Background-Hypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death in the young, is characterized by cardiac hypertrophy, myocyte disarray, and interstitial fibrosis. We propose that hypertrophy and fibrosis are secondary to the activation of trophic and mitotic factors and, thus, potentially reversible. We determined whether the blockade of angiotensin II, a known cardiotrophic factor, could reverse or attenuate interstitial fibrosis in a transgenic mouse model of human HCM. Methods and Results-We randomized 24 adult cardiac troponin T (cTnT-Q 92 ) mice, which exhibit myocyte disarray and interstitial fibrosis, to treatment with losartan or placebo and included 12 nontransgenic mice as controls. The mean dose of losartan and the mean duration of therapy were 14.2Ϯ5.3 mg · kg -1 · d -1 and 42Ϯ9.6 days, respectively. Mean age, number of males and females, and heart/body weight ratio were similar in the groups. Collagen volume fraction and extent of myocyte disarray were increased in the cTnT-Q 92 mice (placebo group) compared with nontransgenic mice (9.9Ϯ6.8% versus 4.5Ϯ2.2%, Pϭ0.01, and 27.6Ϯ10.6% versus 3.9Ϯ2.3%, PϽ0.001, respectively). Treatment with losartan reduced collagen volume fraction by 49% to 4.9Ϯ2.9%. The expression of collagen 1␣ (I) and transforming growth factor-␤1, a mediator of angiotensin II profibrotic effect, were also reduced by 50%. Losartan had no effect on myocyte disarray. Conclusions-Treatment with losartan reversed interstitial fibrosis and the expression of collagen 1␣ (I) and transforming growth factor-␤1 in the hearts of cTnT-Q 92 mice. These findings suggest that losartan has the potential to reverse or attenuate interstitial fibrosis, a major predictor of sudden cardiac death, in human patients with HCM. Key Words: cardiomyopathy Ⅲ fibrosis Ⅲ collagen Ⅲ death, sudden H ypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death (SCD) in the young, 1 is caused by mutations in sarcomeric proteins. 2 It is clinically diagnosed by unexplained cardiac hypertrophy and pathologically by myocyte hypertrophy, disarray, and interstitial fibrosis. 3 Hypertrophy and fibrosis are the major determinants of mortality, morbidity, and SCD 4,5 in HCM and in all acquired forms of cardiac diseases.The genetic basis of HCM has been elucidated, and research efforts are being directed to decipher its molecular pathogenesis and to determine the reversibility of the phenotypes. We previously proposed that interstitial fibrosis, like cardiac hypertrophy, occurs "secondary" to the activation of trophic and mitotic factors in the heart 6 and, thus, is potentially reversible by blocking cardiotrophic factors such as angiotensin II (Ang II). However, despite the well-established role of Ang II blockers in the attenuation of cardiac hypertrophy and fibrosis in acquired cardiac diseases, they are not conventionally used in the treatment of patients with HCM, a genetic paradigm of cardiac hypertrophy and fibrosis. We determined the effects of blocking Ang II on the int...

Background-Hypertrophic cardiomyopathy is a genetic disease characterized by cardiac hypertrophy, myocyte disarray, interstitial fibrosis, and left ventricular (LV) dysfunction. We have proposed that hypertrophy and fibrosis, the major determinants of mortality and morbidity, are potentially reversible. We tested this hypothesis in ␤-myosin heavy chain-Q 403 transgenic rabbits. Methods and Results-We randomized 24 ␤-myosin heavy chain-Q 403 rabbits to treatment with either a placebo or simvastatin (5 mg · kg -1 · d -1 ) for 12 weeks and included 12 nontransgenic controls. We performed 2D and Doppler echocardiography and tissue Doppler imaging before and after treatment. Demographic data were similar among the groups. Baseline mean LV mass and interventricular septal thickness in nontransgenic, placebo, and simvastatin groups were 3.9Ϯ0.7, 6.2Ϯ2.0, and 7.5Ϯ2.1 g (PϽ0.001) and 2.2Ϯ0.2, 3.1Ϯ0.5, and 3.3Ϯ0.5 mm (Pϭ0.002), respectively. Simvastatin reduced LV mass by 37%, interventricular septal thickness by 21%, and posterior wall thickness by 13%. Doppler indices of LV filling pressure were improved. Collagen volume fraction was reduced by 44% (PϽ0.001). Disarray was unchanged. Levels of activated extracellular signal-regulated kinase (ERK) 1/2 were increased in the placebo group and were less than normal in the simvastatin group. Levels of activated and total p38, Jun N-terminal kinase, p70S6 kinase, Ras, Rac, and RhoA and the membrane association of Ras, RhoA, and Rac1 were unchanged. Conclusions-Simvastatin induced the regression of hypertrophy and fibrosis, improved cardiac function, and reduced ERK1/2 activity in the ␤-myosin heavy chain-Q 403 rabbits. These findings highlight the need for clinical trials to determine the effects of simvastatin on cardiac hypertrophy, fibrosis, and dysfunction in humans with hypertrophic cardiomyopathy and heart failure.

Background-Human hypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death in the young, is characterized by cardiac hypertrophy, myocyte disarray, and interstitial fibrosis. The genetic basis of HCM is largely known; however, the molecular mediators of cardiac phenotypes are unknown. Methods and Results-We show myocardial aldosterone and aldosterone synthase mRNA levels were elevated by 4-to 6-fold in humans with HCM, whereas cAMP levels were normal. Aldosterone provoked expression of hypertrophic markers (NPPA, NPPB, and ACTA1) in rat cardiac myocytes by phosphorylation of protein kinase D (PKD) and expression of collagens (COL1A1, COL1A2, and COL3A1) and transforming growth factor-␤1 in rat cardiac fibroblasts by upregulation of phosphoinositide 3-kinase (PI3K)-p100␦. Inhibition of PKD and PI3K-p110␦ abrogated the hypertrophic and profibrotic effects, respectively, as did the mineralocorticoid receptor (MR) antagonist spironolactone. Spironolactone reversed interstitial fibrosis, attenuated myocyte disarray by 50%, and improved diastolic function in the cardiac troponin T (cTnT)-Q92 transgenic mouse model of human HCM. Myocyte disarray was associated with increased levels of phosphorylated ␤-catenin (serine 38) and reduced ␤-catenin-N-cadherin complexing in the heart of cTnT-Q92 mice. Concordantly, distribution of N-cadherin, predominantly localized to cell membrane in normal myocardium, was diffuse in disarrayed myocardium. Spironolactone restored ␤-catenin-N-cadherin complexing and cellular distribution of N-cadherin and reduced myocyte disarray in 2 independent randomized studies. Conclusions-The results implicate aldosterone as a major link between sarcomeric mutations and cardiac phenotype in HCM and, if confirmed in additional models, signal the need for clinical studies to determine the potential beneficial effects of MR blockade in human HCM.

Abstract-Identification of mutations in the ATP binding cassette transporter (ABCA1) gene in patients with Tangier disease, who exhibit reduced HDL cholesterol (HDL-C) and apolipoprotein A1 (apoA1) levels and premature coronary atherosclerosis, has led to the hypothesis that common polymorphisms in the ABCA1 gene could determine HDL-C and apoA1 levels and the risk of coronary atherosclerosis in the general population. We sequenced a 660-bp 5Ј fragment of the ABCA1 gene in 24 subjects and identified 3 novel polymorphisms: Ϫ477C/T, Ϫ419A/C, and Ϫ320G/C. We developed assays, genotyped 372 participants in the prospective Lipoprotein Coronary Atherosclerosis Study (LCAS), and determined the association of the variants with fasting plasma lipids and indices of quantitative coronary angiograms obtained at baseline and 2.5 years after randomization to fluvastatin or placebo. Distribution of Ϫ477C/T and Ϫ320G/C genotypes were 127 CC, 171 CT, and 74 TT and 130 GG, 168 GC, and 75 CC, respectively, and were in complete linkage disequilibrium (PϽ0.0001). Data for Ϫ477C/T are presented. The Ϫ419A/C variant was uncommon (present in 1 of 63 subjects). Heterozygous subjects had a modest reduction in HDL-C (Pϭ0.09) and apoA1 (Pϭ0.05) levels and a lesser response of apoA1 to treatment with fluvastatin (Pϭ0.04). The mean number of coronary lesions causing 30% to 75% diameter stenosis was greater in subjects with the TT genotype (3.1Ϯ2. P lasma levels of HDL cholesterol (HDL-C) and apolipoprotein A1 (apoA1) are under tight control of genetic factors, which are largely unknown. Recent identification of mutations in the ATP binding cassette transporter (ABCA1) gene in patients with Tangier disease, 1-3 who also have very low plasma levels of HDL-C and apoA1 and an increased risk of premature coronary atherosclerosis, suggests a major role for the ABCA1 protein in regulating plasma HDL-C and apoA1 levels. This notion is further supported by the observation of an age-dependent reduction in HDL-C levels and an increased frequency of coronary artery disease in members of families with Tangier or familial hypoalphalipoproteinemia (HA) who were heterozygous for mutations in the ABCA1 gene. 4 These discoveries in conjunction with the wellestablished role of HDL-C in protection against coronary atherosclerosis 5,6 have led to the hypothesis that common polymorphisms in the ABCA1 gene could affect plasma levels of HDL-C and apoA1 and thus serve as genetic risk factors for coronary atherosclerosis in the general population. 4,7 We sequenced the promoter region of the ABCA1 gene, detected novel polymorphisms, and analyzed their association with plasma levels of lipids, the severity and progression of coronary atherosclerosis, and the response to therapy in a prospective study of a well-characterized cohort. 8 Materials and Methods Study PopulationAll subjects provided informed consent, and the institutional review board approved the study. The design 9 and primary result 8 of the Lipoprotein and Coronary Atherosclerosis Study (LCAS) have been pu...

Background-Hypertrophic cardiomyopathy is a genetic disease characterized by cardiac hypertrophy, myocyte disarray, interstitial fibrosis, and left ventricular (LV) dysfunction. We have proposed that hypertrophy and fibrosis, the major determinants of mortality and morbidity, are potentially reversible. We tested this hypothesis in ␤-myosin heavy chain-Q 403 transgenic rabbits. Methods and Results-We randomized 24 ␤-myosin heavy chain-Q 403 rabbits to treatment with either a placebo or simvastatin (5 mg · kg -1 · d -1 ) for 12 weeks and included 12 nontransgenic controls. We performed 2D and Doppler echocardiography and tissue Doppler imaging before and after treatment. Demographic data were similar among the groups. Baseline mean LV mass and interventricular septal thickness in nontransgenic, placebo, and simvastatin groups were 3.9Ϯ0.7, 6.2Ϯ2.0, and 7.5Ϯ2.1 g (PϽ0.001) and 2.2Ϯ0.2, 3.1Ϯ0.5, and 3.3Ϯ0.5 mm (Pϭ0.002), respectively. Simvastatin reduced LV mass by 37%, interventricular septal thickness by 21%, and posterior wall thickness by 13%. Doppler indices of LV filling pressure were improved. Collagen volume fraction was reduced by 44% (PϽ0.001). Disarray was unchanged. Levels of activated extracellular signal-regulated kinase (ERK) 1/2 were increased in the placebo group and were less than normal in the simvastatin group. Levels of activated and total p38, Jun N-terminal kinase, p70S6 kinase, Ras, Rac, and RhoA and the membrane association of Ras, RhoA, and Rac1 were unchanged. Conclusions-Simvastatin induced the regression of hypertrophy and fibrosis, improved cardiac function, and reduced ERK1/2 activity in the ␤-myosin heavy chain-Q 403 rabbits. These findings highlight the need for clinical trials to determine the effects of simvastatin on cardiac hypertrophy, fibrosis, and dysfunction in humans with hypertrophic cardiomyopathy and heart failure.

At the end of 2020, the Network for Genomic Surveillance in South Africa (NGS-SA) detected a SARS-CoV-2 variant of concern (VOC) in South Africa (501Y.V2 or PANGO lineage B.1.351)1. 501Y.V2 is associated with increased transmissibility and resistance to neutralizing antibodies elicited by natural infection and vaccination2,3. 501Y.V2 has since spread to over 50 countries around the world and has contributed to a significant resurgence of the epidemic in southern Africa. In order to rapidly characterize the spread of this and other emerging VOCs and variants of interest (VOIs), NGS-SA partnered with the Africa Centres for Disease Control and Prevention and the African Society of Laboratory Medicine through the Africa Pathogen Genomics Initiative to strengthen SARS-CoV-2 genomic surveillance across the region. Here, we report the first genomic surveillance results from Angola, which has had 21 500 reported cases and around 500 deaths from COVID-19 up to March 2021 (Supplemental Fig S1). On 15 January 2021, in response to the international spread of VOCs, the government instituted compulsory rapid antigen testing of all passengers arriving at the main international airport, in addition to the existing requirement to present a negative PCR test taken within 72 hours of travel. All individuals with a positive antigen test are isolated in a government facility for a minimum of 14 days and require two negative RT-PCR tests at least 48 hours apart for de-isolation, whilst all travelers with a negative test on arrival proceed to mandatory self-quarantine for 10 days followed by a repeat test. In March 2021, we received 118 nasopharyngeal swab samples collected between June 2020 and February 2021, a number of which were from incoming air travelers (Supplemental Fig S1). From these, we produced 73 high quality genomes (>80% coverage), 14 of which were known VOCs/VOIs (seven 501Y.V2/B.1.351, six B.1.1.7, one B.1.525), 44 of which were C.16 (a common lineage circulating in Portugal), and twelve of which were other lineages (Supplemental Fig S2). In addition, we detected a new VOI in three incoming travelers from Tanzania who were tested together at the airport in mid-February. The three genomes from these passengers were almost identical and presented highly divergent sequences within the A lineage (Figure 1A & 1B). The GISAID database contains nine other sequences reported to be sampled from cases involving travel from Tanzania, two of which are basal to the three sampled in Angola (Figure 1A, Supplemental Table S1). This new VOI, temporarily designated A.VOI.V2, has 31 amino acid substitutions (11 in spike) and three deletions (all in spike) (Figure 1C & 1D). The spike mutations include three substitutions in the receptor-binding domain (R346K, T478R and E484K); five substitutions and three deletions in the N-terminal domain, some of which are within the antigenic supersite (Y144Δ, R246M, SYL247-249Δ and W258L)4; and two substitutions adjacent to the S1/S2 cleavage site (H655Y and P681H). Several of these mutations are present in other VOCs/VOIs and are evolving under positive selection.

Sterol regulatory elements binding factor-1a (SREBF-1a) and SREBF cleavage activating protein (SCAP) regulate lipids homeostasis. Polymorphisms in SREBF-1a and SCAP could affect plasma levels of lipids and risk of atherosclerosis. We determined association of SREBF-1a -36del/G and SCAP 2386A/G genotypes with plasma levels of lipids, severity and progression/regression of coronary atherosclerosis, and response to treatment with fluvastatin in a well-characterized Lipoprotein Coronary Atherosclerosis Study population. Plasma lipids and quantitative indices of coronary atherosclerosis were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo in 372 subjects. Fluvastatin reduced plasma levels of total cholesterol by 16%, LDL-C by 25%, and ApoB by 16% and increased plasma levels of HDL-C by 9% and apoA-1 by 7%. Distributions of SREBF-1a SCAP genotypes were 60 GG, 172 del-G and 140 del-del and 88 GG, 188 GA and 96 AA, respectively. There were no significant differences in baseline plasma levels of lipids or indices of severity of atherosclerosis among the genotypes of each gene. There was a strong graded genotype-treatment interaction between SREBF-1a genotypes and change in apoA-I levels in response to fluvastatin (16.5% increase in GG, 10.5% in del/G, and 0.4% in del/del groups). Modest interactions between SREBF-1a genotypes and changes in HDL-C, and apoC-III levels in response to fluvastatin were also present. No genotype-treatment interaction for progression or regression of coronary atherosclerosis was detected. There were no significant interactions between SCAP genotypes and response to therapy. Thus we detected a strong graded interaction between SREBF-1a -36del/G genotypes and response of plasma apoA-I to treatment with fluvastatin.

The initial phenotype induced by cTnT-Q92 is enhanced myocardial systolic function followed by changes in signaling kinases and interstitial fibrosis. Established phenotypes in HCM reverse upon turning off expression of the mutant protein. These findings provoke pursuing specific therapies directed at correcting the underlying the genetic defect in HCM.