•The impact of diabetes mellitus on hearing loss has been debated for decades, however, the etiopathogenesis of sensorineural hearing loss in the context of diabetes mellitus is still ...controversial.•Microvascular changes due to diabetic angiopathy can lead to sensorineural hearing loss in both humans and rodents.•Female diabetic patients are shown to be more vulnerable to sensorineural hearing loss than males.
There is controversy regarding the association and etiopathogenesis of diabetes mellitus (DM) and sensorineural hearing loss (SNHL). Some studies support that SNHL develops because of angiopathy and/or neuropathy caused by DM, but many of the findings have been inconsistent. This review aims to highlight a select number of studies that effectively describe the relationship between DM and SNHL, thus bringing more attention and awareness to this area of research. This review also describes animal models to understand better the mechanisms of DM contributing to SNHL in the inner ear. The goal of this narrative review is for researchers and healthcare professionals to further their understanding and investigation of the etiopathogenesis of both DM and SNHL, therefore leading to the development of effective treatments for diabetic patients displaying symptoms of SNHL.
Although doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) is considered the standard chemotherapy regimen for Hodgkin's lymphoma (HL), information on the results of this therapy in human ...immunodeficiency (HIV)-related HL is scarce. We analyzed the results of the ABVD regimen and highly active antiretroviral therapy (HAART) in patients with advanced stage, HIV-related HL.
From January 1996 to December 2005, 62 HIV-infected patients with newly diagnosed HL were treated in 15 Spanish hospitals. Six to eight cycles of ABVD and HAART were planned. Response to chemotherapy, overall survival (OS) and event-free survival (EFS) were recorded.
The median age of the patients was 37 years (range, 24-61) and 29 (47%) had a previously known diagnosis of acquired immunodeficiency syndrome. The median CD4 lymphocyte count at diagnosis was 129/muL (range 5-1,209). The histologic subtype of HL was nodular sclerosis in 17 patients (27%), mixed cellularity in 25 (41%), lymphocyte depletion in 10 (16%) and non-specified in the remaining 10 (16%). Twenty-one (34%) patients were in stage III and 41 (66%) in stage IV. The scheduled six to eight ABVD cycles were completed in 82% of cases. Six patients died during induction, 54 (87%) achieved a complete response (CR) and two were resistant. After a median follow-up of 39 and 47 months, 5-year EFS and OS probabilities were 71% (47-95) and 76% (65-87), respectively. An immunological response was observed in 24 out of 43 patients (56%) and a virological response in 27 out of 40 (68%). The immunological response to HAART had a positive impact on OS and EFS (p=0.002 and p=0.001, respectively).
In patients with advanced stage, HIV-related HL, treatment with ABVD together with HAART is feasible and effective. This supports the concept that patients with HIV-related HL should be treated in the same way as immunocompetent patients if HAART, adequate supportive therapy and anti-infectious prophylaxis are given concomitantly. An immunological response to HAART has a positive impact on OS and EFS.
Cochlear sound encoding depends on α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs), but reliance on specific pore-forming subunits is unknown. With 5-week-old male C57BL/6J
...-knockout mice (i.e., subunit GluA3
) we determined cochlear function, synapse ultrastructure, and AMPAR molecular anatomy at ribbon synapses between inner hair cells (IHCs) and spiral ganglion neurons. GluA3
and wild-type (GluA3
) mice reared in ambient sound pressure level (SPL) of 55-75 dB had similar auditory brainstem response (ABR) thresholds, wave-1 amplitudes, and latencies. Postsynaptic densities (PSDs), presynaptic ribbons, and synaptic vesicle sizes were all larger on the modiolar side of the IHCs from GluA3
, but not GluA3
, demonstrating GluA3 is required for modiolar-pillar synapse differentiation. Presynaptic ribbons juxtaposed with postsynaptic GluA2/4 subunits were similar in quantity, however, lone ribbons were more frequent in GluA3
and GluA2-lacking synapses were observed only in GluA3
. GluA2 and GluA4 immunofluorescence volumes were smaller on the pillar side than the modiolar side in GluA3
, despite increased pillar-side PSD size. Overall, the fluorescent puncta volumes of GluA2 and GluA4 were smaller in GluA3
than GluA3
. However, GluA3
contained less GluA2 and greater GluA4 immunofluorescence intensity relative to GluA3
(threefold greater mean GluA4:GluA2 ratio). Thus, GluA3 is essential in development, as germline disruption of
caused anatomical synapse pathology before cochlear output became symptomatic by ABR. We propose the hearing loss in older male GluA3
mice results from progressive synaptopathy evident in 5-week-old mice as decreased abundance of GluA2 subunits and an increase in GluA2-lacking, GluA4-monomeric Ca
-permeable AMPARs.
The epithelial junctional complex, composed of tight junctions, adherens junctions, desmosomes, and an associated actomyosin cytoskeleton, forms the apical junctional ring (AJR), which must maintain ...its continuity in the face of external mechanical forces that accompany normal physiological functions. The AJR of umbrella cells, which line the luminal surface of the bladder, expands during bladder filling and contracts upon voiding; however, the mechanisms that drive these events are unknown. Using native umbrella cells as a model, we observed that the umbrella cell's AJR assumed a nonsarcomeric organization in which filamentous actin and ACTN4 formed unbroken continuous rings, while nonmuscle myosin II (NMMII) formed linear tracts along the actin ring. Expansion of the umbrella cell AJR required formin-dependent actin assembly, but was independent of NMMII ATPase function. AJR expansion also required membrane traffic, RAB13-dependent exocytosis, specifically, but not trafficking events regulated by RAB8A or RAB11A. In contrast, the voiding-induced contraction of the AJR depended on NMMII and actin dynamics, RHOA, and dynamin-dependent endocytosis. Taken together, our studies indicate that a mechanism by which the umbrella cells retain continuity during cyclical changes in volume is the expansion and contraction of their AJR, processes regulated by the actomyosin cytoskeleton and membrane trafficking events.
During development and adulthood, the normal activity of the auditory nerve plays a critical role in the maintenance of both fundamental structural, molecular, and functional parameters of auditory ...nerve synapses, and the postsynaptic excitatory or inhibitory neurons within the cochlear nucleus (CN). In addition, normal activity within the synaptic circuits of the CN is key to developing and maintaining appropriate synapse connectivity as well as the initiation of binaural sound processing in the superior olivary complex (SOC). Development plays a critical role in the proper neuronal connectivity and establishes a topographic map along the entire auditory pathway. Furthermore, evidence shows that neurons and synaptic circuits in the auditory brainstem are not hard-wired, but instead are plastic in response to hearing deficits. Whether this plasticity in response to hearing loss is compensatory or pathological is still unknown.
It has been long assumed that post-mitotic neurons only utilize the error-prone non-homologous end–joining pathway to repair double-strand breaks (DSBs) associated with oxidative damage to DNA, given ...the inability of non-replicating neuronal DNA to utilize a sister chromatid template in the less error-prone homologous recombination (HR) repair pathway. However, we and others have found recently that active transcription triggers a replication-independent recombinational repair mechanism in G0/G1 phase of the cell cycle. Here we observed that the HR repair protein RAD52 is recruited to sites of DNA DSBs in terminally differentiated, post-mitotic neurons. This recruitment is dependent on the presence of a nascent mRNA generated during active transcription, providing evidence that an RNA-templated HR repair mechanism exists in non-dividing, terminally differentiated neurons. This recruitment of RAD52 in neurons is decreased by transcription inhibition. Importantly, we found that high concentrations of amyloid β, a toxic protein associated with Alzheimer’s disease, inhibits the expression and DNA damage response of RAD52, potentially leading to a defect in the error-free, RNA-templated HR repair mechanism. This study shows a novel RNA-dependent repair mechanism of DSBs in post-mitotic neurons and demonstrates that defects in this pathway may contribute to neuronal genomic instability and consequent neurodegenerative phenotypes such as those seen in Alzheimer’s disease.