[Effect of Wenyang Zhenshuai Granules on autophagy and apoptosis of myocardial cells in septic rats via regulating miR-132-3p/UCP2 expression].

This study aimed to investigate the effect of Wenyang Zhenshuai Granules(WYZSG) on autophagy and apoptosis of myocardial cells in rats with sepsis via regulating the expression of microRNA-132-3p(miR-132-3p)/uncoupling protein 2(UCP2). Sixty SD rats were randomly divided into modeling group(n=50) and sham operation group(n=10). The sepsis rat model was constructed by cecal ligation and perforation in the modeling group. The successfully modeled rats were randomly divided into WYZSG low-, medium-and high-dose groups, model group and positive control group. Rats in the sham operation group underwent opening and cecum division but without perforation and ligation. Hematoxylin-eosin(HE) staining was used to observe the pathological changes of rat myocardial tissue. Myocardial cell apoptosis was detected by TdT-mediated dUTP nick end labeling(TUNEL) assay. Real-time quantitative polymerase chain reaction(RT-qPCR) was performed to detect the expression of miR-132-3p and the mRNA expressions of UCP2, microtubule-associated protein light chain 3(LC3-Ⅱ/LC3-Ⅰ), Beclin-1 and caspase-3 in rat myocardial tissue. The protein expressions of UCP2, LC3-Ⅱ/LC3-Ⅰ, Beclin-1 and caspase-3 in myocardial tissue were detected by Western blot. Dual luciferase reporter assay was used to verify the regulatory relationship between miR-132-3p and UCP2. The myocardial fibers of sepsis model rats were disordered, and there were obvious inflammatory cell infiltration as well as myocardial cell edema and necrosis. With the increase of the WYZSG dose, the histopathological changes of myocardium were improved to varying degrees. Compared with the conditions in the sham operation group, the survival rate and left ventricular ejection fraction(LVEF) of rats in the model group, positive control group and WYZSG low-, medium-and high-dose groups were decreased, and the myocardial injury score and apoptosis rate were increased. Compared with the model group, the positive control group and WYZSG low-, medium-and high-dose groups had elevated survival rate and LVEF, and lowered myocardial injury score and apoptosis rate. The expression of miR-132-3p and the mRNA and protein expressions of UCP2 in myocardial tissue in the model group, positive control group and WYZSG low-, medium-and high-dose groups were lower, while the mRNA and protein expressions of LC3-Ⅱ/LC3-Ⅰ, Beclin-1 and caspase-3 were higher than those in the sham operation group. Compared with model group, the positive control group and the WYZSG low-, medium-and high-dose groups had an up-regulation in the expression of miR-132-3p and the mRNA and protein expressions of UCP2, while a down-regulation in the mRNA and protein expressions of LC3-Ⅱ/LC3-Ⅰ, Beclin-1 and caspase-3. WYZSG inhibited excessive autophagy and apoptosis of myocardial cells in septic rats and improved myocardial injury, possibly by regulating the expression of miR-132-3p/UCP2.

Disruption of Kidney-Immune System Crosstalk in Sepsis with Acute Kidney Injury: Lessons Learned from Animal Models and Their Application to Human Health.

In addition to being a leading cause of morbidity and mortality worldwide, sepsis is also the most common cause of acute kidney injury (AKI). When sepsis leads to the development of AKI, mortality increases dramatically. Since the cardinal feature of sepsis is a dysregulated host response to infection, a disruption of kidney-immune crosstalk is likely to be contributing to worsening prognosis in sepsis with acute kidney injury. Since immune-mediated injury to the kidney could disrupt its protein manufacturing capacity, an investigation of molecules mediating this crosstalk not only helps us understand the sepsis immune response, but also suggests that their supplementation could have a therapeutic effect. Erythropoietin, vitamin D and uromodulin are known to mediate kidney-immune crosstalk and their disrupted production could impact morbidity and mortality in sepsis with acute kidney injury.

Impact of Hydrocortisone and of CRH Infusion on the Hypothalamus-Pituitary-Adrenocortical Axis of Septic Male Mice.

PURPOSE: Sepsis is hallmarked by high plasma cortisol/corticosterone (CORT), low adrenocorticotropic hormone (ACTH), and high pro-opiomelanocortin (POMC). While corticotropin-releasing hormone-(CRH) and arginine-vasopressin (AVP)-driven pituitary POMC expression remains active, POMC processing into ACTH becomes impaired. Low ACTH is accompanied by loss of adrenocortical structure, although steroidogenic enzymes remain expressed. We hypothesized that treatment of sepsis with hydrocortisone (HC) aggravates this phenotype whereas CRH infusion safeguards ACTH-driven adrenocortical structure. METHODS: In a fluid-resuscitated, antibiotics-treated mouse model of prolonged sepsis, we compared the effects of HC and CRH infusion with placebo on plasma ACTH, POMC, and CORT; on markers of hypothalamic CRH and AVP signaling and pituitary POMC processing; and on the adrenocortical structure and markers of steroidogenesis. In adrenal explants, we studied the steroidogenic capacity of POMC. RESULTS: During sepsis, HC further suppressed plasma ACTH, but not POMC, predominantly by suppressing sepsis-activated CRH/AVP-signaling pathways. In contrast, in CRH-treated sepsis, plasma ACTH was normalized following restoration of pituitary POMC processing. The sepsis-induced rise in markers of adrenocortical steroidogenesis was unaltered by CRH and suppressed partially by HC, which also increased adrenal markers of inflammation. Ex vivo stimulation of adrenal explants with POMC increased CORT as effectively as an equimolar dose of ACTH. CONCLUSIONS: Treatment of sepsis with HC impaired integrity and function of the hypothalamic-pituitary-adrenal axis at the level of the pituitary and the adrenal cortex while CRH restored pituitary POMC processing without affecting the adrenal cortex. Sepsis-induced high-circulating POMC may be responsible for ongoing adrenocortical steroidogenesis despite low ACTH.

The Therapeutic Effects of Curcumin in Early Septic Acute Kidney Injury: An Experimental Study.

PURPOSE: Sepsis is the leading condition associated with acute kidney injury (AKI) in the hospital and intensive care unit (ICU), sepsis-induced AKI (S-AKI) is strongly associated with poor clinical outcomes. Curcumin possesses an ability to ameliorate renal injury from ischemia-reperfusion, but it is still unknown whether they have the ability to reduce S-AKI. The aim of this study was to investigate the protective effects of curcumin on S-AKI and to assess its therapeutic potential on renal function, inflammatory response, and microcirculatory perfusion. METHODS: Male Sprague-Dawley (SD) rats underwent cecal ligation and puncture (CLP) to induce S-AKI and immediately received vehicle (CLP group) or curcumin (CLP+Cur group) after surgery. At 12 and 24h after surgery, serum indexes, inflammatory factors, cardiac output (CO), renal blood flow and microcirculatory flow were measured. RESULTS: Serum levels of creatinine (Scr), cystatin C (CysC), IL-6 and TNF-α were significantly lower in the CLP+Cur group than those in the CLP group (P < 0.05). Treatment with curcumin improved renal microcirculation at 24h by measurement of contrast enhanced ultrasound (CEUS) quantitative parameters [peak intensity (PI); half of descending time (DT/2); area under curve (AUC); P < 0.05]. In histopathological analysis, treatment with curcumin reduced damage caused by CLP. CONCLUSION: Curcumin can alleviate S-AKI in rats by improving renal microcirculatory perfusion and reducing inflammatory response. Curcumin may be a potential novel therapeutic agent for the prevention or reduction of S-AKI.

Comparison of norepinephrine, dopamine and dobutamine combined with enteral nutrition in the treatment of elderly patients harboring sepsis.

The present study was performed in order to investigate the safety and efficacy of different vasoactive drugs combined with enteral nutrition in terms of treating elderly patients with sepsis. A total of 75 elderly patients with sepsis treated with enteral nutrition in our hospital were randomly divided into three groups: group A (n = 25), group B (n = 25) and group C (n = 25). The three groups were treated with dopamine, dobutamine and norepinephrine respectively. One week after treatment, the therapeutic effects of the three groups were compared, the vascular elastic indexes, hemodynamic indexes and levels of inflammatory factors of the three groups were measured. After treatment, the clinical effective rate of group C was evidently higher than that of group A and group B. The vascular elasticity coefficient and stiffness coefficient in group C were significantly lower than those in group A and group B, and the arterial compliance in group C was significantly higher than that in group A and group B (P < 0.05). The levels of MAP and PVRI in group C were significantly higher than those in group A and B, and the levels of CI, CVP and HR in group C were significantly lower than those in group A and group B (P < 0.05). Norepinephrine elicited greater effects in terms of improving hemodynamic indexes, vascular elasticity and reducing the level of inflammatory factors compared with dopamine and dobutamine in elderly patients harboring sepsis.

The Role and Mechanism of Pyroptosis and Potential Therapeutic Targets in Sepsis: A Review.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Recently was been found that pyroptosis is a unique form of proinflammatory programmed death, that is different from apoptosis. A growing number of studies have investigated pyroptosis and its relationship with sepsis, including the mechanisms, role, and relevant targets of pyroptosis in sepsis. While moderate pyroptosis in sepsis can control pathogen infection, excessive pyroptosis can lead to a dysregulated host immune response and even organ dysfunction. This review provides an overview of the mechanisms and potential therapeutic targets underlying pyroptosis in sepsis identified in recent decades, looking forward to the future direction of treatment for sepsis.

A comprehensive systematic review of the therapeutic effects and mechanisms of action of quercetin in sepsis.

BACKGROUND: Sepsis is a life-threatening condition caused by a dysregulated host response to infection. Several studies have indicated that flavonoids exhibit a wide variety of biological actions including free radical scavenging and antioxidant activities. Quercetin, one of the most extensively distributed flavonoids in the vegetables and fruits, presents various biological activities including modulation of oxidative stress, anti-infectious, anti-inflammatory, and neuroprotective activities. METHODS: The present systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. We searched Web of Sciences, Google Scholar, PubMed, Scopus, and Embase databases up to February 2021 by using the relevant keywords. RESULTS: Out of 672 records screened, 35 articles met the study criteria. The evidence reviewed here indicates that quercetin supplementation may exert beneficial effects on sepsis by attenuating inflammation and oxidative stress, downregulating the mRNA expression of toll-like receptors (TLRs), modulating the immune response, and alleviating sepsis-related organ dysfunctions. CONCLUSION: Due to the promising therapeutic effects of quercetin on sepsis complications and the lack of clinical trials in this regard, future human randomized clinical trials are warranted.

Evaluation of the association between extravascular lung water and prognosis of sepsis: A protocol of systematic review.

BACKGROUND: The purpose of this study is to explore the association between extravascular lung water (EVLW) and prognosis of sepsis (PS). METHODS: We will carry out comprehensive literature search in electronic databases (PUBMED/MEDLINE, EMBASE, CENTRAL, WorldSciNet, PsycINFO, Allied and Complementary Medicine Database, CBM, and CNKI) and additional sources. All electronic databases will be searched from their initial to the present without language restrictions. Case-controlled studies reporting the association between EVLW and PS will be evaluated for inclusion. Outcomes of interest will include mortality rate, extravascular lung water index, pulmonary vascular permeability index, blood lactate clearance, oxygenation index, blood gas analysis, PaO2/FiO2, cardiac output index, global end diastolic volume index, intrathoracic blood volume index, systemic resistance index, acute physiology and chronic health scoring system II, and infection-related organ failure scoring system. Study quality will be evaluated using Newcastle-Ottawa Tool, and statistical analysis will be performed utilizing RevMan 5.4 software. RESULTS: This study will summarize the most recent evidence to investigate the association between EVLW and PS. CONCLUSIONS: The results of this study will provide an exhaustive view of the association between EVLW and PS. STUDY REGISTRATION OSF: osf.io/vhnxw.

Sepsis impairs the propagation of cortical spreading depression in rats and this effect is prevented by antioxidant extract.

Sepsis is a clinical syndrome with high morbidity and mortality. It is characterized by acute inflammatory response and oxidative stress, which is implicated in cerebral dysfunction. Murici (Byrsonimacrassifolia (L.) Kunth) is a fruit rich in antioxidant compounds, which could be an alternative to prevent damage to tissues induced by sepsis . Here, we evaluated the effects of sepsis on the propagation of cortical spreading depression (CSD) and oxidative stress, and tested the action of murici antioxidant extract in prevention against the effect of sepsis. Male Wistar rats (90-210 days, n = 40) were previously supplemented, orogastrically, with murici extract (150 mg/kg/day or 300 mg/kg/day), or an equivalent volume of the vehicle solution, for fifteen days. Then the animals were subjected to experimental sepsis through cecal ligation and perforation (CLP). Subsequently, CSD recordings were obtained and brain oxidative stress was evaluated. Sepsis decelerated CSD and increased the malondialdehyde (MDA) levels in the brain cortex of the animals. In contrast, septic rats that had been previously supplemented with murici antioxidant extract in doses of 150 and 300 mg/kg/day showed an increase in CSD propagation velocity, low levels of MDA and GSH/GSSG ratio and an increase of superoxide dismutase (SOD) activity, regardless of the dose tested. Our results demonstrate that sepsis affects brain excitability and that this effect can be prevented by murici antioxidant extract. The effects of sepsis and/or murici extract on CSD may be due to the oxidative state of the brain.

The current evidence for the treatment of sepsis with Xuebijing injection: Bioactive constituents, findings of clinical studies and potential mechanisms.

ETHNOPHARMACOLOGICAL RELEVANCE: Xuebijing (XBJ) injection is a Chinese medicine containing extracts from Carthamus tinctorius L. (Carthami Flos, hong hua, Asteraceae), Paeonia lactiflora Pall. (Paeoniae radix rubra, chi shao, Ranunculaceae), Ligusticum chuanxiong Hort. (Chuanxiong Rhizoma, chuan xiong, Umbelliferae), Salvia miltiorrhiza Bge. (Salviae miltiorrhizae Radix Et Rhizoma, dan shen, Labiatae) and Angelica sinensis (Oliv.) Diels (Angelicae sinensis Radix, dang gui, Umbelliferae). It has been approved for the treatment of sepsis in China since 2004 and has been widely used as an add-on treatment for sepsis or septic shock with few side effects. AIM OF THE STUDY: The aim of the present review was to analyse up-to-date information related to the treatment of sepsis with XBJ, including the bioactive constituents, clinical studies and potential mechanisms, and to discuss possible scientific gaps, to provide a reliable reference for future studies. MATERIALS AND METHODS: Scientific resources concentrating on treating sepsis with XBJ were searched through PubMed, the Chinese National Knowledge Infrastructure (CNKI) and WanFang databases from inception to November 2018. Dissertations were also searched, and eligible dissertations were selected. Studies related to the identification of constituents, bioactive components and their targets of action or pathways, clinical trials, and animal or cellular experiments that explored pharmacological mechanisms were manually selected. The quality of reporting and methodology of the included pharmacological experiments were assessed using the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines and the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)'s risk of bias tool. RESULTS: A total of 108 relative studies were eventually included, containing 12 bioactivity research studies, 10 systematic reviews on clinical trials and 86 animal or cellular experiments. We noted that as identification methods progressed, further constituents could be detected in XBJ. XBJ was also found to have "multi-ingredient, multi-target and multi-pathway" effects. The systematic review revealed that XBJ could improve the 28-day mortality and other indexes, such as the APACHE II score, body temperature, and white blood cell (WBC) count, to some extent. A major organ protection effect was demonstrated in septic rats. Pharmacological investigations suggested that XBJ acts in both the early and late stages of sepsis by anti-inflammatory, anti-coagulation, immune regulation, vascular endothelial protection, anti-oxidative stress and other mechanisms. However, most of the included studies were poorly reported, and the risk of bias was unclear. CONCLUSIONS: With respect to the multiple therapeutic mechanisms contributing to both the early and late stages of sepsis, the multiple effective constituents detected and randomized controlled trials (RCTs) performed to prove its efficacy, XBJ is a promising therapy for the treatment of sepsis. However, although XBJ has shown some efficacy for the treatment of sepsis, there are currently some scientific gaps. More studies concerning the pharmacokinetics, interactions with antibiotics, real-world efficacy and safety, pharmacological mechanisms of the bioactive components and large-scale clinical trials should be conducted in the future.

Berberine reduces gut-vascular barrier permeability via modulation of ApoM/S1P pathway in a model of polymicrobial sepsis.

AIMS: The hyperpermeability of gut-vascular barrier (GVB) plays a role in gut-derived sepsis. The goal of this study was to evaluate if berberine might improve hepatic apolipoprotein M (ApoM) generation and raise plasma ApoM level to protect the compromised GVB. MATERIALS AND METHODS: The compromised GVB was induced by sepsis. Hepatic ApoM mRNA and phosphoenolpyruvate carboxykinase (PEPCK) mRNA and plasma ApoM level were assayed by qRT-PCR and ELISA, respectively. The permeability of intestinal capillary in vivo and of rat intestinal microvascular endothelial cells (RIMECs) in vitro was assayed by FITC-dextran. The blood glucose was detected by a glucometer. Plasma insulin, TNF-α and IL-1ß were assayed by ELISA. The plasmalemma vesicle-associated protein-1 (PV1), ß-catenin and occludin in RIMECs were assayed by Western blot. KEY FINDINGS: Sepsis decreased hepatic ApoM mRNA and plasma ApoM level, but raised hepatic PEPCK mRNA and plasma glucose, insulin, TNF-α, and IL-1ß levels. The increased vascular endothelial permeability was abrogated by recombinant rat ApoM in vivo or ApoM-bound S1P in vitro. ApoM-bound S1P decreased PV1 but increased occludin and ß-catenin expression in LPS-treated RIMECs. Berberine in a dose-dependent manner raised hepatic ApoM mRNA and plasma ApoM level, but decreased septic hyperglycemia, insulin resistance and plasma TNF-α and IL-1ß levels. Berberine reduced sepsis-induced PEPCK and TLR4 mRNA overexpression in the liver. SIGNIFICANCE: This study demonstrated berberine inhibited TLR4-mediated hyperglycemia, insulin resistance and proinflammatory molecule production, thereby increasing ApoM gene expression and plasma ApoM. Berberine protected the damaged GVB via modulation of ApoM/S1P pathway.

Hypocalcemia in sepsis: analysis of the subcellular distribution of Ca2+ in septic rats and LPS/TNF-α-treated HUVECs.

INTRODUCTION: Hypocalcemia has been widely recognized in sepsis patients. However, the cause of hypocalcemia in sepsis is still not clear, and little is known about the subcellular distribution of Ca2+ in tissues during sepsis. METHODOLOGY: We measured the dynamic change in Ca2+ levels in body fluid and subcellular compartments, including the cytosol, endoplasmic reticulum and mitochondria, in major organs of cecal ligation and puncture (CLP)-operated rats, as well as the subcellular Ca2+ flux in HUVECs which treated by endotoxin and cytokines. RESULTS: In the model of CLP-induced sepsis, the blood and urinary Ca2+ concentrations decreased rapidly, while the Ca2+ concentration in ascites fluid increased. The Ca2+ concentrations in the cytosol, ER, and mitochondria were elevated nearly synchronously in major organs in our sepsis model. Moreover, the calcium overload in CLP-operated rats treated with calcium supplementation was more severe than that in the non-calcium-supplemented rats but was alleviated by treatment with the calcium channel blocker verapamil. Similar subcellular Ca2+ flux was found in vitro in HUVECs and was triggered by lipopolysaccharide (LPS)/TNF-α. CONCLUSIONS: Ca2+ influx from the blood into the intercellular space and Ca2+ release into ascites fluid may cause hypocalcemia in sepsis and that this process may be due to the synergistic effect of endotoxin and cytokines.

Effects of Fusu mixture (Wen-Shen-Qian-Yang Method) on sepsis-induced acute respiratory distress syndrome.

INTRODUCTION: Sepsis is the most common etiology of acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Capillary leakage caused by lung endothelial injury is the central cause of ARDS. The results of research in modern medicine in reducing endothelial damage and restoring endothelial functions are limited. In the previous clinical observations, we found that the Fusu mixture not only improves the clinical symptoms but also reduces the leakage of pulmonary capillaries. Therefore, the purpose of this study is to determine the clinical efficacy of the Fusu mixture combined with Western medicine in the treatment of ARDS caused by sepsis and to explore the mechanism of traditional Chinese medicine. METHODS: This is a prospective, single-center, randomized, single-blind, and controlled clinical study involving 620 eligible patients. The patients will be randomly divided into 2 groups: the Western medicine treatment group and the combination of Chinese and Western medicine treatment group. After 14 days of intervention, the clinical efficacy and safety of the Fusu mixture on sepsis-induced ARDS patients will be observed. The primary outcome will be measured as 28-day mortality. The secondary outcome indices include inflammatory markers (CRP, PCT, IL-6, TNF - α), APACHE II score, SOFA score, days without a ventilator, blood gas analysis (Lac, PaO2 / FiO2), intensive care unit hospital stay time, intensive care unit mortality. Simultaneously, the analysis of the exploratory results will be carried out to analyze the possible mechanism of Fusu mixture in the treatment of sepsis-induced ARDS by the high-throughput sequencing and bioinformatics. DISCUSSION: The purpose of this study is to evaluate the clinical efficacy of Fusu mixture in the treatment of sepsis-induced ARDS and explore its possible mechanism of action. If successful, it will provide evidence-based adjuvant therapy for the clinical treatment of ARDS.

Antecedent Dietary Glutamine Supplementation Benefits Modulation of Liver Pyroptosis in Mice with Polymicrobial Sepsis.

The liver is the main organ responsible for bacterial and endotoxin clearance. Pyroptosis is a form of proinflammatory programmed cell death activated by caspase-1/11 and gasdermin D (GadD). Pyroptosis protects the host against bacterial infection; however, overactive pyroptosis can lead to organ injury. Glutamine (GLN) is a specific amino acid with anti-inflammatory and immunomodulatory properties. This study investigated the effects of GLN pretreatment on liver pyroptosis in a mouse model of polymicrobial sepsis. Mice were assigned to sham, sepsis control (Sepsis-C), and sepsis GLN (Sepsis-G) groups. The sham and Sepsis-C groups were fed the AIN-93G diet. The Sepsis-G group was provided with identical diet components except that part of the casein was replaced by GLN. After feeding the respective diets for 2 weeks, a cecal ligation and puncture (CLP) procedure was performed in the sepsis groups. An antibiotic was administered after CLP. Mice were sacrificed at either 24 or 72 h after CLP. The results showed that sepsis resulted in upregulated liver caspase-1/11 expression. Compared to the Sepsis-C group, the Sepsis-G group had higher liver caspase-11 and NLRP3 gene expressions at 24 h and lower active caspase-1/11 and cleaved GadD protein levels at 72 h after sepsis. Additionally, liver inflammatory cytokine gene expressions had decreased by 72 h post-CLP. The findings suggest that prophylactic administration of GLN initially upregulated liver pyroptosis to eradicate pathogens, yet the process of pyroptosis was suppressed in the late phase of sepsis. This may have beneficially attenuated liver inflammation and injury in an antibiotic-treated septic condition.

Brain Volume Changes in Patients with Acute Brain Dysfunction Due to Sepsis.

BACKGROUND: Sepsis-induced brain dysfunction (SIBD) is often encountered in sepsis patients and is related to increased morbidity. No specific tests are available for SIBD, and neuroimaging findings are often normal. In this study, our aim was to analyze the diagnostic value of volumetric analysis of the brain structures and to find out its significance as a prognostic measure. METHODS: In this prospective observational study, brain magnetic resonance imaging (MRI) sections of 25 consecutively enrolled SIBD patients (17 with encephalopathy and 8 with coma) and 22 healthy controls underwent volumetric evaluation by an automated segmentation method. RESULTS: Ten SIBD patients had normal MRI, and 15 patients showed brain lesions or atrophy. The most prominent volume reduction was found in cerebral and cerebellar white matter, cerebral cortex, hippocampus, and amygdala, whereas deep gray matter regions and cerebellar cortex were relatively less affected. SIBD patients with normal MRI showed significantly reduced volumes in hippocampus and cerebral white matter. Caudate nuclei, putamen, and thalamus showed lower volume values in non-survivor SIBD patients, and left putamen and right thalamus showed a more pronounced volume reduction in coma patients. CONCLUSIONS: Volumetric analysis of the brain appears to be a sensitive measure of volumetric changes in SIBD. Volume reduction in specific deep gray matter regions might be an indicator of unfavorable outcome.

Effect of magnesium supplementation on lactate clearance in critically ill patients with severe sepsis: a randomized clinical trial.

OBJECTIVES: In this study, changes in lactate clearance following magnesium supplementation were evaluated in critically ill patients with severe sepsis. METHODS: Fifty-eight patients with severe sepsis were randomly assigned to receive either magnesium (n = 30) or placebo (n = 28). Patients in the magnesium group received intravenous magnesium sulfate to maintain serum magnesium level around 3 mg/dL for 3 days. The placebo group received the same volume of normal saline. Change in lactate clearance was considered primary outcome of the study. RESULTS: Mean increase in the lactate clearance in the magnesium group was significantly higher than the placebo group on day 2 (27.53% vs. 23.79% respectively, p < 0.001) and day 3 (49.83% vs. 37.02% respectively, p < 0.001). Time to lactate clearance was also significantly shorter in the magnesium group than the placebo group (47.28 ± 20.59 vs. 61.20 ± 24.31 h respectively, p = 0.03). Sepsis-related mortality was not significantly different but median length of ICU stay was significantly shorter in the magnesium group than the placebo group (8 vs. 15 days respectively, p < 0.01). CONCLUSIONS: Magnesium supplementation increased lactate clearance in critically ill patients with severe sepsis. Optimizing serum magnesium level near the upper limit of the normal range may improve severe sepsis outcomes.

Renal Medullary Hypoxia: A New Therapeutic Target for Septic Acute Kidney Injury?

Renal tissue hypoxia has been implicated as a critical mediatory factor in multiple forms of acute kidney injury (AKI), including in sepsis. In sepsis, whole-kidney measures of macrocirculatory flow and oxygen delivery appear to be poor predictors of microcirculatory abnormalities. Studies in experimental hyperdynamic septic AKI have shown that the renal medulla is particularly susceptible to hypoxia early in sepsis, even in the presence of increased global renal blood flow and oxygen delivery. It has been proposed that an early onset of progressive renal medullary hypoxia, leading to oxidative stress and inflammation, can initiate a downward spiral of cellular injury culminating in AKI. Recent experimental studies have shown that clinical therapies for septic AKI, including, fluids, vasopressors, and diuretics, have distinct effects on renal macrocirculation and microcirculation. Herein, we review the clinical and experimental evidence of alterations in global and regional kidney perfusion and oxygenation during septic AKI and associated therapies. We justify the need for investigation of the effects of therapies on renal microcirculatory perfusion and oxygenation. We propose that interventions that do not worsen the underlying renal pathophysiologic and reparative processes in sepsis will reduce the development and/or progression of AKI more effectively.

Mechanistic study of the cause of decreased blood 1,25-Dihydroxyvitamin D in sepsis.

BACKGROUND: Vitamin D deficiency, determined by blood levels of 25-hydroxyvitamin D [25(OH) D, i.e. the major vitamin D form in blood], has been shown to associate with all-cause mortalities. We recently demonstrated that blood levels of 1,25-dihydroxyvitamin D [1,25(OH)2D, i.e. the active vitamin D] were significantly lower in non-survivors compared to survivors among sepsis patients. Unexpectedly, despite the well documented roles of 1,25(OH)2D in multiple biological functions such as regulation of immune responses, stimulation of antimicrobials, and maintenance of barrier function, 1,25(OH)2D supplementation failed to improve disease outcomes. These previous findings suggest that, in addition to 1,25(OH)2D deficiency, disorders leading to the 1,25(OH)2D deficiency also contribute to mortality among sepsis patients. Therefore, this study investigated the mechanisms leading to sepsis-associated 1,25(OH)2D deficiency. METHODS: We studied mechanisms known to regulate kidney 25-hydroxylvitamin D 1α-hydroxylase which physiologically catalyzes the conversion of 25(OH) D into 1,25(OH)2D. Such mechanisms included parathyroid hormone (PTH), insulin-like growth factor 1 (IGF-1), fibroblast growth factor 23 (FGF-23), and kidney function. RESULTS: We demonstrated in both human subjects and mice that sepsis-associated 1,25(OH)2D deficiency could not be overcome by increased production of PTH which stimulates 1α-hydroxylase. Further studies showed that this failure of PTH to maintain blood 1,25(OH)2D levels was associated with decreased blood levels of IGF-1, increased blood levels of FGF-23, and kidney failure. Since the increase in blood levels of FGF-23 is known to associate with kidney failure, we further investigated the mechanisms leading to sepsis-induced decrease in blood levels of IGF-1. Our data showed that blood levels of growth hormone, which stimulates IGF-1 production in liver, were increased but could not overcome the IGF-1 deficiency. Additionally, we found that the inability of growth hormone to restore the IGF-1 deficiency was associated with suppressed expression and signaling of growth hormone receptor in liver. CONCLUSIONS: Because FGF-23 and IGF-1 have multiple biological functions besides their role in regulating kidney 1α-hydroxylase, our data suggest that FGF-23 and IGF-1 are warranted for further investigation as potential agents for the correction of 1,25(OH)2D deficiency and for the improvement of survival among sepsis patients.

Adipose tissue protects against sepsis-induced muscle weakness in mice: from lipolysis to ketones.

BACKGROUND: ICU-acquired weakness is a debilitating consequence of prolonged critical illness that is associated with poor outcome. Recently, premorbid obesity has been shown to protect against such illness-induced muscle wasting and weakness. Here, we hypothesized that this protection was due to increased lipid and ketone availability. METHODS: In a centrally catheterized, fluid-resuscitated, antibiotic-treated mouse model of prolonged sepsis, we compared markers of lipolysis and fatty acid oxidation in lean and obese septic mice (n = 117). Next, we compared markers of muscle wasting and weakness in septic obese wild-type and adipose tissue-specific ATGL knockout (AAKO) mice (n = 73), in lean septic mice receiving either intravenous infusion of lipids or standard parenteral nutrition (PN) (n = 70), and in lean septic mice receiving standard PN supplemented with either the ketone body 3-hydroxybutyrate or isocaloric glucose (n = 49). RESULTS: Obese septic mice had more pronounced lipolysis (p ≤ 0.05), peripheral fatty acid oxidation (p ≤ 0.05), and ketogenesis (p ≤ 0.05) than lean mice. Blocking lipolysis in obese septic mice caused severely reduced muscle mass (32% loss vs. 15% in wild-type, p < 0.001) and specific maximal muscle force (59% loss vs. 0% in wild-type; p < 0.001). In contrast, intravenous infusion of lipids in lean septic mice maintained specific maximal muscle force up to healthy control levels (p = 0.6), whereas this was reduced with 28% in septic mice receiving standard PN (p = 0.006). Muscle mass was evenly reduced with 29% in both lean septic groups (p < 0.001). Lipid administration enhanced fatty acid oxidation (p ≤ 0.05) and ketogenesis (p < 0.001), but caused unfavorable liver steatosis (p = 0.01) and a deranged lipid profile (p ≤ 0.01). Supplementation of standard PN with 3-hydroxybutyrate also attenuated specific maximal muscle force up to healthy control levels (p = 0.1), but loss of muscle mass could not be prevented (25% loss in both septic groups; p < 0.001). Importantly, this intervention improved muscle regeneration markers (p ≤ 0.05) without the unfavorable side effects seen with lipid infusion. CONCLUSIONS: Obesity-induced muscle protection during sepsis is partly mediated by elevated mobilization and metabolism of endogenous fatty acids. Furthermore, increased availability of ketone bodies, either through ketogenesis or through parenteral infusion, appears to protect against sepsis-induced muscle weakness also in the lean.

Vagus Nerve Stimulation Attenuates Multiple Organ Dysfunction in Resuscitated Porcine Progressive Sepsis.

OBJECTIVES: To investigate the potential benefits of vagus nerve stimulation in a clinically-relevant large animal model of progressive sepsis. DESIGN: Prospective, controlled, randomized trial. SETTING: University animal research laboratory. SUBJECTS: Twenty-five domestic pigs were divided into three groups: 1) sepsis group (eight pigs), 2) sepsis + vagus nerve stimulation group (nine pigs), and 3) control sham group (eight pigs). INTERVENTIONS: Sepsis was induced by cultivated autologous feces inoculation in anesthetized, mechanically ventilated, and surgically instrumented pigs and followed for 24 hours. Electrical stimulation of the cervical vagus nerve was initiated 6 hours after the induction of peritonitis and maintained throughout the experiment. MEASUREMENTS AND MAIN RESULTS: Measurements of hemodynamics, electrocardiography, biochemistry, blood gases, cytokines, and blood cells were collected at baseline (just before peritonitis induction) and at the end of the in vivo experiment (24 hr after peritonitis induction). Subsequent in vitro analyses addressed cardiac contractility and calcium handling in isolated tissues and myocytes and analyzed mitochondrial function by ultrasensitive oxygraphy. Vagus nerve stimulation partially or completely prevented the development of hyperlactatemia, hyperdynamic circulation, cellular myocardial depression, shift in sympathovagal balance toward sympathetic dominance, and cardiac mitochondrial dysfunction, and reduced the number of activated monocytes. Sequential Organ Failure Assessment scores and vasopressor requirements significantly decreased after vagus nerve stimulation. CONCLUSIONS: In a clinically-relevant large animal model of progressive sepsis, vagus nerve stimulation was associated with a number of beneficial effects that resulted in significantly attenuated multiple organ dysfunction and reduced vasopressor and fluid resuscitation requirements. This suggests that vagus nerve stimulation might provide a significant therapeutic potential that warrants further thorough investigation.