Could signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 be a therapeutic target in the pathogenesis of preeclampsia?

OBJECTIVE: Determination of biomolecules that play a role in the etiopathogenesis of preeclampsia and their application as therapeutic targets may increase surveillance in this patient group. The aim of this study was to investigate the relationship between signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1, a marker of endothelial dysfunction and platelet activation, and the development of preeclampsia. METHODS: In this observational cross-sectional study conducted between April 2021 and December 2022, 73 consecutive pregnant women with preeclampsia and 73 healthy pregnant women were included. Blood samples were taken from all patients with preeclampsia to measure signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 levels at the time of hospitalization. Excluded from the study were pregnant women with certain medical conditions or treatments, and the signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 levels of the groups were compared according to the development of preeclampsia. RESULTS: Signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 levels were significantly higher in the preeclampsia group than in the controls (p<0.001). In multivariate analysis, signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 was determined as an independent predictor for preeclampsia (OR: 1.678, 95%CI 1.424-1.979, p<0.001). Receiver operating characteristic curve analysis showed that the best cutoff value of signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 at 3.25 ng/mL predicted the development of preeclampsia with 71% sensitivity and 68% specificity (area under the curve, 0.739; 95% confidence interval (95%CI), 0.681-0.798, p<0.001). CONCLUSION: Signal peptide complement C1r/C1s, Uegf, and Bmp1, and epidermal growth factor-containing protein 1 is significantly elevated in pregnant women with preeclampsia compared with healthy controls.

Obtención de un preparado del componente C1 (q, r, s) del sistema complemento / Obtaining a preparation of C1 component (q, r, s) of the complement system

Se obtuvo un preparado concentrado del componente C1 (q, r, s) del sistema completo en forma inactiva por un método de precipitación, libre de contaminación con los restantes componentes iniciales de la vía clásica, el C2 y el C4. Este preparado se mantuvo estable a 2 °C y en los ensayos funcionales fue capaz de fijarse al complejo EAC4, activar los componentes C2 y C4 para formar la convertasa del C3, y provocar la lisis de estas células. La reacción de hemólisis fue activada por el C2 e inhibida por el Cl inhibidor, lo que indica la especificidad del C1 obtenido.Este pudiera emplearse para lograr un antisuero específico, para la obtención de los subcomponentes C1q, C1r y C1s, o para la estandarización de métodos funcionales de estudiar el C1, el C2 o el C1 inhibidor.

Purificación de C1r a partir de la fracción I de Cohn / Purification of C1r starting from Chron's fraction I

Se describe un método de purificación del componente C1r del sistema complemento a partir de la fracción I de Cohn mediante cromatografías secuenciales en Bio Rex 70, DEAE Sephacel y Sephacryl S 200. La presencia de C1r en las fracciones eluidas en las diferentes corridas cromatográficas se detectó por nefelometría. La pureza del C1r obtenido se determinó por inmunoelectroforesis contra un suero anti proteínas séricas humanas y un antisuero específico. A partir del C1r purificado se produjo en conejos un antisuero de buena calidad, útil para la cuantificación del C1r sérico

SC5b-9 is the most sensitive marker in assessing disease activity in Brazilian SLE patients.

This study investigated whether increased plasma levels of terminal complement complex (SC5b-9) or split products correlate with disease activity and clinical manifestations in Brazilian systemic lupus erythematosus (SLE) patients. Comparisons with conventional measurements of complement and other inflammatory markers were also performed. Plasma levels of SC5b-9, C3a desArg, C1rs-C1Inhibitor, C3b(Bb)P, C3, C4, erythrocyte sedimentation rate (ESR) and mucoproteins (MP) were measured in 41 patients with SLE of different disease activity: 10 patients with none, 15 patients with mild, and 16 patients with moderate or severe activity. All parameters, with the exception of C3 and C3b(Bb)P, showed a statistically significant correlation with disease activity. Plasma levels of SC5b-9, C3a desArg, C4, CH50, ESR and MP revealed significant differences between the groups of patients without activity and those with moderate or severe disease. Although none of the variables were able to discriminate between patients without and those with mild activity, SC5b-9, C3a desArg, C4, ESR and mucoproteins showed significant differences between the patients with mild and those with moderate or severe disease. Among all the variables, SC5b-9 levels showed the most significant results and correlated well with the severity of the disease (p < 0.0005). Our data suggest that elevated levels of complement activation products, particularly of SC5b-9 are more sensitive markers in assessing disease activity than conventional laboratory diagnosis. Modern complement diagnosis is therefore recommended for monitoring disease progress in SLE patients.

An improved method for complement subcomponent C1R typing.

An improved method has been developed for the reliable classification of different C1R genetic variant forms from human serum or plasma. The method combines the use of neuraminidase-digested samples followed by monodimensional isoelectric focusing in the pH range 5 to 8 followed by immunoblotting. The method yields a simple pattern, with one major band in homozygote and two major bands in heterozygote cases.

Genetic studies of low-abundance human plasma proteins. XI. Linkage analysis and population genetics of the C1S subcomponent of the first complement component.

Although subcomponents C1r and C1s of the first complement component, C1, have been established to be in the same linkage group as the proline-rich protein gene cluster on chromosome 12p13.2, no direct analysis of linkage between the C1R and C1S structural gene loci has been available. We have detected through a population screening study 5 families which are heterozygous at the structural loci for both C1R and C1S. Three of the 5 families, 21 individuals, were informative for linkage. A maximum lod score of 1.505 at theta = 0.00 was found in a two-point analysis between C1R and C1S. Ten populations were screened for structural variation at the C1S locus. Only US Whites and a Kodiak Island Eskimo group expressed heterogeneity. The frequencies of the designated alleles, C1S*1 and C1S*2, were 0.992 and 0.007, respectively, in the US White population and 0.998 and 0.002, respectively, in the Kodiak Island Eskimo population. In addition, the product of a putative new allele, designated C1S*4, was observed in a single US White individual but segregation of this variant was not observed in the limited family data available.

Atypical hypocomplementemic vasculitis syndrome in a child.

We report a patient who developed recurrent urticaria and angioedema at age 2 years, severe hypocomplementemic glomerulonephritis at 11 years, and end-stage renal disease at 14 years. His disease resembled the hypocomplementemic vasculitis syndrome but was atypical in its early age of presentation, severe hypocomplementemia, and progression to end-stage renal disease. Serum C1q levels were extremely low, and C4, C2, C3, and C5 levels were significantly reduced. Serum C1 inhibitor (C1INH) levels were slightly low, presumably from consumption. Circulating C1INH-C1r-C1s complexes were evidenced by reduced ratios of functional to antigenic C1INH and antigenic C1r to C1s. Family members had normal functional and antigenic levels of all complement components studied. The patient's serum, erythrocytes, platelets, and mononuclear cells did not activate complement when mixed with normal target serum. Absence of a circulating complement activator and the low serum C3 and C5 levels suggested the presence of a solid-phase complement activator, possibly related to renal or systemic vascular endothelium. As in patients with homozygous deficiencies of classical pathway components, a severe, prolonged, acquired C1q deficiency may have predisposed this patient to the development of glomerulonephritis.

Inherited disorders of complement

Isolated complement component deficiencies are uncommon. Deficiencies of all eleven components and two inhibitors of the classical pathway have been described. Complete absence of the components of the alternative pathway has not been described. The consequences of a single defect in complement are often predictable from an understanding of the biologic activities associated with activation of the complement system. Deficiency of C1 esterase inhibitor gives rise to the disease, hereditary angioedema; deficiency of the early components of the classical pathway are associated with lupus erythematosus; C3 and C3 inactivator deficiencies with pyogenic infections; C5 dysfunction with Leiner's disease; deficiencies of the terminal components with recurrent Neisseria bacteremia; and C9 deficiency with normal health. The complement system and its associated biologic activities are reviewed. The present knowledge of the inherited complement deficiencies and associated diseases, with particular emphasis on the dermatologic manifestations, genetics, and diagnosis, is summarized.