17: OBESE ADIPOCYTE-DERIVED EXOSOMAL MIRNAS TARGETING TGF-β SIGNALING ARE ASSOCIATED WITH POOR ASTHMA CONTROL

Purpose of Study

Obesity is a major risk factor for difficult-to-control asthma. We reported obese visceral adipose-derived exosomes contain miRNAs capable of impairing TGF-β signaling, a pathway involved in airway remodeling, associated with poor asthma clinical outcomes. We hypothesized that adipose-derived exosomal miRNAs from obese youth with asthma would be associated with poor asthma control.

Methods Used

AsthMaP-2 Subjects (youth with physician-diagnosed asthma) were selected at extremes of obesity (n=10) and leanness (n=10). We profiled RNA from adipose-derived exosomes from serum and urine and identified significant correlations (p≤0.05) between obese adipose-derived exosomal miRNAs and Asthma Control Test (ACT) scores. Ingenuity Pathway Analysis generated predicted mRNA targets and pathways.

Summary of Results

Obese subjects had a BMI≥98th percentile and lean subjects had a BMI≤13th percentile for age and sex. Serum adipose-derived exosomes contained 12 ACT-correlated miRNAs predicted to target 2,963 mRNAs with TGF-β Signaling as the top pathway (ratio=36/87; p=3×10−9). Urinary adipose-derived exosomes contained 7 ACT-correlated miRNAs predicted to target 2,387 mRNAs with TGF-β Signaling among the top pathways (ratio=18/87; p=0.01). The serum exosomal miRNAs were predicted to target TGF-β signaling mediators' mRNAs: downregulation of ACVR2B, SMAD3, SMAD5, and SMAD7 by miR-15a-5p (Fold Change (FC)=1.5; p=0.039) and upregulation of TGFB2 and TGFBR2 by miR-153-3p (FC=−1.7; p=0.041). The urinary exosomal miRNAs were also predicted to target TGF-β signaling mediators' mRNAs, the net effects were the opposite direction: upregulation of ACVR2B and SMAD4 by miR-138-5p (FC=−1.2; p=0.033) and downregulation of TGFB2 and TGFBR2 by miR-153-3p (FC=1.6; p=0.026) and SMAD6 by miR-3187-5p (FC=2.3; p=0.008).

Conclusions

Poor asthma control in obese youth is associated with adipose-derived exosomal miRNAs in both serum and urine, in particular those that are predicted to affect TGF-β signaling. Due to anatomic considerations, visceral adipose-derived exosomes are expected to predominate in urine, while serum will contain a mix of both visceral and subcutaneous adipose-derived exosomes. Therefore, adipose-derived exosomes derived from urine may be useful biomarkers in obese subjects with asthma.

Incarcerated Amyand's hernia in a premature infant associated with circumcision: a case report and literature review

Amyand's hernia is a rare presentation of an appendix within an inguinal hernia sac. It is commonly mistaken for an incarcerated or strangulated hernia. Prompt diagnosis requires awareness of this entity, as well as associated radiologic findings on computed tomography (CT) and ultrasound. Treatment includes antibiotics and surgical intervention involving appendectomy and hernia repair. We present a case of a premature infant who developed systemic symptoms after a circumcision and was eventually diagnosed with an Amyand's hernia with concurrent appendicitis.

What price for a year of life? A survey of U.S. and Canadian oncologists

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Background: New cancer drugs are increasingly expensive and raise difficult questions about the magnitude of therapeutic benefit needed to justify their incremental cost. In this context, it is unclear whether oncologists endorse standard thresholds of $50,000 to $100,000 per year of life. Methods: We surveyed 1,379 U.S. and 356 Canadian (Cdn) oncologists and asked how much longer a patient would need to survive metastatic cancer to justify the expense of a new treatment. To determine the stability of attitudes towards cost-effectiveness (CE) we randomized oncologists to receive two different versions of the scenario in which the price of the new treatment was varied (higher versus lower drug cost). In the U.S. survey, oncologists were also randomized to receive surveys in which we varied the provision of contextual information about the CE of several familiar interventions. Both U.S. and Cdn oncologists were asked to indicate what they “thought was ‘good value for money’ expressed as cost per life-year gained (LYG).” Results: Response rate was 57% in the U.S. and 48% in Canada. CE ratios implied by oncologists’ responses differed significantly between the groups randomized to the higher versus lower price of the hypothetical treatment (p < 0.001 U.S., p < 0.0001 Canada), but were independent of randomization to varying contextual information (p > 0.1). The median willingness to pay for a quality-adjusted year of life ranged from $150,000 (for oncologists considering the lower priced drug) to $250,000 (for those considering the more expensive drug) in both countries. Among those who considered the more expensive drug, 25% of respondents implicitly endorsed a CE ratio greater than $600,000 (U.S.) and $500,000 (Canada). In contrast, when asked directly to indicate CE ratios that were good value for the money outside of the clinical scenario, 70% (U.S.) and 64% (Canada) of respondents indicated values of less than $100,000 per LYG. Conclusions: Oncologists responding to our survey provided inconsistent views on how much benefit expensive new drugs should provide to be worthwhile. This suggests that means of eliciting input from physicians that reflect more stable attitudes need to be developed to appropriately inform decision-makers.

No significant financial relationships to disclose.

A survey of U.S. and Canadian oncologists’ attitudes toward the cost, cost-effectiveness (CE), and reimbursement of cancer drugs

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Background: Drug costs and reimbursement issues offer significant challenges to U.S. and Canadian oncologists even though they practice in substantially different health care systems. However, little is known about the attitudes of American and Canadian oncologists towards these issues. Methods: We surveyed 1,379 U.S. and 356 Cdn oncologists to assess their attitudes to cancer drug costs, CE and reimbursement policies. Results: Response rate was 57% in the U.S. and 48% in Canada. Oncologists in both countries stated that patients' “out-of-pocket” drug costs influenced their treatment recommendations (84% U.S., 80% Cdn respondents). Most respondents felt that every patient should have access to effective cancer treatments regardless of cost (66% US; 54% Cdn), while 59% of U.S. and 72% of Cdn and respondents believed that patients should only have access to effective cancer treatments that provided “good value for money.” 70% of U.S. and 64% Cdn respondents felt that <$100,000 per life year gained was a reasonable definition of “good value for money” but less than half of respondents (42% US, 49% Cdn) felt well prepared to interpret and use CE information in their treatment decisions. A majority of respondents (57% US, 69% Cdn) felt government price controls for cancer drugs are needed while a minority felt that more cost-sharing by patients was needed (29% US, 37% Cdn). Most oncologists felt that evaluating whether a drug provides “good value” should be overseen by an independent non-profit agency (57% US, 71% Cdn) or physicians (61% US and Cdn); in contrast, few believed that government (21% US, 33% Cdn), patients (36% US, 37% Cdn) or insurance companies (6% US, 10% Cdn) should determine “good value”. 79% of U.S. and 69% of Cdn respondents felt more use of CE data in coverage and reimbursement decisions is needed. Conclusions: Oncologists in the U.S. and Canada share many similar attitudes to cancer drug costs, CE, and reimbursement policies despite differences in their health care systems. In both countries, oncologists favor more use of CE information.

No significant financial relationships to disclose.

Can history and physical examination be used as markers of quality? An analysis of the initial visit note in musculoskeletal care

BACKGROUND

The medical record serves as an important source of information regarding the care process, but few studies have examined whether thoroughness of documentation is associated with outcomes.

OBJECTIVE

The objectives of this study were to analyze the initial visit note for 513 patients presenting with acute musculoskeletal pain, compare thoroughness of documentation by physician specialty, and determine whether thoroughness of documentation was associated with clinical improvement or patient satisfaction.

METHODS

A structured medical record abstraction was performed to examine whether treating physicians documented key historical and physical exam findings. Satisfaction with care, symptom relief, and functional improvement were assessed after 3 months with validated survey instruments.

RESULTS

In the initial visit note, 43+/-16% of selected historical findings and 28+/-17% of physical examination findings were documented. Orthopedic surgeons documented 2 to 4 more historical and physical examination items (P <0.01) and assigned more specific diagnoses (P <0.01) than rheumatologists and general internists. Multivariate models showed a very weak association between all aspects of documentation and patient satisfaction with the provider-patient interaction (all partial R2 <0.016) and no association between documentation and 3-month pain relief or functional status. Patients' perception of physician communication was more highly associated with patient satisfaction (P = 0.0001) than was documentation.

CONCLUSIONS

No provider types consistently documented many important historical items and physical examination findings. While thoroughness of documentation was not associated with clinical outcomes, there was a very weak relationship between documentation and patient satisfaction with provider-patient interactions.

NOX, a novel nitric oxide scavenger, reduces bacterial translocation in rats after endotoxin challenge

Endotoxemia promotes gut barrier failure and bacterial translocation (BT) by upregulating inducible nitric oxide synthase (iNOS) in the gut. We hypothesized that administration of a dithiocarbamate derivative, NOX, which scavenges nitric oxide (NO), may reduce intestinal injury and BT after lipopolysaccharide (LPS) challenge. Sprague-Dawley rats were randomized to receive NOX or normal saline via subcutaneously placed osmotic pumps before or after LPS challenge. Mesenteric lymph nodes, liver, spleen, and blood were cultured 24 h later. Transmucosal passage of Escherichia coli C-25 or fluorescent beads were measured in an Ussing chamber. Intestinal membranes were examined morphologically for apoptosis, iNOS expression, and nitrotyrosine immunoreactivity. NOX significantly reduced the incidence of bacteremia, BT, and transmucosal passage of bacteria and beads when administered before or up to 12 h after LPS challenge. LPS induced enterocyte apoptosis at the villus tips where bacterial entry was demonstrated by confocal microscopy. NOX significantly decreased the number of apoptotic nuclei and nitrotyrosine residues. NOX prevents LPS-induced gut barrier failure by scavenging NO and its toxic derivative, peroxynitrite.

Prognostic factors associated with long-term survival for retroperitoneal sarcoma: implications for management

PURPOSE

Retroperitoneal soft tissue sarcomas are rare tumors. Studies characterizing long-term follow-up and patterns of recurrence are limited. The purpose of this analysis is to identify patterns of recurrence and prognostic factors associated with long-term survival after resection of retroperitoneal soft tissue sarcomas.

METHODS

Between July 1, 1982, and June 30, 1990, 198 adult patients were identified from our prospective soft tissue sarcoma database carrying the diagnosis of retroperitoneal soft tissue sarcoma who were eligible for > or = 5 years of follow-up. Of these, 48 patients (25%) were documented to be alive > or = 5 years from the time of operation. Statistical analysis was by log-rank or Wilcoxon test for univariate analysis. Multivariate analysis was by the Cox model.

RESULTS

The recurrence rate during the follow-up period was approximately 5% per year from the time of initial operation. Of the patients who were disease-free for > or = 5 years from initial surgery, 40% recurred by 10 years. Radiation therapy was the only factor significant (P = .02) for a reduction in the risk of local recurrence. Age < or = 50 years and high-grade tumors were significant factors (P = .003 and .009, respectively) for an increased risk of distant metastasis. Incomplete gross resection was the only factor significant for an increased risk of tumor mortality (P = .003).

CONCLUSION

Complete surgical resection at the time of primary presentation is likely to afford the best chance for long-term survival. With long-term follow-up, it is clear that recurrence will continue to occur, and a 5-year disease-free interval is not a cure. Patients with an incomplete initial resection, age less than 50 years, and high-grade tumors are candidates for investigational adjuvant therapy.

Acute effects of 17 beta-estradiol on the rat heart

OBJECTIVE

Our purpose was to study the acute effects of 17 beta-estradiol on mechanical and electrical activities of cardiac function and on coronary arteries in the rat heart.

STUDY DESIGN

The effects of 17 beta-estradiol were studied on perfused working heart isolated from Charles River male rats. Heart rates, coronary flow, aortic flow, and left ventricular pressure were measured. To avoid coronary interaction, chronotropic and inotropic effects were also tested on isolated atria. Data were analyzed with the paired Student t test.

RESULTS

17 beta-Estradiol produced a dose-dependent negative chronotropic effect in right atria but did not affect the contractility of left atria. A decrease in heart rate was also observed in perfused hearts treated with 5 x 10(-6) mol/L 17 beta-estradiol. 17 beta-Estradiol (5 x 10(-6) mol/L) significantly increased coronary flow (p < 0.005) but had a negligible effect on cardiodynamic index values. A significant effect of 17 beta-estradiol on cardiac function was observed when coronary arteries were precontracted with acetylcholine.

CONCLUSION

Both the experimental coronary vasodilatory effect and the negative chronotropic effect of 17 beta-estradiol support the clinical observations that suggest that this hormone may have an important role in prevention of cardiovascular diseases.

Positive inotropic effect in the heart produced by acetylcholine

The effect of acetylcholine on cardiac muscle contractility and hemodynamics was investigated in human atrial strips and in isolated working rat heart. Activation of the muscarinic receptor in the heart muscle is generally known to result in negative chronotropic and inotropic effects. In our study, positive inotropic effects of acetylcholine (ACh) were observed in both human right atrial strips and in the working rat heart. Exposure of the human right atrial strips to ACh (10(-7)-10(-4) M) produced a dose dependent tri-phasic (positive-negative-positive) inotropic effect in approximately 40% of the strips. In muscle strips that exhibited only a negative inotropic effect, a positive response was observed following washout of ACh. Both positive and negative effects were antagonized by atropine. Exposure of the paced working rat heart to ACh (10(-7) - 10(-5) M) resulted in a dose dependent decrease in mean coronary flow followed by depression in cardiac function. When the heart was initially treated with the vasodilator adenosine (2 x 10(-6) M), exposure to ACh (10(-7) - 10(-5) M) had no effect on coronary flow and produced a dose dependent augmentation of all cardiodynamic indices: left ventricular pressure, isovolumic pressure, cardiac output, maximal aortic flow and stroke work. This positive response was antagonized by atropine. Exposure of the rat ventricular strips increased the formation of [3H]phosphoinositide breakdown products (e.g. inositol phosphates IP, IP2, IP3). These observations demonstrate that cholinergic muscarinic stimulation may produce positive inotropic effects in both human and rat cardiac muscle. Furthermore, our results suggest that IP3 may be a mediator in this process.

The determination of drugs of abuse in whole blood by means of FPIA and EMIT-dau immunoassays--a comparative study

Six groups of common drugs of abuse (cannabinoids, benzoylecgonine, opiates, barbiturates, benzodiazepines and amphetamines) were determined in whole blood after acetone precipitation, using enzyme multiplied immunoassay (EMIT dau) and fluorescence polarisation immunoassay (FPIA--Abbott TDx and ADx) methods. Both methods, designed primarily for urine, allowed the determination of all above mentioned class of drugs but amphetamine. Only 1 ml of a pre- or postmortem blood sample was needed. The sensitivity of cannabinoids determination was higher by FPIA. The FPIA method gave more precise results, particularly in the case of autopsy blood. The method was applied for drug screening in autopsy and police blood samples. The results (both positive and negative) were in agreement with those obtained with chromatographic methods.

Myocardial response to alpha-agonist (phenylephrine) in relation to age

We studied the inotropic effect of the alpha-agonist phenylephrine on human and rat myocardium in relation to age. Strips of human atrial myocardium, discarded during cardiac surgery, were obtained from pediatric (2 to 18 months) and adult (40 to 60 yr) patients, and their electrically driven contractions were studied. The inotropic response of pediatric myocardium to phenylephrine was five times larger than that of the adult myocardium (p less than .05). The beta-agonist, isoproterenol, was also administered to the same myocardial specimens, and the average pediatric myocardial response was three times larger than that of the adult myocardium (p less than .05). Strips of right ventricular myocardium were obtained from four age groups of rats: 14 days, 3 months, 6 months, and 18 months, and exposed to phenylephrine. We demonstrated two age-related phenomena: a) a biphasic response with an early short negative inotropic effect preceding a sustained positive inotropic effect was registered in most of the rats aged 3 months and older, but in none of the youngest age group. b) A high mean positive inotropic response (211% of basal response) was generated in the youngest age group, whereas the oldest age group of rats showed only a slight response (8% of basal response, p less than .05). We conclude that loss of myocardial responsiveness to alpha and beta-agonist with increasing age is a prominent feature. The pattern of the ventricular responsiveness to phenylephrine also changes during aging as it turns from monophasic to biphasic.

The involvement of inositol 1,4,5-trisphosphate and calcium in the two-component response to acetylcholine in Xenopus oocytes

1. The membrane response to acetylcholine (ACh), inositol 1,4,5-trisphosphate (IP3) and intracellular Ca2+ was studied in Xenopus laevis oocytes under voltage-clamp conditions. 2. Shallow, submembranal injections of IP3 in the animal hemisphere of the oocyte evoked a two-component response comprised of a rapid, transient component followed by a slow, sustained component. 3. When the injection pipette was inserted further into the cell (to 300 microns below the cell membrane), the fast component diminished and the slow component remained unchanged or even increased. 4. The rapid component exhibited an apparent higher sensitivity to IP3 compared to the slow component. 5. The two components of the IP3 response were retained in a Ca2+-free environment. 6. Injection of a single large dose (20-50 pmol) of CaCl2 into the oocyte evoked a typical two-component response, whereas repetitive threshold doses (0.1 pmol CaCl2) elicited large current fluctuations which developed into a small depolarization current. 7. The delay in the peak of the slow component of the response to either IP3 or to CaCl2 injections appeared too long to be accounted for by diffusion alone. 8. Depletion of oocyte Ca2+ by the divalent cation ionophore A23187 (greater than 1 microM) inhibited the response to ACh and IP3. Low concentrations of A23187 selectively inhibited the rapid component of the ACh response, though not the rapid component of the IP3 response. 9. Our data suggest that the two-component membrane response to ACh in Xenopus oocytes can be accounted for by ACh-induced elevation of IP3 and subsequent IP3-induced release of intracellular Ca2+.

Acetylcholine- and inositol 1,4,5-trisphosphate-induced calcium mobilization in Xenopus laevis oocytes

Acetylcholine induces a complex electrical membrane response in Xenopus laevis oocytes. This response is mimicked, and probably mediated by injected inositol 1,4,5-trisphosphate. Oocytes prelabelled with 45Ca released calcium in two phases, the second, slow phase exhibiting first order kinetics of release. Brief exposure of prelabelled oocytes to acetylcholine resulted in a significant increase in the rate of calcium release that returned to control values 2-3 min following the removal of the neurotransmitter. Intracellular injection of inositol 1,4,5-trisphosphate resulted in increased rate of calcium release similar to, but longer than that caused by acetylcholine. Experiments conducted on single oocytes permitted the investigation of the relationship between acetylcholine-induced and inositol 1,4,5-trisphosphate-induced calcium mobilization and the resulting electrical membrane response. Our data reinforce our previous suggestion that inositol 1,4,5-trisphosphate is the intracellular second messenger of the muscarinic membrane electrical response in Xenopus oocytes.

Inositol 1,4,5-trisphosphate mimics muscarinic response in Xenopus oocytes

The enhanced metabolism of phosphoinositides, which is associated with a wide variety of stimuli and physiological responses, has been studied intensively. Berridge and his collaborators demonstrated that the first measurable reaction following cell membrane receptor activation is a rapid hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), and that the product of this reaction, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), could cause a release of non-mitochondrial calcium. These findings have been verified in other systems. Although the relationship between the hydrolysis of PtdIns(4,5)P2 and the mobilization of intracellular calcium was clearly demonstrated, the direct link between Ins(1,4,5)P3 production and the physiological response was only implied. We have investigated the possibility that the intracellular release of Ins(1,4,5)P3 mediates the muscarinic-cholinergic response is Xenopus oocytes, and we show here that intracellularly injected Ins(1,4,5)P3 mimics the muscarinic depolarizing chloride current in Xenopus oocytes. This is the first demonstration of a direct link between phosphoinositides metabolism and a neuro-transmitter-induced physiological response.

Phosphoinositide breakdown in isolated rat parotid membranes. Stimulation by cholinergic and alpha-adrenergic agonists

Parotid gland membranes labelled with [3H]inositol were challenged with the cholinergic agonist, carbamylcholine, or with epinephrine in the presence of propranolol. Both agonists caused a significant breakdown of labelled phosphoinositides (17.5%) in membranes suspended in Krebs-Ringer bicarbonate buffer. This effect was abolished by the respective antagonists, atropine or phentolamine. The carbamylcholine-induced breakdown of labelled phosphoinositides did not require cytosol. The addition of cytosol alone, or the exposure of membranes to a medium of low ionic strength caused a significant breakdown of phosphoinositides (10-40%). No further breakdown due to the addition of carbamylcholine was observed under these conditions. It is suggested that neurotransmitter-induced breakdown of phosphoinositides is effected by membrane-associated enzyme(s) and can be observed only in a medium of high ionic strength.

Osmotic fragility of erythrocytes in myopathies

Erythrocytes taken from patients with myopathy have previously been reported to have increased osmotic fragility. We have examined the osmotic fragility of erythrocytes from patients with various myopathies and from carriers. The osmotic fragility was the same as in unaffected controls.