The implication of this study I think is that CRISPR or other gene therapy technology could potentially be used to elevate Chondromodulin levels to either quicken limb lengthening surgery or maybe induce ectopic cartilage formation?
“Chondromodulin (Cnmd) is a glycoprotein known to stimulate chondrocyte growth. We examined in this study the expression and functional role of Cnmd during distraction osteogenesis that is modulated by mechanical forces. The right tibiae of the mice were separated by osteotomy and subjected to slow progressive distraction using an external fixator. In situ hybridization and immunohistochemical analyses of the lengthened segment revealed that Cnmd mRNA and its protein in wild-type mice were localized in the cartilage callus, which was initially generated in the lag phase and was lengthened gradually during the distraction phase. In Cnmd null (Cnmd−/−) mice, less cartilage callus was observed, and the distraction gap was filled by fibrous tissues. Additionally, radiological and histological investigations demonstrated delayed bone consolidation and remodeling of the lengthened segment in Cnmd−/− mice. Eventually, Cnmd deficiency caused a one-week delay in the peak expression of VEGF, MMP2, and MMP9 genes and the subsequent angiogenesis and osteoclastogenesis. We conclude that Cnmd is necessary for cartilage callus distraction.“
So CNMD gene therapy could potentially be used to treat non-unions in limb lengthening surgery too.
“Cnmd−/− mice did not show abnormalities in cartilage development or endochondral bone formation during embryogenesis or normal growth, and further did not affect natural articular cartilage development. Thus, Cnmd functions as a chondrocyte modulator in specific conditions, causing osteogenesis such as cartilage or bone injury, but not in normal cartilage development and growth.”
“the relationship between mechanical stress and Cnmd in the process of cartilage callus formation during bone repair/regeneration.”<-Perhaps we could induce Cnmd via other mechanical stress mechanisms?
“We focused on distraction osteogenesis, which involves an osteotomy followed by a slow progressive distraction to lengthen congenitally or traumatically shortened extremities”
“Cnmd could directly stimulate chondrocyte proliferation and proteoglycan synthesis in vitro“
“Cnmd is required for cartilage callus formation due to tensile stress on the periosteum and is less involved in it due to hydrostatic pressure between the gaps”<-we can induce hydrostatic pressure and tensile stress via other mechanisms.
” the gap tissue is subject to approximately 15% deformation (compression and tension) during walking in a rabbit tibial lengthening model, indicating that compression as well as tensile forces act on the gap tissue during the distraction phase”
” the fibula spontaneously fractured during the distraction phase and lengthened in the same manner as the tibia.”
“increased expression of Tnmd mRNA in Cnmd−/− mice at the distraction phase. Tnmd is a type II transmembrane protein that shares a cysteine-rich domain with Cnmd at the C-terminus”<-we actually want Tnmd to increase as Tendons are one of the limiting factors in the amount of growth you can get in limb lengthening surgery.
“Tnmd mRNA expression was strongly upregulated by 5% axial cyclic strain in tendon stem/progenitor cells”
“elongation of cartilage callus during distraction osteogenesis was suppressed in Cnmd−/− mice and subsequent bone formation and remodeling slowed and partially failed. The study results indicate that Cnmd-mediated cartilage callus elongation is necessary for distraction osteogenesis and Cnmd could be a mechanical response chondrogenic factor. New insights into the function of Cnmd may establish this molecule as a candidate therapeutic agent for successful bone healing.”
Yam-derived exosome-like nanovesicles stimulate osteoblast formation and prevent osteoporosis in mice
“Plants-releasing exosome-like nanovesicles (PENs) contain miRNA, bioactive lipids, mRNAs, and proteins to exert antioxidant, anti-inflammatory, and regenerative activity. Substances extracted from yams have been reported to promote osteoblast growth in bone regeneration, which prevent weak and brittle bones in osteoporosis. Herein, we describe the beneficial effects of yam-derived exosome-like nanovesicles (YNVs) on promoting differentiation and mineralization of osteoblasts for bone regeneration in ovariectomized (OVX)-induced osteoporotic mice. YNVs were successfully isolated and characterized. YNVs stimulate the proliferation, differentiation, and mineralization of osteoblasts with increased bone differentiation markers (OPN, ALP, and COLI). Interestingly, YNVs do not contain saponins including diosgenin and dioscin known to mainly exert osteogenic activity of yams. Instead, the osteogenic activity of YNVs was revealed to be resulted from activation of the BMP-2/p-p38-dependent Runx2 pathway{and BMP2 can stimulate longitudinal bone growth}. As a result, YNVs promote longitudinal bone growth and mineral density of the tibia in the OVX-induced osteoporotic mice in vivo, and these results positively correlate the significant increases in osteoblast-related parameters. In addition, the orally administered YNVs were transported through the GI tract and absorbed through the small intestine. These results showed an excellent systemic biosafety determined by histological analysis and liver/kidney toxicity tests. Taken together, YNVs can serve as a safe and orally effective agent in the treatment of osteoporosis{and possibly growing taller pre-skeletal maturity}.”
Looking at slide 3 the Yam group looks significantly longer.
“Plants release exosome-like nanovesicles (PENs) containing miRNA, bioactive lipids, mRNAs, and proteins into their extracellular spaces, and these PENs serve as extracellular messengers that stimulate cell-cell communication and biological defense against pathological diseases. Recently, PENs have been widely explored as a drug delivery system in various therapeutics by isolating diverse plant sources including starchy roots and tubers, nuts and seeds, as well as fresh and dried plants”
“safe, biocompatible, and biodegradable without any negative effects on intestinal barrier function or other organ toxicities, but can also be prepared in large amounts.”
I couldn’t get this full study to check how significantly it influenced longitudinal bone growth.
The next study suggests that mechanisms that inhibit SPIN4 whether via gene therapy or supplements etc may be a way to enhance longitudinal bone growth. The next study is also by Jeffrey Baron who is huge in growth research.
A new genetic cause of overgrowth syndrome
“Pathogenic genetic variants in epigenetic regulatory proteins can cause overgrowth syndromes, such as Sotos syndrome due to mutations in NSD1 or Weaver syndrome due to mutations in EZH2. The identified genes encode DNA or histone methyltransferases, primarily serving as epigenetic writers. However, no overgrowth disorder has previously been described in a gene that acts primarily as an epigenetic reader{epigenetics are involved in delaying growth plate senescence so epigenetic alterations may keep growth plates open for longer}. We studied a 13-year-old male patient with generalized overgrowth of prenatal onset. His birth weight and length were 5.85 kg (+4.3 SDS) and 62 cm (+4.8 SDS), respectively. His height growth was striking at > +4 SDS without a significantly advanced bone age, eventually requiring epiphysiodesis at age 13 to reduce his adult height{I don’t know why they would do this with all the advantages of tall stature}. His timing of puberty was as expected. His biochemical studies, including IGF-1, were all negative. Karyotype, mutation analysis in NSD1 for Sotos syndrome, and chromosome 11p15 analysis (MLPA and methylation) for Beckwith-Wiedemann syndrome were normal. Furthermore, he had normal development and intelligence. His mother and maternal grandmother showed a significant height gain (+2 SDS gain) compared to their midparental height, suggesting an X-linked semi-dominant inheritance. Exome sequencing on the extended family identified a frameshift variant (NM_001012968.3, c.312_313AGdel) in Spindlin 4 (SPIN4), one of the epigenetic readers, with X-linked inheritance. Neither this variant nor any other loss-of-function variant in SPIN4 was present in a population database (gnomAD). In functional studies, we found evidence that SPIN4 binds specific histone modifications, promotes canonical WNT signaling, inhibits cell proliferation in vitro, and that the identified frameshift variant had lost all of these functions.Ablation of Spin4 in mice (either male or female) recapitulated the human phenotype with generalized overgrowth, including increased longitudinal bone growth{so SPIN4 inhibitors during development may stimulate longitudinal bone growth?}. Growth plate analysis revealed increased cell proliferation in the proliferative zone and an increased number of progenitor chondrocytes in the resting zone. We also found evidence of decreased canonical Wnt signaling in growth plate chondrocytes, providing a potential explanation for the increased number of resting zone chondrocytes. In conclusion, our findings provide strong evidence that SPIN4 is an epigenetic reader that negatively regulates mammalian body growth and that loss of SPIN4 causes an overgrowth syndrome in humans, expanding our knowledge of the epigenetic regulation of human growth.”
I can’t get this fully study yet but I will keep trying.
There’s not a lot of data on SPIN4 so this is really a novel finding. I also can’t find any research on compounds other than antibodies that inhibit SPIN4.
I tried not to information dump as much this time but I did last. So I didn’t press him enough on the Kleinburg paper. I also haven’t really explained fluid flow theory so I will have to do a video on that.
I touched on everything I wanted to touch(obviously not in as much detail) in but I wanted to add that one advantage that an exercise based routine would have over the surgery is that it would provide potentially daily stimulation to bones and could have anti-aging effect as bones are reservoir of stem cells for other tissues.
NMN is a popular supplement in the longevity circles. But can it boost height gain? IT’s also possible that Niacin supplementation could increase if NMN can as Niacin and NMN are related. NMN is derived from Niacin and NMN is part of the Vitamin B3 family. But NMN likely only will increase height if taken early in development but it is also possible that NMN will only increase height if one is deficient.
“Sirtuin 6 (Sirt6) is a mammalian homologue of NAD1-dependent histone deacetylase Sir2. Although Sirt6-KO mice exhibit growth retardation”
“In Sirt6-KO mice exhibited impaired proliferation and differentiation of chondrocytes, reduced expression of Indian hedgehog (Ihh), and a senescent phenotype. When Sirt6 was knocked down in chondrocytes in vitro, expression of Ihh and its downstream genes were reduced.”
“stress-response and chromatin-silencing factor Sir2, a yeast sirtuin, is a NAD1-dependent histone deacetylase and is involved in various nuclear actions”
“Sirt6 inhibits inflammation by suppressing NF-kB target molecules via interaction with the RelA subunit of NF-kB and by deacetylating H3K9 at target promoters”
“Sirt6–null mice exhibit dwarfism”
Here’s the part of the study about NMN:
“to study the effect of gain of Sirt6 activity on chondrocyte differentiation, nicotinamide mononucleotide (NMN), a key NAD1 intermediate, was administered to ATDC5 cells. NMN facilitates activity of sirtuins through enhancement of NAD biosynthesis. NMN administration enhanced Col10a1 expression together with increased expression of Ihh and Gli1, and these effects were clearly abrogated by Sirt6 silencing”
“NMN treatment enhanced Col10a1, Ihh and Gli1”
This study here:
Nicotinamide Mononucleotide Alleviates Osteoblast Senescence Induction and Promotes Bone Healing in Osteoporotic Mice
says that NMN can “NMN supplementation attenuates senescent cell induction in growth plates”<- so it’s possible NMN can keep the growth plates open for longer. Couldn’t get the full study though.
“NMN supplementation stimulated osteogenesis of endogenous MSCs, and protected bone from aging and irradiation induced damage in mice. Mechanistically, we found that NMN treatment upregulated SIRT1”
It should be noted that NMN is available in foods and laboratory animals tend not to have the most diverse diets. So we don’t know if enough NMN is gotten from foods.
There are studies in mice/rats that show that swimming increases bone length. But the kind of swimming that rats due is different than the kind of swimming that humans do.
The kind of swimming that rats/mice do is more akin to doggy paddling style swimming. This is doggy paddling that kind of mimics what the rat is doing but I think the rat style of doggy peddling is more upright.
This style may grow the arms but not the legs as when you’re upright there’s more load on the bones and more torsion. And I believe that torsion is why tennis players get longer arms and also some weightlifters. There’s more torsional load on the arms than the legs as arms can grip things. Hence why there’s more anecdotal evidence of arms growing in length rather than legs but that does not mean mechanisms to grow in the legs do not exist.
Effects of swimming training on bone mass and the GH/IGF-1 axis in diabetic rats
“The aim of this study was to examine the influence of moderate swimming training on the GH/IGF-1 growth axis and tibial mass in diabetic rats. Male Wistar rats were allocated to one of four groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD) and trained diabetic (TD). Diabetes was induced with alloxan (35 mg/kg b.w.). The training program consisted of a 1 h swimming session/day with a load corresponding to 5% of the b.w., five days/week for six weeks. At the end of the training period, the rats were sacrificed and blood was collected for quantification of the serum glucose, insulin, GH, and IGF-1 concentrations. Samples of skeletal muscle were used to quantify the IGF-1 peptide content. The tibias were collected to determine their total area, length and bone mineral content. The results were analyzed by ANOVA with P < 0.05 indicating significance. Diabetes decreased the serum levels of GH and IGF-1, as well as the tibial length, total area and bone mineral content in the SD group (P < 0.05). Physical training increased the serum IGF-1 level in the TC and TD groups when compared to the sedentary groups (SC and SD), and the tibial length, total area and bone mineral content were higher in the TD group than in the SD group (P < 0.05). Exercise did not alter the level of IGF-1 in gastrocnemius muscle in nondiabetic rats, but the muscle IGF-1 content was higher in the TD group than in the SD group. These results indicate that swimming training stimulates bone mass and the GH/IGF-1 axis in diabetic rats.”
Columns: SC – sedentary control, TC – trained control, SD – sedentary diabetic, TD – trained diabetic. So the swimming groups had non-statistically significant increases in bone length between sedentary and trained control and statistically significant between sedentary diabetic and trained diabetic.
Here’s another study that finds an increase in bone length:
The Effect of Swimming on Bone Modeling and Composition in Young Adult Rats
“The purpose of this study was to investigate the adaptability of long bones of young adult rats to the stress of chronic aquatic exercise. Twenty-eight female Sabra rats (12 weeks old) were randomly assigned to two groups and treatments: exercise (14 rats) and sedentary control (14 rats) matched for age and weight. Exercised animals were trained to swim in a water bath (35°±1°C, 1 hour daily 5 times a week) for 12 weeks loaded with lead weights on their tails (2% of their body weight) (BW). At the end of the training period following blood sampling for alkaline phosphatase, all rats were sacrificed and the humeri and tibiae bones were removed for the following measurements: bone morphometry, bone water compartmentalization, bone density (BD), bone mineral content (BMC), and bone ions content (Ca, Pi, Mg, Zn). The results indicate that exercise did not significantly affect the animals’ body weight, bone volume, or length and diameters. However, bone hydration properties, BD, bone mass, and mineralization revealed significant differences between swim-trained rats and controls (P<0.05). Longitudinal (R1) measurement was higher by 43% for both humerus and tibia, and Transverse (R2) relaxation rates of hydrogen proton were higher by 117 and 76% for humerus and tibia, respectively; fraction of bound water was higher by 36 and 46% for humerus and tibia, respectively. BD, bone weight, and ash were higher by 13%. BMC and bone ions content were higher by 10%, and alkaline phosphatase was higher by 67%. These results indicate that long bones of young adult rats after the age of rapid growth can adapt positively to nonweight-bearing aquatic exercise. This adaptation is evident by an increase in bone mass, density, mineralization, and hydration properties.”
So perhaps upright doggy paddling is a method to induce torsional strain on relevant bones and increase height.
“In exercises involving running, muscle power and gravitational forces act together to affect bone mass in accordance with Wolff’s law. However, the direct effect of muscle activity on bones in non-weight-bearing activities, such as swimming, has not been explored. Previous data indicate that swimming exerts a positive effect on bone growth and development in young rats. We performed a histomorphometric study on the effect of swimming on the growth plate and subepiphyseal area of young adult rats. The experiments were carried out on 28 12-week-old albino Sabra rats. One group of 14 rats was trained to swim 1 hour/day, 5 days a week, for 12 weeks. Another group of 14 rats served as controls. The proximal femur and humerus of each animal were examined histomorphometrically. There was an increase in the subepiphyseal cancellous bone trabecullae of the femur. In the growth plate there was an increase in the number of column cells and proliferative cells. These changes were more pronounced in the femur than the humerus. We conclude that swimming induces an increase in subepiphyseal cancellous bone in young adult rats by enhancing growth plate activity.”
Humerus length increased but femoral length decreased.
Articular cartilage height increased in both groups which is very promising:
“During swimming, rats use their hind legs in extensive, forceful upward and downward movements, while the forelegs move in a small circular, balancing fashion. Therefore the effort of the hind legs is greater than that of the forelegs, explaining the differences in the muscle stresses of the humerus and femur and the consequent histomorphological changes in the bones.”
“Growing bones are most responsive to mechanical loading. We investigated bone mass acquisition patterns following a swimming or running exercise intervention of equal duration, in growing rats. We compared changes in bone mineral properties in female Sprague Dawley rats that were divided into three groups: sedentary controls (n = 10), runners (n = 8) and swimmers (n = 11). Runners and swimmers underwent a six week intervention, exercising five days per week, 30min per day. Running rats ran on an inclined treadmill at 0.33 m.s−1, while swimming rats swam in 250C water. Dual energy X-ray absorptiometry scans measuring bone mineral content (BMC), bone mineral density (BMD) and bone area at the femur, lumbar spine and whole body were recorded for all rats before and after the six week intervention. Bone and serum calcium and plasma parathyroid hormone (PTH) concentrations were measured at the end of the 6 weeks. Swimming rats had greater BMC and bone area changes at the femur and lumbar spine (p < 0.05) than the running rats and a greater whole body BMC and bone area to that of control rats (p < 0.05). There were no differences in bone gain between running and sedentary control rats. There was no significant difference in serum or bone calcium or PTH concentrations between the groups of rats. A swimming intervention is able to produce greater beneficial effects on the rat skeleton than no exercise at all, suggesting that the strains associated with swimming may engender a unique mechanical load on the bone.”
“There was no significant difference for femur length between the runners (34.55 ± 1.40mm), swimmers (33.50 ± 0.70mm) or sedentary control rats (34.21 ± 1.99mm, F=1.34, p = 0.28).”<-another study that found shorter femur length for swimming rats. It could be biomechanically upright swimming results in compressive deformation.
Reduced Bone Mass Accrual in Swim-Trained Prepubertal Mice
“Prepubertal female mice underwent a 16-wk training program, in which they swam for progressively increasing durations up to 55 min for 5 d·wk−1. A sham group was subjected to the water, but they did not perform the swimming exercise. Skeletal sites that were assessed included the proximal humerus, lumbar spine, midshaft and distal femur, proximal tibia, and the skull.”
This study found a decrease in length.
Here are the bone images:
The swimming studies that resulted in growth seem to be swimming studies with attached weight. That may be the key/weight equals more torsion.
