Paternal microbiome perturbations impact offspring fitness

The gut microbiota operates at the interface of host-environment interactions to influence human homoeostasis and metabolic networks1-4. Environmental factors that unbalance gut microbial ecosystems can therefore shape physiological and disease-associated responses across somatic tissues5-9. However, the systemic impact of the gut microbiome on the germline-and consequently on the F1 offspring it gives rise to-is unexplored10. Here we show that the gut microbiota act as a key interface between paternal preconception environment and intergenerational health in mice. Perturbations to the gut microbiota of prospective fathers increase the probability of their offspring presenting with low birth weight, severe growth restriction and premature mortality. Transmission of disease risk occurs via the germline and is provoked by pervasive gut microbiome perturbations, including non-absorbable antibiotics or osmotic laxatives, but is rescued by restoring the paternal microbiota before conception. This effect is linked with a dynamic response to induced dysbiosis in the male reproductive system, including impaired leptin signalling, altered testicular metabolite profiles and remapped small RNA payloads in sperm. As a result, dysbiotic fathers trigger an elevated risk of in utero placental insufficiency, revealing a placental origin of mammalian intergenerational effects. Our study defines a regulatory 'gut-germline axis' in males, which is sensitive to environmental exposures and programmes offspring fitness through impacting placenta function.

Genome Reduction Is Associated with Bacterial Pathogenicity across Different Scales of Temporal and Ecological Divergence

Emerging bacterial pathogens threaten global health and food security, and so it is important to ask whether these transitions to pathogenicity have any common features. We present a systematic study of the claim that pathogenicity is associated with genome reduction and gene loss. We compare broad-scale patterns across all bacteria, with detailed analyses of Streptococcus suis, an emerging zoonotic pathogen of pigs, which has undergone multiple transitions between disease and carriage forms. We find that pathogenicity is consistently associated with reduced genome size across three scales of divergence (between species within genera, and between and within genetic clusters of S. suis). Although genome reduction is also found in mutualist and commensal bacterial endosymbionts, genome reduction in pathogens cannot be solely attributed to the features of their ecology that they share with these species, that is, host restriction or intracellularity. Moreover, other typical correlates of genome reduction in endosymbionts (reduced metabolic capacity, reduced GC content, and the transient expansion of nonfunctional elements) are not consistently observed in pathogens. Together, our results indicate that genome reduction is a consistent correlate of pathogenicity in bacteria.

The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass--A comparison of two systems of cardiopulmonary bypass

OBJECTIVE

To determine the influence of haemodilution, bypass flow rates and calculated oxygen delivery during cardiopulmonary bypass (CPB) with either a conventional CPB (C-CPB) circuit or a miniaturised (Mini-CPB) circuit on cerebral oxygen desaturation. The effect of minimal haemodilution with a Mini-CPB was investigated.

PARTICIPANTS

Eighty patients scheduled for elective cardiac surgery.

INTERVENTION

Oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI) were measured with near-infrared spectroscopy (NIRS).

RESULTS

The average indexed bypass pump flow was significantly lower with Mini-CPB. When combined with haemoglobin concentration, the average oxygen delivery was the same between groups. Patients in the C-CPB group had a greater duration and severity of cerebral desaturation to a level <20% below baseline values, but none reached the depth and duration of the cerebral desaturation associated with poor outcome. Cerebral oxygen desaturation with C-CPB was significantly associated with low flows during bypass, whereas desaturation with Mini-CPB was associated with low perioperative haemoglobin concentration.

Clinical and angiographic outcome of different surgical strategies of bilateral internal mammary artery grafting

Long-term survival, relief of angina, and prevention of myocardial infarction after coronary revascularization are related to the preoperative status of the patient, progression of coronary artery atherosclerosis, and the patency of the conduits used. The increased use of the internal mammary artery for coronary grafting depends upon the accumulation of data on superior late patency compared with venous conduits. These data have supported the simultaneous use of both left and right internal mammary arteries with reported improved late survival. However, controversy still surrounds the clinical and angiographic outcomes of some of the surgical strategies of bilateral internal mammary artery grafting. This review examines a range of surgical strategies of bilateral internal mammary artery grafting and their mid- and long-term clinical and angiographic outcomes. From the available data, careful preoperative selection of patients is paramount. Clinical and angiographic outcome of bilateral internal mammary grafting is superior to single internal mammary grafting with supplemental vein grafts when pedicled, sequential, or free aorto-coronary internal mammary artery is used. Further studies are needed to evaluate the midterm and long-term clinical and angiographic outcomes of complex strategies such as Y or T procedures.

Reduced postoperative blood loss and transfusion requirement after beating-heart coronary operations: a prospective randomized study

OBJECTIVE

Coronary artery bypass grafting on the beating heart through median sternotomy is a relatively new treatment, which allows multiple revascularization without the use of cardiopulmonary bypass. A prospective randomized study was designed to investigate the effect of coronary bypass with or without cardiopulmonary bypass on postoperative blood loss and transfusion requirement.

METHODS

Two hundred patients with coronary artery disease were prospectively randomized to (1) on-pump treatment with conventional cardiopulmonary bypass and cardioplegic arrest and (2) off-pump treatment on the beating heart. Postoperative blood loss identified as total chest tube drainage, transfusion requirement, and related costs together with hematologic indices and clotting profiles were analyzed.

RESULTS

There was no difference between the groups with respect to preoperative and intraoperative patient variables. The mean ratio of postoperative blood loss and 95% confidence interval between groups was 1.64 and 1.39 to 1.94, respectively, suggesting on average a postoperative blood loss 1.6 times higher in the on-pump group compared with the off-pump group. Seventy-seven patients in the off-pump group required no blood transfusion compared with only 48 in the on-pump group (P <.01). Furthermore, less than 5% of patients in the on-pump group required fresh frozen plasma and platelet transfusion compared with 30% and 25%, respectively, in the on-pump group (both P <.05). Mean transfusion cost per patient was higher in the on-pump compared with that in the off-pump group ($184.8 +/- $35.2 vs $21.47 +/- $6.9, P <.01).

CONCLUSIONS

Coronary artery bypass grafting on the beating heart is associated with a significant reduction in postoperative blood loss, transfusion requirement, and transfusion-related cost when compared with conventional revascularization with cardiopulmonary bypass and cardioplegic arrest.

Predictors of atrial fibrillation after conventional and beating heart coronary surgery: A prospective, randomized study

BACKGROUND

Atrial fibrillation (AF) increases the morbidity of CABG. The pathophysiology is uncertain, and its prevention remains suboptimal. This prospective, randomized study was designed to define the role of cardiopulmonary bypass (CPB) and cardioplegic arrest in the pathogenesis of this complication.

METHODS AND RESULTS

Two hundred patients were prospectively randomized to (1) on-pump conventional surgery [(100 patients, 79 men, mean age 63 (40 to 77) years)] with normothermic CPB and cardioplegic arrest of the heart or (2) off-pump surgery [(100 patients, 82 men, mean age 63 (38 to 86) years)] on the beating heart. Heart rate and rhythm were continuously monitored with an automated arrhythmia detector during the first 72 hours after surgery. Thereafter, routine clinical observation was performed and continuous monitoring restarted in the case of arrhythmia. The association of perioperative factors with AF was investigated by univariate analysis. Significant variables were then included into a stepwise logistic regression model to ascertain their independent influence on the occurrence of AF. There were no significant baseline differences between groups. Thirty-nine patients in the on-pump group and 8 patients in the off-pump group had postoperative sustained AF (P:=0.001). Univariate analysis showed that CPB inclusive of cardioplegic arrest, postoperative inotropic support, intubation time, chest infection, and hospital length of stay were predictors of AF (all P:<0.05). However, stepwise multivariate regression analysis identified CPB inclusive of cardioplegic arrest as the only independent predictor of postoperative AF (OR 7.4; CI 3.4 to 17.9).

CONCLUSIONS

CPB inclusive of cardioplegic arrest is the main independent predictor of postoperative AF in patients undergoing coronary revascularization.

Inflammatory response after coronary revascularization with or without cardiopulmonary bypass

BACKGROUND

We sought to investigate the effect of multiple coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass (CPB) on the perioperative inflammatory response.

METHODS

Sixty patients undergoing CABG were randomly assigned to one of two groups: (A) on pump with conventional CPB and cardioplegic arrest, and (B) off pump on the beating heart. Serum samples were collected for estimation of neutrophil elastase, interleukin 8 (IL-8), C3a, and C5a preoperatively and at 1, 4, 12, and 24 hours postoperatively. Furthermore, white blood cell (WBC), neutrophil, and monocyte counts were carried out preoperatively and at 1, 12, 36 and 60 hours postoperatively. Overall incidence of infection and perioperative clinical outcome were also recorded.

RESULTS

The groups were similar in terms of age, weight, gender ratio, extent of coronary disease, left ventricular function, and number of grafts per patient. Neutrophil elastase concentration peaked early after CPB in the on-pump group, with a decline with time. Repeated-measures analysis of variance between groups and comparisons at each time point (modified Bonferroni) showed elastase concentrations were significantly higher in the on-pump than the off-pump group (both p < 0.0001). IL-8 increased significantly after surgery in the on-pump group, with no decline during the observation period (p = 0.01 vs off pump). C3a and C5a rose early after surgery in both groups when compared with baseline values. Postoperative WBC, neutrophil, and monocyte counts were significantly higher in the on-pump than the off-pump group (p < 0.01). Finally, the incidence of postoperative overall infections was significantly higher in the on-pump group (p < 0.0001 vs off pump).

CONCLUSIONS

CABG on the beating heart is associated with a significant reduction in inflammatory response and postoperative infection when compared with conventional revascularization with CPB and cardioplegic arrest.

Inhibition of late vein graft neointima formation in human and porcine models by adenovirus-mediated overexpression of tissue inhibitor of metalloproteinase-3

BACKGROUND

Autologous saphenous vein coronary artery bypass graft surgery is complicated by late graft failure due to neointima formation and subsequent atherosclerosis. Growth factors and metalloproteinases (MMPs) act in concert to promote neointima formation. Tissue inhibitor of metalloproteinase-3 (TIMP-3), an extracellular matrix-associated MMP inhibitor, uniquely promotes apoptosis of isolated vascular smooth muscle cells. Here, we overexpressed TIMP-3 at the luminal surface of human saphenous veins before organ culture and in pig saphenous veins before interposition grafting into carotid arteries in vivo to assess neointima formation.

METHODS AND RESULTS

In both models, high TIMP-3 immunoreactivity occurred in the luminal and upper medial extracellular matrix after adenovirus delivery. MMP activity measured by in situ zymography was reduced throughout the veins, confirming a bystander effect. By use of 3 independent techniques, apoptosis levels in the neointima and medial layer were significantly elevated by TIMP-3 overexpression. Neointima formation was reduced by 84% in 14-day human organ cultures and by 58% in 28-day pig vein grafts (both P<0.05). In contrast, TIMP-2 overexpression had no effect on neointima formation in vivo.

CONCLUSIONS

Our results highlight the potential therapeutic benefit for TIMP-3 overexpression to reduce neointima formation associated with late vein graft failure.

Serum S-100 protein release and neuropsychologic outcome during coronary revascularization on the beating heart: a prospective randomized study

OBJECTIVES

Our purpose was to establish whether coronary revascularization on the beating heart without cardiopulmonary bypass is less harmful to the brain than conventional surgery with cardiopulmonary bypass as indicated by measures of cognitive function or by changes in serum concentrations of S-100 protein, a recognized biochemical marker of cerebral injury.

METHODS

We conducted a prospective randomized trial in which the assessors of the outcome measures were blind to the treatment received. Sixty patients without known neurologic abnormality, undergoing coronary revascularization, were prospectively randomized to 1 of 2 groups: (1) cardiopulmonary bypass (32 degrees C-34 degrees C) and cardioplegic arrest (on pump) with intermittent antegrade warm blood cardioplegia or (2) surgery on the beating heart (off pump). Neuropsychologic performance was assessed before and 12 weeks after the operation. Serum S-100 protein concentration was measured at intervals up to 24 hours after the operation.

RESULTS

The groups had similar preoperative characteristics. There were no deaths or major neurologic complications in either group, nor was there any difference between groups in the chosen index of neurologic deterioration. Serum S-100 protein concentrations were higher in the on-pump group at 30 minutes, but any such difference between groups had disappeared 4 hours later. The extent of the changes in S-100 protein was unrelated to the index of neuropsychologic deterioration.

CONCLUSIONS

The changes in S-100 protein concentration suggest that the brain and/or blood-brain barrier may be more adversely affected during coronary artery surgery with cardiopulmonary bypass than during surgery on the beating heart, but that this may not be reflected in detectable neuropsychologic deterioration at 12 weeks.

Economic outcome of off-pump coronary artery bypass surgery: a prospective randomized study

BACKGROUND

Emphasis on cost containment in coronary artery bypass surgery is becoming increasingly important in modern hospital management. The revival of interest in off-pump (beating heart) coronary artery bypass surgery may influence the economic outcome. This study examines these effects.

METHODS

Two hundred patients undergoing first-time coronary artery bypass surgery were prospectively randomized to either conventional cardiopulmonary bypass and cardioplegic arrest or off-pump surgery. Variable and fixed direct costs were obtained for each group during operative and postoperative care. The data were analyzed using parametric methods.

RESULTS

There was no difference between the groups with respect to pre- and intraoperative patient variables. Off-pump surgery was significantly less costly than conventional on-pump surgery with respect to operating materials, bed occupancy, and transfusion requirements (total mean cost per patient: on pump, $3,731.6+/-1,169.7 vs off-pump, $2,615.13+/-953.6; p < 0.001). Morbidity was significantly higher in the on-pump group, which was reflected in an increased cost.

CONCLUSIONS

Off-pump revascularization offers a safe, cost-effective alternative to conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest.

Integrated left anterior small thoracotomy and angioplasty for coronary artery revascularization

BACKGROUND

The minimal access surgical technique of a left anterior small thoracotomy (LAST) for coronary artery bypass grafting is now well established. This procedure however, does not allow multivessel revascularization. We present our early experience of an integrated approach using LAST and percutaneous transluminal coronary angioplasty (PTCA), either staged or simultaneous.

METHODS

Eighteen patients (14 men and 4 women), mean age 63 (range 35-87 years) were treated. Four patients underwent simultaneous LAST and PTCA revascularization. The remaining 14 patients were first treated with the LAST procedure, followed 1-3 days later by angioplasty. Angiographic assessment was carried out before PTCA and at 6 months after.

RESULTS

The 14 patients who underwent the staged procedure all had patent left internal mammary artery/left anterior descending coronary artery grafts. Angioplasty was performed on 21 vessels (10 stented) with good early angiographic results. All patients were extubated early, mean intensive care stay was 14.7 + 9.4 hours, mean hospital stay was 5 + 1.5 days. All patients were symptom free at 18 months follow-up.

CONCLUSIONS

Staged LAST and angioplasty is a safe and effective approach suitable for patients in whom there are contraindications to the use of extracorporeal circulation. The simultaneous approach is limited by the risk of bleeding associated with the use of anticoagulation when coronary stenting is required.

Evaluation of myocardial metabolism and function during beating heart coronary surgery

Coronary artery bypass surgery on the beating heart either via a left anterior small thoracotomy (LAST) or a median sternotomy is becoming increasing popular world-wide. Concern still remains about the potential for a temporary regional myocardial ischaemia associated with the stabilisation and occlusion of the coronary during construction of the anastomosis. This review summarises the results of a series of studies intended to evaluate the effect of beating heart coronary revascularization on myocardial function, myocardial tissue injury and clinical outcome.

Abdominal abscess: late complication after gastroepiploic coronary artery bypass grafting

The gastroepiploic artery is widely used an arterial conduit during coronary artery revascularisation surgery. We report an unusual complication of a 56-year-old man who developed a late intra-abdominal abscess extending into the mediastinum adjacent to the right ventricle more than 2 years after surgery. This was managed with percutaneous drainage and the patient made a full recovery. The case illustrates the potential problems associated with harvesting of this artery and the need for careful haemostasis.

On-pump versus off-pump coronary revascularization: evaluation of renal function

BACKGROUND

Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investigated whether this prevents renal compromise.

METHODS

A prospective, randomized, controlled trial was performed in 50 patients (45 males, mean age 61+/-3.7 years) undergoing elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on pump) or beating heart revascularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively.

RESULTS

There were no deaths, myocardial infarctions or acute renal failure in either group. Glomerular filtration as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular function was also impaired in the on pump group as assessed by increased N-acetyl glucosaminidase activity (p < 0.0272).

CONCLUSIONS

These results suggest that off pump coronary revascularization offers a superior renal protection when compared with conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients.

Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study

OBJECTIVE

Conventional coronary artery bypass grafting (CABG) is both safe and effective. Nevertheless, the use of cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with several adverse effects. Over the last 2 years there has been a revival of interest in performing CABG on the beating heart. In this prospective randomized study we evaluated the efficacy and safety of on and off pump coronary revascularization on myocardial function.

METHODS

Eighty patients (65 males, mean age 61+/-9.7 years) undergoing first time CABG were prospectively randomized to: (i) conventional revascularization with CPB at normothermia and cardioplegic arrest with intermittent warm blood cardioplegia (on pump) or (ii) beating heart revascularization (off pump). Troponin I (Tn I) release was serially measured as a specific marker of myocardial damage. Haemodynamic measurements as well as inotropic requirement, incidence of arrhythmia and postoperative myocardial infarction were also recorded.

RESULTS

There were no significant differences between the two groups in terms of age, sex, extent of disease, left ventricular function and number of grafts. There were no deaths or intraoperative myocardial infarctions in either group. Tn I release was constantly lower in the off pump group and this was significant at 1, 4, 12 and 24 h postoperatively. Furthermore, in this group there was a significantly reduced incidence of arrhythmias. Inotropic requirements were less in the off pump group but this did not reach statistical significance.

CONCLUSION

These results suggest that off pump coronary revascularization is a safe and effective strategy for myocardial revascularization. Myocardial injury as assessed by Tn I release is also reduced when compared with conventional coronary revascularization with CPB and cardioplegic arrest.

Dysrhythmia update. Differential diagnosis of supraventricular tachycardia in an elderly man

An 82-year-old man was admitted to the hospital with a narrow complex tachycardia. This article presents his case history, examples of the dysrhythmia, and a differential diagnosis approach to identifying the source of the tachycardia. The mechanism of the tachycardia is described and diagrammed and the follow-up care of the patient presented.

Dysrhythmia update. Case study: analysis of dual chamber rate responsive pacing in atrial fibrillation

This article presents a case study of a patient who required a dual chamber rate responsive pacemaker to assist in managing atrial fibrillation. The patient developed significant bradycardia when treated with the dose of propafenone required to convert atrial fibrillation, so the pacemaker was inserted. An example of a paced rhythm is presented and a differential diagnosis approach is used to discuss the possible interpretations of the rhythm. A brief explanation of the actual cause of the observed paced rhythm is presented.

Case study: analysis of dual chamber rate responsive pacing in atrial fibrillation

This article presents a case study of a patient who required a dual chamber rate responsive pacemaker to assist in managing atrial fibrillation. The patient developed significant bradycardia when treated with the dose of propafenone required to convert atrial fibrillation, so the pacemaker was inserted. An example of a paced rhythm is presented and a differential diagnosis approach is used to discuss the possible interpretations of the rhythm. A brief explanation of the actual cause of the observed paced rhythm is presented.