losartan-potassium and Hearing-Loss

The problem of hearing loss occurrence in the course of chronic renal failure (CRF) was investigated in numerous research studies, attempting to explain both the etiological factors and treatment possibilities. According to various authors, the percentage of hearing loss occurrence in patients suffering from CRF differs between 20% and 80%. The idea of this paper is based on an observation that if peripheral blood parameters such; haemoglobin, amount of red blood cells improve when influenced by rhEPO, then tissue oxidation improvement connected with it causes also better metabolism of cilliar's cells, what helps to improve hearing. The purpose of this study has been to assess the influence of treatment with human recombinant erythropoietin obtained through genetic recombination and by haemodialysis upon the condition of the hearing organ in patients with CRF (as a result of both a single procedure and long-term treatment). 65 haemodialysed patients with chronic renal failure were enrolled in this study. 31 of them (with haematocrit value below 28%) were treated with rhEPO for 4 months (3 times a week, 4000 units). The remaining 34 patients (with haematocrit values of above 28%) were not treated with rhEPO. Impairment of hearing was found in 87.1% of the CRF patients examined, while the hearing loss in high frequency range (9-18 kHz) was significantly more pronounced than those observed in the conventional range. In 70% of the patients the hearing loss was the cochlear type. Thus, combining haemodialysis with recombinant human erythropoietin in treatment of CRF patients results in significant improvement of hearing, correlated with positive results in fighting anaemia. The improved hearing found is, most surely, related to better oxygen supply of ciliated cells of internal ear, resulting from improved oxygen supply in peripheral blood and tissues of the body, and may also be related to the centric activity of erythropoietin, as the presence of receptors for EPO was found in the central nervous system (CNS) neurocytes, and it was also proven that EPO is produced in CNS, probably in astrocytes.

Topics: Adult; Anemia; Audiometry; Combined Modality Therapy; Erythropoietin; Female; Hearing; Hearing Loss; Humans; Kidney Failure, Chronic; Male; Middle Aged; Recombinant Proteins; Renal Dialysis; Time Factors; Treatment Outcome

The present study aimed to determine the expression of erythropoietin (EPO) and the EPO receptor (EPOR) in spiral ganglion neurons (SGNs) in the inner ear of rats of various ages, and the associated neuronal apoptosis and hearing alterations. A total of 15 healthy rats (n=30 ears), were divided into three groups: i) A nominated infant group at post‑natal day (PND) 12‑14, ii) an adult group at PND 60 and iii) a 3‑year postnatal aged group. Auditory brainstem response (ABR) measurements were performed on all rats. EPO and EPOR expression in the inner ear was detected by immunohistochemistry. In situ terminal deoxynucleotidyl transferase dUTP nick end labeling assays were performed to detect the apoptosis of SGNs. The average hearing thresholds of the ABR (decibels above normal hearing level) were 5.625±4.955 in the infant, 15.000±8.498 in the adult and 23.500±13.134 in the aged groups. Hearing thresholds for aged and adult rats increased significantly compared with infant rats. However, the difference in latencies of peak I was not significant (P>0.05). EPO in SGNs was detected during different developmental periods without significant alterations, but were reduced compared with Corti's organ or the stria vascularis. EPOR expression increased significantly from infant to adult stage, and this increased expression was maintained in the aged group. An age‑associated increase in the apoptosis of SGNs was detected in all three groups (P=0.0347). The potential neuroprotective effects of EPO in SGNs may not be revealed during the aging process under natural conditions, and may be associated with spontaneous neuronal apoptosis and consequently, hearing diminution. However, the age‑associated increase in EPOR in SGNs may exert a role in neuroprotection when necessary, for example in presbycusis.

Topics: Aging; Animals; Apoptosis; Ear, Inner; Erythropoietin; Female; Hearing Loss; Hearing Tests; Immunohistochemistry; Male; Neurons; Presbycusis; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Spiral Ganglion

The aim of this study is to test the hypotheses that central auditory pathology as well as inner ear pathology is contributing mechanisms to observed hypoxic-ischemic encephalopathy (HIE) induced hearing loss and that recombinant erythropoietin (rhEPO) will reduce this cellular pathology and attenuate hearing loss.. Twenty-eight 7-day Wistar albino rat pups were divided into four groups: Control group (n=8) was given only intraperitoneal saline solution. Sham group (n=5) had only a midline neck incisions without carotid ligation under general anesthesia and administration of intraperitoneal saline solution. HIE group (n=8) and rhEPO treated group (n=7) were subjected to left common carotid artery ligation followed by 2.5h hypoxia exposure to a mixture of 8% oxygen and 92% pure nitrogen. HIE group was injected with intraperitoneal saline solution, while the rhEPO treated group received rhEPO 100 U/kg within the same volume as the saline-alone solution. At the end of the seventh week of age hearing (ABRs) was evaluated in response to clicks, 6 kHz and 8 kHz tone burst stimuli. Animals were sacrificed and both temporal lobes, cochleas and brainstems of the animals were collected. Tissue samples were evaluated with light microscopy, immunohistochemical studies, including TUNEL and caspase-3 stainings, and electron microscopy.. Hearing thresholds were elevated in HIE animals. In rhEPO treated animals, ABR values were similar to controls. HIE caused apoptotic changes in brainstem structures as shown by light microscopy and immunohistochemical methods. Apoptotic changes also were found within the organ of Corti, spiral ganglion cells and neurons of temporal lobe by electron microscopic investigation. In rhEPO animals many of these apoptotic changes were observed, but reduced compared to untreated animals.. Mechanisms underlying HIE-induced hearing loss are based on apoptosis in inner ear; however central auditory pathway pathology occurs as well, likely contributing to changes in auditory processing and perception of complex signals not reflected by the ABR threshold shifts. For both clinical and basic significance 'rhRPO' is found to reduce those effects.

Topics: Animals; Apoptosis; Caspase 3; Disease Models, Animal; Erythropoietin; Evoked Potentials, Auditory, Brain Stem; Female; Hearing Loss; Humans; Hypoxia-Ischemia, Brain; Immunohistochemistry; In Situ Nick-End Labeling; Infant, Newborn; Male; Rats; Rats, Wistar; Recombinant Proteins; Spiral Ganglion

An animal model of cochlear implantation has been developed, and the hearing threshold was evaluated after different surgical procedures. The effect of perioperative systemic administration of erythropoietin on the hearing loss induced by cochlear implantation was tested.. Twenty-nine guinea pigs with normal hearing underwent implantation of a 254-microm-diameter array through a cochleostomy. The effects on hearing of cochleostomy and transient and long-term array implantation (21 days) were assessed by testing of the auditory brain stem responses and compound action potentials. Eleven implanted animals received intraperitoneal administration of erythropoietin. Selected computed tomographic scans and cochlear histologic studies were performed 1 month after implantation to confirm proper placement of the array. The erythropoietin concentration at the time of surgery was assessed in samples of perilymph, cerebrospinal fluid, and blood.. The cochleostomy and transient array insertion had no effect on hearing thresholds. Long-term array implantation induced a stable decrease of hearing threshold (30 dB), a decrease that was reduced by 12 dB in erythropoietin-treated animals. The erythropoietin-treated animals had better hearing preservation at higher frequencies. Fibrosis surrounding the array was seen in both groups.. The hearing loss observed was probably due to the presence of the array in the cochlea. The intraperitoneal injection of erythropoietin improved the hearing threshold shift induced by implantation.

Topics: Action Potentials; Animals; Auditory Threshold; Cochlear Implantation; Disease Models, Animal; Erythropoietin; Evoked Potentials, Auditory, Brain Stem; Guinea Pigs; Hearing Loss; Injections, Intraperitoneal; Male; Treatment Outcome