Structural, molecular and functional characterization of the aorta in HCM

Introduction

Changes in the Extracellular Matrix (ECM) in Hypertrophic Cardiomyopathy (HCM) is thought to involve the myocardium as well as extracardiac tissues. The extent and significance of extra-myocardial changes has not been adequately studied.

Purpose

To describe the structural, molecular, and functional changes in the aorta of HOCM patients.

Methods

The structural and molecular changes in the aortic wall were studied in a cohort of 102 consecutive patients with hypertrophic obstructive cardiomyopathy undergoing myectomy. The biopsies were examined histologically, immunohistochemically and by Electron microscopy. The findings were compared to 10 normal controls obtained from the homograft bank of the Harefield hospital, following IRB guidelines. Changes in expression were quantified using morphometry and western blotting. For aortic stiffness, pulse wave velocity [PWV] was measured using Cardiac Magnetic Resonance (CMR), in the 102 HCM patients as well as age-matched 166 normal controls.

Results

Specimens from HCM aortas showed a misalignment in collagen and elastin fibres. There was a significant reduction in smooth muscle cells [SMCs] markers; integrin beta1 and smooth muscle actin, and an increase in an apoptosis marker, Caspase3. In addition, there was a significant decrease in the number of lamellae and an increase in the interlamellar distance in HCM aortas. FBLNs 1, 2 and 5 showed a reduction in expression in tunica intima and tunica media of HCM biopsies. PWV was significantly higher in HCM patients compared to healthy controls with the highest levels in patients with LV fibrosis.

Conclusion

This study illustrates the link between functional abnormalities in the aorta of HCM patients with structural and molecular changes. These findings can have a potential value in risk stratification and identify new therapeutic targets in HCM.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): STDF-EgyptMagdi Yacoub Foundation

Chemical priming enhances plant tolerance to salt stress

Salt stress severely limits the productivity of crop plants worldwide and its detrimental effects are aggravated by climate change. Due to a significant world population growth, agriculture has expanded to marginal and salinized regions, which usually render low crop yield. In this context, finding methods and strategies to improve plant tolerance against salt stress is of utmost importance to fulfill food security challenges under the scenario of the ever-increasing human population. Plant priming, at different stages of plant development, such as seed or seedling, has gained significant attention for its marked implication in crop salt-stress management. It is a promising field relying on the applications of specific chemical agents which could effectively improve plant salt-stress tolerance. Currently, a variety of chemicals, both inorganic and organic, which can efficiently promote plant growth and crop yield are available in the market. This review summarizes our current knowledge of the promising roles of diverse molecules/compounds, such as hydrogen sulfide (H2S), molecular hydrogen, nitric oxide (NO), hydrogen peroxide (H2O2), melatonin, chitosan, silicon, ascorbic acid (AsA), tocopherols, and trehalose (Tre) as potential primers that enhance the salinity tolerance of crop plants.

Simultaneous malignant hyperthermia reactions in two siblings during living donor liver transplantation

We report a case of simultaneous malignant hyperthermia reactions occurring in two siblings during living donor liver transplantation. This report highlights the conflicting goals in the clinical management of liver transplantation and malignant hyperthermia, including the use of total intravenous anaesthesia and dantrolene in the face of the potential for drug-induced hepatotoxicity in the remnant liver or transplanted liver graft, as well as cautious fluid management needed for liver transplantation balanced against the liberal fluid therapy required to prevent acute kidney injury associated with malignant hyperthermia. The logistical challenges of managing this emergency in two closely related patients are discussed, including rapid preparation of two vapour-free anaesthesia machines, the need for availability of additional dantrolene and the requirement for additional personnel. Prompt recognition, immediate removal of the triggering agents and conversion to total intravenous anaesthesia helped to curtail the malignant hyperthermic reactions in our patients, both of whom made a full recovery.

General fractional integral inequalities for convex and m-convex functions via an extended generalized Mittag-Leffler function

In this paper some new general fractional integral inequalities for convex and m-convex functions by involving an extended Mittag-Leffler function are presented. These results produce inequalities for several kinds of fractional integral operators. Some interesting special cases of our main results are also pointed out.

Sherman's and related inequalities with applications in information theory

In this paper we give extensions of Sherman's inequality considering the class of convex functions of higher order. As particular cases, we get an extended weighted majorization inequality as well as Jensen's inequality which have direct connection to information theory. We use the obtained results to derive new estimates for Shannon's and Rényi's entropy, information energy, and some well-known measures between probability distributions. Using the Zipf-Mandelbrot law, we introduce new functionals to derive some related results.

MDM2 overexpression in benign and malignant lesions of the human breast

MDM2 overexpression has been detected in women with benign or cancerous lesions of the breast. Immunohistochemical methods were used to identify overexpression in 11 of 27 benign cases (41%) and 15 of 22 (68%) cancer cases. MDM2 overexpression correlated well with immunohistochemically detected estrogen receptor (ER), suggesting that expression of these proteins was coordinately regulated. To test this, the MCF-10A human breast cell line, negative for both ER and MDM2 expression, was transfected with a wild-type ER. Following transfection, both ER and MDM2 were strongly expressed in two independent clones. Expression of both was reduced in the presence of increasing concentrations of estradiol (10(-10)-10(-8) M) thus, estrogen may be involved in regulation of MDM2 expression in proliferative breast lesions.

Characterization of molecules mediating cell-cell communication in human cardiac valve interstitial cells

Cell-cell interactions and adhesion determine cellular architectural organization, proliferation, signaling, differentiation, and death. We have identified the molecular components of different cell-cell junctions in human valve interstitial cells (ICs) both in situ and in culture. ICs were isolated, cultured, and phenotyped for cell surface and cytoplasmic markers by flow cytometry and immunocytochemistry. Western blotting was used to identify and quantify the molecular components of these cell-cell junctions in human valve ICs and compared with expression in smooth muscle and fibroblast cell types. N-cadherin and desmoglein were weakly detected on a low percentage of ICs, and the other classical cadherins were not detected. alpha- and beta-catenin, but not gamma-catenin, were expressed at equivalent levels by all valve ICs. Valve ICs did not express connexin-32 and -40; however, connexin-26 and -43 were equally expressed by a low percentage of ICs, demonstrating cell surface and cytoplasmic expression ,and connexin-45 was weakly expressed. The other cell types also expressed N-cadherin, alpha- and beta-catenin, desmoglein and connexin-43. The expression of these junctional molecules was predominantly by valve ICs on the inflow side of the valves. Human valve ICs have the ability to communicate with other valve ICs and mediate cell-cell adhesion via N-cadherin, connexin-26 and -43, and desmoglein. The junctions between valve ICs could support an interconnecting and coordinated cellular unit capable of controlling the functionality of the valve.

Molecules mediating cell-ECM and cell-cell communication in human heart valves

The specific phenotype of different tissues depends on the interactions of cells with neighboring cells and the surrounding extracellular matrix, which is mediated by cell adhesion receptors including integrins, immunoglobulin family members, syndecans, and selectins. The aim of this study was to investigate the adhesion profile of native human valve interstitial cells (ICs) in situ and in vitro by analyzing these adhesion receptors. Flow cytometry and immunocytochemistry was used to quantify the expression of the specific receptors on ICs cultured from all human cardiac valves, and immunohistochemistry were used to profile their distribution pattern in valve tissue sections. The valve leaflets and cultured ICs from all valves expressed alpha1, alpha2, alpha3, alpha4, and alpha5 integrins to varying degrees and percentages with very little expression of alpha6 and alphaV. Valve leaflet ICs from all valves, expressed predominantly beta1 integrin but no beta3 or beta4 integrin. Syndecan-1 and Syndecan-4 were not detected. Intercellular adhesion molecule-1 was weakly detected, whereas vascular adhesion molecule-1 was barely detectable and E-selectin was not detected. This study has delineated the identity of some of the integrins synthesized and expressed by human valve ICs and the specificity of adhesion molecules with which the valve ICs interact with the extracellular matrix and mediate intercellular interactions. This pattern of expression of cell surface adhesion molecules may be considered as a basis for a fingerprint on which to base future cell alternatives and would provide useful information for valve tissue engineering.

Quantitative myocardial cytokine expression and activation of the apoptotic pathway in patients who require left ventricular assist devices

BACKGROUND

Molecular mechanisms underlying the deterioration of patients undergoing LV assist device (LVAD) implantation remain poorly understood. We studied the cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta and IL-6 and the terminal stage of the apoptotic pathway in patients with decompensating heart failure who required LVAD support and compared them with patients with less severe heart failure undergoing elective heart transplantation.

METHODS AND RESULTS

Myocardial and serum samples from 23 patients undergoing LVAD implantation were compared with those from 36 patients undergoing elective heart transplantation. Myocardial TNF-alpha mRNA (1.71-fold; P<0.05) and protein (3.43+/-0.19 versus 2.95+/-0.10 pg/mg protein; P<0.05) were elevated in the LVAD patients. Immunocytochemistry demonstrated TNF expression in the myocytes. Serum TNF-alpha was also elevated (12.5+/-1.9 versus 4.0+/-0.4 pg/mL; P<0.0001) in the LVAD patients. IL-6 mRNA (2.57-fold higher; P<0.005) and protein (27.83+/-9.35 versus 4.26+/-1.24 pg/mg protein; P<0.001) were higher in the LVAD candidates, as was serum IL-6 (79.3+/-23.6 versus 7.1+/-1.6 pg/mL; P<0.0001). Interleukin-1beta mRNA expression was 9.78-fold higher in the LVAD patients (P<0.001). iNOS mRNA expression was similar to that in advanced heart failure patients and was not further elevated in the LVAD patients. Levels of procaspase-9 (8.02+/-0.91 versus 6.16+/-0.43 oligodeoxynucleotide [OD] units; P<0.01), cleaved caspase-9 (10.02+/-1.0 versus 7.34+/-0.40 OD units; P<0.05), intact and spliced DFF-45 (4.58+/-0.75 versus 2.84+/-0.23 OD units; P<0.05) were raised in LVAD patients, but caspase-3 and human nuclease CPAN were not.

CONCLUSIONS

Elevated TNF-alpha, IL-1beta, and IL-6 and alterations in the apoptotic pathway were found in the myocardium and elevated TNF-alpha and IL-6 in serum of deteriorating patients who required LVAD support. These occurrences may have therapeutic implications and influence the timing of LVAD insertion.

Heat shock protein 70 gene transfection protects mitochondrial and ventricular function against ischemia-reperfusion injury

BACKGROUND

Upregulation of heat shock protein 70 (HSP70) is beneficial in cardioprotection against ischemia-reperfusion injury, but the mechanism of action is unclear. We studied the role of HSP70 overexpression through gene therapy on mitochondrial function and ventricular recovery in a protocol that mimics clinical donor heart preservation.

METHODS AND RESULTS

Hemagglutinating virus of Japan (HVJ)-liposome technique was used to transfect isolated rat hearts via intracoronary infusion of either the HSP70 gene (HSP group, n=16) or no gene (CON group, n=16), which was heterotopically transplanted into recipient rats. Four days after surgery, hearts were either perfused on a Langendorff apparatus for 30 minutes at 37 degrees C (preischemia studies [n=8/group]) or perfused for 30 minutes at 37 degrees C, cardioplegically arrested for 4 hours at 4 degrees C, and reperfused for 30 minutes at 37 degrees C (postischemia studies [n=8/group]). Western blotting and immunohistochemistry confirmed HSP70 upregulation in the HSP group. Postischemic mitochondrial respiratory control indices (RCIs) were significantly better preserved in HSP than in CON hearts: NAD(+)-linked RCI values were 9.54+/-1.1 versus 10.62+/-0.46 before ischemia (NS) but 7.98+/-0.69 versus 1.28+/-0.15 after ischemia (P<0.05), and FAD-linked RCI values were 6.87+/-0.88 versus 6.73+/-0.93 before ischemia (NS) but 4.26+/-0.41 versus 1.34+/-0.13 after ischemia (P<0.05). Postischemic recovery of mechanical function was greater in HSP than in CON hearts: left ventricular developed pressure recovery was 72.4+/-6.4% versus 59.7+/-5.3% (P<0.05), maximum dP/dt recovery was 77.9+/-6.6% versus 52.3+/-5.2% (P<0.05), and minimum dP/dt recovery was 72.4+/-7.2% versus 54.8+/-6.9% (P<0.05). Creatine kinase release in coronary effluent after reperfusion was 0.20+/-0.04 versus 0.34+/-0.06 IU. min(-1). g wet wt(-1) (P<0.05) in HSP versus in CON hearts.

CONCLUSIONS

HSP70 upregulation protects mitochondrial function after ischemia-reperfusion injury; this was associated with improved preservation of ventricular function. Protection of mitochondrial function may be important in the development of future cardioprotective strategies.

Heat stress contributes to the enhancement of cardiac mitochondrial complex activity

Hyperthermic stress is known to protect against myocardial dysfunction after ischemia-reperfusion injury. It is unclear however, what energetic mechanisms are affected by the molecular adaptation to heat stress. We hypothesized that mild hyperthermic stress can increase mitochondrial respiratory enzyme activity, affording protection to mitochondrial energetics during prolonged cardiac preservation for transplantation. Rat hearts were excised after heat-stress or sham treatment and subjected to cold cardioplegic arrest and ischemia followed by reperfusion in an ex vivo perfusion system. Cardiac function, mitochondrial respiratory, and complex activities were assessed before and after ischemia. Heat shock protein (Hsp 32, 60, and 72) expression was increased in heat-stressed hearts. This was associated with increased mitochondrial complex activities in heat-stress versus sham-treated groups for complex I-V. During reperfusion, higher complex activities and respiratory control ratios were observed in heat-stressed versus sham-treated groups. Recovery of ventricular function was improved in heat-stressed hearts. Furthermore, mitochondria in reperfused heat-stressed myocardium exhibited intact membranes with packed, parallel, lamellar cristae, whereas in sham-treated myocardium, mitochondria were severely disrupted. This study provides the first evidence of heat-stress-mediated enhancement of mitochondrial energetic capacity. This is associated with increased tolerance to ischemia-reperfusion injury. Protection by heat stress against myocardial dysfunction may be partially due to enhancement of mitochondrial energetics.

Activation of apoptotic and inflammatory pathways in dysfunctional donor hearts

BACKGROUND

Myocardial dysfunction is common after brain death, but the mechanisms remain unclear. Apoptosis is tightly regulated by enzymes termed the caspases. We have investigated the caspases involved in the terminal part of the apoptotic pathway in dysfunctional (nontransplanted) donor hearts and their relation to inflammatory markers and compared them to hearts with good ventricular function (transplanted donors).

METHODS

Thirty-one donor hearts assessed for transplantation were examined. Western blotting was used to measure pro-caspase-9, caspase-3, DFF45, the activated nuclease CPAN and poly (ADP-ribose) polymerase, a DNA repair enzyme inactivated by caspase-3. Caspase-3 activity was also measured. Histologic and immunocytochemical analysis for HLA Class II and Real Time polymerase chain reaction for tumor necrosis factor-alpha and interleukin 6 were performed to detect inflammatory activation.

RESULTS

Cleaved caspase-9 was higher (5.53+/-0.6 vs. 3.64+/-0.4 O.D. units, P<0.01) in nontransplanted compared with transplanted donors and there was a trend for higher pro-caspase-9 (5.20+/-1.0 vs. 4.22+/-0.4 O.D. units, P=NS). Levels of pro-caspase-3 were higher in nontransplanted (9.66+/-0.5 vs. 5.15+/-0.5 O.D. units, P<0.00001) donors and cleavage products of caspase-3 were elevated in 14 of 14 nontransplanted and 2 of 17 transplanted donors. Intact DFF-45 (8.94+/-0.36 vs. 6.14+/-0.30 O.D. units, P<0.000005), its spliced product (2.38+/-0.35 vs. 0.4+/-0.21 O.D. units, P=0.0001) and the nuclease caspase-activated nuclease (2.01+/-0.3 vs. 0.66+/-0.16 OD units, P=0.001) were higher in nontransplanted donors. The caspase-3 substrate poly (ADP-ribose) polymerase was higher in nontransplanted (1.16+/-0.13 vs. 0.61+/-0.22 O.D. units, P=0.57) donors.

CONCLUSIONS

The caspases are elevated in dysfunctional donor hearts compared with hearts with good ventricular function with a possible link to inflammatory activation supporting the concept that brain death causes inflammatory activation which can lead to apoptosis with a possible important effect on function.

Gene therapy for myocardial protection: transfection of donor hearts with heat shock protein 70 gene protects cardiac function against ischemia-reperfusion injury

BACKGROUND

Heat shock protein 70 (HSP70) gene transfection has been shown to enhance myocardial tolerance after normothermic ischemia-reperfusion. We investigated the effect of HSP70 gene transfection on mechanical and endothelial function in a protocol mimicking clinical heart preservation.

METHODS AND RESULTS

Rat hearts were infused ex vivo with Hemagglutinating Virus of Japan-liposome complex containing HSP70 gene (HSP, n=8) or no gene (CON, n=8), and heterotopically transplanted into recipient rats. Four days after surgery, transfected hearts were perfused on a Langendorff apparatus for 45 minutes, arrested with St Thomas' No. 1 cardioplegia for 4 hours at 4 degrees C, and reperfused for 1 hour. Mechanical and endothelial function was studied before and after ischemia. Creatine kinase was measured in reperfusion effluent. Hearts underwent Western blotting and immunohistochemistry to confirm HSP70 overexpression. Postischemic recovery of mechanical function (% preischemic+/-SEM) was greater in HSP versus CON: Left ventricular developed pressure recovery was 76.7+/-3.9% versus 60. 5+/-3.1% (P:<0.05); dP/dtmax recovery was 79.4+/-4.9% versus 56. 2+/-3.2% (P:<0.05); dP/dtmin recovery was 74.8+/-4.6% versus 57. 3+/-3.6% (P:<0.05). Creatine kinase release was attenuated in HSP versus CON: 0.22+/-0.02 versus 0.32+/-0.04 IU/min/g wet wt. (P:<0. 05). Recovery of coronary flow was greater in HSP versus CON: 76. 5+/-3.8% versus 59.2+/-3.2% (P:<0.05). Recovery of coronary response to 5-hydroxytryptamine (5 x 10(-)(5) mol/L) was 55.6+/-4.7% versus 23. 9+/-3.2% (P:<0.05); recovery of coronary response to glyceryltrinitrate (15 mg/L) was not different between HSP and CON: 87.4+/-6.9% versus 84.3+/-5.8% (NS).

CONCLUSIONS

In a clinically relevant donor heart preservation protocol, HSP70 gene transfection protects both mechanical and endothelial function.

Upregulation of the Bcl-2 family of proteins in end stage heart failure

OBJECTIVES

To elucidate the pattern of expression of four members of the Bcl-2 family of proteins and to correlate this with terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end labelling (TUNEL) and DNA fragmentation.

BACKGROUND

Apoptosis has been implicated as a possible mechanism in the development of heart failure. However, the mechanisms involved remain unclear.

METHODS

We have studied the expression of four members of the Bcl-2 family that are involved in the regulation of apoptosis and analyzed DNA fragmentation as a marker of apoptosis and as a biochemical criterion to distinguish between apoptosis and necrosis in dilated cardiomyopathy (DCM), ischemic heart disease (IHD) and normal donors.

RESULTS

Western blot analysis and immunocytochemistry of the proapoptotic and antiapoptotic Bcl-2 proteins demonstrated significantly higher levels of all these proteins in the diseased groups compared with normal donors. Additionally, Bax was significantly higher in the IHD group compared with DCM. Terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end labelling analysis demonstrated a significantly higher percentage of TUNEL-positive cells in the diseased groups compared with the control. Genomic DNA extraction of ventricular myocardial tissue showed no demonstrable DNA laddering for any of the groups.

CONCLUSIONS

The significant increases in the levels of the proapoptotic proteins Bak and Bax and the higher percentage of TUNEL-positive cells in both diseased groups suggests the presence of ongoing apoptosis. However, increases in the antiapoptotic proteins, Bcl-2 and Bcl-xL, suggest a possible concomitant, compensatory antiapoptotic mechanism in patients with heart failure.

What is the effect of riskshaw noise on its driver?

OBJECTIVE

Occupational hearing loss is common in the industrialized world. Road noise is a major contributor to perceived environmental noise. The objective of this study was to assess hearing loss in rickshaw drivers due to rickshaw noise.

METHODS

Hearing loss in rickshaw drivers and taxi drivers of Karachi who were 50 years of age or younger was estimated, with a Smith Hearing Screening (SHS) questionnaire that was modified, translated into the national language, Urdu and field tested prior to administration.

RESULTS

Interviews for 91 rickshaw drivers and 94 taxi drivers were completed. All subjects were male; mean ages were 34 and 33 years for rickshaw and taxi drivers respectively. None of the rickshaws were fitted with silencers. Rickshaw drivers were about thrice as likely to be screened as hearing impaired by the SHS questionnaire (RR 2.9, 95% confidence interval 1.6, 5.0), twice as likely to report tinnitus (RR 2.2, 95% confidence interval, 1.1, 3.3) and two and a half times as likely to have difficulty in following telephonic conversations (RR 2.4, 95% confidence interval 1.2, 4.8).

CONCLUSION

There is loss of hearing and tinnitus among rickshaw drivers that could be attributed to their trade. Use of silencers by rickshaw drivers could result in less hearing loss among rickshaw drivers and less noise in the environment for the other 11 million residents in the city.

The expression of heat shock protein 60 in patients with dilated cardiomyopathy

OBJECTIVE

Heat shock proteins (hsps) have been shown to be important antigens in a number of autoimmune diseases. We have previously shown the presence of autoantibodies against hsp60 in a high proportion of patients with dilated cardiomyopathy (DCM). This study set out to investigate the expression of hsp60 in the myocardium of 30 patients with DCM and a control group of 30 normal donors.

DESIGN

The expression of hsp60 was quantitated at the protein and mRNA level by Western blotting and RT-PCR, respectively, and its distribution was investigated by immunocytochemistry.

RESULTS

Quantitation of hsp60 showed a 5-fold increase in the DCM hearts over that in the donor hearts. By immunocytochemistry 13 patients with DCM showed increased positive staining localised to the connective tissue. Semi-quantitative RT-PCR analysis of hsp60 showed a significantly increased amount of hsp60 at the mRNA level in the DCM hearts than in the controls.

CONCLUSIONS

These results unequivocally demonstrate a raised level of expression of endogenous hsp60 in the myocardium of patients with DCM. The increased expression of hsp60 in the myocardium of patients with DCM may render such cells susceptible to react with circulating autoantibodies to hsp60 and hsp65 found in a high proportion of patients with this disease.

Characterization of anti-heart antibodies in mice after infection with coxsackie B3 virus

Coxsackie virus B3 (CVB3) infection results in a marked inflammatory response and the production of autoantibodies to cardiac antigens, with cardiac myosin heavy chain documented to be the most immunogenic antigen. The present study investigated the temporal appearance of anti-heart antibodies in mice after mock infection or infection with an attenuated variant of CVB3 or wildtype CVB3 by SDS-PAGE and Western blotting. Further characterization of the autoantigens was carried out using 2D electrophoresis followed by Western blotting. Mice infected with wildtype CVB3 demonstrated high levels of IgG anti-heart antibodies, reacting predominantly with myosin heavy chain but also with numerous other myocardial proteins. Significant increases in anti-myosin heavy chain, anti-actin, and anti-tropomyosin antibodies were seen in wildtype-infected mice as early as day 7 postinfection compared to those mice that were mock infected or infected with attenuated virus. Characterization of other antigens revealed novel reactivities against myosin subfragments, heat shock proteins, and desmin and its subfragments.

Relative induction of heat shock protein in coronary endothelial cells and cardiomyocytes: implications for myocardial protection

OBJECTIVES

Induction of the 70 kd heat shock protein in the heart is known to exert a protective effect against postischemic mechanical and endothelial dysfunction. However, the exact site of induction and the mechanisms involved remain unknown. The aim of this study was to investigate the relative capacity of endothelial and myocardial cells to express the 70 kd heat shock protein in response to heat stress, as well as their significance.

METHODS

(1) Postischemic recovery of cardiac mechanical and endothelial function was studied in isolated rat hearts with and without endothelial denudation with saponin. (2) Semiquantitative determination of induction of 70 kd heat shock protein by Western immunoblotting was performed in the whole cardiac homogenate, in isolated cardiac myocytes, and in coronary endothelial cells. (3) Immunocytochemistry was used to visualize the distribution of induction of 70 kd heat shock protein in both cell types.

RESULTS

Postischemic recovery (percent preischemic value +/- standard error of the mean) of cardiac output in hearts from heat-stressed animals was significantly improved (66.7 +/- 6.9 vs 44.5 +/- 4.5 in the control group, p < 0.01). In heat-stressed hearts treated with saponin no improvement in the recovery of cardiac output was noted (44.7 +/- 6.9 in heat-stressed hearts vs 38.0 +/- 4.0 in heat-stressed, saponin-treated hearts, p = not significant). Endothelial function (as assessed by the vasodilatory response to the endothelium-dependent vasodilator 5-hydroxytryptamine) improved from 31.0 +/- 5.2 in the control group to 65.8 +/- 7.1 in heat-stressed hearts (p < 0.02 vs control) and dropped to -1.9 +/- 3.8 in heat-stressed hearts treated with saponin. Immunocytochemistry showed that only sections of hearts from heat-treated rats showed a strong specific reaction with heat shock protein antibody. The positive staining was seen in endothelial cells. Induction of 70 kd heat shock protein content in the whole cardiac homogenate from heat-stressed rats as measured by Western immunoblotting was 5.2 +/- 1.9 (vs 0.0 in non-heat-stressed rats, p < 0.0001) and dropped to 0.0 in heat-stressed hearts treated with saponin. The tentative amount of 70 kd heat shock protein was 18.1 +/- 7.8 in isolated endothelial cells from heat-stressed hearts and 2.3 +/- 2.3 in isolated cardiac myocytes (p < 0.01 vs endothelial cells).

CONCLUSIONS

Coronary endothelial cells are the main site of induction of 70 kd heat shock protein in the heart and appear to contribute to the protective effects of heat stress on the recovery of mechanical and endothelial function.

Coxsackievirus B3-induced myocarditis. Characterization of stable attenuated variants that protect against infection with the cardiovirulent wild-type strain

Coxsackievirus B3 (CVB3) is the enterovirus most frequently involved in human myocarditis or dilated cardiomyopathy. Attenuated variants were derived from a cardiovirulent CVB3 reactivated from a sequenced, full-length cDNA clone. The prophylactic potential of these variants was assessed in SWR/Ola (H-2q) mice. Animals immunized with attenuated variants of CVB3 were protected from myocarditis when challenged subsequently with the cardiovirulent wild-type virus. In contrast to nonimmunized controls, the wild-type virus was not isolated from myocardium of protected mice, nor was viral RNA detected in myocardium by reverse transcription nested polymerase chain reaction. Specific antibody to CVB3 was demonstrated by virus neutralization assay and by indirect immunofluorescence. The attenuated phenotype of one variant, p14V-1, remained stable throughout 20 consecutive passages in SWR mice and induced a markedly lower level of autoantibody against mouse cardiac myosin heavy chain than the cardiovirulent wild type. These data demonstrate that attenuated strains protect against CVB3-induced myocarditis in mice, that the attenuated phenotype is stable, and that they do not persist in myocardium nor induce a significant level of anti-heart anti-body against myosin heavy chain. These attenuants may be the basis of a live vaccine against CVB3 in the prevention of enteroviral heart muscle disease.

Construction of an internal standard for semiquantitative polymerase chain reaction analysis of heat shock proteins

We describe a simple and effective method for generating competitive cDNA fragments for use as an internal standard in semi-quantitative polymerase chain reaction (PCR). The use of a nested composite primer to a region slightly within the expected amplicon but with heat shock protein 60 kDa (hsp60) primer sequence appended to the 5' terminus of the primer produces a "mimic" DNA that will model the PCR kinetics of the target template in sequence context, and PCR primer site, and that will be similar in size. This ensures that both competitor and target template are subjected to similar PCR kinetics and so allows more meaningful quantitation.

Association of pretransplantation antiheart antibodies with clinical course after heart transplantation

METHODS

Sera from 129 patients awaiting heart transplantation were assayed for the presence of IgM and IgG antiheart antibodies by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting. The patients' posttransplantation clinical course was assessed with regard to the amount of methylprednisolone, rabbit antithymocyte globulin, and OKT3 anti-T cell antibody, and the number of biopsy-confirmed rejection episodes. Before undergoing heart transplantation, approximately half the patients had weak IgM (45%) and weak IgG (48%) antiheart antibodies. However, 22.5% of the patients had strong IgM antiheart antibodies before transplantation, and they required more methylprednisolone than those who were negative and weak and approximately twice as much rabbit antithymocyte globulin as those who were negative, weak, or moderate. Six of the patients in this group required OKT3 therapy, and additionally they had a significantly greater number of rejection episodes than those patients who were negative (p = 0.006), or who had weak antiheart antibodies before transplantation (p = 0.001).

RESULTS AND CONCLUSIONS

Analysis of the pattern of banding of strong IgM antiheart antibody sera showed antiheart antibodies most frequently against myocardial proteins of 35, 42, 50, 60, 70, 110, 120, 150, 180, and 200 kDa. Several of these proteins were characterized by two-dimensional polyacrylamide gel electrophoresis and Western blotting as tropomyosin (35 kDa), actin (42 kDa), heat shock protein 60 (60 kDa), and heat shock protein 70 (70 kDa). All strong antiheart antibody sera showed reactivity against a 200 kDa protein corresponding to myosin heavy chain.

Use of indirect immunofluorescence and western blotting to assess the role of circulating antimyocardial antibodies in dogs with dilated cardiomyopathy

The presence of circulating anti-heart IgG and IgM autoantibodies was assessed by indirect immunofluorescence and by probing Western blot transfers of normal canine myocardial proteins separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis with samples of sera from dogs with dilated cardiomyopathy (n = 27) and from healthy control dogs (n = 20). No difference was demonstrated between the two groups using either method. Sera taken from the affected dogs at three monthly intervals throughout the course of the disease showed no change at all in the pattern of reactivity. The results of this study suggest that indirect immunofluorescence and the probing of Western blot transfers of a crude preparation of normal canine myocardium with canine sera will demonstrate too many apparent autoantigens for the technique to identify unique, disease-associated autoantibodies.

Complement-mediated cytotoxic activity of anti-heart antibodies present in the sera of patients with dilated cardiomyopathy

A microcytotoxicity assay has been used to determine the cytotoxic activity of anti-heart antibodies which we have previously shown to be present with greater frequencies and reactivities in patients with dilated cardiomyopathy (DCM) than in patients with ischaemic heart disease (IHD). Serum samples from 45 patients with DCM and 43 patients with IHD were screened against W1, a transformed human fetal cardiac cell line and also against EA.hy 926, an endothelial and IBR3, a fibroblast cell line. In the presence of complement, sera from 28 (62%) DCM patients showed killing of the W1 cell line as compared to sera from 13 (30%) of IHD patients (p < 0.005) and 3 (15%) of normal individuals. In contrast, only 1 patient with DCM showed killing of the endothelial cell line and 1 patient with IHD showed killing of the fibroblast cell line. These results provide evidence for a complement-dependent, antibody-mediated mechanism of damage to cardiac myocytes which may contribute to the pathogenesis of DCM.

Frequency and specificity of antiheart antibodies in patients with dilated cardiomyopathy detected using SDS-PAGE and western blotting

OBJECTIVES

This study was designed to investigate the organ and disease specificity of antiheart antibodies in patients with dilated cardiomyopathy.

BACKGROUND

Autoimmune disease is characterized by the presence of circulating autoantibodies, and autoimmune mechanisms may play a role in the pathogenesis of dilated cardiomyopathy.

METHODS

An SDS-PAGE (sodium dodecylsulfate polyacrylamide gel electrophoresis) procedure followed by Western blotting was used to screen serum samples for antiheart antibodies of two immunoglobulin classes, IgM and IgG, from 52 patients with dilated cardiomyopathy and 48 patients with ischemic heart disease as control subjects. Use of two-dimensional gel electrophoresis followed by Western blotting and protein sequencing enabled us to identify the protein bands against which antiheart antibodies were produced in both groups of patients.

RESULTS

Strong IgG antiheart antibodies against myocardial proteins, cross-reacting with skeletal muscle proteins, were detected in significantly more patients with dilated cardiomyopathy (n = 24 [46%]) than with ischemic heart disease (n = 8 [17%]) (p = 0.001). Patients with dilated cardiomyopathy showed a significantly greater frequency and reactivity of IgG antiheart antibodies against six myocardial proteins (molecular weight 30, 35, 40, 60, 85 and 200 kD) than did patients with ischemic heart disease. These were identified as myosin light chain 1, tropomyosin, actin, heat shock protein (HSP)-60, an unidentified protein and myosin heavy chain, respectively.

CONCLUSIONS

We detected strong IgG antiheart antibodies in significantly more patients with dilated cardiomyopathy than with ischemic heart disease. The most immunogenic band was that corresponding to HSP-60. Antibodies against HSP-60 were found in 85% and 42% of patients with dilated cardiomyopathy and ischemic heart disease, respectively, confirming our hypothesis of an immune involvement in dilated cardiomyopathy.

Subchronic MK-801 treatment to juvenile rats attenuates environmental effects on adult spatial learning

Treatment with the non-competitive NMDA receptor blocker MK-801 (0.16 mg/kg), given to juvenile rats before and after the exposure to an enriched environment on alternate days for 4 weeks, attenuated the improvements in spatial learning and open field adaptation which resulted from such environmental stimulation. Drug treatment affected the consolidation of experiences as an injection given after exposure to the enriched environment was needed to demonstrate this effect. In addition, MK-801 administration diminished the adverse effect of stimulus deprivation-the slow learning rate normally seen in rats housed in impoverished environment. Radioligand binding studies showed that drug treatment decreased [3H]MK-801 binding sites in cortex. The learning, activity and receptor binding effects were measured 4 months from cessation of the drug treatment and environmental manipulation. The results support the role of NMDA receptors in mediating cognitive changes associated with environmental stimulation.

Antiheart antibodies following open heart surgery: incidence and correlation with postpericardiotomy syndrome

One-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis of myocardial proteins followed by Western blotting is a sensitive method for the detection of antiheart antibodies after cardiac transplantation. In a previous study we found that the majority of patients made antiheart antibodies after cardiac transplantation. It is possible that these antibodies were formed in response to cardiac damage caused during the surgical procedure rather than being specific to the transplantation situation. In this study we have evaluated the role of open cardiac surgery in the formation of antiheart antibodies for the first 9 months of the postoperative period using the Western blotting technique and correlated that with the development of post-pericardiotomy syndrome. Only 25% (9/36) of patients showed any increase in the pre-existing level of antiheart antibodies or developed antiheart antibodies with new reactivities. None of the patients in the study developed manifestations specific for post-pericardiotomy syndrome during the period of follow-up. The results support the contention that the high incidence of antiheart antibodies formed after cardiac transplantation is due to a humoral immune response to the presence of alloantigens on the grafted heart rather than as a result of the surgical procedure itself.

Demonstration by western blotting of antiheart antibodies before and after cardiac transplantation

Western blotting has been used to detect antiheart antibodies in two groups of patients: two who required retransplantation for hyperacute rejection, and 22 consecutive patients, whose serum was tested at monthly intervals for three months following transplantation. Pretransplant and posttransplant serum samples were tested for IgM and IgG reactivity against the patients own heart and donor heart. In all patients the pretransplant lymphocytic crossmatch had been negative. In the two patients requiring retransplantation, both had multiple bands of strong IgM and IgG against their own heart prior to transplantation as well as antibodies against the donor heart. The study of 22 consecutive patients revealed that (1) the presence of strong antibody prior to transplantation is associated with unusually severe or frequent rejection episodes, (2) 20/22 patients made antiheart antibody following transplantation, but in 12 patients it was IgM only, and (3) most of the antiheart antibodies made posttransplant were not specific for the donor heart. Comparison of Western blotting with immunofluorescent detection of antibodies on frozen sections revealed that the Western blotting procedure is more sensitive and results are easier to interpret.