Elisabeth I. Minder

Troponin as a risk factor for mortality in critically ill patients without acute coronary syndromes

OBJECTIVES We sought to assess the mechanism and prognostic value of elevated troponins in patients without acute coronary syndromes (ACS). BACKGROUND Cardiac troponins are used as specific markers for the diagnosis of ACS. Recent studies reported a considerable number of critically ill patients without ACS as being troponin-positive, especially patients with sepsis, pulmonary embolism, renal failure, and stroke. METHODS We analyzed 58 consecutive, critically ill patients admitted for reasons other than ACS, according to their troponin status. Thirty-day mortality, left ventricular ejection fraction (LVEF), and a panel of inflammatory cytokines were compared between troponin-positive and troponin-negative patients. Relevant coronary artery disease was excluded either by stress echocardiography or autopsy. RESULTS Of the 58 critically ill patients, 32 (55%) without evidence of ACS were troponin-positive. Positive troponin levels were associated with higher mortality (22.4% vs. 5.2%, p < 0.018) and a lower LVEF (p = 0.0006). Troponin-positive patients had significantly higher median levels of tumor necrosis factor (TNF)-alpha, its soluble receptor, and interleukin (IL)-6. A subgroup of 10 aplastic patients was troponin-negative at study entry. Three became troponin-positive during leukocyte recovery and subsequently died, whereas all the others stayed troponin-negative and survived. Flow-limiting coronary artery disease was not demonstrable at autopsy or stress echocardiography in 72% of troponin-positive patients. CONCLUSIONS Elevated troponin is a mortality risk factor for medical intensive care patients admitted for reasons other than ACS. It is associated with decreased left ventricular function and higher levels of TNF-alpha and IL-6.

Proinflammatory cytokines in acute myocardial infarction with and without cardiogenic shock.

BackgroundInflammatory response is an important feature of acute coronary syndromes and myocardial infarction (MI). The prognostic value of proinflammatory cytokines in patients with acute MI complicated by cardiogenic shock is unknown.Methods and resultsIn 41 patients admitted with acute MI (age 60 ± 11 years, six females, 19 Killip class IV) serial plasma concentration of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1 receptor antagonist (IL-1Ra) were measured. Seven patients with cardiogenic shock (CS) developed a systemic inflammatory response syndrome (SIRS). Patients with CS—particularly those who developed SIRS—showed significantly higher cytokine levels than patients with uncomplicated MI. In patients with CS and SIRS peak levels of IL-1Ra were 223,973 pg/ml, IL-6 252.8 pg/ml and TNF-α 7.0 pg/ml. In CS without SIRS IL-1Ra levels were 19,988 pg/ml, IL-6 109.3 pg/ml and TNF-α 3.8 pg/ml. In uncomplicated MI peak IL-1Ra levels were 1,088 pg/ml, IL-6 34.1 pg/ml and TNF-α 2.6 pg/ml.ConclusionsThe inflammation-associated cytokines TNF-α, IL-6 and IL-1Ra are significantly elevated in patients with MI complicated by CS when compared to patients with uncomplicated MI. Among shock-patients IL-1Ra levels are promising diagnostic markers for early identification of patients developing SIRS, heralding a poor outcome.

New insights into the pathogenesis of erythropoietic protoporphyria and their impact on patient care

Abstract Erythropoietic protoporphyria (EPP, MIM 177000) is an inherited disorder caused by a partial deficiency of ferrochelatase (FECH) which catalyses the chelation of iron into protoporphyrin to form haem. The majority of EPP patients experience solely a painful photosensitivity whereas a small number of them develop liver complications due to the accumulation of excessive amount of protoporphyrin in the liver. EPP is considered to be an autosomal dominant disorder, however, with a low clinical penetrance. To date, a total of 65 different mutations have been identified in the FECH gene of EPP patients. Among the 89 EPP patients who carry a “null allele” mutation which results in the formation of a truncated protein, 18 of them developed EPP-related liver complications. None of the 16 missense mutations identified among 19 patients on the other hand, have been associated with liver disease (P = 0.038). The allelic constellation of an overt patient consists of a mutated FECH allele and a “low expressed” normal allele and that of an asymptomatic carrier, a combination of a mutated and a normally expressed FECH allele. The identification of the “low expressed” allele is facilitated by haplotype analysis using two single nucleotide polymorphisms, −251 A/G in the promoter region and IVS1−23C/T. At the current time when only partially effective therapies are available, the disclosures of both “null allele” and the “low expression” mechanisms will improve patient management. Conclusion While covering the important clinical aspect of erythropoietic protoporphyria, this article emphasises the latest achievements in the molecular genetics of the disorder.

Mitigating Photosensitivity of Erythropoietic Protoporphyria Patients by an Agonistic Analog of α‐Melanocyte Stimulating Hormone†

Erythropoietic protoporphyria (EPP) is a rare hereditary disorder characterized by dermal accumulation of the photosensitizer protoporphyrin IX. Following sunlight exposure, the resulting photosensitivity is manifested first as pain, later as erythema, edema and dermal lesions. Afamelanotide (Nle4‐d‐Phe7‐α‐MSH), a synthetic analog of α‐melanocyte stimulating hormone and agonist of the melanocortin‐1‐receptor, promotes melanin synthesis, increasing skin pigmentation. This study examines the efficacy of afamelanotide in preventing symptoms in patients with EPP. A sustained‐release subcutaneous implant of 20 mg afamelanotide was administered twice, with a 60‐day interval to five EPP patients. Therapeutic efficacy was assessed by a photoprovocation test using standardized white light irradiation, melanin density (MD) determination and daily recording of sunlight exposure and symptoms. From Day 30 to Day 120 tolerance to photoprovocation significantly increased compared with baseline (P = 0.007) and skin MD was significantly higher than that recorded at baseline (P = 0.004). Except for two low‐grade pain episodes, patients recorded no phototoxic events past Day 4 of treatment. Tolerance to natural sunlight was up to 24 times longer than prior to therapy. The findings demonstrate beneficial effects of afamelanotide in patients with EPP. Due to the limited number of patients enrolled and the design being an open‐label study, confirmation by a large‐scale trial is required.

Influence of age and gender on the clinical expression of acute intermittent porphyria based on molecular study of porphobilinogen deaminase gene among Swiss patients.

BackgroundAcute intermittent porphyria (AIP) is an inherited disorder in the heme biosynthetic pathway caused by a partial deficiency of porphobilinogen (PBG) deaminase. Clinically, AIP is characterized as acute neurovisceral attacks that are often precipitated by exogenous factors such as drugs, hormones, and alcohol. An early detection of mutation carriers is essential for prevention of acute attacks by avoiding precipitating factors. This study was aimed at analyzing genetic defects causing AIP among Swiss families to further investigate aspects concerning the clinical expression of the disease.Materials and MethodsThe PBGD gene of index patients from 21 Swiss AIP families was systematically analyzed by denaturing gradient gel electrophoresis of polymerase chain reaction (PCR) amplified DNA fragments and direct sequencing.ResultsFive new mutations insA503, del L170, T190I, P241S, and R321H, as well as three known mutations (R26H, R173Q and W283X) were detected. Twelve of the 21 index patients (57%) carried the prevalent mutation W283X previously found among the Swiss AIP population. Family-specific mutations were then screened among relatives of the index patients. Among the 107 studied individuals, 58 carried a PBGD gene mutation—30 were overt AIP patients and 28 were asymptomatic carriers. The apparent rate of overt disease in the study cohort was 52%, which is significantly higher than the previously reported penetrance of 10–20%. To further examine the clinical expression of AIP, the cumulative life-time risk was calculated among 58 mutation-positive individuals after stratifying for age. The result shows a linear increase of the percentage of the symptomatic patients with age, reaching up to 75% among carriers aged over 60. More-over, statistical analysis of the gender distribution among patients and asymptomatic carriers indicated that the disease was more frequently expressed among females than males (Fisher’s exact test two sided, p = 0.001).ConclusionsThis comprehensive search for genetic defects in the PBGD gene confirmed the existence of a prevalent mutation W283X among Swiss AIP patients, as well as a number of family-private mutations. Genetic analysis laid a groundwork for further studies such as the effects of gender and age on the clinical expression of AIP.

Molecular and functional analysis of the C-terminal region of human erythroid-specific 5-aminolevulinic synthase associated with X-linked dominant protoporphyria (XLDPP)

Frameshift mutations in the last coding exon of the 5-aminolevulinate synthase (ALAS) 2 gene were described to activate the enzyme causing increased levels of zinc- and metal-free protoporphyrin in patients with X-linked dominant protoporphyria (XLDPP). Only two such so-called gain-of-function mutations have been reported since the description of XLDPP in 2008. In this study of four newly identified XLDPP families, we identified two novel ALAS2 gene mutations, a nonsense p.Q548X and a frameshift c.1651-1677del26bp, along with a known mutation (delAGTG) found in two unrelated families. Of relevance, a de novo somatic and germinal mosaicism was present in a delAGTG family. Such a phenomenon may explain the high proportion of this mutation in XLDPP worldwide. Enhancements of over 3- and 14-fold in the catalytic rate and specificity constant of purified recombinant XLDPP variants in relation to those of wild-type ALAS2 confirmed the gain of function ascribed to these enzymes. The fact that both p.Q548X and c.1651-1677del26bp are located in close proximity and upstream from the two previously described mutations led us to propose the presence of a large gain-of-function domain within the C-terminus of ALAS2. To test this hypothesis, we generated four additional nonsense mutants (p.A539X, p.G544X, p.G576X and p.V583X) surrounding the human XLDPP mutations and defined an ALAS2 gain-of-function domain with a minimal size of 33 amino acids. The identification of this gain-of-function domain provides important information on the enzymatic activity of ALAS2, which was proposed to be constitutively inhibited, either directly or indirectly, through its own C-terminus.

Molecular defects in erythropoietic protoporphyria with terminal liver failure.

We identified two additional mutations in the ferrochelatase gene in two Swiss patients with erythropoietic protoporphyria (EPP). Ferrochelatase cDNA from patients was amplified by the polymerase chain reaction (PCR) and subjected to mutation analysis by sequencing PCR products either directly or after subcloning. The first patient, who underwent liver transplantation because of terminal liver failure, was identified as having a single point mutation (C to T) at nucleotide 175 that resulted in a Gln to stop codon conversion in one allele of the gene. In the second case, in which the patient has so far no liver involvement, a two-base deletion (T899G900) was found in one allele. Frameshift as a result of the deletion creates a stop codon. This study presents two new genotypes of EPP, including one with liver failure, a rare and fatal form of EPP.

Identification of a Prevalent Nonsense Mutation (W283X) and Two Novel Mutations in the Porphobilinogen Deaminase Gene of Swiss Patients with Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by decreased activity of porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthetic pathway. We report the first molecular analysis of PBGD gene mutations in AIP patients of Swiss origin. The PBGD gene of 18 Swiss AIP patients was analyzed by denaturing gradient gel electrophoresis screening of the genomic DNA and direct sequencing. Thirteen of the 18 patients (72%) carried a nonsense mutation G849→A, W283X. In addition, 4 different mutations including 2 novel mutations (Q217L and Q292X), were identified in the 5 remaining AIP patients originating from both German- and Italian-speaking regions of Switzerland.

Hypericin and 5-aminolevulinic acid-induced protoporphyrin IX induce enhanced phototoxicity in human endometrial cancer cells with non-coherent white light

BACKGROUND The in vitro experiments described in this study were aimed at exploring a synergistic effect between 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) and hypericin. In a previous study, enhanced phototoxicity was observed in a patient during a clinical study on 5-ALA-based photodynamic tumor localization of breast cancer. This patient ingested a hypericin containing plant extract in parallel to orally applied 5-ALA. METHODS Human endometrial cancer cells (HEC-1A) were treated with 0.5mM of 5-ALA and 60 nM of hypericin, either separately or combined. Colony formation was assessed after illumination of the cells with both red (635 nm) and white light (400-800 nm) at a dose of 2.5 J/cm(2). Porphyrin metabolites were quantified by HPLC in cells treated with photosensitizers without subsequent illumination. RESULTS After white light illumination, cells treated with a combination of 5-ALA and hypericin had a significant reduction in colony formation compared with cells treated with 5-ALA only. No significantly enhanced toxicity was found with red light and the 5-ALA plus hypericin combination. In addition, cells treated with both 5-ALA and hypericin tended to produce more PpIX than cells treated with 5-ALA only. CONCLUSIONS This study demonstrated that treatment of endometrial cancer cells with both 5-ALA and hypericin followed by illumination with white light induced a significantly higher phototoxicity as revealed by colony formation. This setting which generated an in vitro effect similar to the patients situation, might be applied in the future as an affordable and effective photodynamic therapy (PDT) modality.

Hepatocellular carcinoma in variegate porphyria: a serious complication.

Variegate porphyria is an acute hepatic porphyria resulting from a partial deficiency of protoporphyrinogen oxidase, the penultimate enzyme in haem biosynthesis. Cutaneous symptoms and acute neurovisceral attacks are well-known clinical characteristics of the disease. Less studied, however, is the risk of developing hepatocellular carcinoma, an aggressive type of liver cancer. We describe here two Swiss patients with variegate porphyria and this serious complication. Common risk factors, including alcohol over-consumption or chronic hepatitis, were absent in both patients. Interestingly, one patient carried mutation 1082-1083insC in the PPOX gene, a prevalent sequence deviation in the Swiss variegate porphyria population, which was also found in a French patient with variegate porphyria and hepatocellular carcinoma. Recent studies indicate that individuals with acute hepatic porphyria have a 36- to 61-fold increased risk of manifesting hepatocellular carcinoma. The incidence rate ratio in the Swiss population was estimated to be 34, comparable with those found in the French and Finnish populations. Because this tumour is associated with a rising mortality, we suggest regular screening for hepatocellular carcinoma in all patients with variegate porphyria.