Kinetics of circulating fetuin-A may predict mortality independently from adiponectin, high molecular weight adiponectin and prognostic factors in critically ill patients with sepsis: A prospective study

Clinical metabolomics: Useful insights, perspectives and challenges

Metabolomics, a cutting-edge omics technique, is a rapidly advancing field in biomedical research, concentrating on the elucidation of pathogenetic mechanisms and the discovery of novel metabolite signatures predictive of disease risk, aiding in earlier disease detection, prognosis and prediction of treatment response. The capacity of this omics approach to simultaneously quantify thousands of metabolites, i.e. small molecules less than 1500 Da in samples, positions it as a promising tool for research and clinical applications in personalized medicine. Clinical metabolomics studies have proven valuable in understanding cardiometabolic disorders, potentially uncovering diagnostic biomarkers predictive of disease risk. Liquid chromatography-mass spectrometry is the predominant analytical method used in metabolomics, particularly untargeted. Metabolomics combined with extensive genomic data, proteomics, clinical chemistry data, imaging, health records, and other pertinent health-related data may yield significant advances beneficial for both public health initiatives, clinical applications and precision medicine, particularly in rare disorders and multimorbidity. This special issue has gathered original research articles in topics related to clinical metabolomics as well as research articles, reviews, perspectives and highlights in the broader field of translational and clinical metabolic research. Additional research is necessary to identify which metabolites consistently enhance clinical risk prediction across various populations and are causally linked to disease progression.

Adiponectin as a predictor of mortality and readmission in patients with community-acquired pneumonia: a prospective cohort study

Background

Adiponectin is secreted by adipocytes and is inversely associated with obesity. Given the association between low body mass index (BMI) and higher mortality risk after community-acquired pneumonia (CAP), we hypothesized that high adiponectin levels are associated with a higher risk of adverse clinical outcomes in patients with CAP.

Methods

In a prospective cohort study of 502 patients hospitalized with CAP, adiponectin was measured in serum at admission. The associations between adiponectin and clinical outcomes were estimated with logistic regression analyses adjusted for age, sex, and measures of obesity (BMI, waist circumference or body fat percentage).

Results

Adiponectin was associated with higher 90-day mortality for each 1 μg/mL increase [OR 1.02, 95% CI (1.00, 1.04), p = 0.048] independent of age and sex. Likewise, adiponectin was associated with a higher risk of 90-day readmission for each 1 μg/mL increase [OR 1.02, 95% CI (1.01, 1.04), p = 0.007] independent of age and sex. The association between adiponectin and 90-day mortality disappeared, while the association with 90-day readmission remained after adjusting for adiposity.

Conclusion

Adiponectin was positively associated with mortality and readmission. The association with mortality depended on low body fat, whereas the association with readmission risk was independent of obesity.

Intrinsic factors behind long COVID: IV. Hypothetical roles of the SARS-CoV-2 nucleocapsid protein and its liquid-liquid phase separation

When the SARS-CoV-2 virus infects humans, it leads to a condition called COVID-19 that has a wide spectrum of clinical manifestations, from no symptoms to acute respiratory distress syndrome. The virus initiates damage by attaching to the ACE-2 protein on the surface of endothelial cells that line the blood vessels and using these cells as hosts for replication. Reactive oxygen species levels are increased during viral replication, which leads to oxidative stress. About three-fifths (~60%) of the people who get infected with the virus eradicate it from their body after 28 days and recover their normal activity. However, a large fraction (~40%) of the people who are infected with the virus suffer from various symptoms (anosmia and/or ageusia, fatigue, cough, myalgia, cognitive impairment, insomnia, dyspnea, and tachycardia) beyond 12 weeks and are diagnosed with a syndrome called long COVID. Long-term clinical studies in a group of people who contracted SARS-CoV-2 have been contrasted with a noninfected matched group of people. A subset of infected people can be distinguished by a set of cytokine markers to have persistent, low-grade inflammation and often self-report two or more bothersome symptoms. No medication can alleviate their symptoms efficiently. Coronavirus nucleocapsid proteins have been investigated extensively as potential drug targets due to their key roles in virus replication, among which is their ability to bind their respective genomic RNAs for incorporation into emerging virions. This review highlights basic studies of the nucleocapsid protein and its ability to undergo liquid-liquid phase separation. We hypothesize that this ability of the nucleocapsid protein for phase separation may contribute to long COVID. This hypothesis unlocks new investigation angles and could potentially open novel avenues for a better understanding of long COVID and treating this condition.

Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges

Long COVID (LC) encompasses a constellation of long-term symptoms experienced by at least 10% of people after the initial SARS-CoV-2 infection, and so far it has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; a chronic, low-grade inflammatory response; immune dysregulation and a defective immune response; the reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal and metabolic dysregulation; mitochondrial dysfunction; and autonomic nervous system dysfunction. There are no specific tests for the diagnosis of LC, and clinical features including laboratory findings and biomarkers may not specifically relate to LC. Therefore, it is of paramount importance to develop and validate biomarkers that can be employed for the prediction, diagnosis and prognosis of LC and its therapeutic response, although this effort may be hampered by challenges pertaining to the non-specific nature of the majority of clinical manifestations in the LC spectrum, small sample sizes of relevant studies and other methodological issues. Promising candidate biomarkers that are found in some patients are markers of systemic inflammation, including acute phase proteins, cytokines and chemokines; biomarkers reflecting SARS-CoV-2 persistence, the reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; and cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers, their link to etiopathogenetic mechanisms or the diagnostic work-up in a comprehensive manner. Herein, we aim to appraise and synopsize the available evidence on the typical laboratory manifestations and candidate biomarkers of LC, their classification based on pathogenetic mechanisms and the main LC symptomatology in the frame of the epidemiological and clinical aspects of the syndrome and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.

Diagnostic and Prognostic Value of Serum Omentin-1 in Sepsis: A Prospective Study in Critically Ill Patients

Background and Objectives: Omentin-1, also known as intelectin-1, is a novel adipokine with anti-inflammatory activities implicated in inflammatory diseases and sepsis. We aimed to explore serum omentin-1 and its kinetics in critically ill patients early in sepsis and its association with severity and prognosis. Materials and Methods: Serum omentin-1 was determined in 102 critically ill patients with sepsis during the first 48 h from sepsis onset and 1 week later, and in 102 age- and gender-matched healthy controls. The outcome of sepsis at 28 days after enrollment was recorded. Results: Serum omentin-1 at enrollment was significantly higher in patients compared to controls (763.3 ± 249.3 vs. 451.7 ± 122.3 μg/L, p < 0.001) and it further increased 1 week after (950.6 ± 215.5 vs. 763.3 ± 249.3 μg/L, p < 0.001). Patients with septic shock (n = 42) had higher omentin-1 compared to those with sepsis (n = 60) at enrollment (877.9 ± 241.2 vs. 683.1 ± 223.7 μg/L, p < 0.001) and 1 week after (1020.4 ± 224.7 vs. 901.7 ± 196.3 μg/L, p = 0.007). Furthermore, nonsurvivors (n = 30) had higher omentin-1 at sepsis onset (952.1 ± 248.2 vs. 684.6 ± 204.7 μg/L, p < 0.001) and 1 week after (1051.8 ± 242 vs. 908.4 ± 189.8 μg/L, p < 0.01). Patients with sepsis and survivors presented higher kinetics than those with septic shock and nonsurvivors (Δ(omentin-1)% 39.8 ± 35.9% vs. 20.2 ± 23.3%, p = 0.01, and 39.4 ± 34.3% vs. 13.3 ± 18.1%, p < 0.001, respectively). Higher omentin-1 at sepsis onset and 1 week after was an independent predictor of 28-day mortality (HR 2.26, 95% C.I. 1.21-4.19, p = 0.01 and HR: 2.15, 95% C.I. 1.43-3.22, p < 0.001, respectively). Finally, omentin-1 was significantly correlated with the severity scores, the white blood cells, coagulation biomarkers, and CRP, but not procalcitonin and other inflammatory biomarkers. Conclusions: Serum omentin-1 is increased in sepsis, while higher levels and lower kinetics during the first week of sepsis are associated with the severity and 28-day mortality of sepsis. Omentin-1 may be a promising biomarker of sepsis. However, more studies are needed to explore its role in sepsis.

Could exercise hormone irisin be a therapeutic agent against Parkinson's and other neurodegenerative diseases?

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease (AD). The pathologic hallmarks of the disease are the loss of dopaminergic neurons of substantia nigra pars compacta and the presence of intraneuronal alpha synuclein (a-syn) aggregates. Clinical features of PD include motor symptoms such as bradykinesia, rigidity, tremors, postural instability, and gait impairment, and non-motor symptoms such as constipation, orthostatic hypotension, REM sleep disorder, depression and dementia. Currently, there is no disease-modifying therapy for PD. Several human studies have shown that exercise reduces progression of motor symptoms, improves performance on cognitive tasks, and slows functional deterioration. However, regular exercise may not always be feasible in PD patients. Irisin is an exercise-induced myokine involved in metabolism modulation and body fat reduction, but it also crosses the blood-brain barrier and may mediate some of the benefits of exercise in brain function. Recent evidence has shown that irisin could be therapeutically promising in PD as an "exercise-mimicking" intervention. Exogenous irisin administration decreases brain a-syn pathology and loss of dopaminergic neurons, while it improves motor outcomes in preclinical models. Several other neurodegenerative disorders such as AD share common underlying pathogenetic mechanisms with PD such as protein misfolding and aggregation, neuroinflammation, brain metabolic abnormalities, and neuronal loss. Therefore, investigation of irisin as a disease-modifying therapy could be promising for PD and other neurodegenerative disorders including AD.

Of mice and men: Considerations on adipose tissue physiology in animal models of obesity and human studies

The ever-increasing burden of obesity demands a better pathophysiological understanding, especially regarding adipose tissue pathophysiology. Animal models of obesity are of great importance in investigating potential mechanisms and implications of obesity. Many issues should be considered while interpreting the preclinical results as anatomical and pathophysiological differences exist among species. Importantly, the natural history of obesity development differs considerably. An important example of conflicting results among preclinical models and human physiological studies is that of adipose tissue oxygenation, where rodent models almost unanimously have shown the presence of hypoxia in the adipose tissue of obese animals while human studies have yielded conflicting results to date. Other issues which require further clarification before generalizing preclinical data in humans include adipose tissue browning, endocrine function and fibrosis. The aim of this mini-review is to synopsize similarities and differences between rodent models and humans, which should be taken into consideration in obesity studies.

Decreased plasma fetuin-A level as a novel bioindicator of poor prognosis in community-acquired pneumonia: A multi-center cohort study

Background

Community-acquired pneumonia (CAP) is a respiratory disease that frequently requires hospital admission, and is a significant cause of death worldwide. Plasma fetuin-A levels were significantly lower in patients with sepsis, but data regarding CAP are scarce. This study aimed to evaluate the usefulness of fetuin-A as a prognostic biomarker of CAP.

Methods

A multicenter cohort study on CAP was conducted between January 2017 and December 2018. Demographic and clinical data were recorded for all enrolled patients. Plasma fetuin-A levels were determined using a quantitative enzyme-linked immunosorbent assay. A Cox proportional hazards regression analysis was used to analyse the effect of variables on 30-day mortality. A logistic regression analysis was performed to assess risk factors associated with severe CAP (SCAP) and 30-day mortality. A receiver operating characteristic (ROC) curve was used to verify the association between variables and CAP prognosis. Correlations were assessed using Spearman's test. Survival curves were constructed and compared using the log-rank test.

Results

A total of 283 patients with CAP were enrolled in this study. Fetuin-A levels were decreased in patients with CAP, especially in SCAP and non-survivors. A cox regression analysis showed that CURB-65 and fetuin-A levels were independent prognostic indicators of 30-day mortality. Via a multiple logistic regression analysis, plasma level of fetuin-A (<202.86 mg/L) was determined to be the strongest independent predictor of 30-day mortality considered (odds ratio, 57.365), and also was also determined to be an independent predictor of SCAP. The area under the curve (AUC) of fetuin-A for predicting 30-day mortality was 0.871, and accuracy was high (P < 0.05). Plasma fetuin-A levels were negatively correlated with WBC, NE%, Glu, CRP, PCT, CURB-65, and pneumonia severity index scores and positively correlated with albumin level. Kaplan–Meier curves showed that lower plasma levels of fetuin-A levels were associated with increased 30-day mortality levels (P < 0.0001).

Conclusion

Plasma fetuin-A levels were decreased in patients with CAP. Fetuin-A can reliably predict mortality in patients with CAP, and is a useful diagnostic indicator of SCAP.

Tissue chaperoning—the expanded functions of fetuin-A beyond inhibition of systemic calcification

Traditionally, fetuin-A embodies the prototype anti-calcification protein in the blood, preventing cardiovascular calcification. Low serum fetuin-A is generally associated with mineralization dysbalance and enhanced mortality in end stage renal disease. Recent evidence indicates that fetuin-A is a crucial factor moderating tissue inflammation and fibrosis, as well as a systemic indicator of acute inflammatory disease. Here, the expanded function of fetuin-A is discussed in the context of mineralization and inflammation biology. Unbalanced depletion of fetuin-A in this context may be the critical event, triggering a vicious cycle of progressive calcification, inflammation, and tissue injury. Hence, we designate fetuin-A as tissue chaperone and propose the potential use of exogenous fetuin-A as prophylactic agent or emergency treatment in conditions that are associated with acute depletion of endogenous protein.

Circulating Chemerin and Its Kinetics May Be a Useful Diagnostic and Prognostic Biomarker in Critically Ill Patients with Sepsis: A Prospective Study

Chemerin, a novel adipokine, is a potent chemoattractant molecule with antimicrobial properties, implicated in immune responses. Our aim was to investigate circulating chemerin and its kinetics, early in sepsis in critically ill patients and its association with severity and prognosis. Serum chemerin was determined in a cohort of 102 critically ill patients with sepsis during the first 48 h from sepsis onset and one week later, and in 102 age- and gender-matched healthy controls. Patients were followed for 28 days and their outcomes were recorded. Circulating chemerin was significantly higher in septic patients at onset compared to controls (342.3 ± 108.1 vs. 200.8 ± 40.1 μg/L, p < 0.001). Chemerin decreased significantly from sepsis onset to one week later (342.3 ± 108.1 vs. 308.2 ± 108.5 μg/L, p < 0.001), but remained higher than in controls. Chemerin was higher in patients presenting with septic shock than those with sepsis (sepsis onset: 403.2 ± 89.9 vs. 299.7 ± 99.5 μg/L, p < 0.001; one week after: 374.9 ± 95.3 vs. 261.6 ± 91.9 μg/L, p < 0.001), and in nonsurvivors than survivors (sepsis onset: 427.2 ± 96.7 vs. 306.9 ± 92.1 μg/L, p < 0.001; one week after: 414.1 ± 94.5 vs. 264.2 ± 79.9 μg/L, p < 0.001). Moreover, patients with septic shock and nonsurvivors, presented a significantly lower absolute and relative decrease in chemerin one week after sepsis onset compared to baseline (p < 0.001). Based on ROC curve analyses, the diagnostic performance of chemerin (AUC 0.78, 95% CI 0.69–0.87) was similar to C-reactive protein (CRP) (AUC 0.78, 95% CI 0.68–0.87) in discriminating sepsis severity. However, increased chemerin at sepsis onset and one week later was an independent predictor of 28-day mortality (sepsis onset: HR 3.58, 95% CI 1.48–8.65, p = 0.005; one week after: HR 10.01, 95% CI 4.32–23.20, p < 0.001). Finally, serum chemerin exhibited significant correlations with the severity scores, white blood cells, lactate, CRP and procalcitonin, as well as with biomarkers of glucose homeostasis, but not with cytokines and soluble urokinase-type plasminogen activator receptor (suPAR). Circulating chemerin is increased early in sepsis and its kinetics may have diagnostic and prognostic value in critically ill patients. Further studies are needed to shed light on the role of chemerin in sepsis.

SARS-CoV-2 adipose tissue infection and hyperglycemia: A further step towards the understanding of severe COVID-19

Numerous studies have highlighted the prognostic significance of hyperglycemia in the outcomes of SARS-CoV-2 infection. A number of mechanisms have been proposed as potential drivers of this association, which were, however, up until recently based rather on speculation than on investigational evidence. It has been recently come to light that the development of insulin resistance in the frame of COVID-19 is likely the driving force behind the development of overt hyperglycemia. This results through the infectious insult of the adipose tissue, and is observed in conjunction with aberrant adipokine secretion by host adipocytes, such as decreased adiponectin, as well as a switch towards an antiviral immune secretory profile. These data could have a considerable relevance not only for the management of hyperglycemia in the course of the infection but also for the overall understanding of the pathogenesis of severe COVID-19.

Vascular Endothelial Glycocalyx Plays a Role in the Obesity Paradox According to Intravital Observation

According to the “obesity paradox,” for severe conditions, individuals with obesity may be associated with a higher survival rate than those who are lean. However, the physiological basis underlying the mechanism of the obesity paradox remains unknown. We hypothesize that the glycocalyx in obese mice is thicker and more resistant to inflammatory stress than that in non-obese mice. In this study, we employed intravital microscopy to elucidate the differences in the vascular endothelial glycocalyx among three groups of mice fed diets with different fat concentrations. Male C57BL/6N mice were divided into three diet groups: low-fat (fat: 10% kcal), medium-fat (fat: 45% kcal), and high-fat (fat: 60% kcal) diet groups. Mice were fed the respective diet from 3 weeks of age, and a chronic cranial window was installed at 8 weeks of age. At 9 weeks of age, fluorescein isothiocyanate-labeled wheat germ agglutinin was injected to identify the glycocalyx layer, and brain pial microcirculation was observed within the cranial windows. We randomly selected arterioles of diameter 15–45 μm and captured images. The mean index of the endothelial glycocalyx was calculated using image analysis and defined as the glycocalyx index. The glycocalyx indexes of the high-fat and medium-fat diet groups were significantly higher than those of the low-fat diet group (p < 0.05). There was a stronger positive correlation between vessel diameter and glycocalyx indexes in the high-fat and medium-fat diet groups than in the low-fat diet group. The glycocalyx indexes of the non-sepsis model in the obese groups were higher than those in the control group for all vessel diameters, and the positive correlation was also stronger. These findings indicate that the index of the original glycocalyx may play an important role in the obesity paradox.

Circulating Omentin-1 as a Biomarker at the Intersection of Postmenopausal Breast Cancer Occurrence and Cardiometabolic Risk: An Observational Cross-Sectional Study

Aberrant circulating omentin-1, which is an anti-inflammatory and pro-apoptotic adipokine, has been reported in various solid tumors. Therefore, we investigated whether or not circulating omentin-1 could be associated with postmenopausal BC (PBC) and could be used as a potential diagnostic and clinical tool taking into consideration clinicopathologic features, tumor markers, as well as anthropometric, metabolic, and inflammatory parameters. Serum omentin-1, tumor markers (CA15-3 and CEA); metabolic (insulin, glucose, HOMA index, and serum lipids), anthropometric (BMI, waist circumference, and fat mass), and inflammatory (TNF-α, IL-6, hsCRP) parameters; classic adipokines (leptin and adiponectin); the Mediterranean diet (MedDiet) score; and cardiovascular (CVD) risk were determined in 103 postmenopausal women with pathologically confirmed incident invasive BC, 103 controls matched on age, 51 patients with benign breast lesions (BBL), and 50 obese postmenopausal women of similar age. The mean serum omentin-1 was significantly lower in cases than in controls and patients with BBL (p < 0.001). In the patients, omentin-1 was inversely associated with tumor, metabolic and inflammatory biomarkers, cancer stage, and the number of infiltrated lymph nodes (p < 0.05). In all study participants, omentin-1 was negatively correlated with CVD risk and positively correlated with MedDiet score. Lower circulating omentin-1 was independently associated with PBC occurrence above and beyond known risk factors. According to the ROC curve analysis, the overall diagnostic performance of omentin-1 (0.84, 95% CI 0.79-0.89) is similar to CA15-3. Circulating omentin-1 may be a biomarker at the intersection of PBC and cardiometabolic risk in postmenopausal women, and could be modulated by the adoption of a MedDiet. Further mechanistic and large multicentric prospective and longitudinal studies are required to elucidate the ontological role of omentin-1 in BC and CVD risks, as well as its diagnostic and prognostic ability and its therapeutic potential.

Hemodialysis Patient with Diffuse Liver Calcification After Septic Shock

BACKGROUND Calcification in arteries is sometimes observed in patients undergoing hemodialysis; however, ectopic calcification in other organs is uncommon. In particular, diffuse liver calcification is very rare. We report a case of rapidly developing diffuse liver calcification in a patient undergoing hemodialysis. CASE REPORT An 82-year-old woman started hemodialysis because of diabetic nephropathy, and her renal function worsened due to acute coronary syndrome. Percutaneous coronary intervention was conducted, and she was referred to our hospital. However, she subsequently contracted various infections, including a urinary tract infection and pneumonia. On day 43 of hospitalization, she developed septic shock and liver dysfunction due to catheter-induced infection. Although she did not have any medical history of liver disease, hypoperfusion of the liver resulted in liver dysfunction, and a computed tomography scan conducted 3 months later showed diffuse calcification in her liver. Despite recovering from septic shock, she ultimately died of multiple organ failure 21 months after admission to our hospital. CONCLUSIONS Diffuse liver calcification is extremely rare; however, it can be observed in patients undergoing hemodialysis who experience liver hypoperfusion. The precise mechanisms underlying this disorder remain unknown, but a critically ill status and specific characteristics of hemodialysis patients may play important roles in liver calcification.

Effects of different lipid emulsions on serum adipokines, inflammatory markers and mortality in critically ill patients with sepsis: A prospective observational cohort study

BACKGROUND & AIMS

Intravenous lipid emulsions in parenteral nutrition may cause different metabolic responses and immune effects in critically ill patients with sepsis. The aim of this study is to investigate the effects of different lipid emulsions on changes in concentrations of adipokine and cytokine and their relationship with mortality in patients.

METHODS

Patients enrolled in this prospective, single-center, observational cohort study, were estimated to require more than ten days of parenteral nutrition. They were treated with soybean oil-based or olive oil-based parenteral lipid emulsions. Adipokine and cytokine concentrations of septic patients were determined at enrollment and ten days after, in accordance with the diagnostic criteria of SEPSIS-3. The concentrations levels were measured in an enzyme-linked immunosorbent assay. Mortality was analyzed using the Kaplan-Meier method and Cox regressions.

RESULTS

Over a 25-month period, 145 patients were assessed for eligibility and consequently, 40 patients were analyzed. On admission, both groups had comparable physiological scores, comorbidities, malnutrition risk, anthropometric measurements, metabolic/hematologic biomarkers and concentrations of adipokines and cytokines (p > .05). Serum leptin, resistin, and cytokines (IL-6, IL-10, IL-1β and TNF-α) decreased significantly in the entire cohort over ten days following sepsis (p < .05). Serum resistin decreased in both olive oil-based and soybean oil-based lipid emulsions groups. Serum adiponectin only decreased in soybean oil-based lipid emulsions group (p < .05). There was association between survival and percentage changes in adiponectin, resistin and visfatin concentrations (log rank test: p < .05).

CONCLUSION

Adipokine and cytokine responses are affected by medical nutritional therapy in the sepsis process and adipokines may represent functional prognostic biomarkers in critically ill patients with sepsis.

Circulating leptin, soluble leptin receptor and free leptin index in critically ill patients with sepsis: a prospective observational study

BACKGROUND

Leptin, the prototype adipokine, exerts immunomodulatory actions being implicated in inflammatory responses during sepsis. Clinical evidence regarding its role in sepsis has been contradictory, while free leptin has not been studied. Our aim was to jointly investigate circulating total leptin, its soluble receptor (sOBR), and free leptin, as well as their kinetics in critically ill patients with sepsis regarding their diagnostic and prognostic value.

METHODS

In a prospective study, serum total leptin, sOBR and free leptin index (FLI) were determined in 102 critically ill patients with sepsis within 48 hours from sepsis onset and one week after enrollment, and in 102 age and gender-matched healthy controls.

RESULTS

Upon enrollment, total leptin, sOB-R and FLI were significantly higher in septic patients compared to controls and they were positively correlated with sepsis severity scores, while they presented a significant decrease during the first week (p<0.001). The decrease in total leptin and sOB-R was significantly higher in patients with sepsis compared to septic shock and in survivors compared to nonsurvivors at 28 days (p<0.001). Higher serum total leptin was independently associated with survival at 28 days (enrollment: HR 0.86, p=0.03; one week after: HR 0.77, p<0.001). Higher kinetics of total leptin (but not FLI) was independently associated with survival after adjustment (HR: 0.48, p=0.001).

CONCLUSIONS

Higher circulating total leptin and its higher kinetics during the first week from sepsis onset independently predict 28 day survival in critically ill patients. Free leptin did not present any additional diagnostic and prognostic value in sepsis.

Sepsis and the Obesity Paradox: Size Matters in More Than One Way

OBJECTIVES

Multiple studies have demonstrated an obesity paradox such that obese ICU patients have lower mortality and better outcomes. We conducted this study to determine if the mortality benefit conferred by obesity is affected by baseline serum lactate and mean arterial pressure.

DESIGN

Retrospective analysis of prospectively collected clinical data.

SETTING

Five community-based and one academic medical center in the Omaha, NE.

PATIENTS

7,967 adults hospitalized with sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were categorized by body mass index as underweight, normal weight, overweight, or obese. Multivariable logistic regression models were used to estimate the odds of in-hospital death by body mass index category; two-way interactions between body mass index and each covariate were also evaluated. Subgroup and sensitivity analyses were conducted using an ICU cohort and Acute Physiology and Chronic Health Evaluation III scores, respectively. The overall unadjusted mortality rate was 12.1% and was consistently lower in higher body mass index categories (all comparisons, p < 0.007). The adjusted mortality benefit observed in patients with higher body mass index was smaller in patients with higher lactate levels with no mortality benefit in higher body mass index categories observed at lactate greater than 5 mmol/L. By contrast, the association between lower MAP and higher mortality was constant across body mass index categories. Similar results were observed in the ICU cohort. Finally, the obesity paradox was not observed after including Acute Physiology and Chronic Health Evaluation III scores as a covariate.

CONCLUSIONS

Our retrospective analysis suggests that although patient size (i.e., body mass index) is a predictor of in-hospital death among all-comers with sepsis-providing further evidence to the obesity paradox-it adds that illness severity is critically important whether quantified as higher lactate or by Acute Physiology and Chronic Health Evaluation III score. Our results highlight that the obesity paradox is more than a simple association between body mass index and mortality and reinforces the importance of illness severity.

Serum bilirubin to fetuin-A ratio as a prognostic biomarker in critically ill patients with sepsis

Liver dysfunction during sepsis is associated with increased bilirubin and decreased fetuin-A, a major hepatokine. We aimed to explore the association of bilirubin to fetuin-A (B/F) ratio early in sepsis with severity and outcome in critically ill patients. Based on a previous prospective study, we analyzed data of 90 critically ill patients (52 males, age: 65 ± 15 years, APACHE II: 24 ± 7 and SOFA: 10 ± 3) with sepsis. Bilirubin and fetuin-A increased during the first week of sepsis, (median (IQR) 0.45 (0.32-1) vs 0.55 (0.29-0.78) mg/dL, p = 0.03 and 302 (248-336) vs 358 (307-399) μg/mL, p < 0.001, respectively) while the B/F ratio did not change significantly. However, the B/F ratio at baseline and one week later was significantly higher in patients with septic shock (N = 38) and nonsurvivors (N = 28) compared to patients with sepsis (N = 52) and survivors (N = 62), respectively. The B/F ratio was positively associated with severity scores and outperformed bilirubin as a predictor of mortality in ROC curve analysis (AUC 0.78 (0.69-0.88), p < 0.001 and 0.69 (0.57-0.8), p = 0.003 respectively). The B/F ratio may be a promising sepsis biomarker with possible predictive value in critically ill patients.

Is There an Obesity Paradox in Critical Illness? Epidemiologic and Metabolic Considerations

PURPOSE OF REVIEW

Obesity represents a global epidemic with serious implications in public health due to its increasing prevalence and its known association with a high morbidity and mortality burden. However, a growing number of data support a survival benefit of obesity in critical illness. This review summarizes current evidence regarding the obesity paradox in critical illness, discusses methodological issues and metabolic implications, and presents potential pathophysiologic mechanisms.

RECENT FINDINGS

Data from meta-analyses and recent studies corroborate the obesity-related survival benefit in critically ill patients as well as in selected populations such as patients with sepsis and acute respiratory distress syndrome, but not trauma. However, this finding warrants a cautious interpretation due to certain methodological limitations of these studies, such as the retrospective design, possible selection bias, the use of BMI as an obesity index, and inadequate adjustment for confounding variables. Main pathophysiologic mechanisms related to obesity that could explain this phenomenon include higher energy reserves, inflammatory preconditioning, anti-inflammatory immune profile, endotoxin neutralization, adrenal steroid synthesis, renin-angiotensin system activation, cardioprotective metabolic effects, and prevention of muscle wasting. The survival benefit of obesity in critical illness is supported from large meta-analyses and recent studies. Due to important methodological limitations, more prospective studies are needed to further elucidate this finding, while future research should focus on the pathophysiologic role of adipose tissue in critical illness.

Association between plasma adiponectin levels and left ventricular systolic dysfunction in sepsis patients

PURPOSE

As a well-known cardioprotective factor, the relevance of adiponectin (APN) to heart function following sepsis remains largely unknown. The present study evaluated the effects of plasma APN levels on heart function and 28-day mortality in sepsis patients.

MATERIALS AND METHODS

This was a prospective study that was performed with 98 patients with sepsis and 32 controls. Left ventricular systolic dysfunction (LVSD) was defined as a left ventricular ejection fraction (LVEF) ≤ 45% based on echocardiography. The effects of APN on the development of sepsis-related LVSD and prediction of 28-day mortality were evaluated.

RESULTS

Plasma APN levels significantly decreased in sepsis patients compared with controls, with rising severity of illness, and positively correlated with the LVEF and stroke volume index. Sepsis patients with LVSD had lower APN levels than patients without LVSD. According to the receiver operating characteristic curve, plasma APN levels had the comparable value in prediction of LVSD incidence than those conditional factors, including brain natriuretic peptide (BNP) and highly sensitive cardiac troponin T (hsTnT). Twenty-three of the 98 sepsis patients (23.47%) died at 28 days. Adiponectin levels were an independent predictive factor for 28-day mortality.

CONCLUSIONS

Low APN levels were associated with the incidence of LVSD and 28-day mortality in sepsis patients. Adiponectin may be a novel factor that may be useful for the diagnosis of LVSD.

Adiponectin as a sepsis biomarker in dogs: Diagnostic and prognostic value

BACKGROUND

Adiponectin (ADPN) is an adipocytokine with insulin-sensitizing, vascular-protective, and anti-inflammatory properties for which concentration changes occur in response to inflammation. Little is known about the regulation of ADPN and the impact of this adipocytokine in septic dogs.

OBJECTIVE

We aimed to assess the diagnostic and prognostic value of ADPN vs other traditional acute-phase proteins (APPs), such as albumin (ALB), haptoglobin (HPT), fibrinogen (FBG), ferritin (FRT), and C-reactive protein (CRP) in dogs with naturally acquired sepsis.

METHODS

This prospective observational study included 20 dogs with sepsis, 27 with low-grade systemic inflammation (LGSI), and 18 clinically healthy dogs as controls. For method analyses, plasma samples were obtained from all dogs on admission and then every 24-48 hours until discharge or death in the septic group.

RESULTS

Septic dogs had lower ADPN (2.4 ± 0.46 vs 4.5 ± 0.41mg/L, P < .001) dand ALB (17 ± 1 vs 22 ± 0.8g/L, P = .002), and tended to have higher CRP (87 ± 4.8 vs 73 ± 4.1mg/L, P < .079) concentrations than dogs with LGSI on admission. Only ADPN and ALB were able to successfully discriminate animals with LGSI from those presenting with sepsis with areas under the curve (AUCs) for the receiver operating characteristic (ROC) curves of 0.811 and 0.789, respectively. In the septic group, ADPN concentration did not differ between survivors and non-survivors, either on admission or at discharge or death.

CONCLUSIONS

Although plasma ADPN can be used as a reliable negative APP in dogs with sepsis, further studies are warranted to confirm the usefulness of this biomarker in terms of disease progression and recovery.

Mortality in sepsis and septic shock in Europe, North America and Australia between 2009 and 2019- results from a systematic review and meta-analysis

Background

Sepsis and septic shock remain drivers for mortality in critically ill patients. The heterogeneity of the syndrome hinders the generation of reproducible numbers on mortality risks. Consequently, mortality rates range from 15 to 56%. We aimed to update and extend the existing knowledge from meta-analyses and estimate 30- and 90-day mortality rates for sepsis and septic shock separately, stratify rates by region and study type and assess mortality rates across different sequential organ failure assessment (SOFA) scores.

Methods

We performed a systematic review of articles published in PubMed or in the Cochrane Database, between 2009 and 2019 in English language including interventional and observational studies. A meta-analysis of pooled 28/30- and 90-day mortality rated separately for sepsis and septic shock was done using a random-effects model. Time trends were assessed via Joinpoint methodology and for the assessment of mortality rate over different SOFA scores, and linear regression was applied.

Results

Four thousand five hundred records were identified. After title/abstract screening, 783 articles were assessed in full text for eligibility. Of those, 170 studies were included. Average 30-day septic shock mortality was 34.7% (95% CI 32.6–36.9%), and 90-day septic shock mortality was 38.5% (95% CI 35.4–41.5%). Average 30-day sepsis mortality was 24.4% (95% CI 21.5–27.2%), and 90-day sepsis mortality was 32.2% (95% CI 27.0–37.5%). Estimated mortality rates from RCTs were below prospective and retrospective cohort studies. Rates varied between regions, with 30-day septic shock mortality being 33.7% (95% CI 31.5–35.9) in North America, 32.5% (95% CI 31.7–33.3) in Europe and 26.4% (95% CI 18.1–34.6) in Australia. A statistically significant decrease of 30-day septic shock mortality rate was found between 2009 and 2011, but not after 2011. Per 1-point increase of the average SOFA score, average mortality increased by 1.8–3.3%.

Conclusion

Trends of lower sepsis and continuous septic shock mortality rates over time and regional disparities indicate a remaining unmet need for improving sepsis management. Further research is needed to investigate how trends in the burden of disease influence mortality rates in sepsis and septic shock at 30- and 90-day mortality over time.

The Role of Adipose Tissue and Adipokines in Sepsis: Inflammatory and Metabolic Considerations, and the Obesity Paradox

PURPOSE

Sepsis has become a global health problem with rising incidence and high mortality, creating a substantial social and economic burden. Early diagnosis and treatment can improve outcome, but reliable sepsis biomarkers are lacking. This review summarizes current evidence of the pathophysiological mechanisms linking adipose tissue to sepsis and presents experimental and clinical data on adipokines and sepsis along with important insights into the obesity paradox in sepsis survival.

RECENT FINDINGS

Sepsis is characterized by significant alterations in circulating cytokines and adipokines, biologically active molecules produced by the adipose tissue, being implicated in metabolic and inflammatory processes. Although data are inconclusive regarding classic adipokines such as leptin and adiponectin, recent evidence have highlighted the striking elevation of resistin and visfatin in critical illness and sepsis as well as their association with sepsis severity and outcomes. Given that inflammatory and metabolic pathways are involved in sepsis, studying adipokines presents an attractive, innovative, and promising research field that may provide more powerful diagnostic and prognostic biomarkers as well as novel therapeutic targets, empowering the therapeutic armamentarium for sepsis management in order to improve survival.

New insights into different adipokines in linking the pathophysiology of obesity and psoriasis

Psoriasis is a chronic, systemic, hyper-proliferative immune-mediated inflammatory skin disease. The results of epidemiological investigations have shown that psoriasis affects around 2% of the general population worldwide, and the total number of psoriasis patients is more than 6 million in China. Apart from the skin manifestations, psoriasis has been verified to associate with several metabolic comorbidities, such as insulin resistance, diabetes and obesity. However, the underlying mechanism is still not elucidated. Adipocytes, considered as the active endocrine cells, are dysfunctional in obesity which displays increased synthesis and secretion of adipokines with other modified metabolic properties. Currently, growing evidence has pointed to the central role of adipokines in adipose tissue and the immune system, providing new insights into the effect of adipokines in linking the pathophysiology of obesity and psoriasis. In this review, we summarize the current understanding of the pathological role of adipokines and the potential mechanisms whereby different adipokines link obesity and psoriasis. Furthermore, we also provide evidence which identifies a potential therapeutic target aiming at adipokines for the management of these two diseases.

Presepsin and fetuin-A dyad for the diagnosis of proven sepsis in preterm neonates

BACKGROUND

Diagnosis is the most strenuous step in the evaluation of neonatal sepsis. No gold standard diagnostic method is available except for blood culture. We aimed to investigate the role of positive and negative acute phase reactants, namely presepsin and fetuin-A, in the diagnosis of culture-proven late-onset sepsis.

METHODS

A prospective, case-control study with the infants ≤32 weeks of age with a diagnosis of culture-proven late-onset sepsis was designed. Twenty-nine preterm infants with similar gestational and postnatal ages without sepsis constituted the control group. Serum values of presepsin, fetuin-A, C-reactive protein and interleukin-6 were evaluated at the enrollment, third and seventh days of the diagnosis in the infants with positive blood culture results.

RESULTS

First-day presepsin values were significantly higher in the culture-positive infants than the control group [1583 ng/L (1023-1731) vs. 426 ng/L (287-589), p = < 0.0001]. Presepsin was found to have an 88.9% sensitivity and 88.9% specificity with a cut-off value of 823 ng/ml for culture-proven LOS in our study, and area under the receiver-operating curve was 0.939. Fetuin-A levels were similar between the study and control groups (p > 0.05).

CONCLUSION

Presepsin may be an accurate marker for both diagnosis and monitoring of treatment response for culture-proven late-onset sepsis in preterm infants. However, fetuin-A does not seem to be a useful tool for the diagnosis of sepsis.

Circulating eNampt and resistin as a proinflammatory duet predicting independently mortality in critically ill patients with sepsis: A prospective observational study

BACKGROUND

The adipocytokines eNampt and resistin are involved in the regulation of inflammation exerting pro-inflammatory actions. Our aim was to jointly investigate whether circulating eNampt and resistin, and their kinetics predict 28-day mortality of sepsis.

METHODS

In a prospective study, serum eNampt and resistin were determined in 102 critically ill patients fulfilling the diagnostic criteria of SEPSIS-3, at enrollment and one week after, and in 102 healthy controls matched on age, gender and month of diagnosis.

RESULTS

Serum eNampt and resistin were significantly higher in septic patients than controls (p < 0.001), and higher in septic shock compared to sepsis (p < 0.001). Both eNampt and resistin decreased significantly during the first week of sepsis (p < 0.001). However, patients with septic shock presented a sustained elevation of eNampt and resistin compared to patients with sepsis. Both adipocytokines were positively correlated with sepsis severity scores and lactate. Baseline eNampt was a better discriminator of sepsis and septic shock compared to C-reactive protein and procalcitonin. Serum eNampt and resistin were higher in nonsurvivors than in survivors during the first week of sepsis. Prolonged and sustained elevation of both eNampt and resistin, as reflected by a lower percentage change from their baseline values, was independently associated with 28-day mortality (HR: 0.05, 95% C.I. 0.01-0.28, p = 0.001; HR: 0.19, 95% C.I. 0.07-0.50, p = 0.001, respectively), after adjustment for significant clinical and laboratory biomarkers.

CONCLUSION

Circulating eNampt and resistin, and their kinetics may represent useful diagnostic and prognostic biomarkers in critically ill septic patients. More prospective studies are needed to elucidate their ontological and pathophysiological role in sepsis.

Circulating adiponectin levels are paradoxically associated with mortality rate. A systematic review and meta-analysis

CONTEXT

Some studies have surprisingly indicated that serum adiponectin is positively related to mortality rate, thus casting doubts on its role as a therapeutic target for cardiovascular disease.

OBJECTIVE

To summarize evidence about direction, strength and modulators of this controversial association.

DATA SOURCES

MEDLINE, Web of Science, CINHAL, Cochrane Library and Scopus from inception through June 2018.

STUDY SELECTION

English-language prospective studies reporting the association between adiponectin and all-cause or cardiovascular mortality.

DATA EXTRACTION

Two investigators independently extracted data and assessed study quality using standard criteria following the Preferred Reporting Items for Systematic Reviews and Meta-analyses and The Newcastle-Ottawa Scale, respectively. Pooled hazard ratios (HRs) (95% confidence intervals-CIs) were derived using a fixed or random effects models when appropriated and were expressed for one standard deviation (SD) increment of adiponectin.

DATA SYNTHESIS

We identified fifty-five (n=61,676 subjects) and twenty-eight (n=43,979 subjects) studies for all-cause and cardiovascular mortality, respectively. Pooled HRs, were 1.24 (1.17-1.31) and 1.28 (1.19-1.37) for all-cause and cardiovascular mortality, respectively. Similar results were obtained also for High Molecular Weight adiponectin. When meta-analyses were restricted to studies reporting data on natriuretic peptides a 43% and 28% reduction on a log scale of these associations were observed after natriuretic peptides adjustment.

CONCLUSIONS

Our results strongly points to a paradoxical association between high adiponectin levels and increased mortality rate, which is partly modulated by natriuretic peptides.

New Biomarkers for Prediction of Disseminated Intravascular Coagulation in Patients With Sepsis

Complication of disseminated intravascular coagulation (DIC) is a determinant of the prognosis for patients with sepsis. The purpose of this study was to find DIC-related peptides in blood for prediction and early diagnosis of DIC in patients with sepsis. The participants were 20 patients with sepsis (age: 68.9 ± 11.4 years) and they were divided into 2 groups with (n = 8) and without (n = 12) a complication of DIC. Peptides in the serum of the patients were inclusively analyzed by a new method for peptidome analysis using a target plate, BLOTCHIP. By differential analysis of peptides in the blood from patients in the groups with and without DIC, we selected 13 mass spectrometry (MS) peaks as candidate marker peptides for prediction of DIC. By subsequent MS/MS structural analysis, 8 peptides were successfully identified as marker peptides for DIC in patients with sepsis. The peptides were fragments of serum amyloid A-2 protein, α2-HS-glycoprotein, fibrinogen α chain, fibrinogen β chain, serum albumin, collagen α1 (I) chain, collagen α1 (III) chain, and coagulation factor XIII A chain. In receiver–operating characteristic analysis for the relationships between the marker peptides and DIC, the area under the curve for each of these peptides was 0.594 to 0.760. We identified 8 blood marker peptides for prediction of DIC complication in patients with sepsis. Further studies by direct measurements of the serum peptide levels in larger numbers of patients with sepsis-induced DIC are needed to confirm the findings of this study.

Chemerin as a biomarker at the intersection of inflammation, chemotaxis, coagulation, fibrinolysis and metabolism in resectable non-small cell lung cancer

OBJECTIVES

Chemerin is an emerging adipocytokine at the intersection of inflammation, chemotaxis, thrombosis, fibrinolysis and metabolism. Our aims were 1) to explore circulating chemerin in resectable non-small cell lung cancer (NSCLC) taking into account its several interfaces; 2) to study its diagnostic potential; and 3) to assess its associations with clinicopathological features of NSCLC.

MATERIALS AND METHODS

In a large case-control study, serum chemerin, insulin resistance and lipid parameters, classic adipocytokines, inflammatory, coagulation, fibrinolysis and tumor biomarkers were determined in 110 consecutive patients with resectable NSCLC and 110 healthy controls matched on age (± 5 years), gender and date of blood draw (± 1 month).

RESULTS

NSCLC cases exhibited significantly elevated circulating chemerin compared to controls (p < 0.001). In NSCLC cases, chemerin was positively associated with Homeostasis model assessment score of insulin resistance (HOMA-IR), fibrinogen, plasminogen activity, tumor and inflammatory biomarkers, adiponectin, number of infiltrated lymph nodes and NSCLC stage. In control participants, circulating chemerin was positively correlated with somatometric, metabolic, lipid, hemostatic and inflammatory biomarkers, and leptin. Serum chemerin was independently associated with NSCLC, above and beyond NSCLC risk factors (OR: 2.20, 95% CI: 1.09-4.40, p = 0.03). In cases, hemostatic parameters (platelet count and plasminogen activity), HOMA-IR, CYFRA 21-1, creatinine and plant food consumption emerged as independent predictors of circulating chemerin (p < 0.05). Serum chemerin greater than 220 μg/L (cut-off point) yielded a sensitivity and a specificity of 63% and 91.8% respectively with a modest discriminative ability (AUC = 0.72, 95% C.I. 0.64-0.79) for the diagnosis of NSCLC.

CONCLUSION

Chemerin may represent a potentially useful biomarker in NSCLC integrating tumor-promoting networks, inflammatory and hemostatic mechanisms, and cancer-related metabolic pathways. More preclinical, prospective and longitudinal studies highlighting the pathogenetic role of chemerin in NSCLC are needed to corroborate and extend these data.

Evaluation of potential effects of Plastin 3 overexpression and low-dose SMN-antisense oligonucleotides on putative biomarkers in spinal muscular atrophy mice

OBJECTIVES

Spinal muscular atrophy (SMA) is a devastating motor neuron disorder caused by homozygous loss of the survival motor neuron 1 (SMN1) gene and insufficient functional SMN protein produced by the SMN2 copy gene. Additional genetic protective modifiers such as Plastin 3 (PLS3) can counteract SMA pathology despite insufficient SMN protein. Recently, Spinraza, an SMN antisense oligonucleotide (ASO) that restores full-length SMN2 transcripts, has been FDA- and EMA-approved for SMA therapy. Hence, the availability of biomarkers allowing a reliable monitoring of disease and therapy progression would be of great importance. Our objectives were (i) to analyse the feasibility of SMN and of six SMA biomarkers identified by the BforSMA study in the Taiwanese SMA mouse model, (ii) to analyse the effect of PLS3 overexpression on these biomarkers, and (iii) to assess the impact of low-dose SMN-ASO therapy on the level of SMN and the six biomarkers.

METHODS

At P10 and P21, the level of SMN and six putative biomarkers were compared among SMA, heterozygous and wild type mice, with or without PLS3 overexpression, and with or without presymptomatic low-dose SMN-ASO subcutaneous injection. SMN levels were measured in whole blood by ECL immunoassay and of six SMA putative biomarkers, namely Cartilage Oligomeric Matrix Protein (COMP), Dipeptidyl Peptidase 4 (DPP4), Tetranectin (C-type Lectin Family 3 Member B, CLEC3B), Osteopontin (Secreted Phosphoprotein 1, SPP1), Vitronectin (VTN) and Fetuin A (Alpha 2-HS Glycoprotein, AHSG) in plasma.

RESULTS

SMN levels were significantly discernible between SMA, heterozygous and wild type mice. However, no significant differences were measured upon low-dose SMN-ASO treatment compared to untreated animals. Of the six biomarkers, only COMP and DPP4 showed high and SPP1 moderate correlation with the SMA phenotype. PLS3 overexpression neither influenced the SMN level nor the six biomarkers, supporting the hypothesis that PLS3 acts as an independent protective modifier.

Hyperirisinemia is independently associated with subclinical hypothyroidism: correlations with cardiometabolic biomarkers and risk factors

PURPOSE

Irisin, a newly discovered adipo-myokine, is implicated in the modulation of the adipose phenotype, increasing energy expenditure and ameliorating systemic metabolism. Our aim was to investigate circulating irisin in subclinical hypothyroidism (SH) and study its associations with cardiometabolic risk factors.

METHODS

In a large case-control study, serum irisin, insulin resistance and lipid parameters, classic adipokines, inflammatory and hepatic biomarkers, and cardiovascular risk factors were determined in 120 consecutive patients with SH and 120 healthy controls matched on age, gender, and date of blood draw. Sixteen patients with SH received L-T4 treatment and, after 6 months, serum irisin and other biomarkers were assessed.

RESULTS

SH cases exhibited significantly higher circulating irisin than controls (p < 0.001). In all participants, irisin was positively associated with TSH, anti-TG, HOMA-IR, C-peptide, lipid and inflammatory biomarkers, leptin, and cardiovascular risk factors, including Framigham score and apolipoprotein B/apolipoprotein A-I. Irisin was negatively correlated with adiponectin, HDL-C, and thyroid hormones. Serum irisin was independently associated with SH, above and beyond body mass index and cardiometabolic factors (p = 0.02). TSH was an independent predictor of circulating irisin (p = 0.003). L-T4 therapy did not reverse considerably the hyperirisinemic status in treated SH patients (p = 0.09).

CONCLUSIONS

Irisin may represent an adipo-myokine counterbalancing a potential, gradual deterioration of lipid metabolism and insulin sensitivity in SH as well as reflecting a protective compensatory mechanism against oxidative muscle and thyroid cell stress. More mechanistic and prospective studies shedding light on the pathogenetic role of irisin in SH are needed to confirm and extend these data.

The Adiponectin Paradox for All-Cause and Cardiovascular Mortality

Basic science studies have shown beneficial effects of adiponectin on glucose homeostasis, chronic low-grade inflammation, apoptosis, oxidative stress, and atherosclerotic processes, so this molecule usually has been considered a salutary adipokine. It was therefore quite unexpected that large prospective human studies suggested that adiponectin is simply a marker of glucose homeostasis, with no direct favorable effect on the risk of type 2 diabetes and cardiovascular disease. But even more unforeseen were data addressing the role of adiponectin on the risk of death. In fact, a positive, rather than the expected negative, relationship was reported between adiponectin and mortality rate across many clinical conditions, comprising diabetes. The biology underlying this paradox is unknown. Several explanations have been proposed, including adiponectin resistance and the confounding role of natriuretic peptides. In addition, preliminary genetic evidence speaks in favor of a direct role of adiponectin in increasing the risk of death. However, none of these hypotheses are based on robust data, so further efforts are needed to unravel the elusive role of adiponectin on cardiometabolic health and, most important, its paradoxical association with mortality rate.