Skeletal Muscle Bioenergetics in Critical Limb Ischemia and Diabetes

INTRODUCTION

Mitochondrial dysfunction is implicated in the metabolic myopathy accompanying peripheral artery disease (PAD) and critical limb ischemia (CLI). Type-2 diabetes mellitus (T2DM) is a major risk factor for PAD development and progression to CLI and may also independently be related to mitochondrial dysfunction. We set out to determine the effect of T2DM in the relationship between CLI and muscle mitochondrial respiratory capacity and coupling control.

METHODS

We studied CLI patients undergoing revascularization procedures or amputation, and non-CLI patients with or without T2DM of similar age. Mitochondrial respiratory capacity and function were determined in lower limb permeabilized myofibers by high-resolution respirometry.

RESULTS

Fourteen CLI patients (65 ± 10y) were stratified into CLI patients with (n = 8) or without (n = 6) T2DM and were compared to non-CLI patients with (n = 18; 69 ± 5y) or without (n = 19; 71 ± 6y) T2DM. Presence of CLI but not T2DM had a marked impact on all mitochondrial respiratory states in skeletal muscle, adjusted for the effects of sex. Leak respiration (State 2, P < 0.025 and State 4o, P < 0.01), phosphorylating respiration (P < 0.001), and maximal respiration in the uncoupled state (P < 0.001), were all suppressed in CLI patients, independent of T2DM. T2DM had no significant effect on mitochondrial respiratory capacity and function in adults without CLI.

CONCLUSIONS

Skeletal muscle mitochondrial respiratory capacity was blunted by ∼35% in patients with CLI. T2DM was not associated with muscle oxidative capacity and did not moderate the relationship between muscle mitochondrial respiratory capacity and CLI.

HJC0416 Attenuates Fibrogenesis in Activated Hepatic Stellate Cells via STAT3 and NF-κB Pathways

BACKGROUND

Hepatic fibrosis is wound-healing response that is the result of hepatic stellate cell (HSC) activation and subsequent excess extracellular matrix deposition. HSCs can be activated by a variety of inflammatory stimuli as well as through the signal transducer and activator of transcription 3 (STAT3) pathway. HJC0416 is a novel, orally bioavailable small-molecule inhibitor of STAT3 that was developed by our team using a fragment-based drug design approach. Previously, our team has shown that HJC0416 has antifibrogenic effects in activated HSCs. Recently, increasing evidence suggests that nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) plays an important role in the activation of HSCs. In the present study, we examined the role of NF-κB inhibition of HSC activation by HJC0416.

METHODS

LX-2 (human) and HSC-T6 (rat) cell lines were used. Expression levels of extracellular proteins, NF-κB and STAT3 expression and DNA binding, and inflammatory cytokine levels were determined using western blot, ELISA, and immunofluorescence assay.

RESULTS

HJC0416 decreased cell viability in a dose-dependent manner in both cell lines and arrested the cell cycle at the S phase. Increased apoptosis was seen in LX-2 cells through Yo-Pro-1 and propidium iodide immunofluorescent stating. HJC0416 significantly decreased expression of fibronectin and collagen I as well as markedly decreased α-SMA and laminin. HJC0416 inhibited the STAT3 pathway by decreasing phosphorylation of STAT3, as well as signal transduction pathway activation. Notably, HJC0416 also inhibited the classic and alternative pathways of NF-κB activation. HJC0416 inhibited LPS-induced p65 nuclear translocation and DNA binding, as well as prevented phosphorylation and degradation of inhibitory protein IκBα. HJC0416 also prevented phosphorylation of serine residue 536 on p65.

CONCLUSIONS

HJC0416, an inhibitor of STAT3, was found to have antifibrogenic properties in activated hepatic stellate cell lines. In addition, HJC0416 was found to inhibit the NF-κB pathway. Owing to this double effect, HJC0416 demonstrates promise for in vivo experimentation as an antifibrosis treatment.

Acute Thyroid Storm Following Thymectomy: A Surprising Result of Undiagnosed Graves' Disease

Postoperative thyroid storm represents a diagnostic dilemma in patients with overlooked hyperthyroid state undergoing a nonthyroid surgery. We report a 30-year-old female with a history of mixed connective tissue disease who presented with an anterior mediastinal mass and underwent a thoracoscopic resection of the mass. On postoperative day 1, she had an acute change in mental status with fever, tachycardia and hypercapnic respiratory failure requiring intubation and mechanical ventilation. An elevated free thyroxine concentration and almost undetectable serum thyroid stimulating hormone suggested thyroid storm as the culprit. The patient was rendered euthyroid after initiation of therapy with propylthiouracil/methimazole, potassium iodide oral solution and systemic steroid. Histopathology of the resected anterior mediastinal mass showed thymic hyperplasia. In retrospect, the patient had hyperthyroid symptoms before surgery, but this diagnosis was overlooked.

Non-thyroid surgeries can trigger thyroid storm in the setting of poorly controlled or overlooked hyperthyroidism. Although uncommon, thyroid storm should be considered in differential diagnosis of perioperative tachycardia and respiratory failure. We emphasize on the importance of preoperative thyroid workup in patients with tachycardia, palpitation, labile blood pressure, unexplained weight changes or poorly controlled anxiety. The significance of a proper preoperative assessment cannot be overestimated.

Race, Income and Insurance Status Affect Neonatal Sepsis Mortality and Healthcare Resource Utilization

BACKGROUND

Socioeconomic disparities negatively impact neonatal health. The influence of sociodemographic disparities on neonatal sepsis is understudied. We examined the association of insurance payer status, income, race and gender on neonatal sepsis mortality and healthcare resource utilization.

METHODS

We used the Kid's Inpatient Database, a nationwide population-based survey from 2006, 2009 and 2012. Neonates diagnosed with sepsis were included in the study. Multivariable logistic regression (mortality) and multivariable linear regression (length of stay and total hospital costs) were constructed to determine the association of patient and hospital characteristics.

RESULTS

Our study cohort included a weighted sample of 160,677 septic neonates. Several sociodemographic disparities significantly increased mortality. Self-pay patients had increased mortality (odds ratio 3.26 [95% confidence interval: 2.60-4.08]), decreased length of stay (-2.49 ± 0.31 days, P < 0.0001) and total cost (-$5015.50 ± 783.15, P < 0.0001) compared with privately insured neonates. Additionally, low household income increased odds of death compared with the most affluent households (odds ratio 1.19 [95% confidence interval: 1.05-1.35]). Moreover, Black neonates had significantly decreased length of stay (-0.86 ± 0.25, P = 0.0005) compared with White neonates.

CONCLUSIONS

This study identified specific socioeconomic disparities that increased odds of death and increased healthcare resource utilization. Moreover, this study provides specific societal targets to address to reduce neonatal sepsis mortality in the United States.

Luteolin-Mediated Inhibition of Hepatic Stellate Cell Activation via Suppression of the STAT3 Pathway

Hepatic stellate cell (HSC) activation is responsible for hepatic fibrogenesis and is associated with an overexpression of transcription 3 (STAT3). Luteolin, a common dietary flavonoid with potent anti-inflammatory properties, has previously demonstrated antifibrogenic properties in HSCs but the mechanism has not been fully elucidated. Activated human and rat hepatic stellate cell lines LX-2 and HSC-T6 were used to study the effects of luteolin on HSCs. Cellular proteins were determined by western blot and immunofluorescence. Cell proliferation was assessed with Alamar Blue assay. Luteolin significantly decreased LX-2 and HSC-T6 cell viability in a time-and-dose-dependent manner, as well as decreased HSC end-products α-smooth muscle actin (α-SMA), collagen I, and fibronectin. Luteolin decreased levels of total and phosphorylated STAT3, suppressed STAT3 nuclear translocation and transcriptional activity, and attenuated expression of STAT3-regulated proteins c-myc and cyclin D1. STAT3 specific inhibitors stattic and SH-4-54 demonstrated similar effects on HSC viability and α-SMA production. In LX-2 and HSC-T6 cells, luteolin demonstrates a potent ability to inhibit hepatic fibrogenesis via suppression of the STAT3 pathway. These results further elucidate the mechanism of luteolin as well as the effect of the STAT3 pathway on HSC activation.

A Prospective, Randomized, Controlled Trial Comparing the Outpatient Treatment of Pediatric and Adult Partial-Thickness Burns with Suprathel or Mepilex Ag

Modern treatment of partial-thickness burns follows the paradigm of less frequent dressing changes to allow for undisturbed reepithelialization of the burn wound. We compared Mepilex Ag (M), a silver-impregnated foam dressing, and Suprathel (S), a DL-lactid acid polymer, in the outpatient treatment of partial-thickness burns in pediatric and adult patients. Patients were enrolled in a randomized, controlled, prospective clinical trial. We monitored time to reepithelialization, wound pain, discomfort during dressing changes, and treatment cost. Objective scar characteristics (elasticity, transepidermal water loss, hydration, and pigmentation) and subjective assessments (Patient and Observer Scar Assessment Scale) were measured at 1 month post burn. Data are presented as mean ± SEM, and significance was accepted at P < 0.05. Sixty-two patients (S n = 32; M n = 30) were enrolled; age, sex, and burn size were comparable between the groups. Time to reepithelialization was not different between the groups (12 days; P = 0.75). Pain ratings were significantly reduced during the first 5 days after burn in the Suprathel group in all patients (P = 0.03) and a pediatric subgroup (P < 0.001). Viscolelasticity of burned skin was elevated compared with unburned skin in the Mepilex Ag group at 1 month post burn. Patients treated with Suprathel reported better overall scar quality (S: 2; M: 4.5; P < 0.001). The cost of treatment per square centimeter for Mepilex Ag was considerably lower than that of Suprathel. Both dressings are feasible and efficacious for the outpatient treatment of minor and selected moderate partial-thickness burns. Reduced pain, especially in a pediatric patient population, may be advantageous, despite increased treatment cost.

Cardiorespiratory Capacity and Strength Remain Attenuated in Children with Severe Burn Injuries at Over 3 Years Postburn

OBJECTIVES

To compare physical capacity and body composition between children with burn injuries at approximately 4 years postburn and healthy, fit children.

STUDY DESIGN

In this retrospective, case-control study, we analyzed the strength, aerobic capacity, and body composition of children with severe burn injuries (n = 40) at discharge, after completion of a 6- to 12-week rehabilitative exercise training program, and at 3-4 years postburn. Values were expressed as a relative percentage of those in age- and sex-matched children for comparison (n = 40 for discharge and postexercise; n = 40 for 3.5 years postburn).

RESULTS

At discharge, lean body mass was 89% of that in children without burn injuries, and exercise rehabilitation restored this to 94% (P < .01). At 3.5 years postburn, lean body mass (94%), bone mineral content (89%), and bone mineral density (93%; each P ≤ .02) remained reduced, whereas total body fat was increased (148%, P = .01). Cardiorespiratory fitness remained lower in children with burn injuries both after exercise training (75%; P < .0001) and 3.5 years later (87%; P < .001). Peak torque (60%; P < .0001) and average power output (58%; P < .0001) were lower after discharge. Although exercise training improved these, they failed to reach levels achieved in healthy children without burns (83-84%; P < .0001) but were maintained at 85% and 82%, respectively, 3.5 years later (P < .0001).

CONCLUSIONS

Although the benefits of rehabilitative exercise training on strength and cardiorespiratory capacity are maintained at almost 4 years postburn, they are not restored fully to the levels of healthy children. Although the underlying mechanism of this phenomenon remains elusive, these findings suggest that future development of continuous exercise rehabilitation interventions after discharge may further narrow the gap in relation to healthy adolescents.

Health Disparities in Adolescent Bariatric Surgery: Nationwide Outcomes and Utilization

PURPOSE

Bariatric surgery represents an appropriate treatment for adolescent severe obesity, but its utilization remains low in this patient population. We studied the impact of race and sex on preoperative characteristics, outcomes, and utilization of adolescent bariatric surgery.

METHODS

Retrospective analysis (2007-2014) of adolescent bariatric surgery using the Bariatric Outcomes Longitudinal Database, a national database that collects bariatric surgical care data. We assessed the relationships between baseline characteristics and outcomes (weight loss and remission of obesity-related conditions [ORCs]). Using the National Health and Nutrition Examination Survey and U.S. census data, we calculated the ratio of severe obesity and bariatric procedures among races and determined the ratio of ratios to assess for disparities.

RESULTS

About 1,539 adolescents underwent bariatric surgery. Males had higher preoperative body mass index (BMI; 51.8 ± 10.5 vs. 47.1 ± 8.7, p < .001) and higher rates of obstructive sleep apnea and dyslipidemia. Blacks had higher preoperative BMI (52.4 ± 10.6 vs. 47.3 ± 8.3; 48.7 ± 8.8; 48.2 ± 12.1 kg/m2; whites, Hispanics, and others, respectively p < .001) and higher rates of hypertension, obstructive sleep apnea, and asthma. Weight loss and ORCs remission rates did not differ between sexes or races after accounting for the rate of severe obesity in each racial group. White adolescents underwent bariatric surgery at a higher proportion than blacks and Hispanics (2.5 and 2.3 times higher, respectively).

CONCLUSIONS

Preoperative characteristics vary according to race and sex. Race and sex do not impact 12-month weight loss or ORC's remission rates. Minority adolescents undergo bariatric surgery at lower-than-expected rates.

Race and outcomes in gastroschisis repair: a nationwide analysis

BACKGROUND

The incidence of gastroschisis has increased 30% between the periods 1995-2005 and 2006-2012, with the largest increase in Black neonates born to Black mothers younger than 20years old.

OBJECTIVE

Racial disparities in peri- and post-operative outcomes have been previously identified in several types of adult and pediatric surgical patients. Is there an association between race and clinical outcomes and healthcare resource utilization in neonates with gastroschisis?

METHODS

Retrospective study using national administrative data from the Kid's Inpatient Database (KID) from 2006, 2009, and 2012 for neonates (age<28days) with gastroschisis. Multivariable logistic regression was constructed to determine the association of race and socioeconomic characteristics with complications and mortality; linear regression was used for length of stay and hospital charges.

RESULTS

We identified 3846 neonates with gastroschisis that underwent surgical repair, including 676 patients with complex gastroschisis. When controlling for birth weight, payer status, socioeconomic status, and hospital characteristics, Black neonates had increased odds of having complex gastroschisis and associated atresias. Mortality was higher in patients with complex gastroschisis, patients from the lowest income quartiles, and patients with Medicaid as primary payer (compared to those with private insurance). Length of stay (LOS) was increased in patients with complex gastroschisis, birth weight <2500g, and Medicaid patients. Hospital charges were higher in complex gastroschisis, Black and Hispanic neonates (as compared to Whites), males, birth weight <2500g, and Medicaid patients.

CONCLUSIONS

There is an association between race and complex gastroschisis, associated intestinal atresias, and total charges in neonates with gastroschisis. In addition, income status is associated with mortality and hospital charges while payer status is associated with complications, mortality, LOS, and hospital charges. Public health and prenatal interventions should target at-risk populations to improve clinical outcomes.

PROGNOSIS STUDY

Level of Evidence: II.

Predicting and managing sepsis in burn patients: current perspectives

Modern burn care has led to unprecedented survival rates in burn patients whose injuries were fatal a few decades ago. Along with improved survival, new challenges have emerged in the management of burn patients. Infections top the list of the most common complication after burns, and sepsis is the leading cause of death in both adult and pediatric burn patients. The diagnosis and management of sepsis in burns is complex as a tremendous hypermetabolic response secondary to burn injury can be superimposed on systemic infection, leading to organ dysfunction. The management of a septic burn patient represents a challenging scenario that is commonly encountered by providers caring for burn patients despite preventive efforts. Here, we discuss the current perspectives in the diagnosis and treatment of sepsis and septic shock in burn patients.

Herpesviradae infections in severely burned children

OBJECTIVE

Burn-related immunosuppression can promote human herpesviridae infections. However, the effect of these infections on morbidity and mortality after pediatric burn injuries is unclear.

METHODS

We retrospectively analyzed pediatric patients with burns ≥10% of the total body surface area (TBSA) who were admitted between 2010 and 2015. On clinical suspicion of a viral infection, antiviral therapy was initiated. Viral infection was confirmed via Tzanck smear, viral culture, and/or PCR. Study endpoints were mortality, days of antiviral agent administration, type of viral test used, type of viral infection, and length of hospitalization.

RESULTS

Of the 613 patients were analyzed, 28 presented with clinically diagnosed viral infections. The use of Tzanck smears decreased over the past 5 years, whereas PCR and viral cultures have become standard. Patients with viral infections had significantly larger burns (53±15% vs. 38±18%, p<0.001); however, length of stay per TBSA burn was comparable (0.5±0.4 vs. 0.6±0.2, p=0.211). The most commonly detected herpesviridae was herpes simplex virus 1. Two patients died due to sepsis, which was accompanied by HSV infection. The mortality rate among all patients (2.7%) was comparable to that in the infected group (7.1%, p=0.898). Acyclovir was given systemically for 9±8days (N=76) and/or topically for 9±9days for HSV (N=39, combination of both N=33). Ganciclovir was prescribed in three cases for CMV.

CONCLUSIONS

Viral infections occur more commonly in patients suffering from larger burns, and HSV infections can contribute to mortality.

Mitochondrial Bioenergetics in the Metabolic Myopathy Accompanying Peripheral Artery Disease

Peripheral artery disease (PAD) is a serious but relatively underdiagnosed and undertreated clinical condition associated with a marked reduction in functional capacity and a heightened risk of morbidity and mortality. The pathophysiology of lower extremity PAD is complex, and extends beyond the atherosclerotic arterial occlusion and subsequent mismatch between oxygen demand and delivery to skeletal muscle mitochondria. In this review, we evaluate and summarize the available evidence implicating mitochondria in the metabolic myopathy that accompanies PAD. Following a short discussion of the available in vivo and in vitro methodologies to quantitate indices of muscle mitochondrial function, we review the current evidence implicating skeletal muscle mitochondrial dysfunction in the pathophysiology of PAD myopathy, while attempting to highlight questions that remain unanswered. Given the rising prevalence of PAD, the detriment in quality of life for patients, and the associated significant healthcare resource utilization, new alternate therapies that ameliorate lower limb symptoms and the functional impairment associated with PAD are needed. A clear understanding of the role of mitochondria in the pathophysiology of PAD may contribute to the development of novel therapeutic interventions.

STAT3 Inhibition Suppresses Hepatic Stellate Cell Fibrogenesis: HJC0123, a Potential Therapeutic Agent for Liver Fibrosis

Hepatic Stellate Cells (HSCs) are the major source of the excessive extracellular matrix (ECM) production that replaces liver parenchyma with fibrous tissue during liver fibrosis. The signal transducer and activator of transcription 3 (STAT3) promotes HCSs survival, proliferation, and activation contributing to fibrogenesis. We have previously used a fragment-based drug design approach and have discovered a novel STAT3 inhibitor, HJC0123. Here, we explored the biological effects of HJC0123 on the fibrogenic properties of HSCs. HJC0123 treatment resulted in the inhibition of HSCs proliferation at submicromolar concentrations. HJC0123 reduced the phosphorylation, nuclear translocation, and transcriptional activity of STAT3. It decreased the expression of STAT3-regulated proteins, induced cell cycle arrest, promoted apoptosis and downregulated SOCS3. HJC0123 treatment inhibited HSCs activation and downregulated ECM protein fibronectin and type I collagen expression. In addition, HJC0123 increased IL-6 production and decreased TGF-β induced Smad2/3 phosphorylation. These results demonstrate that HJC0123 represents a novel STAT3 inhibitor that suppresses the fibrogenic properties of HSCs, suggesting its therapeutic potential in liver fibrosis.