Serum procollagen III peptide in chronic myeloproliferative disorders

Revisiting Circulating Extracellular Matrix Fragments as Disease Markers in Myelofibrosis and Related Neoplasms

Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The JAK2V617F mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.

Can plasma fibrinogen level predict bone marrow fibrosis?

Objective: We aimed to assess the possible relationship between plasma fibrinogen level and bone marrow fibrosis (BMF) grades in patients who had undergone bone marrow (BM) biopsy for any reason. Patients and Method: This retrospective cohort study included 106 participants aged 18 years and over who had undergone simultaneous BM biopsy and circulatory fibrinogen level measurement during 2020 and 2021 at our center. BMF grade was measured by the modified Bauermeister grading system (MBGS). Participants were divided into two groups according to MBGS as those without BMF and those with BMF. Results: Fifty-eight male were included in our study, and the median age of the patients was 63 (range: 19-97) years. Fibrinogen (p=0.004) and lactate dehydrogenase (LDH) (p=0.030) levels were significantly higher in the fibrosis group. Multiple regression revealed that high fibrinogen (≥359) and high LDH (≥238) were independently associated with a higher likelihood of fibrosis presence (adjusted for age and sex); however, diagnostic analyses revealed low accuracy. Conclusion: High plasma fibrinogen and LDH levels were found to be independently associated with the presence of BMF. However, it was also evident that neither of these parameters could be used for diagnostic purposes.

Immune thrombocytopenia is associated with persistently deranged fibrosis-related seromarker profiles but low bone marrow fibrosis grades: A 2-year observational study on thrombopoietin receptor agonist treatment

Bone marrow (BM) fibrosis is a potential side effect of thrombopoietin receptor agonist (TPO-RA) treatment. We aimed to investigate stromal seromarker profiles and growth factors in order to elucidate pathogenic and dynamic aspects of immune thrombocytopenia (ITP)-related BM fibrosis before and during TPO-RA treatment. Connective tissue metabolites [procollagen I and III peptides (PINP/PIIINP); hyaluronan (HYA), C-terminal-telopeptide (ICTP), and fibrosis-related growth factors (transforming growth factor-beta (TGF-beta), HGF, basic fibroblast growth factor)] were measured in blood samples acquired before initiation of TPO-RA and subsequently at 6-month intervals for up to 2 years. BM fibrosis was graded MF-0 in 8 (18%), MF-1 30 (65%), and MF-2 8 (18%) in the last available BM biopsy. In the 21 patients having more than one biopsy, the grade of fibrosis from the first to the last available biopsy decreased in 2 (10%), remained unchanged in 15 (71%), and increased in 4 (19%). Pretreatment levels of PIIINP, PINP, ICTP, and HYA were significantly increased in ITP versus controls. PINP, PIIINP, and HYA decreased on TPO-RA; ICTP remained unchanged. PINP:ICTP was lower before and during treatment compared to controls. Pretreatment, TGF-beta was lower than in controls; HGF exhibited the opposite pattern. HYA, ICTP, and TGF-beta tended to increase while PINP and platelet-derived growth factor tended to decrease with increasing fibrosis grade. In conclusion, ITP is associated with deranged patterns of extracellular matrix seromarkers and growth factors, indicating that BM stromal remodeling is enhanced. During TPO-RA treatment for up to 2 years, this profile was partially reversed while mild BM reticulin fibrosis was still present in the majority of patients. These observations likely reflect a BM injury by autoimmunity that is modified by TPO-RA.

Bone marrow fibrosis: pathophysiology and clinical significance of increased bone marrow stromal fibres

In bone marrow biopsies, stromal structural fibres are detected by reticulin and trichrome stains, routine stains performed on bone marrow biopsy specimens in diagnostic laboratories. Increased reticulin staining (reticulin fibrosis) is associated with many benign and malignant conditions while increased trichrome staining (collagen fibrosis) is particularly prominent in late stages of severe myeloproliferative diseases or following tumour metastasis to the bone marrow. Recent evidence has shown that the amount of bone marrow reticulin staining often exhibits no correlation to disease severity, while the presence of type 1 collagen, as detected by trichrome staining, is often associated with more severe disease and a poorer prognosis. It was originally thought that increases in bone marrow stromal fibres themselves contributed to the haematopoietic abnormalities seen in certain diseases, but recent studies suggest that these increases are a result of underlying cellular abnormalities rather than a cause. A growing body of evidence suggests that increased deposition of bone marrow stromal fibres is mediated by transforming growth factor-beta and other factors elaborated by megakaryocytes, but it is likely that other cells, cytokines and growth factors are also involved. This suggests new avenues for investigation into the pathogenesis of various disorders associated with increased bone marrow stromal fibres.

TGF-beta1 induces bone marrow reticulin fibrosis in hairy cell leukemia

The mechanisms that lead to reticulin fibrosis of bone marrow (BM) in hairy cell leukemia (HCL) are not fully understood. We therefore investigated the involvement of TGF-beta1, a potent fibrogenic cytokine, in this process. Immunoassays revealed that TGF-beta1 is present at higher concentrations in BM, serum, and plasma of HCL patients in comparison with healthy donors (P < 0.001). RT-PCR and immunofluorescence studies showed that TGF-beta1 is overexpressed at the mRNA and protein levels in peripheral blood, spleen, and BM mononuclear cells and that hairy cells (HCs) are the main source of TGF-beta1. Active TGF-beta1 correlated significantly with grades of BM fibrosis, infiltration with HCs, and serum procollagen type III aminoterminal propeptide (PIIINP). Ex vivo studies demonstrated that TGF-beta1 significantly enhances the production and deposition of reticulin and collagen fibers by BM fibroblasts. In addition, BM plasma of HCL patients increased the synthesis of type I and type III procollagens, the main components of reticulin fibers, at the mRNA and protein levels. This fibrogenic activity of BM plasma was abolished by neutralizing anti-TGF-beta1 antibodies. These results show, for the first time to our knowledge, that TGF-beta1 is highly expressed in HCs and is directly involved in the pathogenesis of BM reticulin fibrosis in HCL.

Serum laminin P1 in idiopathic myelofibrosis and related diseases

The serum concentration of laminin P1 antigen was determined in 32 patients with various myeloproliferative disorders, including 19 patients with idiopathic myelofibrosis. The serum concentration of the aminoterminal propeptide of type III procollagen (PIIINP) was measured concomitantly in 27 patients. Serial laminin measurements were carried out in 25 patients. The median serum laminin concentration in patients with acute disease, i.e. acute myelofibrosis and patients in a transforming disease phase was significantly higher (1.58 U/ml; range 1.15-2.07) as compared with patients with chronic disease (1.02 U/ml; range 0.75-1.76; p = 0.012) and healthy control subjects (1.13 U/ml; range 0.75-1.67; p = 0.00015). In individual patients serum laminin covariated closely with serum PIIINP, the leucocyte count and LDH. The median serum laminin concentration in patients with a huge spleen was significantly lower than in the patient group with a normal spleen size/previous splenectomy. Pronounced splenomegaly was particularly prevalent in patients with chronic disease implicating splenic enlargement as a significant extrahepatic site of laminin uptake/degradation in myeloproliferative disorders.

Idiopathic myelofibrosis--an update with particular reference to clinical aspects and prognosis

Idiopathic myelofibrosis (IMF) is characterized by excessive accumulation of connective tissue in the bone marrow as part of a clinical syndrome which in its classical form is featured by leukoerythroblastic anemia and huge splenomegaly at the time of diagnosis. An acute variant of the disease exists being featured by pancytopenia, nor or minimal splenomegaly and a rapidly fatal clinical course. This review describes the relationship of IMF to other chronic myeloproliferative disorders and highlights current concepts of the pathogenesis of bone marrow fibrosis, implicating the intramedullary release of various growth factors, including platelet-derived growth factor beta. In a subgroup of patients bone marrow fibrosis may develop consequent to autoimmune bone marrow damage. The clinical and laboratory findings in some of the larger series of patients are presented and the reasons for the highly variable clinical presentation and prognosis are critically discussed. It is proposed that studies on prognosis in IMF are based upon simple prognostic staging systems, which should include the Hb-concentration, platelet count, spleen size and the presence/absence of osteomyelosclerosis on X-ray. Using these parameters the patients are easily categorized into three prognostic groups with highly different survival times.

A sequential histological study of bone marrow fibrosis in idiopathic myelofibrosis

A sequential histological study of bone marrow biopsies from 36 patients with idiopathic myelofibrosis was performed to investigate the accumulation of connective tissue in the bone marrow during the course of the disease and the influence of therapy on this process. The degree of bone marrow fibrosis was graded semiquantitatively from 0 (normal) to +5 (extensive collagen fibrosis and ostemyelosclerosis). The median interval between the first and final biopsy was 25 months (range 3 to 103) in patients with chronic idiopathic myelofibrosis and 2 months (range 1 to 14) in patients with a syndrome of acute myelofibrosis. In most patients with chronic IMF the bone marrow fibrosis remained unchanged. Regression of bone marrow fibrosis in 9 patients with chronic IMF was associated with immunosuppressive/-cytotoxic treatment or splenectomy. Severe bone marrow fibrosis completely resolved during intensive chemotherapy of a patient with acute myelofibrosis. No relationship existed between spleen size and the degree of bone marrow fibrosis.

Bone marrow stroma in idiopathic myelofibrosis and other haematological diseases. An immunohistochemical study

Bone marrow stroma was investigated immunohistochemically in 31 patients with haematological diseases, mainly idiopathic myelofibrosis (n = 8) and related chronic myeloproliferative disorders (n = 14). The bone marrow from patients with idiopathic myelofibrosis and some CML patients showed marked staining reactions with antibodies against type III procollagen (pN collagen), type IV collagen, fragment P1 of laminin and factor VIII. Patients with osteomyelosclerosis had particularly increased collagen content, including both newly deposited type III collagen (pN collagen) and mature collagen fibres. As in normal bone marrow, argyrophilic fibres and type III collagen displayed a close co-distribution, which was also demonstrated for type IV collagen and laminin. While normal bone marrow sinusoids had discontinuous basement membranes, fibrosing bone marrow was characterized by endothelial cell proliferation and capillarization, with the development of continuous sheets of basement membrane material beneath endothelial cells.

Circulating hyaluronan in the myelofibrosis/osteomyelosclerosis syndrome and other myeloproliferative disorders

The serum concentration of hyaluronan (HYA) was determined in 59 patients with various myeloproliferative disorders, including 33 patients with idiopathic myelofibrosis. In 18 patients the serum concentration of the aminoterminal propeptide of type III procollagen (PIIINP) was measured concomitantly. Raised serum HYA levels were seen in patients with active disease compared with age-matched healthy subjects, whereas no significant difference in serum HYA was seen between patients with stable disease and age-matched controls. Serum HYA concentrations correlated significantly with the leukocyte count (rho = 0.38; P less than 0.02) and with the serum concentration of PIIINP (rho = 0.50; P less than 0.001). During cytotoxic treatment, the serum HYA and PIIINP concentrations decreased in concert with declining leukocyte counts. These findings suggest that clonal expansion is accompanied by a bone marrow stromal reaction similar to the repair processes following injury to soft connective tissues. The relatively modest changes in serum HYA with frequent overlaps between patient categories and healthy subjects imply that the clinical utility of single determinations of serum HYA in the present disease groups is restrained. On the other hand, sequential measurements of HYA may provide a reflection of the myeloproliferative process in individual patients.

Procollagen type III aminoterminal peptide in serum in idiopathic myelofibrosis and allied conditions: relation to disease activity and effect of chemotherapy

The serum concentration of the aminoterminal propeptide of type III procollagen (PIIINP) was measured serially in patients with idiopathic myelofibrosis and other myeloproliferative syndromes. Two different assays were applied, the RIA-gnost assay (Hoechst, Frankfurt, FRG) and a new equilibrium RIA for the N-terminal propeptide of human type III procollagen (Farmos Diagnostica, Oulu, Finland). A positive correlation was found between the results obtained by the two RIA's (rho = 0.90, P less than 0.001). The highest propeptide levels were recorded in patients with idiopathic myelofibrosis, particularly in those with active disease. Elevated serum PIIINP levels decreased during treatment with various cytotoxic drugs, including intensive chemotherapy. By contrast, serum PIIINP was unchanged or increased in patients undergoing interferon alpha-2b therapy. Gel filtration of sera on Sephacryl S-300 column (Pharmacia, Sweden) showed that smaller PIIINP related peptides dominated in healthy subjects and in osteomyelosclerosis with stable disease. Conversely, the relative proportion of intact propeptide increased in accelerating disease stages and acute myelofibrosis. In conclusion, the present study implicates serum PIIINP as a useful indicator of disease activity in idiopathic myelofibrosis. The propeptide also appears to be a sensitive sero-marker of chemotherapy effect on fibrogenesis related to clonal myeloproliferation. Finally, the propeptide is suggested as an early predictor of relapse during cytotoxic therapy.

Urinary hydroxyproline excretion in the myelofibrosis-osteomyelosclerosis syndrome and related diseases

The total urinary hydroxyproline excretion was assessed in 47 patients with chronic myeloproliferative disorders. Urinary hydroxyproline excretion was normal in 16 patients with idiopathic myelofibrosis and in 5 out of 6 patients with acute myelofibrosis. In patients with osteomyelosclerosis (n = 8) values for urinary hydroxyproline excretion were higher (median 202, range 54-652) than those in idiopathic myelofibrosis (median 139, range 84-216). This difference was not significant (p greater than 0.1). Elevated values for urinary hydroxyproline excretion were found in 10 patients (1 AMF patient, 3 OMS patients and 6 patients with CML in the accelerated phase of the disease). All but 1 of these patients had been treated, or were being treated, with cytotoxic agents at the time of investigation. These findings are compatible with impaired degradation of bone marrow collagen which, together with enhanced collagen synthesis from bone marrow fibroblasts, accounts for progressive accumulation of connective tissue in the bone marrow. This process appears to be influenced by cytotoxic treatment as reflected in increased urinary hydroxyproline excretion in those patients receiving cytotoxic agents.

Measurement of connective tissue parameters in serum for diagnosis and follow-up of liver fibrosis

Hepatic fibrogenesis, i.e. activated synthesis and excessive intercellular deposition of connective tissue molecules (collagens, adhesive glycoproteins, proteoglycans) occurs in chronic alcoholic and viral liver injury and, less frequently, in some other conditions. The process may be monitored biochemically by the radioimmunoassay of some connective tissue molecules or their fragments and by the measurement of the activity of certain enzymes in serum. Currently, the radioimmunoassay of the aminoterminal propeptide of type III procollagen in serum reflects best the activity of liver fibrogenesis. The serum level of laminin, a high molecular weight basement membrane glycoprotein, was found to be correlated with an elevated portal venous pressure.

Serum markers for type IV collagen and type III procollagen in the myelofibrosis-osteomyelosclerosis syndrome and other chronic myeloproliferative disorders

Myelofibrosis is characterized by excessive deposition of interstitial and basement membrane collagens in the bone marrow. In this study, specific radioimmunoassays for the aminoterminal propeptide of type III procollagen and for the 7S collagen domain of type IV (basement membrane) collagen were used to determine how this accumulation is reflected in serum. Of the 41 patients with chronic myeloproliferative disorders studied, the highest levels of both parameters were found in idiopathic myelofibrosis and in chronic myelogenous leukaemia associated with bone marrow fibrosis. Increasing degrees of bone marrow fibrosis were accompanied by increasing serum concentrations of both markers, except for osteomyelosclerosis, where notably low values were seen. Pathologically high values of one or both parameters were also found in a few patients with polycythaemia vera or a transitional myeloproliferative disorder. The antigens related to type III procollagen and type IV collagen correlated significantly with each other and with the leucocyte count. These parameters should provide noninvasive means for following the accumulation of interstitial and basement membrane collagens in the bone marrow.