Insulin resistance, adiponectin and adverse outcomes following elective cardiac surgery: a prospective follow-up study

Association of serum leptin and adiponectin concentrations with echocardiographic parameters and pathophysiological states in patients with cardiovascular disease receiving cardiovascular surgery

Leptin and adiponectin are important regulators of energy metabolism and body composition. Leptin exerts cardiodepressive effects, whereas adiponectin has cardioprotective effects, but several conflicting findings have been reported. The aim of the present study was to assess the relationship between serum leptin and adiponectin levels and echocardiographic parameters and pathophysiological states in patients with cardiovascular disease (CVD) receiving cardiovascular surgery. A total of 128 patients (79 males, average age 69.6 years) that had surgery for CVD including coronary artery bypass graft (CABG) and valve replacement were recruited in this study. Preoperative serum adiponectin and leptin concentrations were measured by enzyme-linked immunosorbent assay and compared with preoperative echocardiographic findings. Body fat volume and skeletal muscle volume index (SMI) were estimated using bioelectrical impedance analysis. We also measured grip strength and gait speed. Sarcopenia was diagnosed based on the recommendations of the Asian Working Group on Sarcopenia. Positive correlations were found between adiponectin and brain natriuretic peptide (BNP), age, left atrial diameter (LAD), E/e’ (early-diastolic left ventricular inflow velocity / early-diastolic mitral annular velocity), and left atrial volume index (LAVI). Negative correlations were observed between adiponectin and body mass index (BMI), estimated glomerular filtration rate (eGFR), triglyceride, hemoglobin, and albumin. Serum leptin was positively correlated with BMI, total cholesterol, triglyceride, albumin, body fat volume, and LV ejection fraction (LVEF), whereas it was negatively correlated with BNP and echocardiographic parameters (LAD, LV mass index (LVMI), and LAVI). Multiple regression analysis showed associations between log (leptin) and log (adiponectin) and echocardiographic parameters after adjusting for age, sex, and BMI. Serum adiponectin was negatively correlated with leptin, but positively correlated with tumor necrosis factor α (TNFα), an inflammatory cytokine. In males, serum leptin level had a positive correlation with skeletal muscle volume and SMI. However, adiponectin had a negative correlation with anterior mid-thigh muscle thickness, skeletal muscle volume and SMI. And, it was an independent predictive factor in males for sarcopenia even after adjusted by age. These results suggest that leptin and adiponectin may play a role in cardiac remodeling in CVD patients receiving cardiovascular surgery. And, adiponectin appears to be a marker of impaired metabolic signaling that is linked to heart failure progression including inflammation, poor nutrition, and muscle wasting in CVD patients receiving cardiovascular surgery.

The Impact of Diabetes on Patient Outcomes After Total Knee Arthroplasty in an Asian Population

BACKGROUND

Diabetes is implicated with poorer outcomes and more complications after total knee arthroplasty (TKA). We aim to determine whether diabetes affects infection risk, functional outcomes, patient-reported outcome measures, and patient satisfaction in Asian patients after TKA.

METHODS

Prospectively collected data for 905 patients who underwent unilateral TKA by a single surgeon from February 2004 to July 2014 were reviewed, of which 123 (13.6%) patients suffered from diabetes. At 2-year follow-up, the change in range of motion of the operated knee, body mass index, Knee Society Score, Oxford Knee Score (OKS), and Short Form-36 from baseline was compared between diabetic and nondiabetic patients. We also analyzed the length of hospitalization stay, infection risk, and patient satisfaction between the 2 groups.

RESULTS

Compared with nondiabetic patients, diabetic patients had significantly poorer preoperative OKS (37.6 on 8.3 to 35.8 .38.0, P = .02) and Short Form-36 Mental Component Score (48.3 Me11.2 to 51.7 1.10.7, P = .01). At 2-year follow-up, diabetes continued to be associated with poorer OKS of 21.2 018.4 and Knee Society Score Function score of 64.7 Fu20.9 compared to 19.1 0.6.2 (P = .02) and 71.8 0220.1 (P = .01) respectively in nondiabetic patients. Interestingly, the difference in mental well-being was no longer significant after TKA. A significantly larger proportion of diabetic patients (50%) had a reduction in body mass index after TKA compared to 36% in nondiabetic patients (P < .01). There was no difference in range of motion, length of hospitalization stay, infection risk, and patient satisfaction.

CONCLUSION

Despite poorer physical scores throughout, diabetic patients are no less satisfied and had significantly greater improvement in mental well-being and weight reduction after surgery.

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.

Elevated levels of adipokines predict outcome after acute myocardial infarction: A long-term follow-up of the Glucose Tolerance in Patients with Acute Myocardial Infarction cohort

OBJECTIVE

Adiponectin and leptin are associated with insulin resistance and cardiovascular disease. Information on the prognostic value after an acute myocardial infarction is still conflicting.

METHODS

Patients (n = 180) without known diabetes and with admission glucose of <11 mmol/L admitted for an acute myocardial infarction in 1998-2000 were followed for mortality and cardiovascular events (first of cardiovascular mortality/acute myocardial infarction/stroke/heart failure) until the end of 2011 (median: 11.6 years). Plasma adiponectin and leptin were related to outcome in Cox proportional-hazard regression analyses.

RESULTS

Median age was 64 years and 69% were male. Total mortality was 34% (n = 61) and 44% (n = 80) experienced a cardiovascular event. Adiponectin at discharge predicted cardiovascular events (hazard ratio; 95% confidence interval; 1.45; 1.02-2.07, p = 0.038), total mortality (2.53; 1.64-3.91, p < 0.001) and cancer mortality (3.64; 1.51-8.74, p = 0.004). After adjustment for age, sex, body mass index, previous myocardial infarction and heart failure, adiponectin predicted total mortality (1.79; 1.07-3.00, p = 0.027) but not cardiovascular events. High levels of leptin were associated with cardiovascular events during the first 7 years, after which the association was attenuated. Leptin did not predict total mortality.

CONCLUSION

In patients with acute myocardial infarction but without previously known diabetes, high levels of adiponectin at discharge predicted total mortality. The present results support the hypothesis that high rather than low levels of adiponectin predict mortality after acute myocardial infarction.

Obesity-related insulin resistance: implications for the surgical patient

In healthy surgical patients, preoperative fasting and major surgery induce development of insulin resistance (IR). IR can be present in up to 41% of obese patients without diabetes and this can rise in the postoperative period, leading to an increased risk of postoperative complications. Inflammation is implicated in the aetiology of IR. This review examines obesity-associated IR and its implications for the surgical patient. Searches of the Medline and Science Citation Index databases were performed using various key words in combinations with the Boolean operators AND, OR and NOT. Key journals, nutrition and metabolism textbooks and the reference lists of key articles were also hand searched. Adipose tissue has been identified as an active endocrine organ and the chemokines secreted as a result of macrophage infiltration have a role in the pathogenesis of IR. Visceral adipose tissue appears to be the most metabolically active, although results across studies are not consistent. Results from animal and human studies often provide conflicting results, which has rendered the pursuit of a common mechanistic pathway challenging. Obesity-associated IR appears, in part, to be related to inflammatory changes associated with increased adiposity. Postoperatively, the surgical patient is in a proinflammatory state, so this finding has important implications for the obese surgical patient.

Metabolic conditioning to attenuate the adverse effects of perioperative fasting and improve patient outcomes

PURPOSE OF REVIEW

To review recent articles, published between October 2009 and September 2011, that examined the adverse metabolic consequences of perioperative fasting and interventions that may be utilized to minimize these effects.

RECENT FINDINGS

Fasting induces metabolic stress and insulin resistance consequent upon effects on cellular mitochondria, gene and protein expression. Development of perioperative insulin resistance leads to increased postoperative morbidity and mortality. Preoperative carbohydrate loading attenuates insulin resistance via effects on cellular gene and protein expression, but its effects on clinical outcomes remain unclear. Perioperative arginine-supplemented diets were shown to be associated with significant reductions in infectious complications and length of hospital stay in patients undergoing elective surgery. Perioperative metabolic conditioning using glutamine and L-carnitine may be used to modulate insulin sensitivity but further studies need to determine whether these interventions result in clinical benefit. Finally, energy and protein provision to critically ill patients remains inadequate and is hampered by a number of factors including reliance on inaccurate means of estimating energy expenditure and enteral feed tolerance, conflicting data on the effects of energy deficit on clinical outcomes, and poor methodological quality of studies of perioperative nutritional interventions.

SUMMARY

Numerous perioperative interventions are available, which if utilized should help attenuate the adverse effects of perioperative fasting and lead to improved patient outcomes.