Eeva Kääpä

A controlled immunohistochemical study of inflammatory cells in disc herniation tissue

Study Design The presence and abundance of inflammatory cells was studied immunocytochemically in lumbar disc herniations (DH) and macroscopically normal discs for comparison. Objectives The objective of the study was to characterize inflammatory cells that appear in herniated disc tissue and to study the relative abundance of various types of inflammatory cells. Summary of Background Data Only few macrophages were observed in control discs, whereas abundant macrophages were present in half of the DH.Other types of inflammatory cells were less often abundant in the present material. In about a third of the DH interleukin-1 beta-expressing cells were also observed. Methods Twenty-four DH and control tissue from five discs were studied immunocytochemically, using specific monoclonal antibodies to various types of inflammatory cells and interleukin-1 beta. The results were compared with corresponding clinical data. Macrophages were studied with an antibody to CD68 antigen and Ber-MAC3 antibody separately. Results The obtained results suggest a variable inflammatory cell response in DH, which seems to be often dominated by macrophages at the time of operation. Thus previous suggestions of sometimes very active inflammation in DH tissue are supported. Conclusions Inflammation may be important in disc tissue pathophysiology, possibly also in discogenic pain mechanisms.

An immunohistochemical study of nerve structures in the anulus fibrosus of human normal lumbar intervertebral discs.

STUDY DESIGN The innervation of the anulus fibrosus of human macroscopically normal intervertebral discs from five patients was investigated immunohistochemically. OBJECTIVES Immunoreactivity to general nerve markers (synaptophysin and protein gene product 9.5) and to neuropeptides (substance P and C-flanking peptide of neuropeptide Y) was studied. SUMMARY OF BACKGROUND DATA In the lumbar disc of a newborn, free nerve endings have been demonstrated in the outer layers of anulus fibrosus. In degenerated and herniated discs, nerve structures have been shown to penetrate deeper into the anulus fibrosus. There are only a few studies on the innervation of normal adult intervertebral disc tissue. METHODS Thin frozen sections of human normal lumbar intervertebral disc tissue were immunostained for general nerve markers and neuropeptides. RESULTS Synaptophysin and protein gene product 9.5 immunoreactive nerve structures were observed penetrating 3.5 mm and 1.1 mm into the anulus, respectively. Immunoreactivity to C-flanking peptide of neuropeptide Y and substance P were observed at a maximum depth of 0.9 and 0.5 mm in the anulus, respectively. Antibodies to the former have been used to study sympathetic nerves, whereas substance P is a transmitter present in sensory nerves. CONCLUSIONS In anulus fibrosus samples from macroscopically normal discs, a general marker for nerve endings can be found at a depth of a few millimeters, whereas neuropeptide markers show nerves only in the outermost layers of the anulus fibrosus. This absence of demonstrable nerves in deeper anulus fibrosus in normal discs is probably not a methodologic artifact, because blood vessels have also been demonstrated only at the disc surface. It is, however, possible that neuropeptide nerves also penetrate to a depth of a few millimeters, but that methodologic limitations permit the visualization of only the neuropeptide nerves closest to the disc surface. The results of the present study lend support to previous suggestions that, except at the surface, a normal intervertebral disc is almost without innervation.

Multidisciplinary group rehabilitation versus individual physiotherapy for chronic nonspecific low back pain: a randomized trial.

Study Design. A randomized trial. Objective. To evaluate the effectiveness of a semi-intensive multidisciplinary rehabilitation for patients with chronic low back pain in an outpatient setting. Summary and Background Data. Systematic reviews have shown that there is strong evidence that intensive multidisciplinary treatment (>100 hours), which includes functional restoration, improves function among chronic patients with low back pain, and moderate evidence that it reduces pain but contradictory evidence regarding improvement of working ability. However, there is paucity of data whether semi-intensive outpatient multidisciplinary rehabilitation in groups is more effective than individual physiotherapy. Materials and Methods. A total of 120 women employed as healthcare and social care professionals with nonspecific chronic low back pain were recruited from two occupational healthcare centers. The patients were randomized into two intervention programs. Multidisciplinary rehabilitation (n = 59) was conducted in groups and comprised of physical training, workplace interventions, back school, relaxation training, and cognitive-behavioral stress management methods for 70 hours. The individual physiotherapy (n = 61) included physical exercise and passive treatment methods administered for 10 hours. Main outcome measures were: back pain and sciatic pain intensity, disability, sick leaves, healthcare consumption, symptoms of depression, and beliefs of working ability after 2 years. Results. There were no statistically significant differences between the two treatment groups in main outcome measures just after rehabilitation, at 6-, at 12-, or 24-month follow-up. In both intervention arms, however, the before-and-after comparison showed favorable effects, and the effects were still maintained at 2 years follow-up. Conclusions. The results of this study indicate that semilight outpatient multidisciplinary rehabilitation program for female chronic low back pain patients does not offer incremental benefits when compared with rehabilitation carried out by a physiotherapist having a cognitive-behavioral way of administering the treatment.

Collagen synthesis and types I, III, IV, and VI collagens in an animal model of disc degeneration.

Study Design. The present study sought to elucidate the changes that occur in collagen chemistry in the early phases of disc degeneration. Objective. To monitor the healing process of the injured anulus fibrosus and the secondary degenerative reactions in the nucleus pulposus. Summary of Background Data. Despite the importance of collagen chemistry under pathologic conditions in the intervertebral disc, knowledge of this aspect is very limited. Methods. Fourteen pigs were stabbed with a scalpel blad in the anterior part of the anulus fibrosus of a lumbar disc. The animals were killed 2 weeks to 5 months after injury. The activities of prolyl 4-hydroxylase adn galactosylhydroxylysyl glucosyltransferase, the total collagen content, adn staining patterns for Types I, III, IV, and VI collagens were analyzed from different parts of the disc. Results. The most active phase of the healing process, assessed from the activities of enzymes involved in collagen biosynthesis, took place during the first month postoperatively. The anular lesion was found to cicatrize through formation of disorganized granulation tissue in which Type I, III, and, IV collagens were depostited. In the nucleus pulposus, activities of pralyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase and total collagen content increased, and the originally rounded cells became more elongated, resembling fibroblasts. Conclusions. The results of this study suggest that the altered composition of collagens observed in the degenerate porcine nucleus pulposus results from changes in cell phenotype: Notochondral cells were replaced by fibroblast-like cells. It is likely that trauma to the anulus fibrosus can initiate a progressive degenerative process in the disc tissue.

Comparison of the prevalence of inflammatory cells in subtypes of disc herniations and associations with straight leg raising

Study Design. The prevalence of inflammatory cells in 205 disc herniations (DHs) and nine macroscopically normal discs for comparison was studied immunohistochemically. Inflammatory cells were separately analyzed in subtypes of DH. Immunohistochemical data were related to clinical parameters, the straight leg raising test (SLR) in particular. Objectives. The objectives of the study were to compare the occurrence of inflammatory cells in various subtypes of DH and to determine the association between clinical data and inflammatory cell occurrence in a more extensive sample of DH, with separate analysis of DH subtypes. Summary of Background Data. Previous studies have suggested a common occurrence of inflammation and inflammatory cells, particularly macrophages, in DHs. No studies on any larger material comprising different subtypes of DH have been done. Methods. For immunohistochemistry the alkaline phosphatase antialkaline phosphatase method was used. Monoclonal antibodies to T cells in general (CD2), activated T cells (CD25), B cells (CD22), and macrophages (CD68) were used. Obtained immunostaining results were then compared with clinical data, e.g., duration of pain, SLR, and type of DH (sequesters 86, extrusions 103, protrusions 16). Associations were studied by the &khgr;2 test or Fisher’s exact test, as applicable (level of significance P < 0.05). Results. Abundant T cells were seen in 17% of the 205 DHs, activated T cells in 17%, B cells in 16%, and macrophages in 37%. All cell types were 2–3 times more prevalent in sequestrated discs than in extrusions. In protrusions macrophages were abundantly seen in 25% (4 of 16) and no other inflammatory cells. In patients with positive SLR and a sequestrated disc abundant lymphocytes were seen three times more often than in extrusions. When patients with bilaterally negative SLR were compared with those with tight SLR (≤30°) with respect to inflammatory cell occurrence, some significant differences were noted (CD68, P < 0.025; CD25, P = 0.04). A comparison between SLR bilaterally positive and bilaterally negative also showed associations for all four inflammatory cell types (P = 0.016 to P = 0.029). There was no correlation between inflammatory cells and duration of pain. Abundant inflammatory cells were never seen in control discs. Conclusions. When SLR was positive and the DH typewas sequestered, inflammatory cells were most commonly seen. Our results showed some statistically significant associations between inflammatory cells and SLR, most clearly when comparing bilaterally positive and negative SLR. Interestingly, a bilaterally positive SLR showed an association with all four inflammatory cell types analyzed. Tight SLR also showed an association, particularly with macrophages. In addition to tissue resorption, they may participate in sciatic pain. Even though lymphocytes were less prevalent, they may have some role in sequestered discs and bilaterally positive SLR.

Correlation of size and type of modic types 1 and 2 lesions with clinical symptoms: a descriptive study in a subgroup of patients with chronic low back pain on the basis of a university hospital patient sample.

Study Design. Intensity of pain and level of disability (Oswestry Disability Index [ODI]) were compared with the relative size of Modic type 1 (M1) and Modic type 2 (M2) lesions. Clinical symptoms of patients having mixed M1–M2 lesion (n = 49) were compared with patients having a “pure” M1 lesion (n = 13). Objective. To determine the relation of the sizes of M1 and M2 lesions and the type of Modic lesion (mixed M1–M2 or pure M1 lesion) with intensity of low back pain and level of perceived disability. Summary of Background Data. Endplate signal abnormalities, particularly M1 changes indicating edema and inflammation, have been suggested to play an important role in the etiopathogenesis of a subgroup of patients with nonspecific chronic low back pain (CLBP). However, their association with clinical symptoms has not been studied in detail previously. Methods. Sixty-two CLBP patients with a large M1 lesion were selected from CLBP patients who were sent for the first time for standard lumbar spine magnetic resonance imaging at a university hospital. To exclude other causes of CLBP, as far as possible, strict exclusion criteria were used: any specific back disease, even a slight nerve root compression, a recent or major spine operation, or age older than 65 years. The relative sizes of M1 and M2 lesions were visually estimated from sagittal images for comparison with clinical symptoms. Results. The majority of patients (91.9%; 57 of 62) had an M1 lesion at a single level, 92% of the lesions being at L4–L5 or L5–S1 level. Forty-nine patients (79.0%) had a mixed M1–M2 lesion, and 13 (21.0%) had a pure M1 lesion. The mean of the pain intensity score was 6.2, and, correspondingly, the Oswestry Disability Index was 30.4. The mean relative sagittal area of the largest M1 lesion was 24.6% (SD = 16.2), and that of the M2 lesion was 10.9% (SD = 11.6). Neither the pain intensity nor the ODI scores were found to correlate with the largest relative size of the M1 lesion. The patients with “pure” M1 lesion had statistically significantly more clinical symptoms than patients having a mixed M1–M2 lesion. Conclusion. We conclude that the size of M1 lesion does not directly correlate with the clinical symptoms but that the type of Modic lesion is more important. This study supports the previous observations that when the inflammatory process turns to the mixed M1–M2 lesions, clinical symptoms decrease.

Effects of tiaprofenic acid and indomethacin on proteoglycans in the degenerating porcine intervertebral disc.

Study Design Eighteen pigs were stabbed with a scaipel in the enterrior part of the anulus fibrosus of a lumbar disc. After surgery, the pigs received either tiaprofenic acid or indomethacin daily, and the a third group did not receive any medication. Objectives Nonsteroidal anti-inflammatory agents are widely used in the treatment of low back patients, but their long-term effects on the matrix molecules in the degenerate disc are unknown. Summary of Background Data Several in vitro and in vivo studies on articular cartilage have suggested that tiaprofenic acid may not have adverse effects on matrix metabolism, whereas indomethacin probably does. Methods Uronic acid, DNA, and water contents were determined from five different locations in each injured disc. Transport and incorporation of sulfate were examined by in vivo radioactive tracer analysis, and proteoglycan structure were analyzed by gel electrophoresis. Results Morphologically, there were no differences between the treatments. Tiaprofenic acid maintained a higher uronic acid content in the nucleus pulposus and outer anulus compared with that of the nonmedicated animals. Tiaprofenic acid decreased the incorporation of sulfate in the injured area and the water content at most sites. Indomethacin had no adverse effects compared with the nonmedicated group, and it increased water contents in the posterior anulus fibrosus. Conclusions Long-term administration of tiaprofenic acid and indomethacin did not have harmful effects on matrix metabolism after disc injury. On the contrary, tiaprofenic acid may slightly protect proteoglycans in the degenerating disc.