Current Hot Potatoes in Atrial Fibrillation Ablation

Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.     

Podocyte Purinergic P2X4 Channels Are Mechanotransducers That Mediate Cytoskeletal Disorganization

Podocytes are specialized, highly differentiated epithelial cells in the kidney glomerulus that are exposed to glomerular capillary pressure and possible increases in mechanical load. The proteins sensing mechanical forces in podocytes are unconfirmed, but the classic transient receptor potential channel 6 (TRPC6) interacting with the MEC-2 homolog podocin may form a mechanosensitive ion channel complex in podocytes. Here, we observed that podocytes respond to mechanical stimulation with increased intracellular calcium concentrations and increased inward cation currents. However, TRPC6-deficient podocytes responded in a manner similar to that of control podocytes, and mechanically induced currents were unaffected by genetic inactivation of TRPC1/3/6 or administration of the broad-range TRPC blocker SKF-96365. Instead, mechanically induced currents were significantly decreased by the specific P2X purinoceptor 4 (P2X₄) blocker 5-BDBD. Moreover, mechanical P2X₄ channel activation depended on cholesterol and podocin and was inhibited by stabilization of the actin cytoskeleton. Because P2X₄ channels are not intrinsically mechanosensitive, we investigated whether podocytes release ATP upon mechanical stimulation using a fluorometric approach. Indeed, mechanically induced ATP release from podocytes was observed. Furthermore, 5-BDBD attenuated mechanically induced reorganization of the actin cytoskeleton. Altogether, our findings reveal a TRPC channel-independent role of P2X₄ channels as mechanotransducers in podocytes.     

Long-term Cancer-specific Outcomes of TaG1 Urothelial Carcinoma of the Bladder

Background

Few studies have investigated the natural history of TaG1 urothelial carcinoma of the bladder (UCB).

Objective

To assess the long-term outcomes of patients with TaG1 UCB and the impact of immediate postoperative instillation of chemotherapy (IPIC).

Design, setting, and participants

A retrospective analysis of 1447 patients with TaG1 UCB treated between 1996 and 2007 at eight centers. Median follow-up was 67.2 mo (interquartile range: 67.9). Patients were stratified into three European Association of Urology (EAU) guidelines risk categories; high-risk patients (n = 11) were excluded.

Intervention

Transurethral resection of the bladder with or without IPIC.

Outcome measurements and statistical analysis

Univariable and multivariable Cox regression models addressed factors associated with disease recurrence, disease progression, death of disease, and any-cause death.

Results and limitations

Of the 1436 patients, 601 (41.9%) and 835 (58.1%) were assigned to low- and intermediate-risk categories, respectively. The actuarial estimate of 5-yr recurrence-free survival was 56% (standard error: ±1). Advancing age (p = 0.04), tumor >3 cm (p = 0.001), multiple tumors (p < 0.001), and recurrent tumors (p < 0.001) were independently associated with increased risk of disease recurrence, whereas IPIC was associated with decreased risk (p = 0.001). The actuarial estimate of 5-yr progression-free survival was 95% ± 1. Advancing age (p < 0.001) and multiple tumors (p = 0.01) were independent risk factors for disease progression. Five-year cancer-specific survival was 98% ± 1. Advancing age (p = 0.001) and previous recurrence (p = 0.04) were associated with increased risk, whereas female gender (p = 0.02) was associated with decreased risk of cancer-specific mortality. Compared with low-risk patients, intermediate-risk patients were at significantly higher risk of disease recurrence, disease progression, and cancer-specific mortality (all p < 0.01). Limitations include the retrospective design of the study and the lack of a central pathology review.

Conclusions

TaG1 UCB patients experience heterogeneous risks of disease recurrence. We validated the EAU guidelines risk stratification in TaG1 UCB patients. IPIC was associated with a reduced risk of disease recurrence in patients with low- and intermediate-risk TaG1 UCB.     

The hypothalamic–pituitary–gonadal axis and prostate cancer: implications for androgen deprivation therapy

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) may play important roles in prostate cancer (PCa) progression. Specifically, LH expression in PCa tissues has been associated with metastatic disease with a poor prognosis, while FSH has been shown to stimulate prostate cell growth in hormone-refractory PCa cell lines. Gonadotropin-realizing hormone (GnRH) analogues are common agents used for achieving androgen deprivation in the treatment for PCa. GnRH analogues include LH-releasing hormone (LHRH) agonists and GnRH antagonists, both of which exhibit distinct mechanisms of action that may be crucial in terms of their overall clinical efficacy. LHRH agonists are typically used as the primary therapy for most patients and function via a negative-feedback mechanism. This mechanism involves an initial surge in testosterone levels, which may worsen clinical symptoms of PCa. GnRH antagonists provide rapid and consistent hormonal suppression without the initial surge in testosterone levels associated with LHRH agonists, thus representing an important therapeutic alternative for patients with PCa. The concentrations of testosterone and dihydrotestosterone are significantly reduced after treatment with both LHRH agonists and GnRH antagonists. This reduction in testosterone concentrations to castrate levels results in significant, rapid, and consistent reductions in prostatic-specific antigen, a key biomarker for PCa. Evidence suggests that careful maintenance of testosterone levels during androgen deprivation therapy provides a clinical benefit to patients with PCa, emphasizing the need for constant monitoring of testosterone concentrations throughout the course of therapy.     

High rates of advanced disease,complications, and decline of renal function after radical nephroureterectomy

ObjectivesRecurrences remain common following radical nephroureterectomy (RNU) for locally advanced upper-tract urothelial carcinoma (UTUC). We review a cohort of RNU patients to identify the incidence of locally advanced disease, decline in renal function, complications, and utilization of adjuvant chemotherapy (AC).MethodsInstitutional databases from 7 academic medical centers identified 414 RNU patients treated between 2003 and 2012 who had not received neoadjuvant chemotherapy. Glomerular filtration rate was estimated using the Modification of Diet in Renal Disease equation. Complications were classified according to the modified Clavien system. Cox proportional hazard modeling and Kaplan-Meier analysis determined factors associated with cancer-specific survival.ResultsOf 414 patients, 177 (43%) had locally advanced disease, including 118 pT3N0/Nx, 13 pT4N0/Nx, and 46 pTanyN+. Estimated 3- and 5-year cancer-specific survival was 47% and 34%, respectively. Only 31% of patients with locally advanced UTUC received AC. Mean estimated glomerular filtration rate declined from 59 to 51 ml/min/1.73 m² following RNU, including a new-onset decline below 60 and 45 ml/min/1.73 m² in 25% and 15% of patients, respectively (P<0.001 for both). Complications occurred in 46 of 177 (26%) patients, of which one-quarter were grade III or IV. Increasing age (Hazard Ratio (HR) 1.4, P = 0.03), positive surgical margins (HR 2.1, P = 0.01), and positive lymph nodes (HR 4.3, P<0.001) were associated with an increased risk of death from UTUC, whereas receipt of AC (HR 0.85, P = 0.05) was associated with a decrease in UTUC mortality.ConclusionsUnder one-third of RNU patients with locally advanced UTUC cancers received AC. Perioperative complications and decline in renal function may have contributed to this low rate. Such data further underscore the need for continued discussion regarding the use of chemotherapy in a neoadjuvant setting for appropriately selected patients with UTUC.     

New insight into active muscarinic receptors with the novel radioagonist [H]iperoxo

Activation of G protein-coupled receptors involves major conformational changes of the receptor protein ranging from the extracellular transmitter binding site to the intracellular G protein binding surface. GPCRs such as the muscarinic acetylcholine receptors are commonly probed with radioantagonists rather than radioagonists due to better physicochemical stability, higher affinity, and indifference towards receptor coupling states of the former. Here we introduce tritiated iperoxo, a superagonist at muscarinic M₂ receptors with very high affinity. In membrane suspensions of transfected CHO-cells, [³H]iperoxo – unlike the common radioagonists [³H]acetylcholine and [³H]oxotremorine M – allowed labelling of each of the five muscarinic receptor subtypes in radioagonist displacement and saturation binding studies. [³H]iperoxo revealed considerable differences in affinity between the even- and the odd-numbered muscarinic receptor subtypes with affinities for the M₂ and M₄ receptor in the picomolar range. Probing ternary complex formation on the M₂ receptor, [³H]iperoxo dissociation was not influenced by an archetypal allosteric inverse agonist, reflecting activation-related rearrangement of the extracellular loop region. At the inner side of M₂, the preferred G_i protein acted as a positive allosteric modulator of [³H]iperoxo binding, whereas G_s and G_q were neutral in spite of their robust coupling to the activated receptor. In intact CHO-hM₂ cells, endogenous guanylnucleotides promoted receptor/G protein-dissociation resulting in low-affinity agonist binding which, nevertheless, was still reported by [³H]iperoxo. Taken together, the muscarinic superagonist [³H]iperoxo is the best tool currently available for direct probing activation-related conformational transitions of muscarinic receptors.     

Maternal Self-confidence Postpartum and at Pre-school Age: The Role of Depression,Anxiety Disorders,Maternal Attachment Insecurity

The aim of this study was to analyze the impact of maternal postpartum depression and/or anxiety disorders according to DMS-IV on maternal self-confidence throughout infancy and early childhood. Exploratively, associations between maternal attachment insecurity and maternal self-confidence at pre-school age were examined. The sample (N = 54) of this prospective longitudinal study was comprised of n = 27 women with postpartum depression and/or anxiety disorders according to DSM-IV criteria and n = 27 healthy women without present or history of mental health disorders or psychotherapy. Data was collected in the postpartum period (M = 60.08 days) and at pre-school age (M = 4.7 years). Subjects were recruited between 2004 and 2011 in South Germany. Data revealed a significant difference in maternal self-confidence between clinical and control group at child′s pre-school age: Women with postpartum depression and/or anxiety disorder scored lower on maternal self-confidence than healthy controls, but only if they had current SCID-diagnoses or partly remitted symptoms. According to explorative analyses maternal attachment insecurity turned out to be the strongest predictor of maternal self-confidence at pre-school age besides maternal mental health status. The results emphasize the impact of attachment insecurity and maternal mental health regarding maternal self-confidence leading to potential adverse long-term consequences for the mother–child relationship. Attachment based interventions taking maternal self-confidence into account are needed.     

Pharmacological inhibition of the chemokine receptor CX3CR1 attenuates disease in a chronic-relapsing rat model for multiple sclerosis

One hallmark of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) is infiltration of leukocytes into the CNS, where chemokines and their receptors play a major mediatory role. CX3CR1 is a chemokine receptor involved in leukocyte adhesion and migration and hence a mediator of immune defense reactions. The role of CX3CR1 in MS and EAE pathogenesis however remains to be fully assessed. Here, we demonstrate CX3CR1 mRNA expression on inflammatory cells within active plaque areas in MS brain autopsies. To test whether blocking CNS infiltration of peripheral leukocytes expressing CX3CR1 would be a suitable treatment strategy for MS, we developed a selective, high-affinity inhibitor of CX3CR1 (AZD8797). The compound is active outside the CNS and AZD8797 treatment in Dark Agouti rats with myelin oligodendrocyte glycoprotein-induced EAE resulted in reduced paralysis, CNS pathology, and incidence of relapses. The compound is effective when starting treatment before onset, as well as after the acute phase. This treatment strategy is mechanistically similar to, but more restricted than, current very late antigen-4–directed approaches that have significant side effects. We suggest that blocking CX3CR1 on leukocytes outside the CNS could be an alternative approach to treat MS.Multiple sclerosis (MS) is a chronic inflammatory, demyelinating and degenerative disease of the central nervous system (CNS). It was already discovered in the early 1900s that a similar disease could be induced in different animal species by injection of spinal cord extracts or myelin-derived proteins (1–3). This group of animal models for MS, called experimental autoimmune encephalomyelitis (EAE), has provided an experimental platform for building an extensive understanding of the pathology of MS, as well as discovering strategies for intervention of the disease. A typical feature of the pathogenesis in both MS and EAE is the infiltration of leukocytes from the blood stream into the CNS (3). Leukocyte adhesion and extravasation includes several well defined steps and various adhesion molecules, chemokines and their receptors are important mediators for this process. In line with this, the recently developed therapeutic drugs natalizumab and fingolimod, which broadly target leukocyte migration to the brain, exhibit efficacy in EAE models (4, 5), and they are now established therapies in MS (6).Natalizumab, blocking the interaction between very late antigen-4 (VLA-4) and CD106 (VCAM-1), is an effective treatment both on clinical endpoints and MRI biomarkers (7). Fingolimod, the first oral drug for relapsing remitting MS (RRMS), acts on S1P receptors preventing lymphocytes from moving out of lymphoid tissue (8). Natalizumab is only approved as a second-line monotherapy in RRMS or in patients with very active disease, because it carries increased risk of developing the often fatal progressive multifocal leukoencephalopathy (7, 9). Treatment with fingolimod is associated with side effects such as signs of immune suppression, including increased frequency of infections (8).Considering the pronounced presence of inflammatory cells in the brain of MS patients, the significant correlation between inflammation and axonal injury (10) and the efficiency of treatments that broadly block infiltration of immune cells, a similar but more restricted therapeutic approach is appealing. Chemokines are synthesized and released at sites of inflammation, where they act on specific receptors expressed by immune cells to mediate directed cell migration in synergy with adhesion molecules, such as VLA-4, from the blood stream and into the sites of inflammation. CX3CR1 is a unique member of the chemokine receptor family (11) and binds with high affinity to its ligand CX3CL1 [fractalkine (FKN)]. FKN is produced in a membrane bound form but can also be released following proteolytic cleavage, making it important for mediating both adhesion and migration of CX3CR1-expressing cells. In contrast to VLA-4, which is broadly expressed on most leukocytes except neutrophils (7, 12), the expression of CX3CR1 is restricted to subpopulations of monocytes, T lymphocytes, and natural killer (NK) cells (13–16). We have previously demonstrated intense accumulation of CX3CR1-expressing microglia/macrophages within inflammatory foci in the spinal cord of Dark Agouti (DA) rats with EAE induced by myelin oligodendrocyte glycoprotein (MOG) (17) and formed the hypothesis that CX3CR1 would be an attractive therapeutic target for treating MS.To test the hypothesis, we have developed a selective, high-affinity small-molecule inhibitor of CX3CR1 (AZD8797) (18). This molecule has the potential to be administered as an oral drug in humans. However, because of the decrease in potency to rat CX3CR1 and a modest oral bioavailability in rats (39%), we have chosen continuous s.c. dosing for the proof-of-concept studies in rats. The MOG_1-125–induced EAE model in DA rats was used, because it exhibits pathology very similar to MS with infiltration of inflammatory cells, demyelination, and axonal degeneration in the CNS, as well as a relapsing remitting disease course (19, 20). To further mimic the human treatment situation, we have not only treated rats before the onset of paralysis but also initiated treatment during ongoing disease. We present efficacy (reduced paralysis) versus exposure data, analysis of CNS pathology, and measurements of functional inhibition of CX3CR1. These data, in combination with an analysis for CX3CR1 expression within MS brain autopsy samples, clearly demonstrate the potential of CX3CR1 inhibition as an alternative and unique approach for treating MS.     

Professionals' experiences of supporting two-mother families in antenatal and child health care in Sweden

Background

In Sweden, antenatal and child health care are offered free of charge to all expectant and new parents. Professionals in antenatal and child health care play an important role in supporting parents. Previous research shows that same-sex mothers face heteronormative assumptions and insufficient support during their transition to parenthood.

Objective

To explore professionals' experiences of supporting two-mother families in antenatal and child health care.

Method

A qualitative method with focus group discussions was used. An interview guide was followed, and the discussions were held online. The data was analysed according to inductive content analysis.

Settings and participants

The participants were midwives (n = 8) and nurses (n = 5) in antenatal and child health care from different parts of Sweden. Participants were recruited through the coordinating midwives and child health care nurses in the different regions.

Findings

One main category was identified: Striving to be open-minded in supporting same-sex mothers. Health care professionals described meeting well-prepared mothers, with an equal commitment between each other, and mothers on guard against heteronormative views. Professionals provided support through empowerment by creating a safe environment and aiming at providing equal support to all parents or tailored support to same-sex mothers. Mothers described handling challenges, as a balancing act to acknowledge both mothers. Struggling with documents and communication and a lack of information were other challenges to be handled. Professionals reflected on their own professional competence and expressed that knowledge acquired through education, experience and personal interest all contributed to their competence.

Conclusions

Forms and documentation need to be updated to be gender neutral to be including to a variety of family constelleations. Health care professionals need time to reflect on norms and challenges to better support both mothers in a two-mother family.