When you mention trials of ear injections with 35 decibel increases, have you ever posted these, please post.
Sorry, it was 30 dB, not 35 dB. 30dB is still very significant.
Here is a collection of quotes from the study.
Growth factors and hair cells:
"As factors that effectively induce HC protection and regeneration, growth factors are considered good candidates. Growth factors are humoral factors, which bind to their specific receptors on the cell membrane to activate intracellular signaling in order to exert their effects. Growth factors play important roles during cell proliferation, differentiation, transdifferentiation, and survival (Anderson, 1989; Bhowmick et al., 2001; Cattaneo and McKay, 1990; Gao et al., 1995; Ghosh and Greenberg, 1995)."
What IGF-1 is:
"IGF1 was isolated from human serum in the 1950s (Salmon and Daughaday, 1957). At first, it was named somatomedin-C, but renamed because of the high degree of sequence identity between IGF1 and insulin. IGF1 has nonsuppressible insulin-like and cell growth-promoting activities (Rinderknecht and Humbel, 1978)."
First clinical trial:
"Based on the findings reviewed in Section 4, clinical trials were performed to study the efficacy of IGF1 in the treatment of SSHL. First, a phase I/II clinical trial was performed to assess the safety and efficacy of IGF1 (UMIN-CTRR000000936) (Nakagawa et al., 2012, 2010). SSHL that was refractory to systemic steroid therapy was selected as the target disease for the clinical trial. Patients (n ¼ 25) with definite SSHL and with no recovery after systemic glucocorticoid treatment for more than 7 days were recruited within 29 days of SSHL onset."
Trial outcomes:
"Hearing improvement at 24 weeks after IGF1 treatment was found to be statistically significant at all five frequencies compared with the hearing levels of the patients at registration. A time course analysis of the changes in hearing threshold revealed that hearing recovery after topical IGF1 treatment occurred during the initial 4 weeks in the majority of patients, but that further recovery (>20 dB) was evident in some patients at a later stage (Nakagawa et al., 2012). No serious adverse events associated with the test treatment occurred during this trial."
Second trial:
"Based on the result of the phase I/II clinical trial described in 5.1., a randomized clinical study was performed (UMIN000004366). Treatment with intra-tympanic steroids, which has been widely used to treat systemic glucocorticoid-resistant SSHL (Choung et al., 2006; Haynes et al., 2007; Ho et al., 2004; Kakehata et al., 2011; Lee et al., 2010; Plontke et al., 2005; Roebuck and Chang, 2006), was chosen as the control treatment (Nakagawa et al., 2014)."
Involved 120 patients:
"Patients (n = 120) were recruited from nine tertiary referral hospitals in Japan and were randomly selected to receive either gelatin hydrogel impregnated with IGF1 on the round window membrane (62 patients) or intratympanic injections with Dex (58 patients)."
Trial outcomes:
"In the IGF1 group, 66.7% (95% CI, 52.9e78.6%) of the patients showed hearing improvement compared to 53.6% (95% CI, 39.7e67.0%) of the patients in the Dex group. There was no significant difference between the proportion of patients with improved hearing in each group (p ＝0.109), primarily because an unexpectedly high proportion of patients showed hearing improvements after Dex therapy compared with previous reports (Choung et al., 2006; Haynes et al., 2007; Ho et al., 2004; Kakehata et al., 2011; Nakagawa, 2014; Nakagawa et al., 2014; Plontke et al., 2005; Roebuck and Chang, 2006). A trend, however, was observed: a higher proportion of patients with 30 dB HL improvements in pure-tone average hearing thresholds was measured for the IGF1 group than in that the intra-tympanic steroids group."
IGF-1 is safe and possibly superior:
"In this trial, no adverse events were observed. The findings of this trial suggest that IGF1 is an effective treatment for SSHL and that IGF1 is a similar or superior therapy compared with intra-tympanic Dex therapy"
Explant cochleas studied with IGF-1:
"The mechanisms of IGF1- induced maintenance of HC number have been evaluated using a cochlear explant culture system (Hayashi et al., 2013)"
"In this study, IGF1 treatment was found to result in the maintenance of both inner and outer HC numbers as shown for the in vivo application of IGF1 for cochlear damage"
"These observations indicate that IGF1 induces the maintenance of HC numbers by activating SCs (Fig. 2)."
IGF-1 is protecting and possibly regenerating hair cells:
"In this review, IGF1 has been described as a novel and potent treatment for SNHL, potentially via HC protection and regeneration."
Source:
Hearing Research 330 (2015) 2e9
Insulin-like growth factor 1: A novel treatment for the protection or regeneration of cochlear hair cells
Kohei Yamahara, Norio Yamamoto* , Takayuki Nakagawa, Juichi Ito Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606- 8507, Japan
I personally have Japanese motorcycles myself. Harley's are too loud and too expensive. A hauling ass head ringer without a care in the world.
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