Defective brain energy metabolism shown by in vivo 31P MR spectroscopy in 28 patients with mitochondrial cytopathies.

We studied brain energy metabolism by phosphorus magnetic resonance spectroscopy (31P MRS) in 28 patients with mitochondrial cytopathies, and 20 normal control subjects. Fourteen patients had myopathy alone, six had only mild brain symptoms, and eight showed different degrees of brain involvement. Brain 31P MRS showed a low phosphocreatine content in all patients, accompanied by a high inorganic phosphate in 14 of 28 patients. The average value of the Pi concentration in the patient group was significantly (p = 0.009) different from the control group. The cytosolic pH was normal. From these data were derived a high concentration of ADP (calculated from the creatine kinase equilibrium), a high percent value of V/Vmax for ATP biosynthesis, and a low phosphorylation potential, all features showing a derangement of brain energy metabolism, in all patients with mitochondrial cytopathies. 31P MRS proved to be sensitive enough to disclose a deficit of mitochondrial functionality not only in the affected patients, but also in those without clinically evident brain symptoms.

The use of phosphorus magnetic resonance spectroscopy to study in vivo the effect of coenzyme Q10 treatment in retinitis pigmentosa.

Phosphorus magnetic resonance spectroscopy (31P-MRS) has emerged as a noninvasive reliable tool for in vivo study of human tissue bioenergetics. It detects and quantifies some phosphorylated compounds present in millimolar concentration inside the cell, including ATP, phosphocreatine (PCr) and inorganic phosphate (Pi). By 31P-MRS we studied brain and skeletal muscle energy metabolism of three patients with retinitis pigmentosa before and after oral coenzyme Q10 (CoQ10) (100 mg/day). Before treatment we found a low PCr content in the brains of all patients, accompanied by a high [Pi] and high [ADP]. In two of three patients CoQ10 treatment resulted in a larger brain energy reserve mainly shown by an increased [PCr]. Abnormal muscle mitochondrial function was found only in one patient as shown by a reduced rate of PCr resynthesis after exercise. In this patient CoQ10 treatment resulted in an increased rate of PCr resynthesis. Our observations indicate that CoQ10 can improve mitochondrial functionality in the brain and skeletal muscle of patients with retinitis pigmentosa.

Phosphorus magnetic resonance spectroscopy in cluster headache.

We performed in vivo MR spectroscopy phosphorus (31P-MRS) on the brain and skeletal muscles of 14 patients affected with cluster headache (CH). We examined patients in interictal periods, and also examined nine of them during the cluster period, although not during the attack. Brain 31P-MRS showed reduced phosphocreatine (PCr) levels, an increased ADP concentration (calculated from the creatine kinase equilibrium), a reduced phosphorylation potential, and a high relative rate of ATP biosynthesis (V/Vmax %). The inorganic phosphate (P(i)) content was increased during the cluster period. Ten of 13 patients also showed a slow rate of PCr recovery in muscle after the exercise. 31P-MRS in CH patients showed abnormalities of brain and skeletal muscle energy metabolism comparable with those seen in various types of migraine, thus leading us to suggest a similarity in biochemical pathogenic mechanisms between CH and migraine.

Abnormal brain and muscle energy metabolism shown by 31P magnetic resonance spectroscopy in patients affected by migraine with aura.

We studied brain and muscle energy metabolism by phosphorus 31 magnetic resonance spectroscopy (31P-MRS) in 12 patients affected by migraine with aura (classic migraine) in interictal periods. Brain 31P-MRS disclosed a low phosphocreatine content in all patients, accompanied by high adenosine diphosphate concentration, a high percentage of V/Vmax (adenosine triphosphate), and a low phosphorylation potential--features showing an unstable state of metabolism in classic migraine. Abnormal muscle mitochondrial function, in the absence of clinical signs of muscle impairment, was present in nine of the 12 patients examined.

Leber's hereditary optic neuropathy: genetic, biochemical, and phosphorus magnetic resonance spectroscopy study in an Italian family.

Three siblings of a family affected with Leber's hereditary optic neuropathy (LHON) showed a mitochondrial DNA mutation at position 11778. The lactate response to a standardized effort was increased in only one case. Muscle biopsies and biochemistry of muscle and platelet mitochondrial enzymes were normal. All patients showed an altered energy metabolism during exercise and during recovery after exercise on phosphorus 31-magnetic resonance spectroscopy (31P-MRS) of muscle. Brain 31P-MRS showed a decreased energy reserve (decreased PCr/Pi ratio) in all patients. 31P-MRS noninvasively demonstrated an altered mitochondrial energy metabolism in muscle and, for the first time, in the brains of LHON patients.

31P-magnetic resonance spectroscopy in migraine without aura.

We investigated 22 patients with migraine without aura, all drug-free and in headache-free periods, by means of 31P-magnetic resonance spectroscopy (MRS) of brain and muscle. Brain 31P-MRS showed significantly low phosphocreatine, increased adenosine diphosphate, and decreased phosphorylation potential. There was a slow rate of phosphocreatine recovery after exercise in the muscle of 12 of 22 patients. Energy metabolism is abnormal in migraine without aura, as previously demonstrated in patients with migraine stroke and migraine with aura.

Defective brain and muscle energy metabolism shown by in vivo 31P magnetic resonance spectroscopy in nonaffected carriers of 11778 mtDNA mutation.

In vivo phosphorus magnetic resonance spectroscopy (31P-MRS) showed defective brain and muscle energy metabolism in three affected siblings in a family with Leber's hereditary optic neuropathy (LHON) with the 11778 mtDNA mutation. We studied 14 nonaffected members of the same pedigree by 31P-MRS and molecular genetics. Nine of 14 individuals studied had the 11778 mtDNA mutation, with various degrees of heteroplasmy. A decreased brain energy reserve, as shown by low phosphocreatine content and phosphorylation potential and high [ADP], was present in eight of these nine subjects with the 11778 mutation. A low rate of postexercise phosphocreatine recovery in muscle was present in six of the nine mutated individuals. Normal MRS findings in the brain of one and the muscle of three carriers were accompanied by a low percentage of mutated mtDNA. All subjects without mutation had normal brain and muscle MRS. 31P-MRS disclosed defective bioenergetics in the brain or muscle or both of all asymptomatic carriers studied from our pedigree.

Muscle phosphoglycerate mutase (PGAM) deficiency in the first Caucasian patient: biochemistry, muscle culture and 31P-MR spectroscopy.

Muscle phosphoglycerate mutase (PGAM) deficiency has been so far identified in only six patients, five of these being African Americans. We report the results of clinical, morphological, biochemical, muscle culture and 31P-MR spectroscopy studies in the first Caucasian patient with muscle PGAM deficiency. A 23-year-old man had a 10-year history of cramps after physical exertion with one episode of pigmenturia. Neurological examination and EMG study were normal. ECG and echocardiography revealed hypertrophy of the interventricular septum and slight dilation of the left chambers of the heart. Muscle biopsy revealed increased glycogen content and some accumulation of mitochondria. Muscle PGAM activity was markedly decreased (6.5% and 9.7% of control value in two different biopsies). Citrate synthase and other mitochondrial respiratory chain enzyme activities were much higher than normal. In contrast to the marked decrease of PGAM activity observed in muscle biopsy, total enzyme activity in the patient's aneural muscle culture was normal, being represented exclusively by BB isoenzyme. The deficiency of PGAM-MM isoenzyme was reproduced in the patient's innervated muscle culture. Muscle 31P-MR spectroscopy showed accumulation of phosphomonoesters only on fast "glycolytic" exercise. On "aerobic" exercise, Vmax, calculated from the work-energy cost transfer function, showed an increase consistent with the morphological and biochemical evidence of mitochondrial proliferation. This might represent a sort of compensatory aerobic effort in an attempt to restore muscle power.

Lipoic (thioctic) acid increases brain energy availability and skeletal muscle performance as shown by in vivo 31P-MRS in a patient with mitochondrial cytopathy.

A woman affected by chronic progressive external ophthalmoplegia and muscle mitochondrial DNA deletion was studied by phosphorus magnetic resonance spectroscopy (31P-MRS) prior to and after 1 and 7 months of treatment with oral lipoic acid. Before treatment a decreased phosphocreatine (PCr) content was found in the occipital lobes, accompanied by normal inorganic phosphate (Pi) level and cytosolic pH. Based on these findings, we found a high cytosolic adenosine diphosphate concentration [ADP] and high relative rate of energy metabolism together with a low phosphorylation potential. Muscle MRS showed an abnormal work-energy cost transfer function and a low rate of PCr recovery during the post-exercise period. All of these findings indicated a deficit of mitochondrial function in both brain and muscle. Treatment with 600 mg lipoic acid daily for 1 month resulted in a 55% increase of brain [PCr], 72% increase of phosphorylation potential, and a decrease of calculated [ADP] and rate of energy metabolism. After 7 months of treatment MRS data and mitochondrial function had improved further. Treatment with lipoate also led to a 64% increase in the initial slope of the work-energy cost transfer function in the working calf muscle and worsened the rate of PCr resynthesis during recovery. The patient reported subjective improvement of general conditions and muscle performance after therapy. Our results indicate that treatment with lipoate caused a relevant increase in levels of energy available in brain and skeletal muscle during exercise.

Early-onset cerebellar ataxia, myoclonus and hypogonadism in a case of mitochondrial complex III deficiency treated with vitamins K3 and C.

A 16-year-old girl presented with early-onset cerebellar ataxia, myoclonus, elevated lactic acidosis and hypogonadotropic hypogonadism. Muscle biopsy specimens revealed fibres with a "ragged" appearance with increased mitochondria and lipid droplets. Biochemical investigation revealed a deficiency of complex bc1 (complex III) of the mitochondrial respiratory chain. Genetic analysis did not show either deletions or known mutations of mitochondrial DNA (mtDNA). Phosphorus magnetic resonance spectroscopy (31P-MRS) showed defective energy metabolism in brain and gastrocnemius muscle. A decreased phosphocreatine (PCr) content was found in the occipital lobes accompanied by normal inorganic phosphate (Pi) and cytosolic pH. These findings represented evidence of a high cytosolic adenosine diphosphate concentration and a relatively high rate of metabolism accompanied by a low phosphorylation potential. Muscle 31P-MRS showed a high Pi content at rest, abnormal exercise transfer pattern and a low rate of PCr post-exercise recovery. These findings suggested a deficit of mitochondrial function. Therapy with vitamins K3 and C normalized brain 31P-MRS indices, whereas it did not affect muscle bioenergetic metabolism. In this patient, the endocrinological disorder is putatively due to a mitochondrial cytopathy. Although an unknown mtDNA mutation cannot be ruled out, the genetic defect may lie in the nuclear genome.

Further impairment of muscle phosphate kinetics by lengthening exercise in DMD/BMD carriers. An in vivo 31P-NMR spectroscopy study.

We used phosphorus magnetic resonance spectroscopy (31P-MRS) to study the effect of exercise-induced muscle injury in the calf muscle of 7 DMD/BMD carriers and 6 non-carrier females. All subjects performed 50-80 lengthening contractions with the right calf muscles. 48 h after lengthening exercise non-carriers showed increased sensitivity to pressure in their gastrocnemius accompanied by increased T2 relaxation times and by elevated Pi/PCr ratios at rest. DMD/BMD carriers did not show any effect of lengthening exercise on these measurements. In-magnet exercise revealed in all carriers a reduced initial rate of Pi recovery and an increased time to fully recovery the resting value of intracellular pH. Lengthening exercise further decreased the initial rate of Pi recovery. Non-carriers did not show any variation attributable to lengthening exercise either during in-magnet work or during recovery from exercise. We found that lengthening exercise contractions causes: (1) less muscle injury in carriers compared to non-carriers, (2) even slower rate of Pi recovery, but (3) no effect on Pi recovery in non-carriers. The use of lengthening exercise and measurements of Pi recovery may be a useful method to evaluate the disease process in DMD/BMD.

31P-NMR spectroscopy of skeletal muscle in Becker dystrophy and DMD/BMD carriers. Altered rate of phosphate transport.

Muscle energy metabolism was studied by phosphorus nuclear magnetic resonance spectroscopy (31P-NMR) in 6 patients with Becker dystrophy, and in 24 female DMD/BMD carriers (n = 18) and non-carriers (n = 6). At rest all patients showed a high Pi/PCr ratio due to low PCr and high Pi contents, and a high intracellular IpH. 31P-NMR of carriers and non-carriers did not differ from controls. In patients and carriers in-magnet exercise revealed a reduced ability to perform work and Pi/PCr ratios higher than controls for comparable relative levels of steady-state work. Post-exercise Pi recovery was found abnormal in patients and in carriers. The 31P-NMR abnormalities found in the working muscle of both BMD patients and female DMD/BMD carriers indicate a defect of phosphate metabolism that, be it primary or secondary, reflects a deficit of energy metabolism.

Muscle mitochondrial DNA deletion and 31P-NMR spectroscopy alterations in a migraine patient.

A 40-year-old female suffering from recurrent migrainous strokes is reported. She did not show any muscle weakness or wasting. Ragged red and cytochrome c oxidase negative fibers were present in the muscle biopsy. Muscle mitochondrial DNA analysis showed a 5 kb deletion, without a point mutation at nucleotide pair 3243 in the mitochondrial tRNALeu(UUR) gene. Phosphorus nuclear magnetic resonance spectroscopy of brain and gastrocnemius muscle showed a defective energy metabolism in both organs. An increased inorganic phosphate to phosphocreatine ratio due to a decreased phosphocreatine content was found in the occipital lobes, while an abnormal work-energy cost transfer function and a low rate of phosphocreatine post-exercise recovery were found in the muscle.

Clinical and brain bioenergetics improvement with idebenone in a patient with Leber's hereditary optic neuropathy: a clinical and 31P-MRS study.

We used phosphorus magnetic resonance spectroscopy (31P-MRS) to study in vivo brain and muscle bioenergetics in a male patient with Leber's hereditary optic neuropathy (LHON) and mtDNA mutation at 11,778 bp who developed spastic paraparesis with white matter lesions on brain MR imaging. The study was performed before and during treatment with idebenone (135 mg t.i.d.) and after withdrawal. Clinical amelioration and worsening were associated with parallel changes in brain and skeletal muscle bioenergetics following the administration or withdrawal of idebenone. Reversal of paraparesis by idebenone was paralleled by normalization of 31P-MRS, serum lactate and central motor conduction. Extra-ocular neurological dysfunction in LHON may be amenable to treatment by appropriate quinones.

Autosomal dominant limb girdle myopathy with ragged-red fibers and cardiomyopathy. A pedigree study by in vivo 31P-MR spectroscopy indicating a multisystem mitochondrial defect.

We describe a late-onset autosomal dominant limb girdle myopathy, associated with dilated cardiomyopathy and mental deterioration. In two affected members of the pedigree with histochemical (ragged-red and cytocrome c oxidase - negative fibers) and ultrastructural abnormalities of muscle mitochondria, in vivo muscle phosphorus MR spectroscopy disclosed a slow rate of phosphocreatine resynthesis after exercise. Brain phosphorus MR spectroscopy revealed a defect of the energy metabolism in the two patients and in a third asymptomatic member, as shown by a significantly low phosphocreatine, increased ADP and decreased phosphorylation potential. Molecular analysis of muscle mitochondrial DNA failed to reveal any known mutation, including multiple deletions of the mtDNA which have been associated with some autosomal dominant mitochondrial diseases. The multisystem clinical involvement, the presence of ragged-red fibers and the alterations revealed by in vivo brain and muscle 31P-MRS suggest that this limb-girdle syndrome represents an unusual phenotype of mitochondrial cytopathy.

Myophosphorylase deficiency affects muscle mitochondrial respiration as shown by 31P-MR spectroscopy in a case with associated multifocal encephalopathy.

We report here a glycogen storage myopathy type V associated with multifocal encephalopathy. The patient, a 43-year-old male with increased serum CK, a heavy drinker and smoker, had been affected by generalized epilepsy since age 24, after a cranial injury. He had had a right hemiparesis 2 years before coming to our observation and a transient left hemiparesis the following year. CT and MRI of the brain showed multiple hemispheric lesions consistent with an ischemic process, as suggested by single photon emission tomography of the brain. Muscle biopsy showed a vacuolar myopathy, and myophosphorylase activity was 13% of the normal mean. Phosphorus magnetic resonance spectroscopy (31P-MRS) performed on resting calf muscles showed increased PCr to ATP and decreased PCr to P(i) ratios. During both aerobic and ischemic exercise 31P-MRS failed to show any cytosolic acidification and phosphomonoesters (PME) accumulation, two MRS findings in agreement with McArdle's syndrome diagnosis. Mitochondrial respiration was also affected as shown by a low PCr to P(i) ratio at rest and by a low rate of PCr re-synthesis during recovery from aerobic exercise. This latter finding in McArdle's disease can be explained by decreased mitochondrial substrate availability, which in turn can contribute to the phenotypic manifestations of the disease.

Epilepsia partialis continua associated with NADH-coenzyme Q reductase deficiency.

We report the clinical, neuroradiological and biochemical features of a patient with epilepsia partialis continua (EPC). MRI studies disclosed multiple cortico-subcortical areas of abnormal signal intensity. The activity of complex I of the mitochondrial respiratory chain was markedly reduced in skeletal muscle. The biochemical defect was reflected in vivo by a failure of brain and skeletal muscle bioenergetics, as shown by exercise and phosphorus magnetic resonance spectroscopy (31P-MRS) studies. Muscle morphology was repeatedly normal, and molecular genetic analysis of mitochondrial DNA was not informative. On the basis of in vivo and in vitro findings, the observed defect of the mitochondrial respiratory chain was considered the underlying biochemical pathogenesis of the disease. The observation of an oxidative defect in the brain and skeletal muscle of a patient with EPC emphasizes the importance of studying mitochondrial energy metabolism in patients with EPC not associated with primary CNS lesions when clinical and morphological findings suggesting a mitochondrial disorder are lacking. 31P-MRS can be a useful method to uncover deficits of CNS mitochondrial function and provide the indication for further biochemical studies.

Abnormal brain and muscle energy metabolism shown by 31P-MRS in familial hemiplegic migraine.

Familial hemiplegic migraine (FHM) is a rare autosomal dominant disorder of unknown pathogenesis characterized by migraine and transitory hemiplegic attacks. We describe a kindred fulfilling the diagnostic criteria for FHM in which: (1) brain phosphorus magnetic resonance spectroscopy (31P-MRS) showed a reduced phosphocreatine content accompanied by high [ADP], high percentage of V/Vmax of ATP biosynthesis and decreased phosphorylation potential; (2) muscle 31P-MRS showed a reduced rate of phosphocreatine recovery after exercise; (3) blood lactate was increased after effort; (4) muscle biopsy showed, in one patient, rare ragged red fibers succinate-dehydrogenase positive and cytochrome c oxidase negative; (5) genetic analysis of muscle mitochondrial DNA did not show any of the two point mutations in the tRNA(Leu(UUR)) associated with the MELAS syndrome (Mitochondrial myopathy, Encephalopathy with Lactic Acidosis and Stroke-like episodes). The defective energy metabolism of brain and muscle found in this pedigree suggests a multisystemic disorder of mitochondrial function in this FHM pedigree.

Plasma fibronectin in hemoblastosis.

Fibronectin (FN) is a glycoprotein whose plasma concentrations are reduced in many pathological conditions. In patients with hemoblastosis plasma FN was correlated with some clinical and biological parameters (stage of the disease, hepatosplenomegaly, infections and DIC), in order to assess its value as a tumor marker. The results suggest a poor relationship between FN levels and the course of the disease. However, the behaviour of the protein in relation with treatment was dynamic.

Effect of oral phosphocreatinine on human skeletal muscle shown by in vivo 31P-NMR.

We used the non-invasive method of in vivo phosphorus magnetic resonance spectroscopy to investigate the effect of oral administration of phosphocreatinine on muscle energy metabolism during graded work and post-exercise recovery in humans. Phosphocreatinine administration results in a smaller depletion of phosphocreatine at high work rates accompanied by a smaller cytosolic acidification during work and recovery. Our findings suggest that oral phosphocreatinine increases the readily available energy for muscle contraction by interfering directly or indirectly with the reaction equilibria involving phosphocreatine.