P-558 Childhood exposure to high-fat diets changes sperm small RNA content up to two unexposed generations of mice

Study question

Is the adoption of high-fat diet from childhood associated with sperm small RNA content in mice? Are those changes inherited by the offspring and grand-offspring?

Summary answer

The adoption of high-fat diet during childhood changes sperm small RNA content up to the grand-offspring even after dietary correction.

What is known already

The prevalence of childhood obesity is increasing worldwide. The adoption of high-fat diet (HFD) from early age is a major factor for this trend. However, the long-lasting health effects of childhood obesity associated to HFD is unknown, particularly after dietary reversion. Multiple studies demonstrated that sperm small non-coding RNA (sncRNA) content changes in response to acute and chronic dietary factors. Also, sperm sncRNAs can transmit acquired traits such as metabolic syndrome. However, it is not known how the HFD-related sperm sncRNA fingerprints varies across generations, and how it relates with the phenotypes of the progeny.

Study design, size, duration

At weaning, 36 C57BL/6 mice were randomly divided into three groups (n = 12) feeding on 1) standard chow (CTRL) for 200 days, 2) HFD for 200 days, or 3) HFD for 60 days reverted to chow for 140 days (childhood HFD, CHFD). Subsequent generations (36 mice/generation, all fed on chow) were obtained by mating F0 and F1 males with same-age normoponderal females 120 days post-weaning and were assigned to the same experimental group as the progenitor.

Participants/materials, setting, methods

Mice were euthanized 200 days after weaning and tissues collected. Epidydimal sperm was collected, and concentration, viability, motility, and morphology were evaluated. Sperm RNA were extracted using the tri-reagent protocol, and sncRNAs sequenced by NGS RNA-seq. Sequences were annotated using SPORTS 1.1 and differential expression analysis performed using DESeq2. Targets of differently expressed sequences were estimated and Gene Ontology (GO) analysis of biological function performed using topGO.

Main results and the role of chance

HFD consumption during childhood is associated with poorer sperm parameters, even after dietary correction. No changes in sperm parameters were found between the offspring of HFD, CHFD and CTRL but, the grand-offspring of HFD and HFDt mice had lower sperm counts than the grand-offspring of CTRL. Regarding sperm sncRNA content, no changes were found between HFD and CTRL, but several mitochondrial transcription initiation RNAs (tiRNA) and repeat-derived RNAs (repRNAs) were differently expressed comparing to CTRL. Sperm sncRNA content of the offspring of HFD (piwi-interacting RNAs and repRNA) and CHFD (tRNA-derived fragments and repRNAs) displayed several differently expressed sequences comparing to CTRL. Only microRNAs (miRNAs) were differently expressed in the grandoffspring (CTRL vs. CHFD). GO analysis of biological function based on the targets of differently expressed sncRNAs showed a potential impact of childhood obesity in pathways related to sperm motility, chemotaxis and membrane integrity. These results suggest that sperm sncRNA content is altered due to childhood obesity even after two generations. This signature is not preserved across the male germline, but may influence the sperm sncRNA content of the progeny. This long-lasting, transgenerational signature of childhood obesity may explain the inheritance of the poor sperm quality phenotype from grand-sire to grand-offspring.

Limitations, reasons for caution

This model does not evaluate the impact of earlier dietary intervention, before sexual maturation. Also, it is not clear if the reported effects are exclusively due to childhood obesity or to excessive caloric intake. The estimates of biological impact using GO analysis of sperm sncRNA targets require further experimental evidence.

Wider implications of the findings

Our findings evidence the long-lasting effects of childhood obesity to sperm parameters, even after dietary reversion, and the potential transgenerational effects to the health of the progeny. Our results raise awareness about the impact of childhood obesity to reproductive health of future fathers and their progeny.

Trial registration number

0421/000/000/2016

New potential antiproliferative monophosphoester 2-aminoethyl dihydrogen phosphate in K-562 and K-562 MDR+ leukemia cells

The main obstacle in the treatment of cancer patients has been resistance to multiple drugs, leading to the need to develop molecules with a higher specificity target. The liposomal formulation DODAC/2-AEH₂P has antitumor potential, inducing apoptosis in several tumor types. Human chronic myeloid leukemia K-562 and K-562 Lucena (MDR⁺) cells were treated with the DODAC carrier and the liposomal formulation 2-AEH₂P. Viability, cell cycle phases, apoptosis, marker expression and mitochondrial potential were analyzed. Significant reduction in viability was observed for all treatments. Changes in the distribution of the cell cycle phases and expression of markers involved in the apoptosis pathways were observed. Reduction of the mitochondrial electrical potential mediated by Bcl-2, being regulated by the reduction of the MTCH2 protein linked to the progression of myeloid leukemia and an increase in the pro-apoptotic proteins Bad and Bax, dependent on p53. This study demonstrated a significant therapeutic potential through apoptotic effects in leukemic cells, regardless of the molecular resistance profile (MDR⁺).

Expanded equine cumulus-oocyte complexes exhibit higher meiotic competence and lower glucose consumption than compact cumulus-oocyte complexes

Equine cumulus-oocyte complexes (COCs) are classified as compact (cCOC) or expanded (eCOC) and vary in their meiotic competence. This difference could be related to divergent glucose metabolism. To test this hypothesis in the present study, eCOCs, cCOCs and expanded or compact mural granulosa cells (EC and CC respectively) were matured in vitro for 30h, at which time maturation rate, glucose metabolism and the expression of genes involved in glucose transport, glycolysis, apoptosis and meiotic competence were determined. There were significant differences between eCOCs and cCOCs in maturation rate (50% vs 21.7% (n=192 and 46) respectively; P<0.001), as well as mean (±s.e.m.) glucose consumption (1.8±0.5 vs 27.9±5.9 nmol per COC respectively) and pyruvate (0.09±0.01 vs 2.4±0.8 nmol per COC respectively) and lactate (4.7±1.3 vs 64.1±20.6 nmol per COC respectively; P<0.05 for all) production. Glucose consumption in EC and CC did not differ significantly. Expression of hyaluronan-binding protein (tumour necrosis factor alpha induced protein 6; TNFAIP6) was increased in eCOCs and EC, and solute carrier family 2 member 1 (SLC2A1) expression was increased in eCOCs, but there were no differences in the expression of glycolysis-related enzymes and solute carrier family 2 member 3 (SLC2A3) between the COC or mural granulosa cell types. The findings of the present study demonstrate that metabolic and genomic differences exist between eCOCs and cCOCs and mural granulosa cells in the horse.

Obesogens and male fertility

In the last decades, several studies evidenced a decrease in male fertility in developed countries. Although the aetiology of this trend in male reproductive health remains a matter of debate, environmental compounds that predispose to weight gain, namely obesogens, are appointed as contributors because of their action as endocrine disruptors. Obesogens favour adipogenesis by an imbalance of metabolic processes and can be found virtually everywhere. These compounds easily accumulate in tissues with high lipid content. Obesogens change the functioning of male reproductive axis, and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. Notably, adverse effects of obesogens may also promote disturbances in the metabolic performance of the following generations, through epigenetic modifications passed by male gametes. Thus, unveiling the molecular pathways by which obesogens induce toxicity that may end up in epigenetic modifications is imperative. Otherwise, a transgenerational susceptibility to metabolic diseases may be favoured. We present an up-to-date overview of the impact of obesogens on testicular physiology, with a particular focus on testicular metabolism. We also address the effects of obesogens on male reproductive parameters and the subsequent consequences for male fertility.

Ghrelin acts as energy status sensor of male reproduction by modulating Sertoli cells glycolytic metabolism and mitochondrial bioenergetics

Ghrelin is a growth hormone-releasing peptide that has been suggested to interfere with spermatogenesis, though the underling mechanisms remain unknown. We studied the effect of ghrelin in human Sertoli cells (hSCs) metabolic phenotype. For that, hSCs were exposed to increasing concentrations of ghrelin (20, 100 and 500 pM) mimicking the levels reported in obese, normal weight, and severely undernourished individuals. The metabolite production/consumption was determined. The protein levels of key glycolysis-related transporters and enzymes were assessed. The lactate dehydrogenase (LDH) activity was measured. Mitochondrial complexes protein levels and mitochondria membrane potential were also measured. We showed that hSCs express the growth hormone secretagogue receptor. At the concentration present in the plasma of normal weight men, ghrelin caused a decrease of glucose consumption and mitochondrial membrane potential in hSCs, though LDH activity and lactate production remained unchanged, illustrating an alteration of glycolytic flux efficiency. Exposure of hSCs to levels of ghrelin found in the plasma of severely undernourished individuals decreased pyruvate consumption and mitochondrial complex III protein expression. All concentrations of ghrelin decreased alanine and acetate production by hSCs. Notably, the effects of ghrelin levels found in severely undernourished individuals were more pronounced in hSCs metabolic phenotype highlighting the importance of a proper eating behavior to maintain male reproductive potential. In conclusion, ghrelin acts as an energy status sensor for hSCs in a dose-dependent manner, showing an inverse association with the production of lactate, thus controlling the nutritional support of spermatogenesis.

Expression of Estrogen Receptors Alpha (ER-α), Beta (ER-β), and G Protein-Coupled Receptor 30 (GPR30) in Testicular Tissue of Men with Klinefelter Syndrome

Men with Klinefelter syndrome (KS) present severe hormonal dysregulation, particularly elevated serum estradiol concentration. Estrogens act through specific receptors and regulate testes development and spermatogenesis. Herein, we evaluated GPR30, ERα, and ERβ mRNA expression in testis of KS men and men with 46XY karyotype by reverse transcriptase and quantitative PCR. ERβ transcripts are the most abundant in testicular tissue of 46XY men. Notably, testicular GPR30 transcription in KS men was approximately 12 times higher. Since GPR30 is essential to mediate estrogen effects over steroidogenesis, our data illustrate that GPR30 may underpin the testicular alterations observed in KS men.

Novel Drug Therapies for Fertility Preservation in Men Undergoing Chemotherapy: Clinical Relevance of Protector Agents

Cancer has been affecting a growing number of children, adolescents and adult males in reproductive age. Male reproductive potential is adversely affected by chemotherapeutic drugs and patients are at risk for prolonged infertility. Fertility recovery is related to the chemotherapeutic agent and dosage used, being thus difficult to predict. As a result, there is a strong need to identify a natural or synthetic compound that is able to preserve male fertility without interfering with the efficacy of the chemotherapeutic regimen. New procedures, as well as several drugs, are being investigated to assess their efficiency in protecting male reproductive functions from the chemotherapy side-effects. This review provides an overview of the wide range of chemotherapeutic drugs regularly used in cancer treatment and their detrimental effects on male fertility. In addition, it also assesses the existing protector agents for male fertility and their usefulness in preserving and protecting male reproductive functions exposed to chemotherapeutics. Several protector agents for male fertility are being studied, and results are promising. Nonetheless, further research must be implemented to identify a supplemental therapy that addresses the multiple side effects of chemotherapy on male reproductive function. Until such therapy is discovered, it is fundamental that all fertility preservation options are discussed with patients, before treatment is initiated, to assure parenthood.

Testicular Metabolic Reprogramming in Neonatal Streptozotocin-Induced Type 2 Diabetic Rats Impairs Glycolytic Flux and Promotes Glycogen Synthesis

Defects in testicular metabolism are directly implicated with male infertility, but most of the mechanisms associated with type 2 diabetes- (T2DM) induced male infertility remain unknown. We aimed to evaluate the effects of T2DM on testicular glucose metabolism by using a neonatal-streptozotocin- (n-STZ) T2DM animal model. Plasma and testicular hormonal levels were evaluated using specific kits. mRNA and protein expression levels were assessed by real-time PCR and Western Blot, respectively. Testicular metabolic profile was assessed by (1)H-NMR spectroscopy. T2DM rats showed increased glycemic levels, impaired glucose tolerance and hyperinsulinemia. Both testicular and serum testosterone levels were decreased, whereas those of 17β-estradiol were not altered. Testicular glycolytic flux was not favored in testicles of T2DM rats, since, despite the increased expression of both glucose transporters 1 and 3 and the enzyme phosphofructokinase 1, lactate dehydrogenase activity was severely decreased contributing to lower testicular lactate content. However, T2DM enhanced testicular glycogen accumulation, by modulating the availability of the precursors for its synthesis. T2DM also affected the reproductive sperm parameters. Taken together these results indicate that T2DM is able to reprogram testicular metabolism by enhancing alternative metabolic pathways, particularly glycogen synthesis, and such alterations are associated with impaired sperm parameters.

High-energy diets: a threat for male fertility?

Male fertility is declining in developed countries, as well as in developing countries. External factors linked to lifestyle, such as eating disorders, negatively affect spermatogenesis, both at central and gonadal levels. The overconsumption of high-energy diets (HED) alters the functioning of the male reproductive axis and consequently affects the testicular physiology, disrupting its metabolism and bioenergetic capacity. Testicular metabolism presents unique characteristics, partly because of its cellular heterogeneity and to the specific functions that each cell type plays within the testicular environment. Disruption of the tightly regulated metabolic pathways leads to adverse reproductive outcomes, such as inefficient energy supply to germ cells, sperm defects or spermatogenesis arrest. Testicular metabolic alterations induced by HED intake may also lead to mitochondrial dysfunction, which is closely associated to reactive oxygen species (ROS) overproduction and oxidative stress. ROS easily target spermatozoa DNA and lipids, contributing to decreased sperm quality. Thus, understanding the detrimental effects of HED overconsumption on the pathways underlying testicular metabolism and sperm production is imperative; otherwise, one may favour a transgenerational amplification of subfertility. Herein, we present an up-to-date overview of the effects of HED on testicular metabolism, sperm parameters and the subsequent consequences for male fertility.

Metformin and male reproduction: effects on Sertoli cell metabolism

BACKGROUND AND PURPOSE

Metformin is commonly used to treat type 2 diabetes (T2D). While new clinical applications have been ascribed to metformin, including treatment of anovulatory infertility, its effects on male reproduction have not been investigated. The Sertoli cell (SC) is crucial for germ cell development, exerting metabolic control of spermatogenesis, therefore, we investigated the effects of metformin on SC metabolism.

EXPERIMENTAL APPROACH

Rat SCs were cultured in the absence and presence of metformin (5, 50 and 500 μM). mRNA and protein levels of glucose transporters (GLUT1 and GLUT3), phosphofructokinase 1 (PFK 1), lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by quantitative PCR and Western blot respectively. LDH activity was assessed and metabolite production/consumption determined by (1) H-NMR.

KEY RESULTS

Metformin (50 μM) decreased mRNA and protein levels of GLUT1, GLUT3, MCT4 and PFK 1 but did not affect LDH mRNA or protein levels. However, although glucose consumption was maintained in metformin-treated cells, LDH activity, lactate and alanine production were increased, indicating an enhanced glycolytic flux. No metabolic cytotoxicity was detected in SCs exposed to supra-pharmacological concentration of metformin.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that metformin: (i) decreases mRNA and protein levels of glycolysis-related transporters in SCs but increases their activity; and (ii) stimulates alanine production, which induces antioxidant activity and maintains the NADH/NAD(+) equilibrium. The increased lactate in metformin-treated SCs provides nutritional support and has an anti-apoptotic effect in developing germ cells. Thus, metformin can be considered as a suitable antidiabetic drug for male patients of reproductive age with T2D.

Molecular basis of bicarbonate membrane transport in the male reproductive tract

Bicarbonate (HCO₃⁻) membrane transport systems are crucial players in the physiology of several tissues. The molecular basis of HCO₃⁻ membrane transport is of major physiological relevance since this ion is involved in the establishment of intracellular and extracellular ionic composition, osmolariy and pH. The membrane HCO₃⁻ transporters are divided in two main families: solute carrier 4 (SLC4) and solute carrier 26 (SLC26), although HCO₃⁻ concentration can also be regulated by the cystic fibrosis transmembrane regulator (CFTR). In most tissues the SLC4 family represents the majority of HCO₃⁻ transporters members, which can be divided in two subgroups: the Na⁺-dependent and the Na⁺-independent transporters. The SLC26 family consists of ten members that can transport diverse ions besides HCO₃⁻. In the male reproductive tract, HCO₃⁻ transport occurs in several processes in order to assure a correct pursuance of the spermatogenetic event and spermatozoa capacitation, being also necessary for egg fertilization. Indeed, the formation of competent spermatozoa, the maintenance of an adequate ductal luminal milieu and spermatozoa capacitation are highly dependent of ionic balance and pH. Perturbations in these processes result in reduced male reproductive health and consequently male subfertility and/or infertility. Thus, it is imperative to understand HCO₃⁻ transport dynamics in order to identify and counteract possible alterations related with reduced male fertility caused by pathological conditions. Herein, we will review the major families and subfamilies of HCO₃⁻ membrane transport, discussing the molecular basis of HCO₃⁻ transport in the male reproductive tract and its role in male-associated subfertility and/or infertility.

Regulation of apoptotic signaling pathways by 5α-dihydrotestosterone and 17β-estradiol in immature rat Sertoli cells

Apoptosis is an important regulatory event in testicular homeostasis and optimization of sperm production. Sertoli cells (SCs) form the blood-testis barrier creating a special microenvironment where germ cells develop and are under strict hormonal control. Estrogens and androgens are known to play critical roles in SCs functioning, improving their in vitro survival by preventing apoptotic progression. Herein, we studied the influence of 17β-estradiol (E2) and 5α-dihydrotestosterone (DHT) on the apoptotic signaling pathways of immature rat cultured SCs. For that we chose key points of the apoptotic pathway that interact with the mitochondria and evaluated the mRNA expression and/or protein levels of several apoptotic markers such as p53, the anti-apoptotic protein Bcl2, the pro-apoptotic Bcl2 family member Bax, the apoptosis-inducing factor (AIF) and caspase-3 and 9. Caspase-3 activity and DNA fragmentation were also evaluated as endpoint markers of apoptosis. E2 and DHT down-regulated the mRNA transcript levels of p53, Bax, caspase-9 and caspase-3. The protein levels of AIF were reduced after DHT treatment while E2-treated cells presented decreased levels of cleaved caspase-9 protein. Moreover, Bax/Bcl2 ratio was significantly decreased in E2-treated cells. The apoptotic endpoints caspase-3 activity and DNA fragmentation presented significant decreased levels after hormonal treatment. Taken together, these results show that E2 and DHT act as apoptotic signaling modulators in in vitro immature rat SCs suggesting that androgens and estrogens may be capable of modulating independent pathways of the apoptotic event by regulating different pro-apoptotic factors.

Biochemical and metabolic effects of a short-term exposure to nanoparticles of titanium silicate in tadpoles of Pelophylax perezi (Seoane)

This study aimed to evaluate sublethal effects of a short-term exposure (96 h) to titanium silicate nanoparticles (TiSiO(4)-NP) on Pelophylax perezi tadpoles. Tadpoles were exposed to five concentrations of TiSiO(4)-NP (8.2, 10.2, 12.8, 16 and 20 mg/L) plus a control. Effect criteria were: mortality, cholinesterases, glutathione S-transferases, lactate dehydrogenase, and catalase activities, and alanine and lactate contents. Light scattering was used for physical characterization of TiSiO(4)-NP suspensions, revealing a high aggregation state of the NP, consistent with low z-potential values (<30 mV). Mortality among TiSiO(4)-NP treatments was <11%. Significant differences relatively to the control were observed at the biochemical level (for CAT and LDH) and in lactate and alanine contents, which may end-up in increased oxidative stress. Overall, some of the monitored endpoints suggest metabolic alterations in TiSiO(4)-NP exposed tadpoles, highlighting the potential of TiSiO(4)-NP long-term effects on these organisms.

High-energy diets may induce a pre-diabetic state altering testicular glycolytic metabolic profile and male reproductive parameters

Diabetes mellitus is a metabolic disorder that may arise from diet habits and is growing to epidemic proportions. Young male diabetic patients present high infertility/subfertility prevalence resulting from impaired reproductive function and poor semen quality. We aimed to evaluate the effects of a high-energy diet (HED) on glucose tolerance/insulin levels and correlate the observed effects on male reproductive function with overall testicular metabolism. After 1 month, HED fed rats showed increased glycaemic levels, impaired glucose tolerance and hypoinsulinaemia. Moreover, an imbalance of intratesticular and serum testosterone levels was observed, whereas those of 17β-estradiol were not altered. High-energy diet also affected the reproductive parameters, with HED rats exhibiting a significant increase in abnormal sperm morphology. Glycolytic metabolism was favoured in testicles of HED rats with an increased expression of both glucose transporters 1 (GLUT1) and 3 (GLUT3) and the enzyme phosphofrutokinase 1. Moreover, lactate production and the expression of metabolism-associated genes and proteins involved in lactate production and transport were also enhanced by HED. Alanine testicular content was decreased and thus intratesticular lactate/alanine ratio in HED rats was increased, suggesting increased oxidative stress. Other energetic substrates such as acetate and creatine were not altered in testis from HED rats, but intratesticular glycine content was increased in those animals. Taken together, these results suggest that HED induces a pre-diabetic state that may impair reproductive function by modulating overall testicular metabolism. This is the first report on testicular metabolic features and mechanisms related with the onset of a pre-diabetic state.

Molecular mechanisms beyond glucose transport in diabetes-related male infertility

Diabetes mellitus (DM) is one of the greatest public health threats in modern societies. Although during a few years it was suggested that DM had no significant effect in male reproductive function, this view has been challenged in recent years. The increasing incidence of DM worldwide will inevitably result in a higher prevalence of this pathology in men of reproductive age and subfertility or infertility associated with DM is expected to dramatically rise in upcoming years. From a clinical perspective, the evaluation of semen parameters, as well as spermatozoa deoxyribonucleic acid (DNA) integrity, are often studied due to their direct implications in natural and assisted conception. Nevertheless, recent studies based on the molecular mechanisms beyond glucose transport in testicular cells provide new insights in DM-induced alterations in male reproductive health. Testicular cells have their own glucose sensing machinery that react to hormonal fluctuations and have several mechanisms to counteract hyper- and hypoglycemic events. Moreover, the metabolic cooperation between testicular cells is crucial for normal spermatogenesis. Sertoli cells (SCs), which are the main components of blood-testis barrier, are not only responsible for the physical support of germ cells but also for lactate production that is then metabolized by the developing germ cells. Any alteration in this tied metabolic cooperation may have a dramatic consequence in male fertility potential. Therefore, we present an overview of the clinical significance of DM in the male reproductive health with emphasis on the molecular mechanisms beyond glucose fluctuation and transport in testicular cells.

Influence of 5α-dihydrotestosterone and 17β-estradiol on human Sertoli cells metabolism

Sertoli cells metabolize glucose, converting it to lactate that is used by developing germ cells for their energy metabolism. Androgens and oestrogens have metabolic roles that reach far beyond reproductive processes. So, the main purpose of this study was to examine the effect of sex steroid hormones on metabolite secretion/consumption in human Sertoli cells. Human Sertoli cell-enriched primary cultures were maintained in a defined medium for 50 h and glucose, pyruvate, lactate and alanine variations were determined using (1) H-NMR spectra analysis, in the absence or presence of 100 nm 17β-estradiol (E(2) ) or 100 nm 5α-dihydrotestosterone (DHT). The mRNA expression levels of glucose transporters, lactate dehydrogenase and monocarboxylate transporters were also determined using semi-quantitative RT-PCR. Cells cultured in the absence (control) or presence of E(2) consumed the same amounts of glucose at similar rates during the 50 h. During the first 15 h of treatment with DHT, glucose consumption and glucose consumption rate were significantly higher. Nevertheless, DHT-treated cells secreted a significantly lower amount of lactate than control and E(2) -treated cells. Such a decrease was concomitant with a significant decrease in lactate dehydrogenase A mRNA levels after 50 h treatment in DHT-treated groups. Finally, alanine production was significantly increased in E(2) -treated cells after 25 h treatment, which indicated a lower redox/higher oxidative state for the cells on those conditions. These results support the existence of a relationship between sex steroid hormones action and energy metabolism, providing the first assessment of androgens and oestrogens as metabolic modulators of human Sertoli cells.

[Significance exercise-induced ST elevation in patients with myocardial infarction]

In 52 patients with previous myocardial infraction, 49 men and 3 women (mean age 56 +/- 7.1 years) the significance of ST-segment elevation during the stress-test, was evaluated. Of the 52 patients 15 (29%) showed St-segment elevation and 37(71%), showed no alteration of the ST-segment. Extension of coronary disease, degree of obstruction, wall motion abnormalities and the presence of residual ischemia were evaluated by coronary angiography, technetium-99M pyrophosphate imaging and exercise TL-201 scintigraphy. From the results of the study one may conclude that, in patients with previous myocardial infraction exercise, ST-segment elevation is a consequence of sub-occlusion of the left anterior descending coronary artery with severe ventricular dysfunction either in patients with one or multiple vessel disease.

Postexercise electrocardiographic and clinical changes in patients with sick sinus syndrome

Forty patients with sick sinus syndrome, 15 women and 25 men with a mean age of 53.83 +/- 13.34 years, were studied using a maximal graded bicycle stress test. None of the patients were using a pacemaker or being treated with drugs that would interfere with the sinus node function; one patient had family myocardiopathy and eight suffered from essential hypertension. All patients, including those suffering from very marked bradycardia (less than 40 beats/min) responded to the increased effort with increased heart rate. The exercise test was stopped in 22 patients (55%) after the appearance of clinical signs and in 4 (10%) after ST-segment depression greater than 1 mm. Eight (20%) finished the stress test after reaching the maximal heart rate according to age, due to an increase in sinus rate. The exercise produced or increased extrasystoles in five patients (12.5%), but only one was forced to suspend the test. The Q-T interval, corrected for heart rate according to Bazett's formula (QTc), was measured on the resting ECG before the start of the test and on the ECG recorded immediately following the end of the exercise in all patients, except one with atrial fibrillation. In 24 patients (60%), a QTc mean increase of 0.040 +/- 0.022 sec was observed at the end of the stress test. Fourteen (35%) had the usual shortening due to the increase in heart rate. One patient showed no variation of the QTc. A lengthening of the QTc at the end of the exercise in more than half of the patients was the most intriguing electrocardiographic change.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac alterations in ankylosing spondylitis

Forty patients, 30 men and 10 women with an average age of 38.47 +/- 11.07 years, suffering from ankylosing spondylitis and attending a Rheumatology Outpatient Clinic, were evaluated for cardiovascular involvement. The evaluation was based on patients' clinical observation, electrocardiography, echocardiography, and chest x-ray. More than a simple review, this study was undertaken with the aim of arriving at a better clinical definition of the cardiovascular manifestations found in ankylosing spondylitis. In fact, of the 40 patients, 8 (20%) had systemic hypertension for which an explanation could not be found, 4 of whom were less than forty-five years old; the echocardiogram showed mitral valve prolapse in 4 patients (10%), 2 of them with a systolic murmur and other 2 with a protosystolic click on auscultation. More significant than the changes in conduction was the finding of a sinus bradycardia in 9 patients (22.5%), and a PR interval below 120 msec in 3 patients (7.5%). The authors conclude that the extension of cardiovascular changes in ankylosing spondylitis is more vast than usually acknowledged.

Barlow's syndrome associated with coronary fistula

In an asymptomatic patient, the first reference to the association of mitral valve prolapse and coronary fistula is described and a pathogenic connection discussed.