Revisiting the Warburg Effect with Focus on Lactate

Rewired metabolism is acknowledged as one of the drivers of tumor growth. As a result, aerobic glycolysis, or the Warburg effect, is a feature of many cancers. Increased glucose uptake and glycolysis provide intermediates for anabolic reactions necessary for cancer cell proliferation while contributing sufficient energy. However, the accompanying increased lactate production, seemingly wasting glucose carbon, was originally explained only by the need to regenerate NAD⁺ for successive rounds of glycolysis by the lactate dehydrogenase (LDH) reaction in the cytosol. After the discovery of a mitochondrial LDH isoform, lactate oxidation entered the picture, and lactate was recognized as an important oxidative fuel. It has also been revealed that lactate serves a variety of signaling functions and helps cells adapt to the new environment. Here, we discuss recent findings on lactate metabolism and signaling in cancer while attempting to explain why the Warburg effect is adopted by cancer cells.

Transoesophageal echocardiography findings in young patients with cryptogenic ischemic stroke

Background and purpose

The cause of ischemic stroke (IS) remains often unclear in young patients. Relevant structural heart abnormities with known embolic potential may represent cause of IS also in young population. The use of transoesophageal echocardiography (TEE) allows reliable detection of most relevant structural pathologies. The aim was to assess frequency and spectrum of relevant cardiac abnormities in young IS patients.

Subjects and methods

The study set consisted of young acute IS patients <50 years enrolled in the prospective HISTORY (Heart and Ischemic STrOke Relationship studY) study, registered on ClinicalTrials.gov NCT01541163). In all patients, the brain ischemia was confirmed on CT or MRI. Admission ECG, serum specific cardiac markers, TEE, 24-hour and 3-week ECG-Holter were performed in all patients.

Results

Out of 1284 patients enrolled in the HISTORY study, 135 (73 males, mean age 40.2±8.1 years) were <40 years. In total, the relevant TEE abnormities were present in 47 (35%) of these patients. Patent foramen ovale (PFO) with evident left to right shunt was detected in 38 (28%) patients, with significant right to left shunt in 25 (19%) patients, and other atrial septal defect with clinically significant bidirectional flow in 4 (3%) patients. Significant valvular heart disease was present in 2 (1%) patients (1 bicuspid aortic valve with moderate aortic regurgitation, 1 chronic severe mitral regurgitation), and 4 (3%) patients severe left ventricular systolic dysfunction (left ventricular ejection fraction ≤35%) due to idiopathic dilated cardiomyopathy. Left atrial myxoma was detected in one patient.

Conclusion

The relevant structural abnormities with embolic potential were detected using TEE in 35% of young IS patients. Routine use of TEE to elucidate the causes of stroke, has a role especially in young patients who present with cryptogenic stroke and no cardiovascular risk factors, as well as in the setting of a PFO associated with a deep venous thrombosis.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): IGA LF UP, MH CZ - DRO

Long-term decline of renal function in patients with resistant and non-resistant arterial hypertension

Background

The negative effect of arterial hypertension on renal function is well known. Until present, the detrimental effect of resistant arterial hypertension (RAH) on kidneys was not clearly defined.

Purpose

To assess the deterioration of renal function in patients with RAH in comparison to patients with non-resistant arterial hypertension (AH) during a long term follow-up.

Methods

We retrospectively reviewed records of 307 patients followed between May 2007 and January 2019 in an Hypertension Excellence Centre of a tertiary hospital. In all patients we assessed basic demographic characteristics, co-morbidities, laboratory findings, secondary causes of AH, medication, blood pressure including ambulatory blood pressure monitoring, studies and invasive procedures (CT, MRI, coronarography). We statistically evaluated differences in both groups and compared the decline of renal function.

Results

160 patients had resistant and 147 patients non-resistant hypertension. Patients were followed for a mean of 6 years. Patients with RAH were older (58.1±10.8 years vs. 51±13 years), more frequently diabetics (39.3% vs. 8.7%), had more frequent exposure to diagnostic studies and invasive procedures (86,5% vs. 64%).

Age at baseline visit and diabetes mellitus were established as statistically significant independent risk factors. Linear mixed effect model adjusted to age and diabetes demonstrated that patients with RAH have increased decline of renal function than patients with AH: patients with AH had mean increase of creatinine +0.24 μmol/l per year, while patients with RAH + 2.12 μmol/l per year (P=0.005). Similarly the decrease of eGFR in patients with AH was −0.66 compared to −1.5 mL/s/1.73 m2 per year in patients with RAH (P=0.005).

Figures 1 and 2 show the difference in mean slope of creatinine and eGFR in patients with resistant and non-resistant hypertension (based on linear mixed effect models)).

Conclusion

Patients with resistant hypertension had faster decline of renal function in comparison to patients with non-resistant hypertension independently on age and diabetes. Further studies are needed to determine the key factors affecting renal function decline in both subgroups.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): University Hospital Olomouc, Palacky University Olomouc, Faculty of Medicine, Czech Republic

Hypertension outcomes of adrenalectomy for unilateral primary aldosteronism

PURPOSE

To evaluate laboratory and clinical results after unilateral adrenalectomy in patients with primary aldosteronism (PHA).

METHODS

A cross-sectional analysis was performed using data from patients who underwent transperitoneal laparoscopic adrenalectomy for PHA, between January 2008 and December 2019. Surgical indications were based on adrenal venous sampling without ACTH stimulation. Analyses included patient demographics; preoperative clinical, pharmacological, laboratory, and radiological data; and postoperative results assessed after a median of 4 months. Antihypertensive drug use was quantified by estimating the daily defined dose (DDD) of antihypertensive medication, thus enabling standardized comparison of dosage between the drug classes. Statistical assessments included univariable and multivariable logistic regression analysis.

RESULTS

This study enrolled 87 patients. The patients were taking 5.4 DDD of antihypertensive medication before surgery, and 3.0 DDD after surgery. Complete biochemical success of surgery was reached 67 patients (77%), 19 patients (22%) had partial biochemical success. Complete clinical success with normalization of blood pressure and withdrawal of all antihypertensive drugs was achieved in 19 patients (22%). 57 patients (65%) exhibited a reduction of DDD after surgery and/or improvement of blood pressure-partial clinical success. Thus, in 76 (87%) of all enrolled patients, surgery had an overall positive effect on hypertension control. Multivariable logistic regression showed that complete clinical success was independently associated with female gender and baseline sum of antihypertensive drugs DDD < 4.

CONCLUSION

A majority of patients undergoing unilateral adrenalectomy for PHA achieved markedly improved hypertension control, despite almost halving their antihypertensive medication. Almost a quarter of patients were cured and able to cease using all antihypertensive drugs.

Sudden cardiac death - a known unknown?

Sudden cardiac death (SCD) is a major medical, economic and social problem. The estimated annual number of SCDs is approximately 4 million cases worldwide. Approximately 50% of SCDs are unexpected first manifestations of cardiac disease. The survival rate after out-of-hospital cardiac arrest is low even in countries with the most advanced health care systems. It all emphasizes the importance of prevention, in which implantable cardioverter-defibrillators play a dominant role. However, our ability to recognize high-risk patients remains insufficient. Moreover, a declining rate of shockable rhythm as the initial recording has been reported in the last decades. Despite numerous SCD studies and undisputed progress, there are still many unanswered questions.

1418Adverse effects of spironolactone in long-term treatment of resistant arterial hypertension

Background

Spironolactone is recommended as a fourth line antihypertensive drug by current hypertension guidelines. This drug had relatively few adverse effects in short term clinical trials, but data about their occurrence during long-term treatment of resistant hypertension are scarce.

Purpose

To evaluate the occurrence and type of adverse effects of spironolactone during long-term treatment and their possible clinical and laboratory predictors.

Methods

We prospectively followed 274 patients with resistant arterial hypertension who started treatment with spironolactone between September 2007 and December 2016. The duration of spironolactone use, its dose, the incidence of adverse events, blood pressure, and laboratory findings were recorded at baseline and during the last clinical examination.

Results

Patients were followed for an average of 35 (± 29) months, the mean dose of spironolactone was 27.5 mg/day. Adverse effects occurred in 72 patients (26.3%) and in 61 (84.7%) lead to discontinuation of spironolactone. The most common adverse reactions were gynaecomastia (30.6%), hyperkalaemia (30.6%) and symptomatic hypotension (26.4%). The mean duration of spironolactone treatment before their occurrence was 25 (± 27) months. According to the Kaplan-Meier curve, the median for the incidence of adverse events would be 97 months (91.5–102.5 months), i.e. 50% of patients could be treated with no adverse events for more than 8 years. Adverse events were more common in the elderly (hazard ratio – HR 1.38, P=0.007), patients with higher baseline serum creatinine (HR 1.12, P=0.035) and patients taking angiotensin receptor blockers (HR 1.65, P=0.040).

Kaplan-Meier estimate – adverse events

Conclusion

During long-term treatment of resistant hypertension with spironolactone, more than a quarter of patients experience adverse reactions that usually require discontinuation of spironolactone.

Acknowledgement/Funding

Supported by the grants of Palacký University in Olomouc Nr. IGA_LF_2016_038 and IGA_LF_2017_029.

Acute effects of right ventricular pacing on cardiac haemodynamics and transvalvular impedance

AIMS

To assess the acute side-effects of right ventricular (RV) stimulation applied in apex and mid-septum, in order to establish the optimal lead location in clinical practice.

METHODS

During pacemaker implantation, the ventricular lead was temporarily fixed in the apex and then moved to mid-septum. In both positions, surface and endocardial electrograms and transvalvular impedance (32 cases), left ventricular (LV) pressure (23), and transthoracic echocardiography (10) were acquired with intrinsic activity and VDD pacing.

RESULTS

A larger increase in QRS duration was noticed with apical than septal pacing (65±25 vs. 45±29 ms; P<10(-4)). The proportion of cases where RV stimulation affected the transvalvular impedance waveform was higher with apical lead location (56% vs. 20%; P<0.02). VDD pacing at either site reduced the maximum dP/dt by 6% with respect to intrinsic AV conduction (IAVC; P<0.005). The maximum pressure drop taking place in 100 ms was reduced by 6 and 8%, respectively, with apical and septal pacing (P<0.01 vs. IAVC). Apical VDD decreased mitral annulus velocity in early diastole (E') from 7.5±1.4 to 5.9±0.9 cm/s (P<0.02) and prolonged the E-wave deceleration time (DT) from 156±33 to 199±54 ms (P<0.02), while septal pacing induced non-significant modifications in E' and DT.

CONCLUSION

Ventricular stimulation acutely impairs LV systolic and diastolic performance, independent of the pacing site. Septal lead location preserves RV contraction mechanics and reduces the electrical interventricular delay.

The prevalence of eustachian valve on transoesophageal echo examination

BACKGROUND

The Eustachian valve (EV) is an embryonic structure redirecting the blood flow from the inferior vena cava through the foramen ovale. It may persist in adults as a floating membrane in the right atrium. A large EV can be associated with thrombosis, embolization, bacterial endocarditis, etc. The prevalence of EV in the normal population is unknown.

AIM

to assess the prevalence and size of EV in unselected patients examined by transoesophageal echo. Methods. 1100 consecutive patients were examined for various reasons by a single operator and interpreter. Routine check was made for the presence of EV in the right atrium. Only patients with a mobile EV and not with a simple rigid rim were counted. Three measurements of the EV length at the level of the aortic valve (i.e. 90°C) were made off-line and the longest distance considered. If the EV was not visualized and recorded as a straight line because of its chaotic movement, the picture of the valve was segmented into several separated valve portions and the sum taken as the true length.

RESULTS

46 patients (24 males) with EV were identified out of total 1100 pts examined. The average length of the EV was 23.6 ± 9.7 mm (7-47 mm, median 23 mm).

CONCLUSIONS

The finding of a persisting Eustachian valve on transoesophageal echo examination is not rare. The prevalence was similar in men and in women. Bearing in mind the possible complications associated with a large valve, we recommend that a proper description of persistent EV is included in routine transoesophageal echo reports.

Genetic diversity of Borrelia burgdorferi sensu lato isolates obtained from Ixodes ricinus ticks collected in Slovakia

In Europe, Borrelia burgdorferi sensu lato is diverse, including B. burgdorferi s.s., B. garinii, B. afzelii, B. valaisiana and B. lusitaniae. In this study, we focused on the distribution of the different B. burgdorferi species among Ixodes ricinus adult ticks collected in an endemic area within Slovakia. We compared results of prevalence of B. burgdorferi infection in ticks obtained by immunofluorescence (IF) and by isolation. Isolates were characterized by restriction fragment length polymorphism (RFLP) of the rrf-rrl intergenic spacer genes using MseI. Using immunofluorescence we observed that 56/114 (49%) ticks were infected by B. burgdorferi s.l. Males were found to be more often infected (32/57, 56%) than females (24/57, 42%) but the difference was not significant (p = 0.1895). From the same 114 ticks a total of 37 isolates were obtained: 19 from males (33%) and 18 from females (32%). The RFLP identification revealed 25 B. afzelii (68%), 5 B. garinii (14%), 5 B. valaisiana (14%) and 2 B. lusitaniae (5%). The infection in ticks was more often detected by IF than by isolation (p = 0.0153) and isolation success was higher when the infection degree in ticks was high (p = 0.0397). The infection prevalence observed in this area is among the highest observed in Europe.