM resistance is ambiguous. Here we show that the pterocarpan medicarpin accumulates at fungal infection sites, as analysed by fluorescein‐tagged medicarpin, and provides penetration and post‐penetration resistance against E. pisi in Medicago truncatula in part through the activation of the salicylic acid (SA) signalling pathway. Comparative gene expression and metabolite analyses revealed an early induction of isoflavonoid biosynthesis and accumulation of the defence phytohormones SA and jasmonic acid (JA) in the highly resistant M. truncatula genotype A17 but not in moderately susceptible R108 in response to PM infection. Pretreatment of R108 leaves with medicarpin increased SA levels, SA‐associated gene expression, and accumulation of hydrogen peroxide at PM infection sites, and reduced fungal penetration and colony formation. Strong parallels in the levels of medicarpin and SA, but not JA, were observed on medicarpin/SA treatment pre‐ or post‐PM infection. Collectively, our results suggest that medicarpin and SA may act in concert to restrict E. pisi growth, providing new insights into the metabolic and signalling pathways required for PM resistance in legumes.     

4‐octyl Itaconate inhibits lipopolysaccharide (LPS)‐induced osteoarthritis via activating Nrf2 signalling pathway

Small molecule drug intervention for chondrocytes is a valuable method for the treatment of osteoarthritis (OA). The 4‐octyl itaconate (OI) is a cellular derivative of itaconate with sound cell permeability and transformation rate. We attempted to confirm the protective role of OI in chondrocytes and its regulatory mechanism. We used lipopolysaccharide (LPS) to induce chondrocyte inflammation injury. After the OI treatment, the secretion and mRNA expression of Il‐6, Il‐10, Mcp‐1 and Tnf‐α were detected by ELISA and qPCR. The protective effect of OI on articular cartilage was further verified in surgical destabilization of the medial meniscus model of OA. Cell death and apoptosis were evaluated based on CCK8, LDH, Typan blue staining, Annexin V and TUNEL analyses. The small interfering RNAs were used to knockout the Nrf2 gene of chondrocytes to verify the OI‐mediated Nrf2 signalling pathway. The results revealed that OI protects cells from LPS‐induced inflammatory injury and attenuates cell death and apoptosis induced by LPS. Similar protective effects were also observed on articular cartilage in mice. The OI activated Nrf2 signalling pathway and promoted the stable expression and translocation of Nrf2 into the nucleus. When the Nrf2 signalling pathway was blocked, the protective effect of OI was significantly counteracted in chondrocytes and a mouse arthritis model. Both itaconate and its derivative (i.e., OI) showed important medical effects in the treatment of OA.     

Oral intake of Lactobacillus plantarum L‐14 extract alleviates TLR2‐ and AMPK‐mediated obesity‐associated disorders in high‐fat‐diet‐induced obese C57BL/6J mice

ObjectivesWhether periodic oral intake of postbiotics positively affects weight regulation and prevents obesity‐associated diseases in vivo is unclear. This study evaluated the action mechanism of Lactobacillus plantarum L‐14 (KTCT13497BP) extract and the effects of its periodic oral intake in a high‐fat‐diet (HFD) mouse model.Materials and methodsMouse pre‐adipocyte 3T3‐L1 cells and human bone marrow mesenchymal stem cells (hBM‐MSC) were treated with L‐14 extract every 2 days during adipogenic differentiation, and the mechanism underlying anti‐adipogenic effects was analysed at cellular and molecular levels. L‐14 extract was orally administrated to HFD‐feeding C57BL/6J mice every 2 days for 7 weeks. White adipose tissue was collected and weighed, and liver and blood serum were analysed. The anti‐adipogenic mechanism of exopolysaccharide (EPS) isolated from L‐14 extract was also analysed using Toll‐like receptor 2 (TLR2) inhibitor C29.ResultsL‐14 extract inhibited 3T3‐L1 and hBM‐MSC differentiation into mature adipocytes by upregulating AMPK signalling pathway in the early stage of adipogenic differentiation. The weight of the HFD + L‐14 group (31.51 ± 1.96 g) was significantly different from that of the HFD group (35.14 ± 3.18 g). L‐14 extract also significantly decreased the serum triacylglycerol/high‐density lipoprotein cholesterol ratio (an insulin resistance marker) and steatohepatitis. In addition, EPS activated the AMPK signalling pathway by interacting with TLR2, consequently inhibiting adipogenesis.ConclusionsEPS from L‐14 extract inhibits adipogenesis via TLR2 and AMPK signalling pathways, and oral intake of L‐14 extract improves obesity and obesity‐associated diseases in vivo. Therefore, EPS can be used to prevent and treat obesity and metabolic disorders.     

Achilles Tendon Reflex in Accidental Hypothermia and Hypothermic Myxoedema

The photomotogram (P.M.G.) of the Achilles tendon reflex was studied in 26 patients with hypothermia (rectal temperature 33·3°C or less), 10 of whom also had myxoedema (serum protein bound iodine 2·8 μg/100 ml or less). No reflex could be elicited in eight (31%) of these patients, including three of those with myxoedema. Hypothermia increases both the contraction and the relaxation times of the reflex, the relaxation phase being particularly prolonged in those with myxoedema. In those patients from whom the reflex was elicited the ratio of the contraction time to the “half-relaxation time” in the P.M.G. was less than unity in six of the seven with myxoedema, and considerably greater than unity in eight of the 11 (73%) who were euthyroid. Thus, analysis of the Achilles tendon reflex P.M.G. correctly predicted the thyroid status in 14 of the 18 hypothermic patients in whom the Achilles tendon reflex was present (78%). The wider use of this rapid test of thyroid function would allow a more rational use of thyroid hormones in hypothermic patients and so lead to a better assessment of their value.     

Sodium butyrate reverses lipopolysaccharide‐induced mitochondrial dysfunction in lymphoblasts

Butyrate is a short‐chain fatty acid that is produced by commensal microbes within the intestinal microbiome through fermentation of dietary fibre. Microbial‐derived butyrate has been shown to promote immunologic and metabolic homeostasis, in part through its beneficial effects on mitochondrial function, and thus has been proposed as a possible anti‐inflammatory therapy. We tested the hypothesis that butyrate could mitigate the decrease in mitochondrial respiration in immune cells under septic conditions as a preliminary step towards better understanding the potential for butyrate as a novel therapy in sepsis. Mitochondrial respiration and content (measured as citrate synthase activity) were compared within four Epstein–Barr virus‐transformed lymphoblast (LB) cell lines exposed to either control media or lipopolysaccharide (LPS) 100 ng/ml. Both co‐incubation of LBs with LPS + butyrate and treatment with butyrate after LPS stimulation reversed the decrease in mitochondrial respiration observed in LBs exposed to LPS without butyrate. Neither LPS nor butyrate led to significant changes in citrate synthase activity. The preliminary findings support further investigation of a potential mitochondrial‐based mechanism through which butyrate may help to mitigate the immuno‐inflammatory response in sepsis.     

Platelet biomarkers for a descending cognitive function: A proteomic approach

Memory loss is the most common clinical sign in Alzheimer''s disease (AD); thus, searching for peripheral biomarkers to predict cognitive decline is promising for early diagnosis of AD. As platelets share similarities to neuron biology, it may serve as a peripheral matrix for biomarkers of neurological disorders. Here, we conducted a comprehensive and in‐depth platelet proteomic analysis using TMT‐LC‐MS/MS in the populations with mild cognitive impairment (MCI, MMSE = 18–23), severe cognitive impairments (AD, MMSE = 2–17), and the age‐/sex‐matched normal cognition controls (MMSE = 29–30). A total of 360 differential proteins were detected in MCI and AD patients compared with the controls. These differential proteins were involved in multiple KEGG pathways, including AD, AMP‐activated protein kinase (AMPK) pathway, telomerase RNA localization, platelet activation, and complement activation. By correlation analysis with MMSE score, three positively correlated pathways and two negatively correlated pathways were identified to be closely related to cognitive decline in MCI and AD patients. Partial least squares discriminant analysis (PLS‐DA) showed that changes of nine proteins, including PHB, UQCRH, CD63, GP1BA, FINC, RAP1A, ITPR1/2, and ADAM10 could effectively distinguish the cognitively impaired patients from the controls. Further machine learning analysis revealed that a combination of four decreased platelet proteins, that is, PHB, UQCRH, GP1BA, and FINC, was most promising for predicting cognitive decline in MCI and AD patients. Taken together, our data provide a set of platelet biomarkers for predicting cognitive decline which may be applied for the early screening of AD.     

Age‐associated expression of p21and p53 during human wound healing

In mice, cellular senescence and senescence‐associated secretory phenotype (SASP) positively contribute to cutaneous wound healing. In this proof‐of‐concept study, we investigated the expressions of p16, p21, and other senescence‐associated biomarkers during human wound healing in 24 healthy subjects using a double‐biopsy experimental design. The first punch biopsy created the wound and established the baseline. The second biopsy, concentric to the first and taken several days after wounding, was used to probe for expression of biomarkers by immunohistochemistry and RNA FISH. To assess the effects of age, we recruited 12 sex‐matched younger (30.2 ± 1.3 years) and 12 sex‐matched older (75.6 ± 1.8 years) subjects. We found that p21 and p53, but not p16, were induced during healing in younger, but not older subjects. A role for Notch signaling in p21 expression was inferred from the inducible activation of HES1. Further, other SASP biomarkers such as dipeptidyl peptidase‐4 (DPP4) were significantly induced upon wounding in both younger and older groups, whereas matrix metallopeptidase 9 (MMP9) was induced only in the younger group. Senescence‐associated β‐galactosidase (SA‐β‐gal) was not detectable before or after wounding. This pilot study suggests the possibility that human cutaneous wound healing is characterized by differential expression of p21 and p53 between younger and older subjects.     

Procalcitonin Predicts Real-Time PCR Results in Blood Samples from Patients with Suspected Sepsis

Background

Early diagnosis and rapid bacterial identification are of primary importance for outcome of septic patients. SeptiFast® (SF) real-time PCR assay is of potential utility in the etiological diagnosis of sepsis, but it cannot replace blood culture (BC) for routine use in clinical laboratory. Procalcitonin (PCT) is a marker of sepsis and can predict bacteremia in septic patients. The aim of the present study was to investigate whether PCT serum levels could predict SF results, and could help screening febrile patients in which a SF assay can improve the etiological diagnosis of sepsis.

Methods

From 1009 febrile patients with suspected sepsis, 1009 samples for BC, SF real-time PCR, and PCT determination were obtained simultaneously, and results were compared and statistically analysed. Receiver operating characteristic (ROC) curves were generated to determine the area under the curve and to identify which cut-off of PCT value produced the best sensitivity to detect SF results.

Results

Mean PCT values of sera drawn simultaneously with samples SF positive (35.42±61.03 ng/ml) or BC positive (23.14±51.56 ng/ml) for a pathogen were statistically higher than those drawn simultaneously with SF negative (0.84±1.67 ng/ml) or BC negative (2.79±16.64 ng/ml) samples (p<0.0001). For SF, ROC analysis showed an area under the curve of 0.927 (95% confidence interval: 0.899–0.955, p<0.0001). The PCT cut-off value of 0.37 ng/ml showed a negative predictive value of 99%, reducing the number of SF assays of 53.9%, still identifying the 96.4% of the pathogens.

Conclusion

PCT can be used in febrile patients with suspected sepsis to predict SF positive or negative results. A cut-off value of 0.37 ng/ml can be considered for optimal sensitivity, so that, in the routine laboratory activity, SF assay should not be used for diagnosis of sepsis in an unselected patient population with a PCT value <0.37 ng/ml.