Anterior cruciate ligament-derived cells have high chondrogenic potential

Anterior cruciate ligament (ACL)-derived cells have a character different from medial collateral ligament (MCL)-derived cells. However, the critical difference between ACL and MCL is still unclear in their healing potential and cellular response. The objective of this study was to investigate the mesenchymal differentiation property of each ligament-derived cell. Both ligament-derived cells differentiated into adipogenic, osteogenic, and chondrogenic lineages. In chondrogenesis, ACL-derived cells had the higher chondrogenic property than MCL-derived cells. The chondrogenic marker genes, Sox9 and α1(II) collagen (Col2a1), were induced faster in ACL-derived pellets than in MCL-derived pellets. Sox9 expression preceded the increase of Col2a1 in both pellet-cultured cells. However, the expression level of Sox9 and a ligament/tendon transcription factor Scleraxis did not parallel the increase of Col2a1 expression along with chondrogenic induction. The present study demonstrates that the balance between Sox9 and Scleraxis have an important role in the chondrogenic differentiation of ligament-derived cells

Mechanical stretch stimulates integrin αVβ3-mediated collagen expression in human anterior cruciate ligament cells

Biomechanical stimuli have fundamental roles in the maintenance and remodeling of ligaments including collagen gene expressions. Mechanical stretching signals are mainly transduced by cell adhesion molecules such as integrins. However, the relationships between stress-induced collagen expressions and integrin-mediated cellular behaviors are still unclear in anterior cruciate ligament cells. Here, we focused on the stretch-related responses of different cells derived from the ligament-to-bone interface and midsubstance regions of human anterior cruciate ligaments. Chondroblastic interface cells easily lost their potential to produce collagen genes in non-stretched conditions, rather than fibroblastic midsubstance cells. Uni-axial mechanical stretches increased the type I collagen gene expression of interface and midsubstance cells up to 14- and 6-fold levels of each non-stretched control, respectively. Mechanical stretches also activated the stress fiber formation by shifting the distribution of integrin αVβ3 to the peripheral edges in both interface and midsubstance cells. In addition, integrin αVβ3 colocalized with phosphorylated focal adhesion kinase in stretched cells. Functional blocking analyses using anti-integrin antibodies revealed that the stretch-activated collagen gene expressions on fibronectin were dependent on integrin αVβ3-mediated cellular adhesions in the interface and midsubstance cells. These findings suggest that the integrin αVβ3-mediated stretch signal transduction might have a key role to stimulate collagen gene expression in human anterior cruciate ligament, especially in the ligament-to-bone interface

Combined use of bFGF and GDF-5 enhances the healing of medial collateral ligament injury

Basic fibroblast growth factor (bFGF) and growth and differentiation factor (GDF)-5 stimulate the healing of medial collateral ligament (MCL) injury. However, the effect of isolated and combined use of bFGF/GDF-5 remains still unclear. We investigated cellular proliferation and migration responding to bFGF/GDF-5 using rabbit MCL fibroblasts. Rabbit MCL injury was treated by bFGF and/or GDF-5 with peptide hydrogels. Gene expression and deposition of collagens in healing tissues were evaluated. bFGF/GDF-5 treatment additively enhanced cell proliferation and migration. bFGF/GDF-5 hydrogels stimulated Col1a1 expression without increasing Col3a1 expression. Combined use of bFGF/GDF-5 stimulated type I collagen deposition and the reorganization of fiber alignment, and induced better morphology of fibroblasts in healing MCLs. Our study indicates that combined use of bFGF/GDF-5 might enhance MCL healing by increasing proliferation and migration of MCL fibroblasts, and by regulating collagen synthesis and connective fiber alignment

Topical insulin-like growth factor 1 treatment using gelatin hydrogels for glucocorticoid-resistant sudden sensorineural hearing loss: a prospective clinical trial

<p>Abstract</p> <p>Background</p> <p>Sudden sensorineural hearing loss (SSHL) is a common condition in which patients lose the hearing in one ear within 3 days. Systemic glucocorticoid treatments have been used as standard therapy for SSHL; however, about 20% of patients do not respond. We tested the safety and efficacy of topical insulin-like growth factor 1 (IGF1) application using gelatin hydrogels as a treatment for SSHL.</p> <p>Methods</p> <p>Patients with SSHL that showed no recovery to systemic glucocorticoid administration were recruited. We applied gelatin hydrogels, impregnated with recombinant human IGF1, into the middle ear. The primary outcome measure was the proportion of patients showing hearing improvement 12 weeks after the test treatment. The secondary outcome measures were the proportion of patients showing improvement at 24 weeks and the incidence of adverse events. The null hypothesis was that 33% of patients would show hearing improvement, as was reported for a historical control after hyperbaric oxygen therapy.</p> <p>Results</p> <p>In total, 25 patients received the test treatment at a median of 23 days (range 15-32) after the onset of SSHL, between 2007 and 2009. At 12 weeks after the test treatment, 48% (95% CI 28% to 69%; <it>P </it>= 0.086) of patients showed hearing improvement, and the proportion increased to 56% (95% CI 35% to 76%; <it>P </it>= 0.015) at 24 weeks. No serious adverse events were observed.</p> <p>Conclusions</p> <p>Topical IGF1 application using gelatin hydrogels is well tolerated and may be efficacious for hearing recovery in patients with SSHL that is resistant to systemic glucocorticoids.</p

Marine teleost locates live prey through pH sensing

We report that the Japanese sea catfish Plotosus japonicus senses local pH-associated increases in H(+)/CO2 equating to a decrease of ≤0.1 pH unit in ambient seawater. We demonstrated that these sensors, located on the external body of the fish, detect undamaged cryptic respiring prey, such as polychaete worms. Sensitivity is maximal at the natural pH of seawater (pH 8.1 to 8.2) and decreases dramatically in seawater with a pH \u3c8.0

Gustatory responses of the rainbow trout (Salmo gairdneri) palate to amino acids and derivatives

Summary1.Gustatory responses to amino acids and derivatives obtained from the palatine nerve (VIIth cranial nerve) of rainbow trout (Salmogairdneri) were studied. 2.The response to an amino acid was characterized by its fast-adapting, phasic nature that returned to baseline within 5 s during continuous stimulation. 3.Complete recovery of the response took place 120 s after stimulation when tested with two identical stimuli given successively (Figs. 2, 3). 4.Among common amino acids tested, onlyL-isomers of proline, hydroxyproline, alanine, leucine, and phenylalanine were stimulatory (Table 1), demonstrating that the facial taste system is more narrowly-tuned to amino acid stimuli than the olfactory system. The arginine derivative,L-α-amino-β-guanidinopropionic acid (L-AGPA) andL-argininic acid, and betaine were also effective. 5.Concentration-response relations, when plotted semi-logarithmically, were generally sigmoidal, saturating at higher concentrations ( \u3e 1 mM) (Fig. 5). The threshold concentration forL-proline, the most effective amino acid tested, was estimated to be 50 nM. The thresholds for other stimulatory chemicals ranged between 1 and 100 μM. 6.L-AGPA, though having higher threshold (10 μM), could induce responses three times the magnitude of that ofL-proline at 1 mM. 7.The stimulatory activity of heterocyclic-imino acids having 4-, 5-, and 6-membered rings and also of thioproline and hydroxyproline suggests that the receptor recognizes primarily the imino acid region (Fig. 6). 8.Taste responses to amino acids were independent of pH, except that arginine analogues were only active at basic pHs (Fig. 7 and Table 3). larginine was active only at pHs higher than 8.5. The palatal chemoreceptors were stimulated by waters with pHs below 7.0, suggesting the existence of receptors for pH and/or CO2 (Fig. 7)

Amino acid specificity of fibers of the facial/trigeminal complex innervating the maxillary barbel in the Japanese sea catfish, Plotosus japonicus

The Japanese sea catfish, Plotosus japonicus, possesses taste and solitary chemoreceptor cells (SCCs) located on the external body surface that detect specific water-soluble substances. Here, we identify two major fiber types of the facial/trigeminal complex that transmit amino acid information to the medulla. Both single and few fiber preparations respond to amino acid stimulation in the 0.1 μM to mM range. One fiber type responds best to glycine and l-alanine (i.e. Gly/Ala fibers) whereas the other fiber type is best stimulated by l-proline and glycine betaine (hereafter referred to only as betaine) (i.e. Pro/Bet fibers). We demonstrate that betaine, which does not alter the pH of the seawater and therefore does not activate the animals\u27 highly sensitive pH sensors (Caprio et al., Science 344:1154-1156, 2014), is sufficient to elicit appetitive food search behavior. We further show that the amino acid specificity of fibers of the facial/trigeminal complex in P. japonicus is different from that in Ariopsis felis (Michel and Caprio, J. Neurophysiol. 66:247-260, 1991; Michel et al., J. Comp. Physiol. A. 172:129-138, 1993), a representative member of the only other family (Ariidae) of extant marine catfishes