Multifactorial low remodeling bone disease during cyclic total parenteral nutrition

Area of Science:

• Bone Metabolism
• Nutritional Science
• Endocrinology

Background:

• Metabolic bone disease is a known complication of long-term total parenteral nutrition (TPN).
• The exact physiopathology of TPN-associated bone disease remains poorly understood.
• This study investigates bone status in adult patients receiving cyclic TPN.

Purpose of the Study:

• To prospectively assess the bone status in adult patients undergoing long-term cyclic TPN.
• To identify potential contributing factors to metabolic bone disease in this patient population.
• To characterize the histomorphometric changes in bone tissue.

Main Methods:

• Prospective assessment of bone status in seven adult patients on cyclic TPN for a mean of 7 months.
• Measurement of calciuria, calcium balance, serum mineral and vitamin D levels, and parathyroid hormone (PTH).
• Histomorphometric analysis of bone biopsies to evaluate bone formation and resorption.

Main Results:

• All patients exhibited hypercalciuria, with six showing a negative calcium balance.
• A significant correlation was found between protein intake and calciuria.
• High aluminum load from phosphate solutions was associated with elevated serum aluminum levels.
• Bone histomorphometry revealed reduced bone formation and low trabecular bone volume, without osteomalacia.
• Two patients had elevated PTH with skeletal unresponsiveness.

Conclusions:

• Cyclic TPN is associated with hypercalciuria and negative calcium balance, potentially linked to amino acid delivery.
• High aluminum load from phosphate supplements may contribute to bone defects.
• TPN-induced metabolic bone disease presents with reduced bone formation and low bone volume, distinct from osteomalacia.