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PubMed2003

C-1 esterase inhibitor dysfunction localised to the periodontal tissues: clues to the role of stress in the pathogenesis of chronic periodontitis?

BACKGROUND: C1-esterase inhibitor (C1eIn) is an important modulator of complement activation via the classical pathway. Deficiencies or dysfunction involving this inhibitor underlie the condition of angioneurotic oedema. AIM: The purpose of this report is to describe a female patient who presented at the age of 24 years with an apparently aggressive form of periodontitis and severe oedema, localised to the free gingival tissues. After 21 years of repeated surgical reduction of the gingiva, a diagnosis of C1eIn dysfunction was made. METHODS: Exhaustive serological investigations were performed along with histopathology. RESULTS: All investigations were unremarkable, until the function of the C1eIn molecule was investigated. These demonstrated a functional activity of only 29% and a raised C1q at 157 mg/l. Subsequent repeated investigation with careful specimen handling demonstrated undetectable levels of C1eIn and normal C1q. A diagnosis of C1eIn dysfunction was made, although at present it is unclear whether this represents an unusual variant of hereditary dysfunctional C1eIn deficiency. The patient was managed by various means, including steriodal and non-steroidal drugs, the latter forming part of her maintenance regime. CONCLUSIONS: To our knowledge, this is the first case of angio-oedema localised to the free gingiva. The role of stress in the acute exacerbations of oedema and bone loss is discussed along with the diagnostic pitfalls associated with this case.

Adult↗
PubMed1994

Absence of glomerulonephritis in guinea pigs deficient in the fourth component of complement.

Genetically determined deficiencies of the early components of the classical complement pathway (C1, C4, C2) or of the third component of complement (C3) in both human beings and experimental animals are known to be associated with renal disease, including glomerulonephritis. The current study was performed to examine the C4-deficient (C4D) guinea pig for the presence of renal disease. Eighteen C4D animals and 17 control animals (Crl:Hartley) (divided by sex into four age categories) were examined. Light microscopic examination revealed no differences in mesangium, glomerular cellularity, thickness of capillary loops, or presence of epithelial crescents in the kidneys of C4D guinea pigs as compared with control animals. Electron microscopic examination did not reveal glomerular or tubular immune complex deposits in either C4D or control animals. C4D guinea pigs apparently do not demonstrate glomerulonephritis.

Animals↗
PubMed1989

Synthesis and expression of C1 inhibitor by human umbilical vein endothelial cells.

The biologic activity of C1 esterase, activated forms of factor XII and kallikrein at sites of vascular inflammation may be regulated by C1 inhibitor (C1 INH) elaborated by endothelial cells. Therefore, we investigated whether human umbilical vein endothelial cells (HUVEC) in culture produce C1 INH. Passaged HUVEC contain 1.6 +/- 0.8 micrograms of C1 INH/10(8) cells (mean +/- S.D.; n = 7) which was immunochemically similar to plasma C1 INH measured by a competitive enzyme-linked immunosorbent assay. Methylamine-treated lysates of HUVEC contained a functional inhibitor of purified kallikrein (2.7 +/- 0.8 micrograms activity/10(8) cells, mean +/- S.D.; n = 4). The HUVEC-derived kallikrein inhibitory activity was mostly C1 INH because it was reversed by chemically treating the lysate with chloroform and was neutralized by anti-C1 INH antibody. A lysate of HUVEC derived from an umbilical cord from a patient with Type I hereditary angioedema contained less than 30% of the normal levels of C1 INH antigen and activity. Immunohistochemical staining of HUVEC demonstrated a diffuse pattern of staining for C1 INH. HUVEC C1 INH was also expressed on the endothelial cell surface as detected by binding of anti-C1 INH antibody to intact monolayers and was elaborated progressively into the overlying media over the first 24 h in culture. HUVEC incubated with [35S] methionine secreted a metabolically labeled protein having a molecular mass of 92 kDa immunoisolated using polyclonal or monoclonal antibodies to human C1 INH. A mRNA transcript encoding for C1 INH was detected by slot blot hybridization. Incubation of HUVEC with gamma-interferon stimulated the expression of the 2.1 kilobase mRNA for C1 INH and increased the level of C1 INH produced by these cells. Production and expression of C1 INH by endothelial cells may help modulate the complement system and the contact system of plasma proteolysis on the vascular surface in vivo.

Blotting, Northern↗
PubMed1982

A postulated mechanism for heparin's potentiation of C1 inhibitor function.

Conflicting reports exist in the literature concerning the primary mechanism for heparin's inhibition of C1 hemolytic function. We provide evidence here that heparin's most effective inhibition is mediated through interaction with and potentiation of C1-INH. The molecular nature of the interaction between heparin and the C1-INH molecule is evidenced by an anodal shift in the electrophoretic mobility of C1-INH upon the addition of heparin.l We also demonstrate that C3 and C4 conversions in normal human serum by classical pathway activators such as heat-aggregated IgG are inhibited by addition of heparin, yet heparin does not prevent similar C3 conversion in serum depleted of C1-INH Heparin's inhibitory action is restored to C1-INH-depleted serum by the addition of purified C1-INH.

Complement Activation↗
PubMedDate not supplied

[Hereditary angioedema by defict of C1 esterase. Our experience in 8 cases].

Eight cases of hereditary angioedema, all of them with low values of C1-sterase inhibitor are analyzed. In 7 cases the C3 and C4 components of the complement were assessed; the results showed marked descent of C4. The 8 patients came from 4 different families; only 2 of them were males. Six patients presented digestive disorders, reporting colic pain, nausea and vomiting. In 1 of them the abdominal picture was the only evidence of the disease. In 5 patients the angioedema episodes occurred following traumatisms and in 3 because of emotional states. The duration of the attacks varied from several hours to six days. There was a familial history in all cases. Three of the patients had repeated episodes of pharyngolaryngeal angioedema, two of them requiring emergency tracheotomy because of suffocating crisis. Six patients were treated with Epsilon aminocaproic acid (16 to 20 gr daily) or with tranexamic acid (1 to 3 gr. daily). In 4 cases the results were excellent with either of these antifibrinolytic drugs. No side effects were observed in the tranexamic acid therapy whilst they were frequent in the treatment with Epsilon aminocaproic acid.

Adolescent↗
PubMed1983

C1 inactivator-C1s complexes in inflammatory joint disease.

A newly developed enzyme linked immunosorbent assay for the quantitation of C1 inhibitor (C1In)-C1s complexes was used to study activation of the classical pathway of complement in inflammatory joint diseases. Synovial fluid (SF) specimens were obtained from patients with rheumatoid arthritis (RA), other arthritides and non-inflammatory joint effusions. Paired serum (S) samples were obtained in 17 cases. Immune complexes (IC) were measured by the staphylococcal binding assay. C1In-C1s were higher in RA SF samples than in paired RAS samples (P less than 0.01). IC were higher in RA SF than non-RA SF. There was a significant inverse correlation between SF C1In-C1s complexes and SF total haemolytic complement. For all SF samples there was a correlation between IC and C1In-C1s complexes, but for RA SF alone there was no significant correlation between these parameters. There was no correlation between titre of rheumatoid factor and C1In-C1s complexes. These results demonstrate that activation of the classical pathway of complement is the hallmark of rheumatoid synovitis, yet also suggest functional heterogeneity of both circulating and intra-articular IC.

Antigen-Antibody Complex↗
PubMed1978

Remissions induced in hereditary angioneurotic edema with an attenuated androgen (danazol): correlation between concentrations of C1-inhibitor and the forth and second components of complement.

Serum concentrations of antigenic and functional C1-INH increased in patients in whom remissions from attacks of HANE were induced with danazol. The levels of C4 were directly related to serum concentrations of C1-INH antigens up to a concentration of about half the C1-INH found in normal plasma; at this point, the C4 concentrations were in the normal range and no longer correlated well with C1-INH concentration. Serum C2 levels correlated less well with C1-INH concentration. In normal serum there was a poor correlation between C1-INH, C4, and C2 levels, suggesting that C1-INH is normally present in excess of the amount needed for normal C4 levels. The increments in serum C1-INH were related to the dose of danazol.

Angioedema↗
PubMed2001

The potentiation of human C1-inhibitor by dextran sulphate is transient in vivo: studies in a rat model.

C1-inhibitor (C1-Inh) is an important regulator of inflammatory reactions because it is a potent inhibitor of the contact and complement system. C1-Inh application in inflammatory disease is, however, restricted because of the high doses required. The glycosaminoglycan-like molecule dextran sulphate (DXS) enhances C1-Inh function in vitro. Hence, we investigated whether co-administration with dextran sulphate reduces the amount of C1-Inh required, through enhancement in vivo. C1-Inh potentiation was measured in a newly developed C1s-inactivation assay that is based on activation of C4 by purified C1s. Activated C4 in rat plasma was quantified with a newly developed ELISA. Human C1-Inh (2.5 microM) inhibited C1s in rat plasma 55-fold faster in the presence of dextran sulphate (15 kDa, 5 microM). To study the stability of the complex in vivo, rats were given a mixture of C1-Inh (10 mg/kg) and dextran sulphate (3 mg/kg). C1-Inh activity during 5 h was analyzed ex vivo with the C1s inactivation assay. The noncovalent C1-Inh-dextran sulphate complex resulted in a transient enhancement of the inhibitory capacity of C1-Inh, lasting for 60-90 min. Dextran sulphate did not affect plasma clearance of C1-Inh. We conclude that the enhanced inhibitory capacity of C1-Inh complexed to dextran sulphate is transient in vivo. Hence, co-administration of these compounds seems a feasible approach to achieve short-term inhibition of complement in vivo.

Animals↗
PubMed1987

Interferon-gamma is a major regulator of C1-inhibitor synthesis by human blood monocytes.

C1 inhibitor (C1INH) is the major control factor for the activation of the classical pathway of complement and for contact system activation. Hepatocytes and blood monocytes are known to synthesize this protease inhibitor. We studied the regulation of monocyte C1INH production by mediators that are generated during inflammatory responses. Purified blood monocytes spontaneously synthesized and secreted C1INH only after prolonged culture. In the presence of interferon (IFN)-gamma, C1INH was detectable within 24 hr and continued to be released at high levels throughout an 8-day culture period. Monocyte C1INH was newly synthesized and was functionally active as determined by forming stable complex with C1s. Other monocyte stimuli were either less potent (IFN-alpha, IFN-beta) or not capable of increasing C1INH release (lipopolysaccharide, interleukin 1, and tumor necrosis factor). The second component of complement, C2, was induced by IFN-gamma to a similar extent as C1INH. These findings demonstrate that IFN-gamma is a major regulator of monocyte C1INH production and may warrant consideration of IFN-gamma in the treatment of C1INH deficiency states.

Cells, Cultured↗
PubMed1989

[Stepwise dissociation of subcomponents of C1, the first component of human complement, upon activation on an affinity sorbent].

An affinity sorbent comprising macroporous glass coated with the polymer with the polymer with immobilized immunoglobulin IgG was used for the isolation from human serum of the first component of the complement and for its separation into subcomponents C1r, C1s and C1q by the one-step procedure. Serum C1 was quantitatively bound to the sorbent at 0 degrees C. The unbound part of the serum can be used as a R1 reagent for determining the hemolytic activity of C1. After activation of bound C1 by heating (30 degrees C, 40 min) the activated subcomponent C1r is eluted from the sorbent. Stepwise elution with EDTA at pH 7.4 or with EDTA + 1 M NaCl at pH 8.5 results in a selective and quantitative elution of the activated subcomponent C1s and subcomponent C1q. Stepwise elution of C1 subcomponents from the affinity sorbent after activation reflects the process of C1 breakdown following its activation on immune complexes.

Animals↗