Ethics in pre-ART genetics: a missed X-linked Menkes disease case.

Assisted reproductive technology (ART) has experienced dramatic progress over the last 30 years, and gamete donation is routine in fertility clinics. Major advances in genetic diagnostics are part of this development due to the ability to analyze multiple genes or whole genomes fast and to an affordable prize. This requires knowledge and capability to evaluate genetic variants correctly in a clinical setting. Here we report a Menkes disease case, born after ART, where genetic screening and variant scoring failed to identify an egg donor as carrier of this fatal X-linked disorder. The gene variant is a deletion of a single base pair leading to a frameshift and premature termination of the protein, predicted to result in no or severely diminished function. The variant would be classified as likely pathogenic (class 4) and should be readily detectable by molecular genetic screening techniques. We wish to highlight this case to prevent future similar cases. IVI Igenomix has developed and embarked on an ambitious screening program to detect and prevent a large number of inherited severe childhood disorders in ART pregnancies. The company has recently achieved ISO 15189 certification with competence to evaluate and deliver timely, accurate, and reliable results. Failure to identify a pathogenic variant in the ATP7A gene leading to birth of two boys with Menkes disease invokes the required procedures to screen and detect disease-causing gene variants. This calls for ethical and legal considerations in ART diagnostics to prevent fatal errors like the present.

Evaluation of tumor-infiltrating lymphocytes and association with prognosis in BRCA-mutated breast cancer.

BACKGROUND: Patients with a BRCA1 or BRCA2 mutation (BRCA-mutated breast cancer) are frequently diagnosed with low differentiated and highly proliferating breast cancer characterized by high amounts of tumor-infiltrating lymphocytes (Tils). Stromal Tils (sTils) are highly prognostic in sporadic triple-negative and HER2 positive breast cancer however, their prognostic importance in BRCA-mutated breast cancers is unknown. MATERIAL AND METHODS: Formalin-fixed paraffin-embedded primary tumor tissue from 411 patients with a germline BRCA1 or BRCA2 mutation and diagnosed with early breast cancer was included. The percentage of sTils was quantified on full HE sections according to guidelines proposed by the Immuno-Oncology Biomarker in Breast Cancer Working Group. Distribution of sTils and associates with patient and tumor characteristics were assessed according to categorical sTils groups defined as low (<10%), intermediate (10-59%) and high (≥60%). Prognostic associations of sTils were evaluated as a continuous variable in univariate and multivariate models. Only follow-up time beyond date of BRCA mutation test was included. RESULTS: A large proportion had high sTils (27% in the full cohort, 36% in BRCA1-mutated, and 44% in ER negative breast cancers). Higher sTils were associated with BRCA1, ER negative breast cancer, high histological grade and medullary histology. In combined analysis for BRCA1 and BRCA2-mutated breast cancers, increasing sTils in 10% intervals were significantly associated with OS (HR 0.92, 95% CI 0.84-1.00, p = .05). For each 10% increment of sTils in BRCA1 breast cancers, a 10% reduction of mortality (adjusted HR 0.90 95% CI 0.81-0.99, p = .03) and a 13% reduction in risk of DFS-event (HR 0.87 95% CI 0.76-1.00, p = .05) was observed even after adjustment for ER status. No significant association with survival was of observed in the BRCA2 subgroup. Test for interaction of sTils and BRCA status was not statistically significant (p = .3). CONCLUSIONS: Breast cancer patients with a germline BRCA mutation had higher sTils than previously reported in sporadic breast cancers, and sTils were associated with favorable survival among BRCA carriers.

Clinical and molecular characterization of BRCA-associated breast cancer: results from the DBCG.

BACKGROUND: In breast cancer (BC) patients a cancer predisposing BRCA1/2 mutation is associated with adverse tumor characteristics, risk assessment and treatment allocation. We aimed to estimate overall- (OS) and disease-free survival (DFS) according to tumor characteristics and treatment among women who within two years of definitive surgery for primary BC were shown to carry a mutation in BRCA1/2 . MATERIAL AND METHODS: From the clinical database of the Danish Breast Cancer Group we included 141 BRCA1 and 96 BRCA2 BC patients. Estrogen receptor and HER2 status were centrally reviewed on paraffin-embedded tumor tissue. Information on risk reducing surgery was obtained from the Danish Pathology and Patient Registries and included as time-dependent variables in Cox proportional hazard models. RESULTS: Ten-year OS and DFS for BRCA1 BC patients were 78% (95% CI 69-85) and 74% (95% CI 64-81). Ten-year OS and DFS for BRCA2 BC were 88% (95% CI 78-94) and 84% (95% CI 74-91). BRCA1 BC patients as compared to BRCA2 BC patients had a higher risk of BC relapse or non-breast cancer within ten years of follow-up, independent of ER status (adjusted HR 2.78 95% CI 1.28-6.05, p = .01), but BRCA mutation was not associated with OS (adjusted HR 1.98, 95% CI 0.87-4.52, p = .10). In multivariate analysis, including both BRCA1 and BRCA2 carriers, no chemotherapy was associated with a higher risk of death (adjusted OS HR 3.58, 95% CI 1.29-9.97, p = .01) and risk reducing contralateral mastectomy (RRCM) was associated with a significantly reduced risk of death (adjusted OS HR 0.42, 95% CI =0.21-0.84, p = .01). CONCLUSION: Difference in OS between BRCA1 and BRCA2 BC patients could be ascribed to tumor-biology. BRCA1 BC patients may have a shorter ten-year DFS than BRCA2 BC patients. Chemotherapy and risk reducing contralateral mastectomy reduce mortality for both BRCA1 and BRCA2 BC patients.

JP-HHT phenotype in Danish patients with SMAD4 mutations.

Patients with germline mutations in SMAD4 can present symptoms of both juvenile polyposis syndrome (JPS) and hereditary hemorrhagic telangiectasia (HHT): the JP-HHT syndrome. The complete phenotypic picture of this syndrome is only just emerging. We describe the clinical characteristics of 14 patients with SMAD4-mutations. The study was a retrospective, register-based study. SMAD4 mutations carriers were identified through the Danish HHT-registry, the genetic laboratories - and the genetic departments in Denmark. The medical files from relevant departments were reviewed and symptoms of HHT, JPS, aortopathy and family history were noted. We detected 14 patients with SMAD4 mutations. All patients had polyps removed and 11 of 14 fulfilled the diagnostic criteria for JPS. Eight patients were screened for HHT-symptoms and seven of these fulfilled the Curaçao criteria. One patient had aortic root dilation. Our findings support that SMAD4 mutations carriers have symptoms of both HHT and JPS and that the frequency of PAVM and gastric involvement with polyps is higher than in patients with HHT or JPS not caused by a SMAD4 mutation. Out of eight patients screened for aortopathy, one had aortic root dilatation, highlighting the need for additional screening for aortopathy.

Disease pattern in Danish patients with Peutz-Jeghers syndrome.

PURPOSE: In this paper, we aimed to collect genetic and medical information on all Danish patients with Peutz-Jeghers syndrome (PJS), in order to contribute to the knowledge of phenotype and genotype. Peutz-Jeghers syndrome is a hereditary syndrome characterized by multiple hamartomatous polyps in the GI tract, mucocutaneous pigmentations, and an increased risk of cancer in the GI tract and at extraintestinal sites. Over 90 % of patients harbour a pathogenic mutation in STK11. METHODS: Based on the Danish Pathology Data Bank, the Danish National Patient Register, as well as information from relevant departments at Danish hospitals, we identified patients and collected clinical and genetic information. RESULTS: We identified 43 patients of which 14 were deceased. The prevalence was estimated to be ∼1 in 195,000 individuals. The median age at first symptom was 27.5 with invagination of the small bowel as the most frequent presenting symptom. We noted 18 occurrences of cancer at various anatomical sites, including a case of thyroid cancer and penile cancer. Eight of the deceased patients had died of cancer. Eighteen different mutations in STK11 had been detected in 28 patients. CONCLUSION: This is the first comprehensive study of patients with Peutz-Jeghers syndrome in the Danish population identified from nationwide registers and databases. We have demonstrated that the expressivity of Peutz-Jeghers syndrome varies greatly among the patients, even within the same families, underlining the great phenotypic spectrum. Patients with PJS should be offered surveillance from childhood in order to prevent morbidity and reduce mortality.

A recurrent germline BAP1 mutation and extension of the BAP1 tumor predisposition spectrum to include basal cell carcinoma.

We report four previously undescribed families with germline BRCA1-associated protein-1 gene (BAP1) mutations and expand the clinical phenotype of this tumor syndrome. The tumor spectrum in these families is predominantly uveal malignant melanoma (UMM), cutaneous malignant melanoma (CMM) and mesothelioma, as previously reported for germline BAP1 mutations. However, mutation carriers from three new families, and one previously reported family, developed basal cell carcinoma (BCC), thus suggesting inclusion of BCC in the phenotypic spectrum of the BAP1 tumor syndrome. This notion is supported by the finding of loss of BAP1 protein expression by immunochemistry in two BCCs from individuals with germline BAP1 mutations and no loss of BAP1 staining in 53 of sporadic BCCs consistent with somatic mutations and loss of heterozygosity of the gene in the BCCs occurring in mutation carriers. Lastly, we identify the first reported recurrent mutation in BAP1 (p.R60X), which occurred in three families from two different continents. In two of the families, the mutation was inherited from a common founder but it arose independently in the third family.

Breast cancer after bilateral risk-reducing mastectomy.

This study aims to evaluate the incidence of breast cancer after risk-reducing mastectomy (RRM) in healthy BRCA mutation carriers. This study is a long-term follow-up of 307 BRCA mutation carriers of whom 96 chose RRM. None of the study participants had a previous history of breast or ovarian cancer nor had they undergone RRM or risk-reducing bilateral salpingo-oophorectomy (BSO) prior to the time of BRCA testing. The annual incidence of post-mastectomy breast cancer was 0.8% compared with 1.7% in the non-operated group. Implications of these findings in relation to genetic counseling and future management are discussed.

Risk-reducing mastectomy and salpingo-oophorectomy in unaffected BRCA mutation carriers: uptake and timing.

Once female carriers of a BRCA mutation are identified they have to make decisions on risk management. The aim of this study is to outline the uptake of risk-reducing surgery in the Danish population of BRCA mutation positive women and to search for factors affecting this decision. We analysed data from 306 healthy BRCA carriers with no personal history of ovarian or breast cancer. We found a 10-year uptake of 75% for risk-reducing salpingo-oophorectomy and 50% for risk-reducing mastectomy by time to event analysis. Age and childbirth influenced this decision. The uptake rate has not changed significantly over the last decade. Risk-reducing surgeries are widely acceptable among Danish BRCA mutation positive women and the uptake of prophylactic mastectomy is higher than in most other countries.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA).

BACKGROUND: In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers. METHODS: We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach. RESULTS: We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93-1.04, P = 0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89-1.06, P = 0.5) mutation carriers. CONCLUSION: This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.

A healthy individual with a homozygous PTCH2 frameshift variant: Are variants of PTCH2 associated with nevoid basal cell carcinoma syndrome?

Variants in PTCH2 have been described to be associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS). We report a family with a healthy female who is homozygous for a frameshift variant, c.269delG, p.(Gly90Alafs*4), in PTCH2 and her heterozygous daughter. The variant predicts a frameshift and a premature stop codon. A summary of reported heterozygous individuals with germline PTCH2 variants along with the existence of a healthy homozygous individual question whether variants in PTCH2 are associated with NBCCS.

Nordic collaborative study of the BARD1 Cys557Ser allele in 3956 patients with cancer: enrichment in familial BRCA1/BRCA2 mutation-negative breast cancer but not in other malignancies.

BACKGROUND: BARD1 was originally identified as a BRCA1-interacting protein but has also been described in tumour-suppressive functions independent of BRCA1. Several studies have indicated that the BARD1 gene is a potential target for germline changes predisposing to breast and ovarian cancer. The C-terminal Cys557Ser change has previously been uncovered to associate with an increased risk of breast cancer and was recently shown to result in defective apoptotic activities. AIM AND METHODS: Conformation-sensitive gel electrophoresis, minisequencing, TaqMan assays, denaturing high-performance liquid chromatography analysis and DNA sequencing were used to investigate the prevalence of the Cys557Ser allele in a large Nordic case-control study cohort consisting of 2906 patients with breast or ovarian cancer, 734 with prostate cancer, 188 with colorectal cancer, 128 men with breast cancer, and 3591 controls from Finland, Iceland, Denmark, Sweden and Norway. RESULTS: The frequency of the BARD1 Cys557Ser variant seemed to increase among patients from families with breast or ovarian cancer lacking BRCA1 or BRCA2 mutations: a significant difference was obtained compared with controls (6.8% v 2.7%; p<0.001; odds ratio (OR) 2.6; 95% confidence interval (CI) 1.7 to 4.0) and with patients from BRCA1/BRCA2 mutation-positive families (6.8% v 2.2%; p = 0.01; OR 3.2; 95% CI 1.2 to 8.3). In contrast, no major association with male breast, ovarian, colorectal or prostate cancer was observed. Additionally, a novel BARD1 allele resulting in Ser558Pro was identified in familial breast cancer cases. CONCLUSION: These results provide further evidence that BARD1 Cys557Ser confers a slightly increased risk of breast cancer in women.

Expression of R120G-alphaB-crystallin causes aberrant desmin and alphaB-crystallin aggregation and cardiomyopathy in mice.

Upregulation of alphaB-crystallin (CryAB), a small heat shock protein, is associated with a variety of diseases, including the desmin-related myopathies. CryAB, which binds to both desmin and cytoplasmic actin, may participate as a chaperone in intermediate filament formation and maintenance, but the physiological consequences of CryAB upregulation are unknown. A mutation in CryAB, R120G, has been linked to a familial desminopathy. However, it is unclear whether the mutation is directly causative. We created multiple transgenic mouse lines that overexpressed either murine wild-type CryAB or the R120G mutation in cardiomyocytes. Overexpression of wild-type CryAB was relatively benign, with no increases in mortality and no induction of desmin-related cardiomyopathy even in a line in which CryAB mRNA expression was increased approximately 104-fold and the protein level increased by 11-fold. In contrast, lines expressing the R120G mutation were compromised, with a high-expressing line exhibiting 100% mortality by early adulthood. Modest expression levels resulted in a phenotype that was strikingly similar to that observed for the desmin-related cardiomyopathies. The desmin filaments in the cardiomyocytes were overtly affected, myofibril alignment was significantly impaired, and a hypertrophic response occurred at both the molecular and cellular levels. The data show that the R120G mutation causes a desminopathy, is dominant negative, and results in cardiac hypertrophy.

Effect of increased gene dosage expression on the alpha-interferon receptors in Down's syndrome.

The gene coding for the alpha, beta-interferon (alpha, beta-IFN) receptor is localized to chromosome 21. Cells from patients with Down's syndrome contain an extra chromosome 21, and thereby an expected 1.5-times increase in the number of genes located to this chromosome and in consequence a 1.5-times increase in cell surface alpha-IFN receptors. Actual measurements of these by competition binding experiments with human recombinant alpha-IFN on peripheral blood mononuclear cells (PBMC) from patients with Down's syndrome resulted in a mean of 1.69, which is in accordance to the theoretical 1.50, but slightly overestimated due to the calculation method. The increased gene dosage of the alpha-IFN receptor was quantitatively verified by Southern blot-hybridizations. Further characterization of alpha-IFN receptor binding showed insignificant differences in dissociation constants among patients and healthy individuals.

Reverse remodeling of cardiac myocyte hypertrophy in hypertension and failure by targeting of the renin-angiotensin system.

BACKGROUND: ACE inhibitors (ACEIs) and angiotensin II type 1 (AT(1)) receptor blockers are effective in reducing left ventricular mass in hypertension and heart failure. However, the ability of these drugs to reverse excessive myocyte lengthening and transverse growth in heart failure is unknown. METHODS AND RESULTS: L-158,809 (an AT(1) blocker; AT(1)), enalapril (an ACEI), and hydralazine (a vasodilator) were administered to spontaneously hypertensive heart failure rats between 6 and 10 months of age (early treatment) and between 18 and 22 months of age (late treatment). After 4 months of treatment, hemodynamics and chamber dimensions were collected before left ventricular myocyte isolation and subsequent analysis of myocyte shape. Each drug reduced systolic blood pressures to normal values. In the early and late studies, the ACEI reduced myocyte volume. Myocyte length was also reduced in the late study. However, the AT(1) was most effective in reversing myocyte dimensions to near-normal values in both studies. Hydralazine was ineffective in reducing cell size but arrested progression of myocyte lengthening in the late study. Changes in myocyte shape reflected alterations in chamber dimensions and wall thickness. CONCLUSIONS: Reversal of myocyte hypertrophy was produced in hypertensive/heart failure rats with an AT(1). The ACEI was effective but to a lesser extent. Results indicate that it is possible to significantly reverse myocyte remodeling pharmacologically even if therapy is initiated near the onset of failure. Further work is needed to determine whether similar results can be obtained in humans.

Mouse model of desmin-related cardiomyopathy.

BACKGROUND: The consequence of upregulation of desmin in the heart is unknown. Mutations in desmin have been linked to desmin-related myopathy (DRM), which is characterized by abnormal intrasarcoplasmic accumulation of desmin, but direct causative evidence that a desmin mutation leads to aberrant intrasarcoplasmic desmin accumulation, aggregation, and cardiomyopathy is lacking. METHODS AND RESULTS: Multiple transgenic mouse lines that expressed either murine wild-type desmin or a 7-amino acid deletion (R173 through E179) desmin (D7-des) mutation linked to DRM were made. The distribution of desmin protein was unchanged, and no overt phenotype was detected in the wild-type desmin transgenic mice. In contrast, the D7-des mouse heart showed aberrant intrasarcoplasmic and electron-dense granular filamentous aggregates that were desmin-positive and characteristic of human DRM. The desmin filament network was significantly disrupted, and myofibril alignment was visibly compromised. Although systolic function at the whole-organ level was substantially conserved in the young adult animals, the ability of the heart to respond to beta-agonist stimulation, as measured in the intact animal, was significantly blunted. CONCLUSIONS: Upregulation of desmin protein at moderate levels is not detrimental. However, the D7-des mutation is dominant negative, and expression of the mutant protein leads to the appearance of aggregates that are characteristic of and diagnostic for human desmin-related cardiomyopathy.

Aberrations of the p53 pathway components p53, MDM2 and CDKN2A appear independent in diffuse large B cell lymphoma.

The two gene products of the CDKN2A gene, p16 and p19ARF, have recently been linked to each of two major tumour suppressor pathways in human carcinogenesis, the RB1 pathway and the p53 pathway. p16 inhibits the phosphorylation of the retinoblastoma gene product by cyclin D-dependent kinases, whereas p19ARF targets MDM2, a p53 inhibitory protein, for degradation. A deletion of CDKN2A would therefore disturb both pathways. To explore the p53 pathway genes as a functional unit in diffuse large B cell non-Hodgkin's lymphomas (DLCL), we wanted to see whether there exists mutually exclusiveness of aberrations of CDKN2A, MDM2 and p53, since this has not been analysed previously. We investigated 37 DLCL for aberrations of p15, p16, p19ARF, MDM2, and p53 at the epigenetic, genetic and/or protein levels. Homozygous deletion of CDKN2A was detected in seven (19%) of 37 tumours, and another three cases were hypermethylated at the 5' CpG island of p16. No point mutations were found in CDKN2B or CDKN2A. Immunohistochemical staining of formalin-fixed, paraffin-embedded tissue for p16 confirmed these results, as all tumours with alterations of CDKN2A were p16 immunonegative. We found p53 mutations in eight (22%) cases and MDM2 overexpression in 16 (43%) tumours. Twenty-three (62%) tumours had alterations of one or more p53 pathway components (p53, p19ARF and MDM2). Furthermore, 7/9 (78%) p16-immunonegative tumours showed co-aberration of p53 and/or MDM2. The lack of correlation between these aberrations suggests that DLCL acquire additional growth advantage by inactivating both of these critical regulatory pathways.

Frequent disruption of the RB1 pathway in diffuse large B cell lymphoma: prognostic significance of E2F-1 and p16INK4A.

In the present study, we analysed 34 de novo diffuse large B cell lymphoma (DLCL) from a population-based lymphoma registry for alterations of the RB1 pathway at the genetic (RB1 and CDK4) and protein (pRb, cyclin D1, cyclin D3, CDK4, and E2F-1) level. The results were correlated with the data from our previous studies of CDKN2A deletion and hypermethylation, other p53 pathway components, p27Kip1 expression, and proliferation, as well as with clinical outcome, including prognosis. We found aberrant pRb expression in four (12%) of 34 DLCLs. One of these had a point mutation in intron 3 10 bp downstream of exon 3 generating a novel splice signal. Seven tumours (21%) showed cyclin D3 overexpression, including all three thyroid lymphomas (P = 0.006). Cyclin D3 overexpression and p16INK4A/pRb aberrations were mutually exclusive, supporting an oncogenic role for cyclin D3 in DLCL. p16INK4A inactivation, cyclin D3 overexpression, or aberrant pRb expression was identified in 18 of 34 DLCLs (53%). Combining these results with our previous p53 pathway studies showed that 82% of the de novo DLCLs had alterations of these pathways, and that both pathways were altered in 13 cases (38%). Low E2F-1 expression was associated with treatment failure (P = 0.020), and multivariate analysis of overall survival identified both low E2F-1 expression (relative risk = 6.9; P = 0.0037) and p16INK4A inactivation (relative risk = 3.3; P = 0.0247) as independent prognostic markers. These data support a role of E2F-1 as tumour suppressor gene in lymphoma and strongly suggest that the RB1 and p53 pathways are important in the development of de novo DLCL. Furthermore, low E2F-1 expression and p16INK4A inactivation may serve as prognostic markers for patients with this type of lymphoma.

Disrupted p53 function as predictor of treatment failure and poor prognosis in B- and T-cell non-Hodgkin's lymphoma.

Mutation of the p53 gene has been associated with treatment failure and poor outcome in various malignancies. It has been suggested that immunohistochemical analysis of p53 and p21Waf1, a downstream target, can be used to screen for p53 gene mutations. We determined the value of immunohistochemical screening for p53 gene mutations as a prognostic marker in a population-based group of B- and T-cell non-Hodgkin's lymphomas (NHLs). On the basis of p53 gene mutation status and immunohistochemically detected p53 and p21Waf1 expression in 34 lymphomas, we established an immunophenotype (delta p53) correlating with p53 gene mutation. The immunohistochemical analysis was extended to encompass 199 lymphomas from a population-based registry and was correlated with clinical parameters. Delta p53 showed 100% concordance with p53 gene mutation and was detected in 42 cases (21%). Multivariate analysis of advanced stage lymphomas showed that delta p53 was independently associated with treatment failure (relative risk, 3.8; P = 0.001). Delta p53 predicted poor survival when analyzing all patients (P = 0.0001), as well as B-cell (P = 0.04) and T-cell NHL (P = 0.000002). In multivariate analysis, delta p53 (relative risk, 2.2; P = 0.001) maintained prognostic significance. The impact on prognosis of delta p53 was highly significant in the low-intermediate-risk group (P = 0.00002). Comparing survival of the aggressive lymphoma patients in this group showed that the 8 delta p53 patients died within 1 year, whereas the median survival of the 28 non-delta p53 patients was 36 months. These results suggest that immunohistochemically assessed p53 status may predict treatment response and outcome in B- and T-cell NHL patients.

The use of isolated myocytes to evaluate myocardial remodeling.

It has been postulated that changes in the gross anatomic features of the heart due to various hemodynamic alterations (for example, pressure or volume overloading) are mirrored by specific changes in myocyte shape. The development of the isolated cardiac myocyte preparation has been instrumental in providing a more consistent and expeditious means for assessing changes in cellular dimensions. Data obtained from isolated myocytes collected from adult rats with various types of hemodynamic overloading confirm that cell shape changes in a consistent and predictable manner and that hypertrophy, rather than hyperplasia, is responsible for the increase in cardiac mass. The use of isolated myocytes should provide answers to many other questions regarding ventricular remodeling.

Gender-related differences in myocyte remodeling in progression to heart failure.

Gender-related differences responsible for the better prognosis of females with heart failure have not been clearly established. To address this issue, we investigated potential gender-related differences in myocyte remodeling in spontaneously hypertensive heart failure rats. Echocardiograms and myocyte growth were compared between males and females at compensated (2, 4, and 6 months) and decompensated (18 months in males and 24 months in females) stages of cardiac hypertrophy. Although left ventricular diastolic dimensions did not differ significantly between failing male and female rats, fractional shortening declined significantly only in failing males. Myocyte cross-sectional area did not change after 4 months of age in both genders, which is likely to be responsible for the absence of a change in left ventricular wall thickness during the progression to heart failure. Myocyte volume and cross-sectional area were significantly larger in males than females at 2, 4, and 6 months of age, although there were no significant differences at the failing stage. Reduced adaptive hypertrophic reserve was observed in males, which is likely to contribute to the higher morbidity and mortality of males with chronic heart failure.