Hyposomatomedinemia in Men with Post‐Poliomyelitis Syndrome

Abstract

The age of onset of the post-poliomyelitis syndrome (PPS) coincides with the tendency for declining activity of the growth hormone/somatomedin C (GH/SmC) axis. The normal plasma SmC range in men before the age of 40 is 0.50 to 1.50 units/mL. After age 40 about 30% of men have a plasma SmC level below 0.35 units/mL, signifying no detectable spontaneous GH secretory pulses. Because the GH/SmC axis stimulates DNA, RNA, and protein synthesis in muscle cells and increases their size and number, a deficiency of the GH/SmC axis could theoretically contribute as a secondary factor to the occurrence or severity of the PPS. Accordingly, the authors measured the plasma SmC level in 10 men with PPS, ages 35 to 63, and in 94 healthy men of similar age. In the PPS men, 100% of the values were less than or equal to 0.40 units/mL, and 90% were less than or equal to 0.35 units/mL. The corresponding proportions in the healthy men were 40% and 27%. Analysis of variance including age as a factor showed SmC to be significantly lower in the PPS men than in the healthy men. In an additional comparison, totally immobile nursing home men did not have lowered SmC values. In fact their SmC values were slightly higher than those of healthy men of similar age. The data revealed a new biochemical feature of PPS, hyposomatomedinemia, which might play a contributory role in the pathogenesis of the syndrome.

Prediction of voluntary activation, strength and endurance of elbow flexors in postpolio patients

“…In the present study, mean levels of IGF-1 in patients were not abnormal and there was no significant correlation between IGF-1 levels and maximal 31,33 A recent study reports a negative correlation between muscle force and IGF-1 levels. 38 Serum creatine kinase levels were mildly increased in prior-polio patients.…”

“…It remains to be determined whether decreased levels of IGF-1 are linked to impairment in voluntary activation in these patients and whether the maximal level of voluntary activation improves when IGF-1 levels are increased. 31,33,35,38 Some investigators 40,42 have found increased serum creatine kinase levels in postpolio patients. Therefore, we hypothesized that IGF-1 and creatine kinase may predict impaired voluntary activation and impaired endurance, respectively.…”

Circulating insulin-like growth factors and related binding proteins are selectively altered in amyotrophic lateral sclerosis and multiple sclerosis

“…In a pilot study of 10 PPS patients Shetty KR et al [17] reported the mean serum [IGF-I] to be approximately 50% lower than age matched controls. A larger study by Rao et al [18] of 124 PPS patients and 261 age matched controls also reported a 25% lower mean [IGF-I] in the PPS patients.…”

“…The absence of detailed information on the endogenous peripheral IGF system in disease states may be one of the limitations in the design of these clinical trials. To date, conflicting studies of the circulating IGFs report normal or decreased levels of IGF-I in ALS [13][14][15] and post polio syndrome (PPS) [16][17][18] but unchanged levels of IGF-I in MS [14,[19][20][21].…”

Prevalence of Low Plasma IGF‐I in Poliomyelitis Survivors

“…In 1990, the authors found the plasma IGF‐I level to be low in patients with the post‐poliomyelitis syndrome compared with age‐matched controls 10 . They then found that the decreased IGF‐I in these individuals was associated with low or absent levels of nocturnal serum GH 11 .…”