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Amyotrophic lateral sclerosis (ALS) is an incurable chronic progressive neurodegenerative disease with the progressive degeneration of motor neurons in the motor cortex and lower motor neurons in the spinal cord and the brain stem. The etiology and pathogenesis of ALS are being actively studied, but there is still no single concept. The study of ALS risk factors can help to understand the mechanism of this disease development and, possibly, slow down the rate of its progression in patients and also reduce the risk of its development in people with a predisposition toward familial ALS. The interest of researchers and clinicians in the protective role of nutrients in the development of ALS has been increasing in recent years. However, the role of some of them is not well-understood or disputed. The objective of this review is to analyze studies on the role of nutrients as environmental factors affecting the risk of developing ALS and the rate of motor neuron degeneration progression. Methods: We searched the PubMed, Springer, Clinical keys, Google Scholar, and E-Library databases for publications using keywords and their combinations. We analyzed all the available studies published in 2010–2020. Discussion: We analyzed 39 studies, including randomized clinical trials, clinical cases, and meta-analyses, involving ALS patients and studies on animal models of ALS. This review demonstrated that the following vitamins are the most significant protectors of ALS development: vitamin B12, vitamin E > vitamin C > vitamin B1, vitamin B9 > vitamin D > vitamin B2, vitamin B6 > vitamin A, and vitamin B7. In addition, this review indicates that the role of foods with a high content of cholesterol, polyunsaturated fatty acids, urates, and purines plays a big part in ALS development. Conclusion: The inclusion of vitamins and a ketogenic diet in disease-modifying ALS therapy can reduce the progression rate of motor neuron degeneration and slow the rate of disease progression, but the approach to nutrient selection must be personalized. The roles of vitamins C, D, and B7 as ALS protectors need further study.

Histological examination of the metastatic rat mammary adenocarcinoma line MTLn3 showed that macrophages and mast cells were frequently localized at the tumor periphery in the stromal tissues adjacent to the zones of tumor invasion. The interactions of these host cells with tumor cells and tumor-associated fibroblasts could be important in stimulating the production of extracellular matrix-degrading enzymes that facilitate tumor invasion and metastatic spread. Therefore, we examined the effects of isolated, activated macrophages and mast cells on the secretion of collagenolytic activities by normal fibroblasts, metastatic mammary adenocarcinoma cells and tumor-associated fibroblasts. Medium from activated macrophages or degranulated mast cells stimulated significant increases in production of collagenolytic activities by normal and tumor-associated fibroblasts and MTLn3 tumor cells. Medium from activated macrophages that had been pretreated with medium from degranulated mast cells, however, were less stimulatory to fibroblasts and tumor cell production of collagenolytic activities than medium from degranulated mast cells alone. We also examined the effects of two cytokines, interleukin-1 alpha and tumor necrosis factor-alpha on activated macrophage- and degranulated mast cell-stimulation of fibroblast and tumor cell collagenolytic activities. The two cytokines alone or in combination stimulated increased production of collagenolytic activities by fibroblasts and tumor cells. Addition of the cytokines to degranulated mast cell products resulted in secretion of higher collagenolytic enzyme activities by normal fibroblasts (but not by tumor-derived fibroblasts or tumor cells) than with degranulated mast cell product-treatment of either target cell alone. Cytokines used in combination with macrophage-conditioned medium were less effective in stimulating fibroblast and tumor cell collagenase activities than cytokines alone. Thus normal infiltrating host cells such as macrophages and mast cells can have profound effects on the production of degradative enzymes by tumor cells and tumor-associated stromal fibroblasts.

Two-dimensional isoelectric focusing and gel electrophoresis followed by mass spectrometry were used to detect, measure, and identify changes in protein expression correlated with differences in the metastatic potential of cultured rat mammary adenocarcinoma cells. MTC is a non-metastatic cell clone derived from a primary tumor. MTLn2 and MTLn3 are low and high metastatic potential cell clones derived from lung metastases of the primary tumor. A total of 1,500 proteins was detected. The patterns of protein expression of MTLn2 and MTLn3 cells were similar. Only five spots had a threefold or greater statistically significant difference in staining intensity between MTLn2 and MTLn3 cells, whereas 70 spots differed between MTC and MTLn3 cells. Twenty spots were selected for further study, ten that had a positive correlation of staining intensity with metastatic potential and ten that had a negative (inverse) correlation. Of the 17 unique proteins that were identified, five have often been cited as tumor biomarkers. These included the positive biomarkers nucleophosmin (NPM) and 14-3-3 protein sigma and the negative biomarkers raf kinase inhibitor protein (RKIP), peroxiredoxin-2, and galectin-1. The only identified protein that was markedly higher in MTLn3 cells than in the less-metastatic MTLn2 cells was 14-3-3 protein sigma. The results indicate that increased metastatic potential is associated with positive and negative changes in expression of particular proteins. Proteins that are positively correlated with metastatic potential may prove more useful as clinical biomarkers, but those with negative correlations may still provide useful information about underlying mechanisms of metastatic spread.

Mast cells were shown to accumulate around the periphery of the invasive and metastatic rat mammary adenocarcinoma (MTLn3), and histological evidence of mast cell degranulation was observed during the later stages of this model. To assess the physiological role of mast cells in vivo we have used the mast cell-stabilising compound FPL 55618 applied i.p. daily at 1 mg kg-1 for 23 days. Using groups of 12 rats we have found that this compound inhibited tumour growth at the primary site by as much as 70% in most of the treated animals compared with the control group which received equivalent volumes of saline. When the drug treatment was stopped after 23 days, tumour growth of the test group accelerated over the next 7 days and reached a similar tumour size to that of control animals. Histological studies of the tumour and contiguous host tissue at day 24 of the experiment revealed numerous extra-tumoural mast cells often showing signs of degranulation at several sites around the tumour periphery in the control animals. Such observations were not seen in those animals receiving FPL 55618 where, in contrast to controls, numerous intact mast cells were often seen within the tumour mass. Following cessation of the MC-stabilising treatment progressive mast cell activation was evident within 2-4 days, primarily at the tumour periphery. In vitro studies have shown that drug concentrations equivalent to five times the in vivo dose had no effect on the proliferative rate or viability of the MTLn3 cells. Moreover, the proliferative rate of these cells in culture was significantly increased when exposed to soluble mast cell products. Thus our data indicate that a mast cell-stabilising compound has significant benefits in reducing tumour growth in vivo, an observation which supports the concept that mast cell:tumour cell interactions are important for the growth and invasive properties demonstrated by this model of breast carcinoma. Images Figure 2

Significant numbers of mast cells have been demonstrated histologically around the periphery of the invasive rat mammary adenocarcinoma 13672NF. The number of mast cells at microfoci along the tumour:host tissue junction was significantly greater than that found in normal mammary tissues, and few mast cells were detected within the tumour itself. Mast cell degranulation, often associated with disruption and lysis of the connective tissue matrix, was a common feature in later stages of tumour proliferation. When soluble products derived from purified rat peritoneal mast cells were added to monolayer cultures of rat stromal fibroblasts or tumour cells they stimulated a significant increase in total collagenase production, and the mast cell products were also capable of activating the latent collagenases thus produced. Histological examination indicated that degradation of local collagenous matrix was a common feature of mast cell degranulation, an observation possibly explained by the release of mast cell enzymes and/or the potential of this cell to modulate the expression of collagenolytic activity by surrounding cells. These observations suggest that, at least in some tumours, mast cells contribute to the connective tissue breakdown commonly associated with tumour invasiveness and metastatic spread. Images Figure 1 Figure 2

Primary and secondary cultures of VX-2 carcinoma produced high levels of collagenase activity in both active and latent forms in serum-free media. These cultures appeared morphologically heterogeneous in phase-contrast microscopy and revealed the presence of mainly three distinct forms; epithelial-like cells (E cells), fibroblast-like cells (F cells), and large rounded-flat cells which may represent a subclass of the F cells. Cell separation techniques such as brief dispase treatment, Percoll gradient centrifugation, thimerosal treatment, and rabbit serum were used to obtain predominantly one form or the other. The E cells never formed a monolayer but rather grew as limited size clusters of intimately associated cells with large nuclei and often appeared multinucleated. These cells were difficult to maintain in culture or serially passed more than a few times. The F cells, rare in early cultures but having the highest growth potential, appeared in various morphological forms ranging from spindle- to stellate-shaped cells. The cells in their third passage were capable of producing palpable tumors, similar in light and electron microscopic studies to the original tumor from which they were derived, when injected intramuscularly into recipient rabbits and produced specific collagenase activity in active and latent forms in serum-free media. Ultrastructural studies suggested that the E cells were of epithelial origin whereas the F cells were similar to stromal fibroblasts. Cytogenetic studies demonstrated that almost all of the E cells showed both numerical and structural chromosomal changes in a modal number of 54 chromosomes. On the other hand, the major cell population of the F cells resembled normal rabbit fibroblasts; both contained a normal diploid (2 n = 44). However, few cells (4–6%) in the F-cell population were hyperdiploid with a modal chromosome number of 54. These cells may represent inadvertent contaminating E cells and account for the apparent limited turmorigenicity observed in early F-cell cultures. The data suggested that the E cells were of tumor origin whereas the majority of the F-cell population appeared to be of host origin. Furthermore, it is suggested that the E cells stimulate tumor-associated stromal cells to produce elevated levels of collagenolytic activity and contribute to collagen degradation during tumor invasion.

Treatment of dilute solutions of acid-soluble calfskin collagen with tetranitromethane at pH 8.0 resulted in the nitration of all the tyrosine residues in tropocollagen without precipitation of the modified protein. Amino acid analysis of the product showed (a) that no other amino acids were affected and (b) that the 3-nitrotyrosine formed accounted for only 30% of the tyrosine originally present in the molecule. This indicated that some of the tyrosine residues were involved in a reaction which did not produce 3-nitrotyrosine. Polyacrylamide gel electrophoresis, viscometry, and sedimentation analysis of the product showed the formation of predominantly intra-molecular cross-links. However, intermolecular cross-links were also formed but to a limited extent.

Limited proteolysis with pepsin solubilized 25% of the insoluble gingival matrix as mainly soluble collagenous material. Fractional salt precipitation at neutral pH resulted in the separation of types III and I at 1.8 and 2.6 M NaCl, respectively. In addition, a collagenous fraction accounting for 2% of the solubilized collagen and precipitating at 4.5 M NaCl was shown to be identical with type V collagen. Isolation and partial characterization of the constituent-alpha-chains of the 4.5 M PPT by gel filtration, ion exchange and hydroxylapatite chromatography as well as disc electrophoresis showed that gingival type V collagen contains alpha A and alpha B chains in a ratio alpha B/alpha A of 1.73-1.8. Electron microscopic examination of ATP-precipitates showed that this collagen type gave only one kind of SLS aggregates with asymmetric band pattern characteristically different from that of type I collagen. The data provide evidence that gingival AB collagen is a heteropolymer in which the alpha A and alpha B chains are assembled in the same macromolecule in a 1:2 ratio.

The role of collagenolytic enzymes in tumor invasion and metastasis has been emphasized, but the source of enzyme activity has remained unclear. Degradation of stromal connective tissue is a common feature of invasive neoplasia, and host-tumor cell interactions are probably important for localized collagenolysis. We have examined the role of mast cells in malignant cell invasion using cells derived from the rat mammary adenocarcinoma 13762NF. Histologic studies have shown increased numbers of mast cells at the zone of tumor invasion. Mast cell products and conditioned medium from such cells stimulated the production of collagenolytic enzymes by stromal fibroblasts as well as certain subpopulations of tumor cells in vitro. The tumor cell response to mast cell-mediated stimulation of collagenolysis appears to be related to the metastatic potential of the tumor cell. A subpopulation of host fibroblasts derived from the invading tumor zone was also found to be more responsive to mast cell factors than normal fibroblasts, as judged by collagenase production. Thus the mast cell has the potential to induce collagenolytic activity from both host fibroblasts and tumor cells.

PERIODONTAL DISEASE IS a major cause of loss of teeth. Tooth mobility is a result of changes in the supporting structures of the periodontium. Morphological changes in the intercellular components of the gingiva and peri­ odontal membrane were shown to occur in patients with periodontal disease. Collagen, the principal structural protein which is essential for the integrity of the periodontal connective tissue, was shown to be altered in histological sections of inflamed gingiva. 4 , 6 Although various tissue collagens have been under extensive study in several laboratories, periodontal tis­ sue collagen has received only limited attention. The structural components of the gingival matrix are being investigated in our laboratory and in this paper we report the nature of proteins of the insoluble matrix of bovine gingiva. Since most of gingival tissue collagen is insoluble, the technique of CNBr cleavage was applied to solubilize collagen peptides. Limited proteolysis with pepsin was also used to solubilize collagenous compo­ nents.

Immunoreactive Fibronectin (Fn) has been demonstrated in stimulated human parotid saliva by western blot analysis and also found to be a component of the artificial tooth pellicles derived from hydroxyapatite (HA) beads coated with parotid saliva. Saliva depleted of gelatin-binding components showed a significantly lower degree of reactivity with anti-Fn antibodies than did the control saliva when tested by an enzyme-linked immunosorbent assay ( ELISA) . Depletion of gelatin-binding components from saliva was also found to affect the degree of saliva-mediated aggregation of four of the seven oral streptococci tested [Streptococcus mutans strains GS-5 and OMZ 176, S. sobrinus, and S. rattus]. Similarly, the adherence of the same four micro-organisms to the artificial tooth pellicles (derived from saliva which had previously been depleted of gelatin-binding component) was significantly inhibited ( 37-53%) when compared with the control saliva-coated HA beads. Pre-treatment of streptococci with 100 μg of soluble Fn also caused a 34—57% inhibition of adherence of the same oral streptococci to saliva-treated HA beads. Quantitation of Fn in human parotid saliva showed that the amounts of immunoreactive Fn varied from 2 to 6 μg/mL of parotid saliva. Furthermore, the Fn from parotid saliva was found to be adsorbed onto the bacterial surfaces, as demonstrated by immunofluorescence and ELISA. The presence of Fn in parotid saliva and its ability to bind to HA beads (artificial pellicles), in conjunction with the ability of soluble Fn to inhibit the adherence of streptococcal strains to the artificial tooth pellicles, suggest that the microbial ecology of the oral cavity may, in part, be influenced by the interactions mediated by salivary fibronectin.

Fibroblast-like cells (F-cells) and epithelial-like (E-cells) derived from cultures of rabbit VX-2 carcinoma released collagenase in both active and latent forms in serum-free medium at a level higher than that of normal rabbit fibroblast cultures. The enhanced capacity of the F-cells to release the enzyme, however, continued only for a few passages and then decreased significantly to a low level similar to that of the normal fibroblasts. The enzyme-release by the E-cells continued for a few more passages at a relatively moderate level, higher than that of normal fibroblasts. The release of collagenase in cultures of F-cells was enhanced by the presence of E-cells in mixed cultures as well as by medium conditioned by the E-cells type. Addition of cytochalasin B at 2 micrograms/ml did not significantly effect the enzyme activity released in the cultures. Serum from tumor-bearing rabbits appeared to stimulate the release of enzyme activity in cultures of either cell type.

The spread and invasion of tumor cells into host tissues are associated with the release of elevated levels of collagenolytic activity of both host and tumor cell origins. However, the mechanisms of regulation of the enzyme activity is still unresolved. Histological examination of human and animal tumors revealed morphological changes in stromal fibroblasts and mast cells at the tumor periphery. Numerous mast cells appeared at microfoci along the tumor: host tissue junction and mast cell degranulation were associated with collagenolysis. In vitro studies, using rat mammary adenocarcinoma and human lung adenocarcinoma cells, showed that both tumor cells and host fibroblasts participate in matrix degradation. Tumor-associated stromal fibroblasts released higher levels of enzyme activity than normal fibroblasts and were more responsive to stimulation by tumor-conditioned media and soluble mast cell products. Host fibroblasts appear to be heterogeneous populations of responsive and nonresponsive subpopulations based on their response to tumor- or mast-cell-mediated stimulation of collagenase release. Fibroblast subpopulations were obtained by density fractionation of serum-deprived, synchronized confluent fibroblasts on discontinuous Percoll gradient. Density-fractionated fibroblast subpopulations differed in their response to stimulation by mast cell products and tumor-cell-conditioned media. The stimulatory activity of tumor-cell-conditioned media also varied as a function of the metastatic potential of the tumor cells. The data suggest that cellular interactions between tumor cells and select subpopulations of host fibroblasts at the tumor periphery play a key role in host tissue degradation. However, heterogeneity of stromal fibroblasts may determine the site and extent of the tissue damage at foci of tumor invasion.

Serum-free media of minced tissue cultures of VX-2 rabbit carcinoma contained a specific collagenolytic activity capable of releasing soluble radioactive peptides from [14C]-labeled collagen fibrils. It was also capable of reducing the viscosity of acid-soluble collagen solutions by cleaving the tropocollagen (TC) molecules primarily at one site to TCA (75%) and TCB (25%) fragments. Three chromatographic fractions were separated by gel filtration: F1, (MW 85-110,000) present in larger amounts in early cultures of younger tumor tissue; F2, (MW 35-40,000) the major component with maximum production in the day 3 media of younger and advanced tumor tissues; F3, (MW 18-22,000) the minor component. Early cultures of younger tumor tissue contained a latent collagenase and were subject to trypsin activation suggesting the presence of inactive enzyme precursors or an enzyme-inhibitor complex.

Primary cultures of rabbit VX-2 carcinoma appeared to be heterogeneous, containing at least two morphologically distinct cell types, fibroblast-like cells (F cells) and epithelioid cells (E cells). Ultrastructural studies suggested that the E cells were of epithelial origin, whereas the F cells did not differ significantly from normal rabbit fibroblasts. Cytogenetic studies showed that the E cells were characterized by numerical and structural chromosomal changes which remained constant subsequent to serial in vitro culture and in vivo transplants in rabbits. Analysis of G-banded chromosomes from E cells revealed a modal number of 54 with relatively few normal chromosomes and a variety of distinctive, mostly unidentifiable marker chromosomes. The origin of only four marker chromosomes could be partially determined. The ratio of normal to marker chromosomes remained relatively constant following serial transplants in rabbits. The F cells appeared to be derived mainly from host tissue, as they contained a normal diploid complement with sex chromosomes corresponding to the sex of the host.

A cytokine with an apparent molecular weight of 53,000 daltons was isolated from serum-free medium conditioned by MTLn3 cells or from homogenates of MTLn3 cells, a highly metastatic variant of the rat 13762NF mammary adenocarcinoma. The chemotactic responses of MTLn3 and the low metastatic variant MTLn2 cells to this cytokine were tested in vitro using modified Boyden chambers. Both the chemotactic and chemokinetic movements of MTLn3 cells were stimulated by the MTLn3-derived cytokine. In addition, the MTLn3-derived cytokine stimulated a relatively small, but significant chemotactic migration of MTLn2 tumor cells, while these cells did not respond to medium conditioned by MTLn2 cells. MTLn3 cells themselves did not respond chemotactically to type I collagen or medium conditioned by MTLn2 cells. These results suggest that the chemotactic response may be a function of metastatic potential of the invading tumor cells. The production of tumor cytokines that enhance tumor cell motility may thus represent a phenotypic difference between 13762NF tumor cell subpopulations of high and low metastatic potential.

Removal of the telopeptide regions by pepsin inhibits platelet aggregation and release by monomeric collagen in PRP. This inhibitory effect appears to be due to the inability of pepsin modified collagen to form fibrils in plasma, since fibrils formed in buffer cause aggregation and [ 14 C] serotonin release in PRP. Fibrils formed from pepsin modified collagen appear to be quantitatively more effective in causing platelet aggregation and serotonin release than normal fibrils. When pepsin modified collagen is studied as a function of time of digestion, there is a dissociation between platelet aggregation and release. Fibrils formed from pepsin modified collagen become quantitatively more effective the longer the duration of digestion. Platelet aggregation but not release by fibrillar collagen can be inhibited by a 14 fold excess of pepsin soluble collagen. This effect can be overcome by increasing the concentration of fibrillar collagen. Pepsin modified soluble collagen appears to cause serotonin release of gel filtered platelet but not aggregation. These data suggest that the telopeptide regions play a role in collagen quaternary structure and that the atelopeptide tropocollagen may bind to the platelet but is not sufficient to produce platelet aggregation.